NFS: Add support for multiple sec= mount options

Commit Message

Weston Andros Adamson Oct. 11, 2013, 6:44 p.m. UTC

This patch adds support for multiple security options which can be
specified using a colon-delimited list of security flavors (the same
syntax as nfsd's exports file).

This is useful, for instance, when NFSv4.x mounts cross SECINFO
boundaries. With this patch a user can use "sec=krb5i,krb5p"
to mount a remote filesystem using krb5i, but can still cross
into krb5p-only exports.

New mounts will try all security options before failing.  NFSv4.x
SECINFO results will be compared against the sec= flavors to
find the first flavor in both lists or if no match is found will
return EPERM.

This patch cleans up some of the auth flavor logic by separating
the parsed mount options from the currently selected flavor and
sharing more code between the 'no sec= specified' and 'sec= specified'
code paths.

Along with this patch I'm posting a patch to nfs-util's nfs.man to
reflect these changes.

I wrote a script to verify that I haven't broken anything, it tests
all vers= and sec= combinations against a server with the exports:

 /export/sys       *(sec=sys,rw,no_root_squash)
 /export/krb5a     *(sec=krb5,rw,no_root_squash)
 /export/krb5i     *(sec=krb5i,rw,no_root_squash)
 /export/krb5p     *(sec=krb5p,rw,no_root_squash)
 /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
 /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)

The script runs these tests against all exports, and the versions NFSv3,
v4.0, v4.1:
 - no sec= options
 - all single sec= options
 - all combinations of multiple sec= options
 - no sec= SECINFO (mount / then ls export dir, v4.x only)
 - single sec= SECINFO (mount / then ls export dir, v4.x only)
 - all combinations of multiple sec= SECINFO (mount / then ls export dir,
    v4.x only)

Signed-off-by: Weston Andros Adamson <[e-mail]>
---
 fs/nfs/client.c           |   5 +-
 fs/nfs/internal.h         |   5 +-
 fs/nfs/nfs4_fs.h          |   1 -
 fs/nfs/nfs4client.c       |  10 ++-
 fs/nfs/nfs4namespace.c    |  21 +++--
 fs/nfs/nfs4proc.c         |  30 +++++---
 fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
 include/linux/nfs_fs_sb.h |   1 +
 include/linux/nfs_xdr.h   |   7 ++
 9 files changed, 176 insertions(+), 94 deletions(-)

Comments

Chuck Lever Oct. 11, 2013, 6:48 p.m. UTC | #1

On Oct 11, 2013, at 2:44 PM, Weston Andros Adamson <[e-mail]> wrote:

> This patch adds support for multiple security options which can be
> specified using a colon-delimited list of security flavors (the same
> syntax as nfsd's exports file).
> 
> This is useful, for instance, when NFSv4.x mounts cross SECINFO
> boundaries. With this patch a user can use "sec=krb5i,krb5p"
> to mount a remote filesystem using krb5i, but can still cross
> into krb5p-only exports.
> 
> New mounts will try all security options before failing.  NFSv4.x
> SECINFO results will be compared against the sec= flavors to
> find the first flavor in both lists or if no match is found will
> return EPERM.

I can't immediately tell, but do you record the security list somewhere in the in-core data structures for the mount?  The reason I ask is because at some point (say, when a migration or layout recall occurs) the client may want to refer back to this list in order to negotiate security with a server it hasn't encountered before.


> This patch cleans up some of the auth flavor logic by separating
> the parsed mount options from the currently selected flavor and
> sharing more code between the 'no sec= specified' and 'sec= specified'
> code paths.
> 
> Along with this patch I'm posting a patch to nfs-util's nfs.man to
> reflect these changes.
> 
> I wrote a script to verify that I haven't broken anything, it tests
> all vers= and sec= combinations against a server with the exports:
> 
> /export/sys       *(sec=sys,rw,no_root_squash)
> /export/krb5a     *(sec=krb5,rw,no_root_squash)
> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
> 
> The script runs these tests against all exports, and the versions NFSv3,
> v4.0, v4.1:
> - no sec= options
> - all single sec= options
> - all combinations of multiple sec= options
> - no sec= SECINFO (mount / then ls export dir, v4.x only)
> - single sec= SECINFO (mount / then ls export dir, v4.x only)
> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>    v4.x only)
> 
> Signed-off-by: Weston Andros Adamson <[e-mail]>
> ---
> fs/nfs/client.c           |   5 +-
> fs/nfs/internal.h         |   5 +-
> fs/nfs/nfs4_fs.h          |   1 -
> fs/nfs/nfs4client.c       |  10 ++-
> fs/nfs/nfs4namespace.c    |  21 +++--
> fs/nfs/nfs4proc.c         |  30 +++++---
> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
> include/linux/nfs_fs_sb.h |   1 +
> include/linux/nfs_xdr.h   |   7 ++
> 9 files changed, 176 insertions(+), 94 deletions(-)
> 
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index af03258..006fd52 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
> 		goto error;
> 
> 	server->port = data->nfs_server.port;
> +	server->auth_info = data->auth_info;
> 
> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
> +	error = nfs_init_server_rpcclient(server, &timeparms,
> +					  data->selected_flavor);
> 	if (error < 0)
> 		goto error;
> 
> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
> 	target->acdirmax = source->acdirmax;
> 	target->caps = source->caps;
> 	target->options = source->options;
> +	target->auth_info = source->auth_info;
> }
> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
> 
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 38da8c2..5c9cfe0 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
> 	unsigned int		namlen;
> 	unsigned int		options;
> 	unsigned int		bsize;
> -	unsigned int		auth_flavor_len;
> -	rpc_authflavor_t	auth_flavors[1];
> +	struct nfs_auth_info    auth_info;
> +	rpc_authflavor_t        selected_flavor;
> 	char			*client_address;
> 	unsigned int		version;
> 	unsigned int		minorversion;
> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
> extern struct file_system_type nfs4_xdev_fs_type;
> extern struct file_system_type nfs4_referral_fs_type;
> #endif
> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
> 			struct nfs_subversion *);
> void nfs_initialise_sb(struct super_block *);
> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
> index 28842ab..cffed27 100644
> --- a/fs/nfs/nfs4_fs.h
> +++ b/fs/nfs/nfs4_fs.h
> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
> extern struct file_system_type nfs4_fs_type;
> 
> /* nfs4namespace.c */
> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
> 			       struct nfs_fh *, struct nfs_fattr *);
> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> index 511cdce..b446314 100644
> --- a/fs/nfs/nfs4client.c
> +++ b/fs/nfs/nfs4client.c
> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
> 	/* Initialise the client representation from the mount data */
> 	server->flags = data->flags;
> 	server->options = data->options;
> +	server->auth_info = data->auth_info;
> 
> -	if (data->auth_flavor_len >= 1)
> -		pseudoflavor = data->auth_flavors[0];
> +	/* Use the first specified auth flavor. If this flavor isn't
> +	 * allowed by the server, use the SECINFO path to try the
> +	 * other specified flavors */
> +	if (data->auth_info.flavor_len >= 1)
> +		pseudoflavor = data->auth_info.flavors[0];
> 
> 	/* Get a client record */
> 	error = nfs4_set_client(server,
> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
> 	if (!server)
> 		return ERR_PTR(-ENOMEM);
> 
> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
> 
> 	/* set up the general RPC client */
> 	error = nfs4_init_server(server, mount_info->parsed);
> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
> index 2288cd3..caaa7aa 100644
> --- a/fs/nfs/nfs4namespace.c
> +++ b/fs/nfs/nfs4namespace.c
> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
> 
> /**
>  * nfs_find_best_sec - Find a security mechanism supported locally
> + * @server:  Nfs server structure
>  * @flavors: List of security tuples returned by SECINFO procedure
>  *
>  * Return the pseudoflavor of the first security mechanism in
> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
> + * "flavors" that is locally supported and in the sec= mount
> + * options if any were specified.  Return RPC_AUTH_UNIX if
>  * no matching flavor is found in the array.  The "flavors" array
>  * is searched in the order returned from the server, per RFC 3530
>  * recommendation.
>  */
> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
> +					  struct nfs4_secinfo_flavors *flavors)
> {
> 	rpc_authflavor_t pseudoflavor;
> 	struct nfs4_secinfo4 *secinfo;
> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
> 		case RPC_AUTH_GSS:
> 			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
> 							&secinfo->flavor_info);
> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
> +
> +			/* make sure pseudoflavor matches sec= mount opt */
> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
> +			    nfs_auth_info_match(&server->auth_info,
> +						pseudoflavor))
> 				return pseudoflavor;
> 			break;
> 		}
> 	}
> 
> +	/* if there were any sec= options then nothing matched */
> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
> +		return -EPERM;
> +
> 	return RPC_AUTH_UNIX;
> }
> 
> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
> 		goto out;
> 	}
> 
> -	flavor = nfs_find_best_sec(flavors);
> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
> 
> out:
> 	put_page(page);
> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
> 
> 	if (client->cl_auth->au_flavor != flavor)
> 		flavor = client->cl_auth->au_flavor;
> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
> +	else {
> 		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
> 		if ((int)new >= 0)
> 			flavor = new;
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index d2b4845..a926a39 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
> 	int status = -EPERM;
> 	size_t i;
> 
> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> -			continue;
> -		break;
> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
> +			status = nfs4_lookup_root_sec(server, fhandle, info,
> +						server->auth_info.flavors[i]);
> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> +				continue;
> +			break;
> +		}
> +	} else {
> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
> +			status = nfs4_lookup_root_sec(server, fhandle, info,
> +						      flav_array[i]);
> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> +				continue;
> +			break;
> +		}
> 	}
> 
> 	/*
> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
> 		status = nfs4_lookup_root(server, fhandle, info);
> 		if (status != -NFS4ERR_WRONGSEC)
> 			break;
> -		/* Did user force a 'sec=' mount option? */
> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
> -			break;
> 	default:
> 		status = nfs4_do_find_root_sec(server, fhandle, info);
> 	}
> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
> 			err = -EPERM;
> 			if (client != *clnt)
> 				goto out;
> -			/* No security negotiation if the user specified 'sec=' */
> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
> -				goto out;
> 			client = nfs4_create_sec_client(client, dir, name);
> 			if (IS_ERR(client))
> 				return PTR_ERR(client);
> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
> 			break;
> 		}
> 
> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
> +			flavor = RPC_AUTH_MAXFLAVOR;
> +
> 		if (flavor != RPC_AUTH_MAXFLAVOR) {
> 			err = nfs4_lookup_root_sec(server, fhandle,
> 						   info, flavor);
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index a03b9c6..84cf276 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
> 	static const struct {
> 		rpc_authflavor_t flavour;
> 		const char *str;
> -	} sec_flavours[] = {
> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
> +		 * changes */
> 		{ RPC_AUTH_NULL, "null" },
> 		{ RPC_AUTH_UNIX, "sys" },
> 		{ RPC_AUTH_GSS_KRB5, "krb5" },
> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
> 		data->mount_server.port	= NFS_UNSPEC_PORT;
> 		data->nfs_server.port	= NFS_UNSPEC_PORT;
> 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
> -		data->auth_flavor_len	= 0;
> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
> 		data->minorversion	= 0;
> 		data->need_mount	= true;
> 		data->net		= current->nsproxy->net_ns;
> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
> 	}
> }
> 
> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
> -		rpc_authflavor_t pseudoflavor)
> +/*
> + * Add 'flavor' to 'auth_info' if not already present.
> + * Returns true if 'flavor' ends up in the list, false otherwise
> + */
> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
> +			      rpc_authflavor_t flavor)
> {
> -	data->auth_flavors[0] = pseudoflavor;
> -	data->auth_flavor_len = 1;
> +	unsigned int i;
> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
> +					sizeof(auth_info->flavors[0]));
> +
> +	/* make sure this flavor isn't already in the list */
> +	for (i = 0; i < auth_info->flavor_len; i++) {
> +		if (flavor == auth_info->flavors[i])
> +			return true;
> +	}
> +
> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
> +		return false;
> +	}
> +
> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
> +	return true;
> }
> 
> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
> +			 rpc_authflavor_t match)
> +{
> +	int i;
> +
> +	if (!auth_info->flavor_len)
> +		return true;
> +
> +	for (i = 0; i < auth_info->flavor_len; i++) {
> +		if (auth_info->flavors[i] == match)
> +			return true;
> +	}
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
> +
> /*
>  * Parse the value of the 'sec=' option.
>  */
> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
> {
> 	substring_t args[MAX_OPT_ARGS];
> 	rpc_authflavor_t pseudoflavor;
> +	char *p;
> 
> 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
> 
> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
> -	case Opt_sec_none:
> -		pseudoflavor = RPC_AUTH_NULL;
> -		break;
> -	case Opt_sec_sys:
> -		pseudoflavor = RPC_AUTH_UNIX;
> -		break;
> -	case Opt_sec_krb5:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
> -		break;
> -	case Opt_sec_krb5i:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
> -		break;
> -	case Opt_sec_krb5p:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
> -		break;
> -	case Opt_sec_lkey:
> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
> -		break;
> -	case Opt_sec_lkeyi:
> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
> -		break;
> -	case Opt_sec_lkeyp:
> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
> -		break;
> -	case Opt_sec_spkm:
> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
> -		break;
> -	case Opt_sec_spkmi:
> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
> -		break;
> -	case Opt_sec_spkmp:
> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
> -		break;
> -	default:
> -		return 0;
> +	while ((p = strsep(&value, ":")) != NULL) {
> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
> +		case Opt_sec_none:
> +			pseudoflavor = RPC_AUTH_NULL;
> +			break;
> +		case Opt_sec_sys:
> +			pseudoflavor = RPC_AUTH_UNIX;
> +			break;
> +		case Opt_sec_krb5:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
> +			break;
> +		case Opt_sec_krb5i:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
> +			break;
> +		case Opt_sec_krb5p:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
> +			break;
> +		case Opt_sec_lkey:
> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
> +			break;
> +		case Opt_sec_lkeyi:
> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
> +			break;
> +		case Opt_sec_lkeyp:
> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
> +			break;
> +		case Opt_sec_spkm:
> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
> +			break;
> +		case Opt_sec_spkmi:
> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
> +			break;
> +		case Opt_sec_spkmp:
> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
> +			break;
> +		default:
> +			dfprintk(MOUNT,
> +				 "NFS: sec= option '%s' not recognized\n", p);
> +			return 0;
> +		}
> +
> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
> +			return 0;
> 	}
> 
> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
> +	if (mnt->auth_info.flavor_len > 0) {
> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
> +	} else
> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
> +
> 	return 1;
> }
> 
> @@ -1623,12 +1671,14 @@ out_security_failure:
> }
> 
> /*
> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
> - * the server. Returns 0 if it's ok, and -EACCES if not.
> + * Ensure that a specified authtype in args->auth_info is supported by
> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
> + * -EACCES if not.
>  */
> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
> 			rpc_authflavor_t *server_authlist, unsigned int count)
> {
> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
> 	unsigned int i;
> 
> 	/*
> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
> 	 * can be used.
> 	 */
> 	for (i = 0; i < count; i++) {
> -		if (args->auth_flavors[0] == server_authlist[i] ||
> -		    server_authlist[i] == RPC_AUTH_NULL)
> +		flavor = server_authlist[i];
> +
> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
> +		    flavor == RPC_AUTH_NULL)
> 			goto out;
> 	}
> 
> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
> -		args->auth_flavors[0]);
> +	dfprintk(MOUNT,
> +		 "NFS: specified auth flavors not supported by server\n");
> 	return -EACCES;
> 
> out:
> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
> +	args->selected_flavor = flavor;
> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
> 	return 0;
> }
> 
> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
> 	 * Was a sec= authflavor specified in the options? First, verify
> 	 * whether the server supports it, and then just try to use it if so.
> 	 */
> -	if (args->auth_flavor_len > 0) {
> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
> +			 args->selected_flavor);
> 		if (status)
> 			return ERR_PTR(status);
> 		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
> 			/* Fallthrough */
> 		}
> 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
> -		nfs_set_auth_parsed_mount_data(args, flavor);
> +		args->selected_flavor = flavor;
> 		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
> 		if (!IS_ERR(server))
> 			return server;
> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
> 
> 	/* Last chance! Try AUTH_UNIX */
> 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +	args->selected_flavor = RPC_AUTH_UNIX;
> 	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
> }
> 
> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
> 		args->bsize		= data->bsize;
> 
> 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
> +			args->selected_flavor = data->pseudoflavor;
> 		else
> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +			args->selected_flavor = RPC_AUTH_UNIX;
> 		if (!args->nfs_server.hostname)
> 			goto out_nomem;
> 
> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
> 
> 	nfs_set_port(sap, &args->nfs_server.port, port);
> 
> -	if (args->auth_flavor_len > 1)
> -		goto out_bad_auth;
> -
> 	return nfs_parse_devname(dev_name,
> 				   &args->nfs_server.hostname,
> 				   max_namelen,
> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
> out_no_address:
> 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
> 	return -EINVAL;
> -
> -out_bad_auth:
> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
> -	return -EINVAL;
> }
> 
> static int
> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
> 	    data->rsize != nfss->rsize ||
> 	    data->wsize != nfss->wsize ||
> 	    data->retrans != nfss->client->cl_timeout->to_retries ||
> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
> 	    data->acregmin != nfss->acregmin / HZ ||
> 	    data->acregmax != nfss->acregmax / HZ ||
> 	    data->acdirmin != nfss->acdirmin / HZ ||
> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
> 	data->rsize = nfss->rsize;
> 	data->wsize = nfss->wsize;
> 	data->retrans = nfss->client->cl_timeout->to_retries;
> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
> +	data->auth_info = nfss->auth_info;
> 	data->acregmin = nfss->acregmin / HZ;
> 	data->acregmax = nfss->acregmax / HZ;
> 	data->acdirmin = nfss->acdirmin / HZ;
> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
> 					   data->auth_flavours,
> 					   sizeof(pseudoflavor)))
> 				return -EFAULT;
> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
> +			args->selected_flavor = pseudoflavor;
> 		} else
> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +			args->selected_flavor = RPC_AUTH_UNIX;
> 
> 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
> 		if (IS_ERR(c))
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index f9c0a6c..b2c3b82 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -149,6 +149,7 @@ struct nfs_server {
> 	struct timespec		time_delta;	/* smallest time granularity */
> 	unsigned long		mount_time;	/* when this fs was mounted */
> 	dev_t			s_dev;		/* superblock dev numbers */
> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
> 
> #ifdef CONFIG_NFS_FSCACHE
> 	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 49f52c8..488ce9d 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -591,6 +591,13 @@ struct nfs_renameres {
> 	struct nfs_fattr		*new_fattr;
> };
> 
> +/* parsed sec= options */
> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
> +struct nfs_auth_info {
> +	unsigned int            flavor_len;
> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
> +};
> +
> /*
>  * Argument struct for decode_entry function
>  */
> -- 
> 1.7.12.4 (Apple Git-37)
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 11, 2013, 6:57 p.m. UTC | #2

-dros

On Oct 11, 2013, at 2:48 PM, Chuck Lever <[e-mail]>
 wrote:

> 
> On Oct 11, 2013, at 2:44 PM, Weston Andros Adamson <[e-mail]> wrote:
> 
>> This patch adds support for multiple security options which can be
>> specified using a colon-delimited list of security flavors (the same
>> syntax as nfsd's exports file).
>> 
>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>> to mount a remote filesystem using krb5i, but can still cross
>> into krb5p-only exports.
>> 
>> New mounts will try all security options before failing.  NFSv4.x
>> SECINFO results will be compared against the sec= flavors to
>> find the first flavor in both lists or if no match is found will
>> return EPERM.
> 
> I can't immediately tell, but do you record the security list somewhere in the in-core data structures for the mount?  The reason I ask is because at some point (say, when a migration or layout recall occurs) the client may want to refer back to this list in order to negotiate security with a server it hasn't encountered before.

Yes, the nfs_auth_info structure is copied from the parsed_mount_data to the (new) nfs_server->auth_info, so nfs_server_copy_userdata et al can pass these options on.

I tested referrals in an earlier version of this patch, but I should probably run them again.

-dros

> 
> 
>> This patch cleans up some of the auth flavor logic by separating
>> the parsed mount options from the currently selected flavor and
>> sharing more code between the 'no sec= specified' and 'sec= specified'
>> code paths.
>> 
>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>> reflect these changes.
>> 
>> I wrote a script to verify that I haven't broken anything, it tests
>> all vers= and sec= combinations against a server with the exports:
>> 
>> /export/sys       *(sec=sys,rw,no_root_squash)
>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>> 
>> The script runs these tests against all exports, and the versions NFSv3,
>> v4.0, v4.1:
>> - no sec= options
>> - all single sec= options
>> - all combinations of multiple sec= options
>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>   v4.x only)
>> 
>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>> ---
>> fs/nfs/client.c           |   5 +-
>> fs/nfs/internal.h         |   5 +-
>> fs/nfs/nfs4_fs.h          |   1 -
>> fs/nfs/nfs4client.c       |  10 ++-
>> fs/nfs/nfs4namespace.c    |  21 +++--
>> fs/nfs/nfs4proc.c         |  30 +++++---
>> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>> include/linux/nfs_fs_sb.h |   1 +
>> include/linux/nfs_xdr.h   |   7 ++
>> 9 files changed, 176 insertions(+), 94 deletions(-)
>> 
>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>> index af03258..006fd52 100644
>> --- a/fs/nfs/client.c
>> +++ b/fs/nfs/client.c
>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>> 		goto error;
>> 
>> 	server->port = data->nfs_server.port;
>> +	server->auth_info = data->auth_info;
>> 
>> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>> +	error = nfs_init_server_rpcclient(server, &timeparms,
>> +					  data->selected_flavor);
>> 	if (error < 0)
>> 		goto error;
>> 
>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>> 	target->acdirmax = source->acdirmax;
>> 	target->caps = source->caps;
>> 	target->options = source->options;
>> +	target->auth_info = source->auth_info;
>> }
>> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>> 
>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>> index 38da8c2..5c9cfe0 100644
>> --- a/fs/nfs/internal.h
>> +++ b/fs/nfs/internal.h
>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>> 	unsigned int		namlen;
>> 	unsigned int		options;
>> 	unsigned int		bsize;
>> -	unsigned int		auth_flavor_len;
>> -	rpc_authflavor_t	auth_flavors[1];
>> +	struct nfs_auth_info    auth_info;
>> +	rpc_authflavor_t        selected_flavor;
>> 	char			*client_address;
>> 	unsigned int		version;
>> 	unsigned int		minorversion;
>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>> extern struct file_system_type nfs4_xdev_fs_type;
>> extern struct file_system_type nfs4_referral_fs_type;
>> #endif
>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>> 			struct nfs_subversion *);
>> void nfs_initialise_sb(struct super_block *);
>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>> index 28842ab..cffed27 100644
>> --- a/fs/nfs/nfs4_fs.h
>> +++ b/fs/nfs/nfs4_fs.h
>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>> extern struct file_system_type nfs4_fs_type;
>> 
>> /* nfs4namespace.c */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>> 			       struct nfs_fh *, struct nfs_fattr *);
>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>> index 511cdce..b446314 100644
>> --- a/fs/nfs/nfs4client.c
>> +++ b/fs/nfs/nfs4client.c
>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>> 	/* Initialise the client representation from the mount data */
>> 	server->flags = data->flags;
>> 	server->options = data->options;
>> +	server->auth_info = data->auth_info;
>> 
>> -	if (data->auth_flavor_len >= 1)
>> -		pseudoflavor = data->auth_flavors[0];
>> +	/* Use the first specified auth flavor. If this flavor isn't
>> +	 * allowed by the server, use the SECINFO path to try the
>> +	 * other specified flavors */
>> +	if (data->auth_info.flavor_len >= 1)
>> +		pseudoflavor = data->auth_info.flavors[0];
>> 
>> 	/* Get a client record */
>> 	error = nfs4_set_client(server,
>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>> 	if (!server)
>> 		return ERR_PTR(-ENOMEM);
>> 
>> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
>> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>> 
>> 	/* set up the general RPC client */
>> 	error = nfs4_init_server(server, mount_info->parsed);
>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>> index 2288cd3..caaa7aa 100644
>> --- a/fs/nfs/nfs4namespace.c
>> +++ b/fs/nfs/nfs4namespace.c
>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>> 
>> /**
>> * nfs_find_best_sec - Find a security mechanism supported locally
>> + * @server:  Nfs server structure
>> * @flavors: List of security tuples returned by SECINFO procedure
>> *
>> * Return the pseudoflavor of the first security mechanism in
>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>> + * "flavors" that is locally supported and in the sec= mount
>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>> * no matching flavor is found in the array.  The "flavors" array
>> * is searched in the order returned from the server, per RFC 3530
>> * recommendation.
>> */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>> +					  struct nfs4_secinfo_flavors *flavors)
>> {
>> 	rpc_authflavor_t pseudoflavor;
>> 	struct nfs4_secinfo4 *secinfo;
>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>> 		case RPC_AUTH_GSS:
>> 			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>> 							&secinfo->flavor_info);
>> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>> +
>> +			/* make sure pseudoflavor matches sec= mount opt */
>> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>> +			    nfs_auth_info_match(&server->auth_info,
>> +						pseudoflavor))
>> 				return pseudoflavor;
>> 			break;
>> 		}
>> 	}
>> 
>> +	/* if there were any sec= options then nothing matched */
>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> +		return -EPERM;
>> +
>> 	return RPC_AUTH_UNIX;
>> }
>> 
>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>> 		goto out;
>> 	}
>> 
>> -	flavor = nfs_find_best_sec(flavors);
>> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>> 
>> out:
>> 	put_page(page);
>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>> 
>> 	if (client->cl_auth->au_flavor != flavor)
>> 		flavor = client->cl_auth->au_flavor;
>> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>> +	else {
>> 		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>> 		if ((int)new >= 0)
>> 			flavor = new;
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index d2b4845..a926a39 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>> 	int status = -EPERM;
>> 	size_t i;
>> 
>> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> -			continue;
>> -		break;
>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>> +						server->auth_info.flavors[i]);
>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +				continue;
>> +			break;
>> +		}
>> +	} else {
>> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>> +						      flav_array[i]);
>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +				continue;
>> +			break;
>> +		}
>> 	}
>> 
>> 	/*
>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>> 		status = nfs4_lookup_root(server, fhandle, info);
>> 		if (status != -NFS4ERR_WRONGSEC)
>> 			break;
>> -		/* Did user force a 'sec=' mount option? */
>> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> -			break;
>> 	default:
>> 		status = nfs4_do_find_root_sec(server, fhandle, info);
>> 	}
>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>> 			err = -EPERM;
>> 			if (client != *clnt)
>> 				goto out;
>> -			/* No security negotiation if the user specified 'sec=' */
>> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>> -				goto out;
>> 			client = nfs4_create_sec_client(client, dir, name);
>> 			if (IS_ERR(client))
>> 				return PTR_ERR(client);
>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>> 			break;
>> 		}
>> 
>> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
>> +			flavor = RPC_AUTH_MAXFLAVOR;
>> +
>> 		if (flavor != RPC_AUTH_MAXFLAVOR) {
>> 			err = nfs4_lookup_root_sec(server, fhandle,
>> 						   info, flavor);
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index a03b9c6..84cf276 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>> 	static const struct {
>> 		rpc_authflavor_t flavour;
>> 		const char *str;
>> -	} sec_flavours[] = {
>> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>> +		 * changes */
>> 		{ RPC_AUTH_NULL, "null" },
>> 		{ RPC_AUTH_UNIX, "sys" },
>> 		{ RPC_AUTH_GSS_KRB5, "krb5" },
>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>> 		data->mount_server.port	= NFS_UNSPEC_PORT;
>> 		data->nfs_server.port	= NFS_UNSPEC_PORT;
>> 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
>> -		data->auth_flavor_len	= 0;
>> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
>> 		data->minorversion	= 0;
>> 		data->need_mount	= true;
>> 		data->net		= current->nsproxy->net_ns;
>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>> 	}
>> }
>> 
>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>> -		rpc_authflavor_t pseudoflavor)
>> +/*
>> + * Add 'flavor' to 'auth_info' if not already present.
>> + * Returns true if 'flavor' ends up in the list, false otherwise
>> + */
>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>> +			      rpc_authflavor_t flavor)
>> {
>> -	data->auth_flavors[0] = pseudoflavor;
>> -	data->auth_flavor_len = 1;
>> +	unsigned int i;
>> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>> +					sizeof(auth_info->flavors[0]));
>> +
>> +	/* make sure this flavor isn't already in the list */
>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>> +		if (flavor == auth_info->flavors[i])
>> +			return true;
>> +	}
>> +
>> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
>> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>> +		return false;
>> +	}
>> +
>> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
>> +	return true;
>> }
>> 
>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>> +			 rpc_authflavor_t match)
>> +{
>> +	int i;
>> +
>> +	if (!auth_info->flavor_len)
>> +		return true;
>> +
>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>> +		if (auth_info->flavors[i] == match)
>> +			return true;
>> +	}
>> +	return false;
>> +}
>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>> +
>> /*
>> * Parse the value of the 'sec=' option.
>> */
>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>> {
>> 	substring_t args[MAX_OPT_ARGS];
>> 	rpc_authflavor_t pseudoflavor;
>> +	char *p;
>> 
>> 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>> 
>> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
>> -	case Opt_sec_none:
>> -		pseudoflavor = RPC_AUTH_NULL;
>> -		break;
>> -	case Opt_sec_sys:
>> -		pseudoflavor = RPC_AUTH_UNIX;
>> -		break;
>> -	case Opt_sec_krb5:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
>> -		break;
>> -	case Opt_sec_krb5i:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> -		break;
>> -	case Opt_sec_krb5p:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> -		break;
>> -	case Opt_sec_lkey:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
>> -		break;
>> -	case Opt_sec_lkeyi:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> -		break;
>> -	case Opt_sec_lkeyp:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> -		break;
>> -	case Opt_sec_spkm:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
>> -		break;
>> -	case Opt_sec_spkmi:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> -		break;
>> -	case Opt_sec_spkmp:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> -		break;
>> -	default:
>> -		return 0;
>> +	while ((p = strsep(&value, ":")) != NULL) {
>> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
>> +		case Opt_sec_none:
>> +			pseudoflavor = RPC_AUTH_NULL;
>> +			break;
>> +		case Opt_sec_sys:
>> +			pseudoflavor = RPC_AUTH_UNIX;
>> +			break;
>> +		case Opt_sec_krb5:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
>> +			break;
>> +		case Opt_sec_krb5i:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> +			break;
>> +		case Opt_sec_krb5p:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> +			break;
>> +		case Opt_sec_lkey:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
>> +			break;
>> +		case Opt_sec_lkeyi:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> +			break;
>> +		case Opt_sec_lkeyp:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> +			break;
>> +		case Opt_sec_spkm:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
>> +			break;
>> +		case Opt_sec_spkmi:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> +			break;
>> +		case Opt_sec_spkmp:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> +			break;
>> +		default:
>> +			dfprintk(MOUNT,
>> +				 "NFS: sec= option '%s' not recognized\n", p);
>> +			return 0;
>> +		}
>> +
>> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>> +			return 0;
>> 	}
>> 
>> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>> +	if (mnt->auth_info.flavor_len > 0) {
>> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
>> +	} else
>> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>> +
>> 	return 1;
>> }
>> 
>> @@ -1623,12 +1671,14 @@ out_security_failure:
>> }
>> 
>> /*
>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>> + * Ensure that a specified authtype in args->auth_info is supported by
>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>> + * -EACCES if not.
>> */
>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>> 			rpc_authflavor_t *server_authlist, unsigned int count)
>> {
>> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>> 	unsigned int i;
>> 
>> 	/*
>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>> 	 * can be used.
>> 	 */
>> 	for (i = 0; i < count; i++) {
>> -		if (args->auth_flavors[0] == server_authlist[i] ||
>> -		    server_authlist[i] == RPC_AUTH_NULL)
>> +		flavor = server_authlist[i];
>> +
>> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
>> +		    flavor == RPC_AUTH_NULL)
>> 			goto out;
>> 	}
>> 
>> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>> -		args->auth_flavors[0]);
>> +	dfprintk(MOUNT,
>> +		 "NFS: specified auth flavors not supported by server\n");
>> 	return -EACCES;
>> 
>> out:
>> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +	args->selected_flavor = flavor;
>> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>> 	return 0;
>> }
>> 
>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>> 	 * Was a sec= authflavor specified in the options? First, verify
>> 	 * whether the server supports it, and then just try to use it if so.
>> 	 */
>> -	if (args->auth_flavor_len > 0) {
>> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
>> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
>> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>> +			 args->selected_flavor);
>> 		if (status)
>> 			return ERR_PTR(status);
>> 		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>> 			/* Fallthrough */
>> 		}
>> 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>> -		nfs_set_auth_parsed_mount_data(args, flavor);
>> +		args->selected_flavor = flavor;
>> 		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> 		if (!IS_ERR(server))
>> 			return server;
>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>> 
>> 	/* Last chance! Try AUTH_UNIX */
>> 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +	args->selected_flavor = RPC_AUTH_UNIX;
>> 	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> }
>> 
>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>> 		args->bsize		= data->bsize;
>> 
>> 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
>> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>> +			args->selected_flavor = data->pseudoflavor;
>> 		else
>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +			args->selected_flavor = RPC_AUTH_UNIX;
>> 		if (!args->nfs_server.hostname)
>> 			goto out_nomem;
>> 
>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>> 
>> 	nfs_set_port(sap, &args->nfs_server.port, port);
>> 
>> -	if (args->auth_flavor_len > 1)
>> -		goto out_bad_auth;
>> -
>> 	return nfs_parse_devname(dev_name,
>> 				   &args->nfs_server.hostname,
>> 				   max_namelen,
>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>> out_no_address:
>> 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>> 	return -EINVAL;
>> -
>> -out_bad_auth:
>> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>> -	return -EINVAL;
>> }
>> 
>> static int
>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>> 	    data->rsize != nfss->rsize ||
>> 	    data->wsize != nfss->wsize ||
>> 	    data->retrans != nfss->client->cl_timeout->to_retries ||
>> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>> 	    data->acregmin != nfss->acregmin / HZ ||
>> 	    data->acregmax != nfss->acregmax / HZ ||
>> 	    data->acdirmin != nfss->acdirmin / HZ ||
>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>> 	data->rsize = nfss->rsize;
>> 	data->wsize = nfss->wsize;
>> 	data->retrans = nfss->client->cl_timeout->to_retries;
>> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
>> +	data->auth_info = nfss->auth_info;
>> 	data->acregmin = nfss->acregmin / HZ;
>> 	data->acregmax = nfss->acregmax / HZ;
>> 	data->acdirmin = nfss->acdirmin / HZ;
>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>> 					   data->auth_flavours,
>> 					   sizeof(pseudoflavor)))
>> 				return -EFAULT;
>> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>> +			args->selected_flavor = pseudoflavor;
>> 		} else
>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +			args->selected_flavor = RPC_AUTH_UNIX;
>> 
>> 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>> 		if (IS_ERR(c))
>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>> index f9c0a6c..b2c3b82 100644
>> --- a/include/linux/nfs_fs_sb.h
>> +++ b/include/linux/nfs_fs_sb.h
>> @@ -149,6 +149,7 @@ struct nfs_server {
>> 	struct timespec		time_delta;	/* smallest time granularity */
>> 	unsigned long		mount_time;	/* when this fs was mounted */
>> 	dev_t			s_dev;		/* superblock dev numbers */
>> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
>> 
>> #ifdef CONFIG_NFS_FSCACHE
>> 	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>> index 49f52c8..488ce9d 100644
>> --- a/include/linux/nfs_xdr.h
>> +++ b/include/linux/nfs_xdr.h
>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>> 	struct nfs_fattr		*new_fattr;
>> };
>> 
>> +/* parsed sec= options */
>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>> +struct nfs_auth_info {
>> +	unsigned int            flavor_len;
>> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>> +};
>> +
>> /*
>> * Argument struct for decode_entry function
>> */
>> -- 
>> 1.7.12.4 (Apple Git-37)
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to [e-mail]
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Chuck Lever
> chuck[dot]lever[at]oracle[dot]com
> 
> 
> 
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Chuck Lever Oct. 11, 2013, 6:58 p.m. UTC | #3

On Oct 11, 2013, at 2:57 PM, Weston Andros Adamson <[e-mail]> wrote:

> 
> -dros
> 
> On Oct 11, 2013, at 2:48 PM, Chuck Lever <[e-mail]>
> wrote:
> 
>> 
>> On Oct 11, 2013, at 2:44 PM, Weston Andros Adamson <[e-mail]> wrote:
>> 
>>> This patch adds support for multiple security options which can be
>>> specified using a colon-delimited list of security flavors (the same
>>> syntax as nfsd's exports file).
>>> 
>>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>>> to mount a remote filesystem using krb5i, but can still cross
>>> into krb5p-only exports.
>>> 
>>> New mounts will try all security options before failing.  NFSv4.x
>>> SECINFO results will be compared against the sec= flavors to
>>> find the first flavor in both lists or if no match is found will
>>> return EPERM.
>> 
>> I can't immediately tell, but do you record the security list somewhere in the in-core data structures for the mount?  The reason I ask is because at some point (say, when a migration or layout recall occurs) the client may want to refer back to this list in order to negotiate security with a server it hasn't encountered before.
> 
> Yes, the nfs_auth_info structure is copied from the parsed_mount_data to the (new) nfs_server->auth_info, so nfs_server_copy_userdata et al can pass these options on.
> 
> I tested referrals in an earlier version of this patch, but I should probably run them again.

Another use case is when a server administrator alters the security policy for one or more mounted exports.


> 
> -dros
> 
>> 
>> 
>>> This patch cleans up some of the auth flavor logic by separating
>>> the parsed mount options from the currently selected flavor and
>>> sharing more code between the 'no sec= specified' and 'sec= specified'
>>> code paths.
>>> 
>>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>>> reflect these changes.
>>> 
>>> I wrote a script to verify that I haven't broken anything, it tests
>>> all vers= and sec= combinations against a server with the exports:
>>> 
>>> /export/sys       *(sec=sys,rw,no_root_squash)
>>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>>> 
>>> The script runs these tests against all exports, and the versions NFSv3,
>>> v4.0, v4.1:
>>> - no sec= options
>>> - all single sec= options
>>> - all combinations of multiple sec= options
>>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>>  v4.x only)
>>> 
>>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>>> ---
>>> fs/nfs/client.c           |   5 +-
>>> fs/nfs/internal.h         |   5 +-
>>> fs/nfs/nfs4_fs.h          |   1 -
>>> fs/nfs/nfs4client.c       |  10 ++-
>>> fs/nfs/nfs4namespace.c    |  21 +++--
>>> fs/nfs/nfs4proc.c         |  30 +++++---
>>> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>>> include/linux/nfs_fs_sb.h |   1 +
>>> include/linux/nfs_xdr.h   |   7 ++
>>> 9 files changed, 176 insertions(+), 94 deletions(-)
>>> 
>>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>>> index af03258..006fd52 100644
>>> --- a/fs/nfs/client.c
>>> +++ b/fs/nfs/client.c
>>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>>> 		goto error;
>>> 
>>> 	server->port = data->nfs_server.port;
>>> +	server->auth_info = data->auth_info;
>>> 
>>> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>>> +	error = nfs_init_server_rpcclient(server, &timeparms,
>>> +					  data->selected_flavor);
>>> 	if (error < 0)
>>> 		goto error;
>>> 
>>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>>> 	target->acdirmax = source->acdirmax;
>>> 	target->caps = source->caps;
>>> 	target->options = source->options;
>>> +	target->auth_info = source->auth_info;
>>> }
>>> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>>> 
>>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>>> index 38da8c2..5c9cfe0 100644
>>> --- a/fs/nfs/internal.h
>>> +++ b/fs/nfs/internal.h
>>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>>> 	unsigned int		namlen;
>>> 	unsigned int		options;
>>> 	unsigned int		bsize;
>>> -	unsigned int		auth_flavor_len;
>>> -	rpc_authflavor_t	auth_flavors[1];
>>> +	struct nfs_auth_info    auth_info;
>>> +	rpc_authflavor_t        selected_flavor;
>>> 	char			*client_address;
>>> 	unsigned int		version;
>>> 	unsigned int		minorversion;
>>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>>> extern struct file_system_type nfs4_xdev_fs_type;
>>> extern struct file_system_type nfs4_referral_fs_type;
>>> #endif
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>>> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>>> 			struct nfs_subversion *);
>>> void nfs_initialise_sb(struct super_block *);
>>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>>> index 28842ab..cffed27 100644
>>> --- a/fs/nfs/nfs4_fs.h
>>> +++ b/fs/nfs/nfs4_fs.h
>>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>>> extern struct file_system_type nfs4_fs_type;
>>> 
>>> /* nfs4namespace.c */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>>> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>>> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>>> 			       struct nfs_fh *, struct nfs_fattr *);
>>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>>> index 511cdce..b446314 100644
>>> --- a/fs/nfs/nfs4client.c
>>> +++ b/fs/nfs/nfs4client.c
>>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>>> 	/* Initialise the client representation from the mount data */
>>> 	server->flags = data->flags;
>>> 	server->options = data->options;
>>> +	server->auth_info = data->auth_info;
>>> 
>>> -	if (data->auth_flavor_len >= 1)
>>> -		pseudoflavor = data->auth_flavors[0];
>>> +	/* Use the first specified auth flavor. If this flavor isn't
>>> +	 * allowed by the server, use the SECINFO path to try the
>>> +	 * other specified flavors */
>>> +	if (data->auth_info.flavor_len >= 1)
>>> +		pseudoflavor = data->auth_info.flavors[0];
>>> 
>>> 	/* Get a client record */
>>> 	error = nfs4_set_client(server,
>>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>>> 	if (!server)
>>> 		return ERR_PTR(-ENOMEM);
>>> 
>>> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
>>> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>>> 
>>> 	/* set up the general RPC client */
>>> 	error = nfs4_init_server(server, mount_info->parsed);
>>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>>> index 2288cd3..caaa7aa 100644
>>> --- a/fs/nfs/nfs4namespace.c
>>> +++ b/fs/nfs/nfs4namespace.c
>>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>>> 
>>> /**
>>> * nfs_find_best_sec - Find a security mechanism supported locally
>>> + * @server:  Nfs server structure
>>> * @flavors: List of security tuples returned by SECINFO procedure
>>> *
>>> * Return the pseudoflavor of the first security mechanism in
>>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>>> + * "flavors" that is locally supported and in the sec= mount
>>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>>> * no matching flavor is found in the array.  The "flavors" array
>>> * is searched in the order returned from the server, per RFC 3530
>>> * recommendation.
>>> */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>>> +					  struct nfs4_secinfo_flavors *flavors)
>>> {
>>> 	rpc_authflavor_t pseudoflavor;
>>> 	struct nfs4_secinfo4 *secinfo;
>>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>> 		case RPC_AUTH_GSS:
>>> 			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>>> 							&secinfo->flavor_info);
>>> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>>> +
>>> +			/* make sure pseudoflavor matches sec= mount opt */
>>> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>>> +			    nfs_auth_info_match(&server->auth_info,
>>> +						pseudoflavor))
>>> 				return pseudoflavor;
>>> 			break;
>>> 		}
>>> 	}
>>> 
>>> +	/* if there were any sec= options then nothing matched */
>>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> +		return -EPERM;
>>> +
>>> 	return RPC_AUTH_UNIX;
>>> }
>>> 
>>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>>> 		goto out;
>>> 	}
>>> 
>>> -	flavor = nfs_find_best_sec(flavors);
>>> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>>> 
>>> out:
>>> 	put_page(page);
>>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>>> 
>>> 	if (client->cl_auth->au_flavor != flavor)
>>> 		flavor = client->cl_auth->au_flavor;
>>> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>>> +	else {
>>> 		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>>> 		if ((int)new >= 0)
>>> 			flavor = new;
>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>>> index d2b4845..a926a39 100644
>>> --- a/fs/nfs/nfs4proc.c
>>> +++ b/fs/nfs/nfs4proc.c
>>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 	int status = -EPERM;
>>> 	size_t i;
>>> 
>>> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>>> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> -			continue;
>>> -		break;
>>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
>>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +						server->auth_info.flavors[i]);
>>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +				continue;
>>> +			break;
>>> +		}
>>> +	} else {
>>> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +						      flav_array[i]);
>>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +				continue;
>>> +			break;
>>> +		}
>>> 	}
>>> 
>>> 	/*
>>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 		status = nfs4_lookup_root(server, fhandle, info);
>>> 		if (status != -NFS4ERR_WRONGSEC)
>>> 			break;
>>> -		/* Did user force a 'sec=' mount option? */
>>> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> -			break;
>>> 	default:
>>> 		status = nfs4_do_find_root_sec(server, fhandle, info);
>>> 	}
>>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>>> 			err = -EPERM;
>>> 			if (client != *clnt)
>>> 				goto out;
>>> -			/* No security negotiation if the user specified 'sec=' */
>>> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>>> -				goto out;
>>> 			client = nfs4_create_sec_client(client, dir, name);
>>> 			if (IS_ERR(client))
>>> 				return PTR_ERR(client);
>>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 			break;
>>> 		}
>>> 
>>> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
>>> +			flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>> 		if (flavor != RPC_AUTH_MAXFLAVOR) {
>>> 			err = nfs4_lookup_root_sec(server, fhandle,
>>> 						   info, flavor);
>>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>>> index a03b9c6..84cf276 100644
>>> --- a/fs/nfs/super.c
>>> +++ b/fs/nfs/super.c
>>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>>> 	static const struct {
>>> 		rpc_authflavor_t flavour;
>>> 		const char *str;
>>> -	} sec_flavours[] = {
>>> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>>> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>>> +		 * changes */
>>> 		{ RPC_AUTH_NULL, "null" },
>>> 		{ RPC_AUTH_UNIX, "sys" },
>>> 		{ RPC_AUTH_GSS_KRB5, "krb5" },
>>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>>> 		data->mount_server.port	= NFS_UNSPEC_PORT;
>>> 		data->nfs_server.port	= NFS_UNSPEC_PORT;
>>> 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>>> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
>>> -		data->auth_flavor_len	= 0;
>>> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
>>> 		data->minorversion	= 0;
>>> 		data->need_mount	= true;
>>> 		data->net		= current->nsproxy->net_ns;
>>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>>> 	}
>>> }
>>> 
>>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>>> -		rpc_authflavor_t pseudoflavor)
>>> +/*
>>> + * Add 'flavor' to 'auth_info' if not already present.
>>> + * Returns true if 'flavor' ends up in the list, false otherwise
>>> + */
>>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>>> +			      rpc_authflavor_t flavor)
>>> {
>>> -	data->auth_flavors[0] = pseudoflavor;
>>> -	data->auth_flavor_len = 1;
>>> +	unsigned int i;
>>> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>>> +					sizeof(auth_info->flavors[0]));
>>> +
>>> +	/* make sure this flavor isn't already in the list */
>>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>>> +		if (flavor == auth_info->flavors[i])
>>> +			return true;
>>> +	}
>>> +
>>> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
>>> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>>> +		return false;
>>> +	}
>>> +
>>> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
>>> +	return true;
>>> }
>>> 
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>>> +			 rpc_authflavor_t match)
>>> +{
>>> +	int i;
>>> +
>>> +	if (!auth_info->flavor_len)
>>> +		return true;
>>> +
>>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>>> +		if (auth_info->flavors[i] == match)
>>> +			return true;
>>> +	}
>>> +	return false;
>>> +}
>>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>>> +
>>> /*
>>> * Parse the value of the 'sec=' option.
>>> */
>>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>>> {
>>> 	substring_t args[MAX_OPT_ARGS];
>>> 	rpc_authflavor_t pseudoflavor;
>>> +	char *p;
>>> 
>>> 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>>> 
>>> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
>>> -	case Opt_sec_none:
>>> -		pseudoflavor = RPC_AUTH_NULL;
>>> -		break;
>>> -	case Opt_sec_sys:
>>> -		pseudoflavor = RPC_AUTH_UNIX;
>>> -		break;
>>> -	case Opt_sec_krb5:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> -		break;
>>> -	case Opt_sec_krb5i:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> -		break;
>>> -	case Opt_sec_krb5p:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> -		break;
>>> -	case Opt_sec_lkey:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> -		break;
>>> -	case Opt_sec_lkeyi:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> -		break;
>>> -	case Opt_sec_lkeyp:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> -		break;
>>> -	case Opt_sec_spkm:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> -		break;
>>> -	case Opt_sec_spkmi:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> -		break;
>>> -	case Opt_sec_spkmp:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> -		break;
>>> -	default:
>>> -		return 0;
>>> +	while ((p = strsep(&value, ":")) != NULL) {
>>> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
>>> +		case Opt_sec_none:
>>> +			pseudoflavor = RPC_AUTH_NULL;
>>> +			break;
>>> +		case Opt_sec_sys:
>>> +			pseudoflavor = RPC_AUTH_UNIX;
>>> +			break;
>>> +		case Opt_sec_krb5:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> +			break;
>>> +		case Opt_sec_krb5i:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> +			break;
>>> +		case Opt_sec_krb5p:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> +			break;
>>> +		case Opt_sec_lkey:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> +			break;
>>> +		case Opt_sec_lkeyi:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> +			break;
>>> +		case Opt_sec_lkeyp:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> +			break;
>>> +		case Opt_sec_spkm:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> +			break;
>>> +		case Opt_sec_spkmi:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> +			break;
>>> +		case Opt_sec_spkmp:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> +			break;
>>> +		default:
>>> +			dfprintk(MOUNT,
>>> +				 "NFS: sec= option '%s' not recognized\n", p);
>>> +			return 0;
>>> +		}
>>> +
>>> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>>> +			return 0;
>>> 	}
>>> 
>>> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>>> +	if (mnt->auth_info.flavor_len > 0) {
>>> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
>>> +	} else
>>> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>> 	return 1;
>>> }
>>> 
>>> @@ -1623,12 +1671,14 @@ out_security_failure:
>>> }
>>> 
>>> /*
>>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>>> + * Ensure that a specified authtype in args->auth_info is supported by
>>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>>> + * -EACCES if not.
>>> */
>>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>>> 			rpc_authflavor_t *server_authlist, unsigned int count)
>>> {
>>> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>>> 	unsigned int i;
>>> 
>>> 	/*
>>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>> 	 * can be used.
>>> 	 */
>>> 	for (i = 0; i < count; i++) {
>>> -		if (args->auth_flavors[0] == server_authlist[i] ||
>>> -		    server_authlist[i] == RPC_AUTH_NULL)
>>> +		flavor = server_authlist[i];
>>> +
>>> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
>>> +		    flavor == RPC_AUTH_NULL)
>>> 			goto out;
>>> 	}
>>> 
>>> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>>> -		args->auth_flavors[0]);
>>> +	dfprintk(MOUNT,
>>> +		 "NFS: specified auth flavors not supported by server\n");
>>> 	return -EACCES;
>>> 
>>> out:
>>> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +	args->selected_flavor = flavor;
>>> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>>> 	return 0;
>>> }
>>> 
>>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 	 * Was a sec= authflavor specified in the options? First, verify
>>> 	 * whether the server supports it, and then just try to use it if so.
>>> 	 */
>>> -	if (args->auth_flavor_len > 0) {
>>> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
>>> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
>>> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>>> +			 args->selected_flavor);
>>> 		if (status)
>>> 			return ERR_PTR(status);
>>> 		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 			/* Fallthrough */
>>> 		}
>>> 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>>> -		nfs_set_auth_parsed_mount_data(args, flavor);
>>> +		args->selected_flavor = flavor;
>>> 		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> 		if (!IS_ERR(server))
>>> 			return server;
>>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 
>>> 	/* Last chance! Try AUTH_UNIX */
>>> 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>>> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +	args->selected_flavor = RPC_AUTH_UNIX;
>>> 	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> }
>>> 
>>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>>> 		args->bsize		= data->bsize;
>>> 
>>> 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
>>> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>>> +			args->selected_flavor = data->pseudoflavor;
>>> 		else
>>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>> 		if (!args->nfs_server.hostname)
>>> 			goto out_nomem;
>>> 
>>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>>> 
>>> 	nfs_set_port(sap, &args->nfs_server.port, port);
>>> 
>>> -	if (args->auth_flavor_len > 1)
>>> -		goto out_bad_auth;
>>> -
>>> 	return nfs_parse_devname(dev_name,
>>> 				   &args->nfs_server.hostname,
>>> 				   max_namelen,
>>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>>> out_no_address:
>>> 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>>> 	return -EINVAL;
>>> -
>>> -out_bad_auth:
>>> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>>> -	return -EINVAL;
>>> }
>>> 
>>> static int
>>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>>> 	    data->rsize != nfss->rsize ||
>>> 	    data->wsize != nfss->wsize ||
>>> 	    data->retrans != nfss->client->cl_timeout->to_retries ||
>>> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>>> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>>> 	    data->acregmin != nfss->acregmin / HZ ||
>>> 	    data->acregmax != nfss->acregmax / HZ ||
>>> 	    data->acdirmin != nfss->acdirmin / HZ ||
>>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>>> 	data->rsize = nfss->rsize;
>>> 	data->wsize = nfss->wsize;
>>> 	data->retrans = nfss->client->cl_timeout->to_retries;
>>> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>>> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
>>> +	data->auth_info = nfss->auth_info;
>>> 	data->acregmin = nfss->acregmin / HZ;
>>> 	data->acregmax = nfss->acregmax / HZ;
>>> 	data->acdirmin = nfss->acdirmin / HZ;
>>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>>> 					   data->auth_flavours,
>>> 					   sizeof(pseudoflavor)))
>>> 				return -EFAULT;
>>> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>>> +			args->selected_flavor = pseudoflavor;
>>> 		} else
>>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>> 
>>> 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>>> 		if (IS_ERR(c))
>>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>>> index f9c0a6c..b2c3b82 100644
>>> --- a/include/linux/nfs_fs_sb.h
>>> +++ b/include/linux/nfs_fs_sb.h
>>> @@ -149,6 +149,7 @@ struct nfs_server {
>>> 	struct timespec		time_delta;	/* smallest time granularity */
>>> 	unsigned long		mount_time;	/* when this fs was mounted */
>>> 	dev_t			s_dev;		/* superblock dev numbers */
>>> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
>>> 
>>> #ifdef CONFIG_NFS_FSCACHE
>>> 	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
>>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>>> index 49f52c8..488ce9d 100644
>>> --- a/include/linux/nfs_xdr.h
>>> +++ b/include/linux/nfs_xdr.h
>>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>>> 	struct nfs_fattr		*new_fattr;
>>> };
>>> 
>>> +/* parsed sec= options */
>>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>>> +struct nfs_auth_info {
>>> +	unsigned int            flavor_len;
>>> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>>> +};
>>> +
>>> /*
>>> * Argument struct for decode_entry function
>>> */
>>> -- 
>>> 1.7.12.4 (Apple Git-37)
>>> 
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>>> the body of a message to [e-mail]
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> 
>> -- 
>> Chuck Lever
>> chuck[dot]lever[at]oracle[dot]com
>> 
>> 
>> 
>> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

J. Bruce Fields Oct. 11, 2013, 9:01 p.m. UTC | #4

On Fri, Oct 11, 2013 at 02:44:22PM -0400, Weston Andros Adamson wrote:
> This patch adds support for multiple security options which can be
> specified using a colon-delimited list of security flavors (the same
> syntax as nfsd's exports file).
> 
> This is useful, for instance, when NFSv4.x mounts cross SECINFO
> boundaries. With this patch a user can use "sec=krb5i,krb5p"
> to mount a remote filesystem using krb5i, but can still cross
> into krb5p-only exports.
> 
> New mounts will try all security options before failing.  NFSv4.x
> SECINFO results will be compared against the sec= flavors to
> find the first flavor in both lists or if no match is found will
> return EPERM.
> 
> This patch cleans up some of the auth flavor logic by separating
> the parsed mount options from the currently selected flavor and
> sharing more code between the 'no sec= specified' and 'sec= specified'
> code paths.
> 
> Along with this patch I'm posting a patch to nfs-util's nfs.man to
> reflect these changes.
> 
> I wrote a script to verify that I haven't broken anything, it tests
> all vers= and sec= combinations against a server with the exports:

Is the script something that could be added to Anna's or my regular
regression testing?

--b.

> 
>  /export/sys       *(sec=sys,rw,no_root_squash)
>  /export/krb5a     *(sec=krb5,rw,no_root_squash)
>  /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>  /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>  /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>  /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
> 
> The script runs these tests against all exports, and the versions NFSv3,
> v4.0, v4.1:
>  - no sec= options
>  - all single sec= options
>  - all combinations of multiple sec= options
>  - no sec= SECINFO (mount / then ls export dir, v4.x only)
>  - single sec= SECINFO (mount / then ls export dir, v4.x only)
>  - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>     v4.x only)
> 
> Signed-off-by: Weston Andros Adamson <[e-mail]>
> ---
>  fs/nfs/client.c           |   5 +-
>  fs/nfs/internal.h         |   5 +-
>  fs/nfs/nfs4_fs.h          |   1 -
>  fs/nfs/nfs4client.c       |  10 ++-
>  fs/nfs/nfs4namespace.c    |  21 +++--
>  fs/nfs/nfs4proc.c         |  30 +++++---
>  fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>  include/linux/nfs_fs_sb.h |   1 +
>  include/linux/nfs_xdr.h   |   7 ++
>  9 files changed, 176 insertions(+), 94 deletions(-)
> 
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index af03258..006fd52 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>  		goto error;
>  
>  	server->port = data->nfs_server.port;
> +	server->auth_info = data->auth_info;
>  
> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
> +	error = nfs_init_server_rpcclient(server, &timeparms,
> +					  data->selected_flavor);
>  	if (error < 0)
>  		goto error;
>  
> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>  	target->acdirmax = source->acdirmax;
>  	target->caps = source->caps;
>  	target->options = source->options;
> +	target->auth_info = source->auth_info;
>  }
>  EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>  
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 38da8c2..5c9cfe0 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>  	unsigned int		namlen;
>  	unsigned int		options;
>  	unsigned int		bsize;
> -	unsigned int		auth_flavor_len;
> -	rpc_authflavor_t	auth_flavors[1];
> +	struct nfs_auth_info    auth_info;
> +	rpc_authflavor_t        selected_flavor;
>  	char			*client_address;
>  	unsigned int		version;
>  	unsigned int		minorversion;
> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>  extern struct file_system_type nfs4_xdev_fs_type;
>  extern struct file_system_type nfs4_referral_fs_type;
>  #endif
> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>  struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>  			struct nfs_subversion *);
>  void nfs_initialise_sb(struct super_block *);
> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
> index 28842ab..cffed27 100644
> --- a/fs/nfs/nfs4_fs.h
> +++ b/fs/nfs/nfs4_fs.h
> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>  extern struct file_system_type nfs4_fs_type;
>  
>  /* nfs4namespace.c */
> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>  struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>  struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>  			       struct nfs_fh *, struct nfs_fattr *);
> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> index 511cdce..b446314 100644
> --- a/fs/nfs/nfs4client.c
> +++ b/fs/nfs/nfs4client.c
> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>  	/* Initialise the client representation from the mount data */
>  	server->flags = data->flags;
>  	server->options = data->options;
> +	server->auth_info = data->auth_info;
>  
> -	if (data->auth_flavor_len >= 1)
> -		pseudoflavor = data->auth_flavors[0];
> +	/* Use the first specified auth flavor. If this flavor isn't
> +	 * allowed by the server, use the SECINFO path to try the
> +	 * other specified flavors */
> +	if (data->auth_info.flavor_len >= 1)
> +		pseudoflavor = data->auth_info.flavors[0];
>  
>  	/* Get a client record */
>  	error = nfs4_set_client(server,
> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>  	if (!server)
>  		return ERR_PTR(-ENOMEM);
>  
> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>  
>  	/* set up the general RPC client */
>  	error = nfs4_init_server(server, mount_info->parsed);
> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
> index 2288cd3..caaa7aa 100644
> --- a/fs/nfs/nfs4namespace.c
> +++ b/fs/nfs/nfs4namespace.c
> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>  
>  /**
>   * nfs_find_best_sec - Find a security mechanism supported locally
> + * @server:  Nfs server structure
>   * @flavors: List of security tuples returned by SECINFO procedure
>   *
>   * Return the pseudoflavor of the first security mechanism in
> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
> + * "flavors" that is locally supported and in the sec= mount
> + * options if any were specified.  Return RPC_AUTH_UNIX if
>   * no matching flavor is found in the array.  The "flavors" array
>   * is searched in the order returned from the server, per RFC 3530
>   * recommendation.
>   */
> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
> +					  struct nfs4_secinfo_flavors *flavors)
>  {
>  	rpc_authflavor_t pseudoflavor;
>  	struct nfs4_secinfo4 *secinfo;
> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>  		case RPC_AUTH_GSS:
>  			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>  							&secinfo->flavor_info);
> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
> +
> +			/* make sure pseudoflavor matches sec= mount opt */
> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
> +			    nfs_auth_info_match(&server->auth_info,
> +						pseudoflavor))
>  				return pseudoflavor;
>  			break;
>  		}
>  	}
>  
> +	/* if there were any sec= options then nothing matched */
> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
> +		return -EPERM;
> +
>  	return RPC_AUTH_UNIX;
>  }
>  
> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>  		goto out;
>  	}
>  
> -	flavor = nfs_find_best_sec(flavors);
> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>  
>  out:
>  	put_page(page);
> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>  
>  	if (client->cl_auth->au_flavor != flavor)
>  		flavor = client->cl_auth->au_flavor;
> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
> +	else {
>  		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>  		if ((int)new >= 0)
>  			flavor = new;
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index d2b4845..a926a39 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>  	int status = -EPERM;
>  	size_t i;
>  
> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> -			continue;
> -		break;
> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
> +			status = nfs4_lookup_root_sec(server, fhandle, info,
> +						server->auth_info.flavors[i]);
> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> +				continue;
> +			break;
> +		}
> +	} else {
> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
> +			status = nfs4_lookup_root_sec(server, fhandle, info,
> +						      flav_array[i]);
> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
> +				continue;
> +			break;
> +		}
>  	}
>  
>  	/*
> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>  		status = nfs4_lookup_root(server, fhandle, info);
>  		if (status != -NFS4ERR_WRONGSEC)
>  			break;
> -		/* Did user force a 'sec=' mount option? */
> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
> -			break;
>  	default:
>  		status = nfs4_do_find_root_sec(server, fhandle, info);
>  	}
> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>  			err = -EPERM;
>  			if (client != *clnt)
>  				goto out;
> -			/* No security negotiation if the user specified 'sec=' */
> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
> -				goto out;
>  			client = nfs4_create_sec_client(client, dir, name);
>  			if (IS_ERR(client))
>  				return PTR_ERR(client);
> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>  			break;
>  		}
>  
> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
> +			flavor = RPC_AUTH_MAXFLAVOR;
> +
>  		if (flavor != RPC_AUTH_MAXFLAVOR) {
>  			err = nfs4_lookup_root_sec(server, fhandle,
>  						   info, flavor);
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index a03b9c6..84cf276 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>  	static const struct {
>  		rpc_authflavor_t flavour;
>  		const char *str;
> -	} sec_flavours[] = {
> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
> +		 * changes */
>  		{ RPC_AUTH_NULL, "null" },
>  		{ RPC_AUTH_UNIX, "sys" },
>  		{ RPC_AUTH_GSS_KRB5, "krb5" },
> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>  		data->mount_server.port	= NFS_UNSPEC_PORT;
>  		data->nfs_server.port	= NFS_UNSPEC_PORT;
>  		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
> -		data->auth_flavor_len	= 0;
> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
>  		data->minorversion	= 0;
>  		data->need_mount	= true;
>  		data->net		= current->nsproxy->net_ns;
> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>  	}
>  }
>  
> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
> -		rpc_authflavor_t pseudoflavor)
> +/*
> + * Add 'flavor' to 'auth_info' if not already present.
> + * Returns true if 'flavor' ends up in the list, false otherwise
> + */
> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
> +			      rpc_authflavor_t flavor)
>  {
> -	data->auth_flavors[0] = pseudoflavor;
> -	data->auth_flavor_len = 1;
> +	unsigned int i;
> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
> +					sizeof(auth_info->flavors[0]));
> +
> +	/* make sure this flavor isn't already in the list */
> +	for (i = 0; i < auth_info->flavor_len; i++) {
> +		if (flavor == auth_info->flavors[i])
> +			return true;
> +	}
> +
> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
> +		return false;
> +	}
> +
> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
> +	return true;
>  }
>  
> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
> +			 rpc_authflavor_t match)
> +{
> +	int i;
> +
> +	if (!auth_info->flavor_len)
> +		return true;
> +
> +	for (i = 0; i < auth_info->flavor_len; i++) {
> +		if (auth_info->flavors[i] == match)
> +			return true;
> +	}
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
> +
>  /*
>   * Parse the value of the 'sec=' option.
>   */
> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>  {
>  	substring_t args[MAX_OPT_ARGS];
>  	rpc_authflavor_t pseudoflavor;
> +	char *p;
>  
>  	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>  
> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
> -	case Opt_sec_none:
> -		pseudoflavor = RPC_AUTH_NULL;
> -		break;
> -	case Opt_sec_sys:
> -		pseudoflavor = RPC_AUTH_UNIX;
> -		break;
> -	case Opt_sec_krb5:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
> -		break;
> -	case Opt_sec_krb5i:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
> -		break;
> -	case Opt_sec_krb5p:
> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
> -		break;
> -	case Opt_sec_lkey:
> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
> -		break;
> -	case Opt_sec_lkeyi:
> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
> -		break;
> -	case Opt_sec_lkeyp:
> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
> -		break;
> -	case Opt_sec_spkm:
> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
> -		break;
> -	case Opt_sec_spkmi:
> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
> -		break;
> -	case Opt_sec_spkmp:
> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
> -		break;
> -	default:
> -		return 0;
> +	while ((p = strsep(&value, ":")) != NULL) {
> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
> +		case Opt_sec_none:
> +			pseudoflavor = RPC_AUTH_NULL;
> +			break;
> +		case Opt_sec_sys:
> +			pseudoflavor = RPC_AUTH_UNIX;
> +			break;
> +		case Opt_sec_krb5:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
> +			break;
> +		case Opt_sec_krb5i:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
> +			break;
> +		case Opt_sec_krb5p:
> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
> +			break;
> +		case Opt_sec_lkey:
> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
> +			break;
> +		case Opt_sec_lkeyi:
> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
> +			break;
> +		case Opt_sec_lkeyp:
> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
> +			break;
> +		case Opt_sec_spkm:
> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
> +			break;
> +		case Opt_sec_spkmi:
> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
> +			break;
> +		case Opt_sec_spkmp:
> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
> +			break;
> +		default:
> +			dfprintk(MOUNT,
> +				 "NFS: sec= option '%s' not recognized\n", p);
> +			return 0;
> +		}
> +
> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
> +			return 0;
>  	}
>  
> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
> +	if (mnt->auth_info.flavor_len > 0) {
> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
> +	} else
> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
> +
>  	return 1;
>  }
>  
> @@ -1623,12 +1671,14 @@ out_security_failure:
>  }
>  
>  /*
> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
> - * the server. Returns 0 if it's ok, and -EACCES if not.
> + * Ensure that a specified authtype in args->auth_info is supported by
> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
> + * -EACCES if not.
>   */
> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>  			rpc_authflavor_t *server_authlist, unsigned int count)
>  {
> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>  	unsigned int i;
>  
>  	/*
> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>  	 * can be used.
>  	 */
>  	for (i = 0; i < count; i++) {
> -		if (args->auth_flavors[0] == server_authlist[i] ||
> -		    server_authlist[i] == RPC_AUTH_NULL)
> +		flavor = server_authlist[i];
> +
> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
> +		    flavor == RPC_AUTH_NULL)
>  			goto out;
>  	}
>  
> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
> -		args->auth_flavors[0]);
> +	dfprintk(MOUNT,
> +		 "NFS: specified auth flavors not supported by server\n");
>  	return -EACCES;
>  
>  out:
> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
> +	args->selected_flavor = flavor;
> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>  	return 0;
>  }
>  
> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>  	 * Was a sec= authflavor specified in the options? First, verify
>  	 * whether the server supports it, and then just try to use it if so.
>  	 */
> -	if (args->auth_flavor_len > 0) {
> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
> +			 args->selected_flavor);
>  		if (status)
>  			return ERR_PTR(status);
>  		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>  			/* Fallthrough */
>  		}
>  		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
> -		nfs_set_auth_parsed_mount_data(args, flavor);
> +		args->selected_flavor = flavor;
>  		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>  		if (!IS_ERR(server))
>  			return server;
> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>  
>  	/* Last chance! Try AUTH_UNIX */
>  	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +	args->selected_flavor = RPC_AUTH_UNIX;
>  	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>  }
>  
> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>  		args->bsize		= data->bsize;
>  
>  		if (data->flags & NFS_MOUNT_SECFLAVOUR)
> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
> +			args->selected_flavor = data->pseudoflavor;
>  		else
> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +			args->selected_flavor = RPC_AUTH_UNIX;
>  		if (!args->nfs_server.hostname)
>  			goto out_nomem;
>  
> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>  
>  	nfs_set_port(sap, &args->nfs_server.port, port);
>  
> -	if (args->auth_flavor_len > 1)
> -		goto out_bad_auth;
> -
>  	return nfs_parse_devname(dev_name,
>  				   &args->nfs_server.hostname,
>  				   max_namelen,
> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>  out_no_address:
>  	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>  	return -EINVAL;
> -
> -out_bad_auth:
> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
> -	return -EINVAL;
>  }
>  
>  static int
> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>  	    data->rsize != nfss->rsize ||
>  	    data->wsize != nfss->wsize ||
>  	    data->retrans != nfss->client->cl_timeout->to_retries ||
> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>  	    data->acregmin != nfss->acregmin / HZ ||
>  	    data->acregmax != nfss->acregmax / HZ ||
>  	    data->acdirmin != nfss->acdirmin / HZ ||
> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>  	data->rsize = nfss->rsize;
>  	data->wsize = nfss->wsize;
>  	data->retrans = nfss->client->cl_timeout->to_retries;
> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
> +	data->auth_info = nfss->auth_info;
>  	data->acregmin = nfss->acregmin / HZ;
>  	data->acregmax = nfss->acregmax / HZ;
>  	data->acdirmin = nfss->acdirmin / HZ;
> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>  					   data->auth_flavours,
>  					   sizeof(pseudoflavor)))
>  				return -EFAULT;
> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
> +			args->selected_flavor = pseudoflavor;
>  		} else
> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
> +			args->selected_flavor = RPC_AUTH_UNIX;
>  
>  		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>  		if (IS_ERR(c))
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index f9c0a6c..b2c3b82 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -149,6 +149,7 @@ struct nfs_server {
>  	struct timespec		time_delta;	/* smallest time granularity */
>  	unsigned long		mount_time;	/* when this fs was mounted */
>  	dev_t			s_dev;		/* superblock dev numbers */
> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
>  
>  #ifdef CONFIG_NFS_FSCACHE
>  	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 49f52c8..488ce9d 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -591,6 +591,13 @@ struct nfs_renameres {
>  	struct nfs_fattr		*new_fattr;
>  };
>  
> +/* parsed sec= options */
> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
> +struct nfs_auth_info {
> +	unsigned int            flavor_len;
> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
> +};
> +
>  /*
>   * Argument struct for decode_entry function
>   */
> -- 
> 1.7.12.4 (Apple Git-37)
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 11, 2013, 10:35 p.m. UTC | #5

Already on it!

Great minds and all...

-dros

> On Oct 11, 2013, at 5:01 PM, "J. Bruce Fields" <[e-mail]> wrote:
> 
>> On Fri, Oct 11, 2013 at 02:44:22PM -0400, Weston Andros Adamson wrote:
>> This patch adds support for multiple security options which can be
>> specified using a colon-delimited list of security flavors (the same
>> syntax as nfsd's exports file).
>> 
>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>> to mount a remote filesystem using krb5i, but can still cross
>> into krb5p-only exports.
>> 
>> New mounts will try all security options before failing.  NFSv4.x
>> SECINFO results will be compared against the sec= flavors to
>> find the first flavor in both lists or if no match is found will
>> return EPERM.
>> 
>> This patch cleans up some of the auth flavor logic by separating
>> the parsed mount options from the currently selected flavor and
>> sharing more code between the 'no sec= specified' and 'sec= specified'
>> code paths.
>> 
>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>> reflect these changes.
>> 
>> I wrote a script to verify that I haven't broken anything, it tests
>> all vers= and sec= combinations against a server with the exports:
> 
> Is the script something that could be added to Anna's or my regular
> regression testing?
> 
> --b.
> 
>> 
>> /export/sys       *(sec=sys,rw,no_root_squash)
>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>> 
>> The script runs these tests against all exports, and the versions NFSv3,
>> v4.0, v4.1:
>> - no sec= options
>> - all single sec= options
>> - all combinations of multiple sec= options
>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>    v4.x only)
>> 
>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>> ---
>> fs/nfs/client.c           |   5 +-
>> fs/nfs/internal.h         |   5 +-
>> fs/nfs/nfs4_fs.h          |   1 -
>> fs/nfs/nfs4client.c       |  10 ++-
>> fs/nfs/nfs4namespace.c    |  21 +++--
>> fs/nfs/nfs4proc.c         |  30 +++++---
>> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>> include/linux/nfs_fs_sb.h |   1 +
>> include/linux/nfs_xdr.h   |   7 ++
>> 9 files changed, 176 insertions(+), 94 deletions(-)
>> 
>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>> index af03258..006fd52 100644
>> --- a/fs/nfs/client.c
>> +++ b/fs/nfs/client.c
>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>>        goto error;
>> 
>>    server->port = data->nfs_server.port;
>> +    server->auth_info = data->auth_info;
>> 
>> -    error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>> +    error = nfs_init_server_rpcclient(server, &timeparms,
>> +                      data->selected_flavor);
>>    if (error < 0)
>>        goto error;
>> 
>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>>    target->acdirmax = source->acdirmax;
>>    target->caps = source->caps;
>>    target->options = source->options;
>> +    target->auth_info = source->auth_info;
>> }
>> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>> 
>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>> index 38da8c2..5c9cfe0 100644
>> --- a/fs/nfs/internal.h
>> +++ b/fs/nfs/internal.h
>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>>    unsigned int        namlen;
>>    unsigned int        options;
>>    unsigned int        bsize;
>> -    unsigned int        auth_flavor_len;
>> -    rpc_authflavor_t    auth_flavors[1];
>> +    struct nfs_auth_info    auth_info;
>> +    rpc_authflavor_t        selected_flavor;
>>    char            *client_address;
>>    unsigned int        version;
>>    unsigned int        minorversion;
>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>> extern struct file_system_type nfs4_xdev_fs_type;
>> extern struct file_system_type nfs4_referral_fs_type;
>> #endif
>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>>            struct nfs_subversion *);
>> void nfs_initialise_sb(struct super_block *);
>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>> index 28842ab..cffed27 100644
>> --- a/fs/nfs/nfs4_fs.h
>> +++ b/fs/nfs/nfs4_fs.h
>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>> extern struct file_system_type nfs4_fs_type;
>> 
>> /* nfs4namespace.c */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>>                   struct nfs_fh *, struct nfs_fattr *);
>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>> index 511cdce..b446314 100644
>> --- a/fs/nfs/nfs4client.c
>> +++ b/fs/nfs/nfs4client.c
>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>>    /* Initialise the client representation from the mount data */
>>    server->flags = data->flags;
>>    server->options = data->options;
>> +    server->auth_info = data->auth_info;
>> 
>> -    if (data->auth_flavor_len >= 1)
>> -        pseudoflavor = data->auth_flavors[0];
>> +    /* Use the first specified auth flavor. If this flavor isn't
>> +     * allowed by the server, use the SECINFO path to try the
>> +     * other specified flavors */
>> +    if (data->auth_info.flavor_len >= 1)
>> +        pseudoflavor = data->auth_info.flavors[0];
>> 
>>    /* Get a client record */
>>    error = nfs4_set_client(server,
>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>>    if (!server)
>>        return ERR_PTR(-ENOMEM);
>> 
>> -    auth_probe = mount_info->parsed->auth_flavor_len < 1;
>> +    auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>> 
>>    /* set up the general RPC client */
>>    error = nfs4_init_server(server, mount_info->parsed);
>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>> index 2288cd3..caaa7aa 100644
>> --- a/fs/nfs/nfs4namespace.c
>> +++ b/fs/nfs/nfs4namespace.c
>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>> 
>> /**
>>  * nfs_find_best_sec - Find a security mechanism supported locally
>> + * @server:  Nfs server structure
>>  * @flavors: List of security tuples returned by SECINFO procedure
>>  *
>>  * Return the pseudoflavor of the first security mechanism in
>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>> + * "flavors" that is locally supported and in the sec= mount
>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>>  * no matching flavor is found in the array.  The "flavors" array
>>  * is searched in the order returned from the server, per RFC 3530
>>  * recommendation.
>>  */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>> +                      struct nfs4_secinfo_flavors *flavors)
>> {
>>    rpc_authflavor_t pseudoflavor;
>>    struct nfs4_secinfo4 *secinfo;
>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>        case RPC_AUTH_GSS:
>>            pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>>                            &secinfo->flavor_info);
>> -            if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>> +
>> +            /* make sure pseudoflavor matches sec= mount opt */
>> +            if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>> +                nfs_auth_info_match(&server->auth_info,
>> +                        pseudoflavor))
>>                return pseudoflavor;
>>            break;
>>        }
>>    }
>> 
>> +    /* if there were any sec= options then nothing matched */
>> +    if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> +        return -EPERM;
>> +
>>    return RPC_AUTH_UNIX;
>> }
>> 
>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>>        goto out;
>>    }
>> 
>> -    flavor = nfs_find_best_sec(flavors);
>> +    flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>> 
>> out:
>>    put_page(page);
>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>> 
>>    if (client->cl_auth->au_flavor != flavor)
>>        flavor = client->cl_auth->au_flavor;
>> -    else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>> +    else {
>>        rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>>        if ((int)new >= 0)
>>            flavor = new;
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index d2b4845..a926a39 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>    int status = -EPERM;
>>    size_t i;
>> 
>> -    for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> -        status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>> -        if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> -            continue;
>> -        break;
>> +    if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>> +        for (i = 0; i < server->auth_info.flavor_len; i++) {
>> +            status = nfs4_lookup_root_sec(server, fhandle, info,
>> +                        server->auth_info.flavors[i]);
>> +            if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +                continue;
>> +            break;
>> +        }
>> +    } else {
>> +        for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> +            status = nfs4_lookup_root_sec(server, fhandle, info,
>> +                              flav_array[i]);
>> +            if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +                continue;
>> +            break;
>> +        }
>>    }
>> 
>>    /*
>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>>        status = nfs4_lookup_root(server, fhandle, info);
>>        if (status != -NFS4ERR_WRONGSEC)
>>            break;
>> -        /* Did user force a 'sec=' mount option? */
>> -        if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> -            break;
>>    default:
>>        status = nfs4_do_find_root_sec(server, fhandle, info);
>>    }
>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>>            err = -EPERM;
>>            if (client != *clnt)
>>                goto out;
>> -            /* No security negotiation if the user specified 'sec=' */
>> -            if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>> -                goto out;
>>            client = nfs4_create_sec_client(client, dir, name);
>>            if (IS_ERR(client))
>>                return PTR_ERR(client);
>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>            break;
>>        }
>> 
>> +        if (!nfs_auth_info_match(&server->auth_info, flavor))
>> +            flavor = RPC_AUTH_MAXFLAVOR;
>> +
>>        if (flavor != RPC_AUTH_MAXFLAVOR) {
>>            err = nfs4_lookup_root_sec(server, fhandle,
>>                           info, flavor);
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index a03b9c6..84cf276 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>>    static const struct {
>>        rpc_authflavor_t flavour;
>>        const char *str;
>> -    } sec_flavours[] = {
>> +    } sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>> +        /* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>> +         * changes */
>>        { RPC_AUTH_NULL, "null" },
>>        { RPC_AUTH_UNIX, "sys" },
>>        { RPC_AUTH_GSS_KRB5, "krb5" },
>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>>        data->mount_server.port    = NFS_UNSPEC_PORT;
>>        data->nfs_server.port    = NFS_UNSPEC_PORT;
>>        data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>> -        data->auth_flavors[0]    = RPC_AUTH_MAXFLAVOR;
>> -        data->auth_flavor_len    = 0;
>> +        data->selected_flavor    = RPC_AUTH_MAXFLAVOR;
>>        data->minorversion    = 0;
>>        data->need_mount    = true;
>>        data->net        = current->nsproxy->net_ns;
>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>>    }
>> }
>> 
>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>> -        rpc_authflavor_t pseudoflavor)
>> +/*
>> + * Add 'flavor' to 'auth_info' if not already present.
>> + * Returns true if 'flavor' ends up in the list, false otherwise
>> + */
>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>> +                  rpc_authflavor_t flavor)
>> {
>> -    data->auth_flavors[0] = pseudoflavor;
>> -    data->auth_flavor_len = 1;
>> +    unsigned int i;
>> +    unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>> +                    sizeof(auth_info->flavors[0]));
>> +
>> +    /* make sure this flavor isn't already in the list */
>> +    for (i = 0; i < auth_info->flavor_len; i++) {
>> +        if (flavor == auth_info->flavors[i])
>> +            return true;
>> +    }
>> +
>> +    if (auth_info->flavor_len + 1 >= max_flavor_len) {
>> +        dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>> +        return false;
>> +    }
>> +
>> +    auth_info->flavors[auth_info->flavor_len++] = flavor;
>> +    return true;
>> }
>> 
>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>> +             rpc_authflavor_t match)
>> +{
>> +    int i;
>> +
>> +    if (!auth_info->flavor_len)
>> +        return true;
>> +
>> +    for (i = 0; i < auth_info->flavor_len; i++) {
>> +        if (auth_info->flavors[i] == match)
>> +            return true;
>> +    }
>> +    return false;
>> +}
>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>> +
>> /*
>>  * Parse the value of the 'sec=' option.
>>  */
>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>> {
>>    substring_t args[MAX_OPT_ARGS];
>>    rpc_authflavor_t pseudoflavor;
>> +    char *p;
>> 
>>    dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>> 
>> -    switch (match_token(value, nfs_secflavor_tokens, args)) {
>> -    case Opt_sec_none:
>> -        pseudoflavor = RPC_AUTH_NULL;
>> -        break;
>> -    case Opt_sec_sys:
>> -        pseudoflavor = RPC_AUTH_UNIX;
>> -        break;
>> -    case Opt_sec_krb5:
>> -        pseudoflavor = RPC_AUTH_GSS_KRB5;
>> -        break;
>> -    case Opt_sec_krb5i:
>> -        pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> -        break;
>> -    case Opt_sec_krb5p:
>> -        pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> -        break;
>> -    case Opt_sec_lkey:
>> -        pseudoflavor = RPC_AUTH_GSS_LKEY;
>> -        break;
>> -    case Opt_sec_lkeyi:
>> -        pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> -        break;
>> -    case Opt_sec_lkeyp:
>> -        pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> -        break;
>> -    case Opt_sec_spkm:
>> -        pseudoflavor = RPC_AUTH_GSS_SPKM;
>> -        break;
>> -    case Opt_sec_spkmi:
>> -        pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> -        break;
>> -    case Opt_sec_spkmp:
>> -        pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> -        break;
>> -    default:
>> -        return 0;
>> +    while ((p = strsep(&value, ":")) != NULL) {
>> +        switch (match_token(p, nfs_secflavor_tokens, args)) {
>> +        case Opt_sec_none:
>> +            pseudoflavor = RPC_AUTH_NULL;
>> +            break;
>> +        case Opt_sec_sys:
>> +            pseudoflavor = RPC_AUTH_UNIX;
>> +            break;
>> +        case Opt_sec_krb5:
>> +            pseudoflavor = RPC_AUTH_GSS_KRB5;
>> +            break;
>> +        case Opt_sec_krb5i:
>> +            pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> +            break;
>> +        case Opt_sec_krb5p:
>> +            pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> +            break;
>> +        case Opt_sec_lkey:
>> +            pseudoflavor = RPC_AUTH_GSS_LKEY;
>> +            break;
>> +        case Opt_sec_lkeyi:
>> +            pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> +            break;
>> +        case Opt_sec_lkeyp:
>> +            pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> +            break;
>> +        case Opt_sec_spkm:
>> +            pseudoflavor = RPC_AUTH_GSS_SPKM;
>> +            break;
>> +        case Opt_sec_spkmi:
>> +            pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> +            break;
>> +        case Opt_sec_spkmp:
>> +            pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> +            break;
>> +        default:
>> +            dfprintk(MOUNT,
>> +                 "NFS: sec= option '%s' not recognized\n", p);
>> +            return 0;
>> +        }
>> +
>> +        if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>> +            return 0;
>>    }
>> 
>> -    mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> -    nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>> +    if (mnt->auth_info.flavor_len > 0) {
>> +        mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> +        mnt->selected_flavor = mnt->auth_info.flavors[0];
>> +    } else
>> +        mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>> +
>>    return 1;
>> }
>> 
>> @@ -1623,12 +1671,14 @@ out_security_failure:
>> }
>> 
>> /*
>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>> + * Ensure that a specified authtype in args->auth_info is supported by
>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>> + * -EACCES if not.
>>  */
>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>>            rpc_authflavor_t *server_authlist, unsigned int count)
>> {
>> +    rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>>    unsigned int i;
>> 
>>    /*
>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>     * can be used.
>>     */
>>    for (i = 0; i < count; i++) {
>> -        if (args->auth_flavors[0] == server_authlist[i] ||
>> -            server_authlist[i] == RPC_AUTH_NULL)
>> +        flavor = server_authlist[i];
>> +
>> +        if (nfs_auth_info_match(&args->auth_info, flavor) ||
>> +            flavor == RPC_AUTH_NULL)
>>            goto out;
>>    }
>> 
>> -    dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>> -        args->auth_flavors[0]);
>> +    dfprintk(MOUNT,
>> +         "NFS: specified auth flavors not supported by server\n");
>>    return -EACCES;
>> 
>> out:
>> -    dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +    args->selected_flavor = flavor;
>> +    dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>>    return 0;
>> }
>> 
>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>     * Was a sec= authflavor specified in the options? First, verify
>>     * whether the server supports it, and then just try to use it if so.
>>     */
>> -    if (args->auth_flavor_len > 0) {
>> -        status = nfs_verify_authflavor(args, authlist, authlist_len);
>> -        dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +    if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>> +        status = nfs_verify_authflavors(args, authlist, authlist_len);
>> +        dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>> +             args->selected_flavor);
>>        if (status)
>>            return ERR_PTR(status);
>>        return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>            /* Fallthrough */
>>        }
>>        dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>> -        nfs_set_auth_parsed_mount_data(args, flavor);
>> +        args->selected_flavor = flavor;
>>        server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>        if (!IS_ERR(server))
>>            return server;
>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>> 
>>    /* Last chance! Try AUTH_UNIX */
>>    dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>> -    nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +    args->selected_flavor = RPC_AUTH_UNIX;
>>    return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> }
>> 
>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>>        args->bsize        = data->bsize;
>> 
>>        if (data->flags & NFS_MOUNT_SECFLAVOUR)
>> -            nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>> +            args->selected_flavor = data->pseudoflavor;
>>        else
>> -            nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +            args->selected_flavor = RPC_AUTH_UNIX;
>>        if (!args->nfs_server.hostname)
>>            goto out_nomem;
>> 
>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>> 
>>    nfs_set_port(sap, &args->nfs_server.port, port);
>> 
>> -    if (args->auth_flavor_len > 1)
>> -        goto out_bad_auth;
>> -
>>    return nfs_parse_devname(dev_name,
>>                   &args->nfs_server.hostname,
>>                   max_namelen,
>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>> out_no_address:
>>    dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>>    return -EINVAL;
>> -
>> -out_bad_auth:
>> -    dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>> -    return -EINVAL;
>> }
>> 
>> static int
>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>>        data->rsize != nfss->rsize ||
>>        data->wsize != nfss->wsize ||
>>        data->retrans != nfss->client->cl_timeout->to_retries ||
>> -        data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>> +        data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>>        data->acregmin != nfss->acregmin / HZ ||
>>        data->acregmax != nfss->acregmax / HZ ||
>>        data->acdirmin != nfss->acdirmin / HZ ||
>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>>    data->rsize = nfss->rsize;
>>    data->wsize = nfss->wsize;
>>    data->retrans = nfss->client->cl_timeout->to_retries;
>> -    nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>> +    data->selected_flavor = nfss->client->cl_auth->au_flavor;
>> +    data->auth_info = nfss->auth_info;
>>    data->acregmin = nfss->acregmin / HZ;
>>    data->acregmax = nfss->acregmax / HZ;
>>    data->acdirmin = nfss->acdirmin / HZ;
>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>>                       data->auth_flavours,
>>                       sizeof(pseudoflavor)))
>>                return -EFAULT;
>> -            nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>> +            args->selected_flavor = pseudoflavor;
>>        } else
>> -            nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +            args->selected_flavor = RPC_AUTH_UNIX;
>> 
>>        c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>>        if (IS_ERR(c))
>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>> index f9c0a6c..b2c3b82 100644
>> --- a/include/linux/nfs_fs_sb.h
>> +++ b/include/linux/nfs_fs_sb.h
>> @@ -149,6 +149,7 @@ struct nfs_server {
>>    struct timespec        time_delta;    /* smallest time granularity */
>>    unsigned long        mount_time;    /* when this fs was mounted */
>>    dev_t            s_dev;        /* superblock dev numbers */
>> +    struct nfs_auth_info    auth_info;    /* allowed auth flavors */
>> 
>> #ifdef CONFIG_NFS_FSCACHE
>>    struct nfs_fscache_key    *fscache_key;    /* unique key for superblock */
>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>> index 49f52c8..488ce9d 100644
>> --- a/include/linux/nfs_xdr.h
>> +++ b/include/linux/nfs_xdr.h
>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>>    struct nfs_fattr        *new_fattr;
>> };
>> 
>> +/* parsed sec= options */
>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>> +struct nfs_auth_info {
>> +    unsigned int            flavor_len;
>> +    rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>> +};
>> +
>> /*
>>  * Argument struct for decode_entry function
>>  */
>> -- 
>> 1.7.12.4 (Apple Git-37)
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to [e-mail]
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 12, 2013, 7:01 p.m. UTC | #6

I guess I didn't notice the "or" in your question, so to be clear - I'm working with Anna on integrating it into her Jenkins test suite. It will also be available to use as a standalone script.

-dros

On Oct 11, 2013, at 6:35 PM, Weston Andros Adamson <[e-mail]> wrote:

> Already on it!
> 
> Great minds and all...
> 
> -dros
> 
>> On Oct 11, 2013, at 5:01 PM, "J. Bruce Fields" <[e-mail]> wrote:
>> 
>>> On Fri, Oct 11, 2013 at 02:44:22PM -0400, Weston Andros Adamson wrote:
>>> This patch adds support for multiple security options which can be
>>> specified using a colon-delimited list of security flavors (the same
>>> syntax as nfsd's exports file).
>>> 
>>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>>> to mount a remote filesystem using krb5i, but can still cross
>>> into krb5p-only exports.
>>> 
>>> New mounts will try all security options before failing.  NFSv4.x
>>> SECINFO results will be compared against the sec= flavors to
>>> find the first flavor in both lists or if no match is found will
>>> return EPERM.
>>> 
>>> This patch cleans up some of the auth flavor logic by separating
>>> the parsed mount options from the currently selected flavor and
>>> sharing more code between the 'no sec= specified' and 'sec= specified'
>>> code paths.
>>> 
>>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>>> reflect these changes.
>>> 
>>> I wrote a script to verify that I haven't broken anything, it tests
>>> all vers= and sec= combinations against a server with the exports:
>> 
>> Is the script something that could be added to Anna's or my regular
>> regression testing?
>> 
>> --b.
>> 
>>> 
>>> /export/sys       *(sec=sys,rw,no_root_squash)
>>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>>> 
>>> The script runs these tests against all exports, and the versions NFSv3,
>>> v4.0, v4.1:
>>> - no sec= options
>>> - all single sec= options
>>> - all combinations of multiple sec= options
>>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>>   v4.x only)
>>> 
>>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>>> ---
>>> fs/nfs/client.c           |   5 +-
>>> fs/nfs/internal.h         |   5 +-
>>> fs/nfs/nfs4_fs.h          |   1 -
>>> fs/nfs/nfs4client.c       |  10 ++-
>>> fs/nfs/nfs4namespace.c    |  21 +++--
>>> fs/nfs/nfs4proc.c         |  30 +++++---
>>> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>>> include/linux/nfs_fs_sb.h |   1 +
>>> include/linux/nfs_xdr.h   |   7 ++
>>> 9 files changed, 176 insertions(+), 94 deletions(-)
>>> 
>>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>>> index af03258..006fd52 100644
>>> --- a/fs/nfs/client.c
>>> +++ b/fs/nfs/client.c
>>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>>>       goto error;
>>> 
>>>   server->port = data->nfs_server.port;
>>> +    server->auth_info = data->auth_info;
>>> 
>>> -    error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>>> +    error = nfs_init_server_rpcclient(server, &timeparms,
>>> +                      data->selected_flavor);
>>>   if (error < 0)
>>>       goto error;
>>> 
>>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>>>   target->acdirmax = source->acdirmax;
>>>   target->caps = source->caps;
>>>   target->options = source->options;
>>> +    target->auth_info = source->auth_info;
>>> }
>>> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>>> 
>>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>>> index 38da8c2..5c9cfe0 100644
>>> --- a/fs/nfs/internal.h
>>> +++ b/fs/nfs/internal.h
>>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>>>   unsigned int        namlen;
>>>   unsigned int        options;
>>>   unsigned int        bsize;
>>> -    unsigned int        auth_flavor_len;
>>> -    rpc_authflavor_t    auth_flavors[1];
>>> +    struct nfs_auth_info    auth_info;
>>> +    rpc_authflavor_t        selected_flavor;
>>>   char            *client_address;
>>>   unsigned int        version;
>>>   unsigned int        minorversion;
>>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>>> extern struct file_system_type nfs4_xdev_fs_type;
>>> extern struct file_system_type nfs4_referral_fs_type;
>>> #endif
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>>> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>>>           struct nfs_subversion *);
>>> void nfs_initialise_sb(struct super_block *);
>>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>>> index 28842ab..cffed27 100644
>>> --- a/fs/nfs/nfs4_fs.h
>>> +++ b/fs/nfs/nfs4_fs.h
>>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>>> extern struct file_system_type nfs4_fs_type;
>>> 
>>> /* nfs4namespace.c */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>>> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>>> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>>>                  struct nfs_fh *, struct nfs_fattr *);
>>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>>> index 511cdce..b446314 100644
>>> --- a/fs/nfs/nfs4client.c
>>> +++ b/fs/nfs/nfs4client.c
>>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>>>   /* Initialise the client representation from the mount data */
>>>   server->flags = data->flags;
>>>   server->options = data->options;
>>> +    server->auth_info = data->auth_info;
>>> 
>>> -    if (data->auth_flavor_len >= 1)
>>> -        pseudoflavor = data->auth_flavors[0];
>>> +    /* Use the first specified auth flavor. If this flavor isn't
>>> +     * allowed by the server, use the SECINFO path to try the
>>> +     * other specified flavors */
>>> +    if (data->auth_info.flavor_len >= 1)
>>> +        pseudoflavor = data->auth_info.flavors[0];
>>> 
>>>   /* Get a client record */
>>>   error = nfs4_set_client(server,
>>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>>>   if (!server)
>>>       return ERR_PTR(-ENOMEM);
>>> 
>>> -    auth_probe = mount_info->parsed->auth_flavor_len < 1;
>>> +    auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>>> 
>>>   /* set up the general RPC client */
>>>   error = nfs4_init_server(server, mount_info->parsed);
>>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>>> index 2288cd3..caaa7aa 100644
>>> --- a/fs/nfs/nfs4namespace.c
>>> +++ b/fs/nfs/nfs4namespace.c
>>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>>> 
>>> /**
>>> * nfs_find_best_sec - Find a security mechanism supported locally
>>> + * @server:  Nfs server structure
>>> * @flavors: List of security tuples returned by SECINFO procedure
>>> *
>>> * Return the pseudoflavor of the first security mechanism in
>>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>>> + * "flavors" that is locally supported and in the sec= mount
>>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>>> * no matching flavor is found in the array.  The "flavors" array
>>> * is searched in the order returned from the server, per RFC 3530
>>> * recommendation.
>>> */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>>> +                      struct nfs4_secinfo_flavors *flavors)
>>> {
>>>   rpc_authflavor_t pseudoflavor;
>>>   struct nfs4_secinfo4 *secinfo;
>>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>>       case RPC_AUTH_GSS:
>>>           pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>>>                           &secinfo->flavor_info);
>>> -            if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>>> +
>>> +            /* make sure pseudoflavor matches sec= mount opt */
>>> +            if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>>> +                nfs_auth_info_match(&server->auth_info,
>>> +                        pseudoflavor))
>>>               return pseudoflavor;
>>>           break;
>>>       }
>>>   }
>>> 
>>> +    /* if there were any sec= options then nothing matched */
>>> +    if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> +        return -EPERM;
>>> +
>>>   return RPC_AUTH_UNIX;
>>> }
>>> 
>>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>>>       goto out;
>>>   }
>>> 
>>> -    flavor = nfs_find_best_sec(flavors);
>>> +    flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>>> 
>>> out:
>>>   put_page(page);
>>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>>> 
>>>   if (client->cl_auth->au_flavor != flavor)
>>>       flavor = client->cl_auth->au_flavor;
>>> -    else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>>> +    else {
>>>       rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>>>       if ((int)new >= 0)
>>>           flavor = new;
>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>>> index d2b4845..a926a39 100644
>>> --- a/fs/nfs/nfs4proc.c
>>> +++ b/fs/nfs/nfs4proc.c
>>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>>   int status = -EPERM;
>>>   size_t i;
>>> 
>>> -    for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> -        status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>>> -        if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> -            continue;
>>> -        break;
>>> +    if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +        for (i = 0; i < server->auth_info.flavor_len; i++) {
>>> +            status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +                        server->auth_info.flavors[i]);
>>> +            if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +                continue;
>>> +            break;
>>> +        }
>>> +    } else {
>>> +        for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> +            status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +                              flav_array[i]);
>>> +            if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +                continue;
>>> +            break;
>>> +        }
>>>   }
>>> 
>>>   /*
>>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>>>       status = nfs4_lookup_root(server, fhandle, info);
>>>       if (status != -NFS4ERR_WRONGSEC)
>>>           break;
>>> -        /* Did user force a 'sec=' mount option? */
>>> -        if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> -            break;
>>>   default:
>>>       status = nfs4_do_find_root_sec(server, fhandle, info);
>>>   }
>>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>>>           err = -EPERM;
>>>           if (client != *clnt)
>>>               goto out;
>>> -            /* No security negotiation if the user specified 'sec=' */
>>> -            if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>>> -                goto out;
>>>           client = nfs4_create_sec_client(client, dir, name);
>>>           if (IS_ERR(client))
>>>               return PTR_ERR(client);
>>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>>           break;
>>>       }
>>> 
>>> +        if (!nfs_auth_info_match(&server->auth_info, flavor))
>>> +            flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>>       if (flavor != RPC_AUTH_MAXFLAVOR) {
>>>           err = nfs4_lookup_root_sec(server, fhandle,
>>>                          info, flavor);
>>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>>> index a03b9c6..84cf276 100644
>>> --- a/fs/nfs/super.c
>>> +++ b/fs/nfs/super.c
>>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>>>   static const struct {
>>>       rpc_authflavor_t flavour;
>>>       const char *str;
>>> -    } sec_flavours[] = {
>>> +    } sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>>> +        /* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>>> +         * changes */
>>>       { RPC_AUTH_NULL, "null" },
>>>       { RPC_AUTH_UNIX, "sys" },
>>>       { RPC_AUTH_GSS_KRB5, "krb5" },
>>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>>>       data->mount_server.port    = NFS_UNSPEC_PORT;
>>>       data->nfs_server.port    = NFS_UNSPEC_PORT;
>>>       data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>>> -        data->auth_flavors[0]    = RPC_AUTH_MAXFLAVOR;
>>> -        data->auth_flavor_len    = 0;
>>> +        data->selected_flavor    = RPC_AUTH_MAXFLAVOR;
>>>       data->minorversion    = 0;
>>>       data->need_mount    = true;
>>>       data->net        = current->nsproxy->net_ns;
>>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>>>   }
>>> }
>>> 
>>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>>> -        rpc_authflavor_t pseudoflavor)
>>> +/*
>>> + * Add 'flavor' to 'auth_info' if not already present.
>>> + * Returns true if 'flavor' ends up in the list, false otherwise
>>> + */
>>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>>> +                  rpc_authflavor_t flavor)
>>> {
>>> -    data->auth_flavors[0] = pseudoflavor;
>>> -    data->auth_flavor_len = 1;
>>> +    unsigned int i;
>>> +    unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>>> +                    sizeof(auth_info->flavors[0]));
>>> +
>>> +    /* make sure this flavor isn't already in the list */
>>> +    for (i = 0; i < auth_info->flavor_len; i++) {
>>> +        if (flavor == auth_info->flavors[i])
>>> +            return true;
>>> +    }
>>> +
>>> +    if (auth_info->flavor_len + 1 >= max_flavor_len) {
>>> +        dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>>> +        return false;
>>> +    }
>>> +
>>> +    auth_info->flavors[auth_info->flavor_len++] = flavor;
>>> +    return true;
>>> }
>>> 
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>>> +             rpc_authflavor_t match)
>>> +{
>>> +    int i;
>>> +
>>> +    if (!auth_info->flavor_len)
>>> +        return true;
>>> +
>>> +    for (i = 0; i < auth_info->flavor_len; i++) {
>>> +        if (auth_info->flavors[i] == match)
>>> +            return true;
>>> +    }
>>> +    return false;
>>> +}
>>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>>> +
>>> /*
>>> * Parse the value of the 'sec=' option.
>>> */
>>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>>> {
>>>   substring_t args[MAX_OPT_ARGS];
>>>   rpc_authflavor_t pseudoflavor;
>>> +    char *p;
>>> 
>>>   dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>>> 
>>> -    switch (match_token(value, nfs_secflavor_tokens, args)) {
>>> -    case Opt_sec_none:
>>> -        pseudoflavor = RPC_AUTH_NULL;
>>> -        break;
>>> -    case Opt_sec_sys:
>>> -        pseudoflavor = RPC_AUTH_UNIX;
>>> -        break;
>>> -    case Opt_sec_krb5:
>>> -        pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> -        break;
>>> -    case Opt_sec_krb5i:
>>> -        pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> -        break;
>>> -    case Opt_sec_krb5p:
>>> -        pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> -        break;
>>> -    case Opt_sec_lkey:
>>> -        pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> -        break;
>>> -    case Opt_sec_lkeyi:
>>> -        pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> -        break;
>>> -    case Opt_sec_lkeyp:
>>> -        pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> -        break;
>>> -    case Opt_sec_spkm:
>>> -        pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> -        break;
>>> -    case Opt_sec_spkmi:
>>> -        pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> -        break;
>>> -    case Opt_sec_spkmp:
>>> -        pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> -        break;
>>> -    default:
>>> -        return 0;
>>> +    while ((p = strsep(&value, ":")) != NULL) {
>>> +        switch (match_token(p, nfs_secflavor_tokens, args)) {
>>> +        case Opt_sec_none:
>>> +            pseudoflavor = RPC_AUTH_NULL;
>>> +            break;
>>> +        case Opt_sec_sys:
>>> +            pseudoflavor = RPC_AUTH_UNIX;
>>> +            break;
>>> +        case Opt_sec_krb5:
>>> +            pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> +            break;
>>> +        case Opt_sec_krb5i:
>>> +            pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> +            break;
>>> +        case Opt_sec_krb5p:
>>> +            pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> +            break;
>>> +        case Opt_sec_lkey:
>>> +            pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> +            break;
>>> +        case Opt_sec_lkeyi:
>>> +            pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> +            break;
>>> +        case Opt_sec_lkeyp:
>>> +            pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> +            break;
>>> +        case Opt_sec_spkm:
>>> +            pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> +            break;
>>> +        case Opt_sec_spkmi:
>>> +            pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> +            break;
>>> +        case Opt_sec_spkmp:
>>> +            pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> +            break;
>>> +        default:
>>> +            dfprintk(MOUNT,
>>> +                 "NFS: sec= option '%s' not recognized\n", p);
>>> +            return 0;
>>> +        }
>>> +
>>> +        if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>>> +            return 0;
>>>   }
>>> 
>>> -    mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> -    nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>>> +    if (mnt->auth_info.flavor_len > 0) {
>>> +        mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> +        mnt->selected_flavor = mnt->auth_info.flavors[0];
>>> +    } else
>>> +        mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>>   return 1;
>>> }
>>> 
>>> @@ -1623,12 +1671,14 @@ out_security_failure:
>>> }
>>> 
>>> /*
>>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>>> + * Ensure that a specified authtype in args->auth_info is supported by
>>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>>> + * -EACCES if not.
>>> */
>>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>>>           rpc_authflavor_t *server_authlist, unsigned int count)
>>> {
>>> +    rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>>>   unsigned int i;
>>> 
>>>   /*
>>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>>    * can be used.
>>>    */
>>>   for (i = 0; i < count; i++) {
>>> -        if (args->auth_flavors[0] == server_authlist[i] ||
>>> -            server_authlist[i] == RPC_AUTH_NULL)
>>> +        flavor = server_authlist[i];
>>> +
>>> +        if (nfs_auth_info_match(&args->auth_info, flavor) ||
>>> +            flavor == RPC_AUTH_NULL)
>>>           goto out;
>>>   }
>>> 
>>> -    dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>>> -        args->auth_flavors[0]);
>>> +    dfprintk(MOUNT,
>>> +         "NFS: specified auth flavors not supported by server\n");
>>>   return -EACCES;
>>> 
>>> out:
>>> -    dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +    args->selected_flavor = flavor;
>>> +    dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>>>   return 0;
>>> }
>>> 
>>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>>    * Was a sec= authflavor specified in the options? First, verify
>>>    * whether the server supports it, and then just try to use it if so.
>>>    */
>>> -    if (args->auth_flavor_len > 0) {
>>> -        status = nfs_verify_authflavor(args, authlist, authlist_len);
>>> -        dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +    if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +        status = nfs_verify_authflavors(args, authlist, authlist_len);
>>> +        dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>>> +             args->selected_flavor);
>>>       if (status)
>>>           return ERR_PTR(status);
>>>       return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>>           /* Fallthrough */
>>>       }
>>>       dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>>> -        nfs_set_auth_parsed_mount_data(args, flavor);
>>> +        args->selected_flavor = flavor;
>>>       server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>>       if (!IS_ERR(server))
>>>           return server;
>>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 
>>>   /* Last chance! Try AUTH_UNIX */
>>>   dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>>> -    nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +    args->selected_flavor = RPC_AUTH_UNIX;
>>>   return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> }
>>> 
>>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>>>       args->bsize        = data->bsize;
>>> 
>>>       if (data->flags & NFS_MOUNT_SECFLAVOUR)
>>> -            nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>>> +            args->selected_flavor = data->pseudoflavor;
>>>       else
>>> -            nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +            args->selected_flavor = RPC_AUTH_UNIX;
>>>       if (!args->nfs_server.hostname)
>>>           goto out_nomem;
>>> 
>>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>>> 
>>>   nfs_set_port(sap, &args->nfs_server.port, port);
>>> 
>>> -    if (args->auth_flavor_len > 1)
>>> -        goto out_bad_auth;
>>> -
>>>   return nfs_parse_devname(dev_name,
>>>                  &args->nfs_server.hostname,
>>>                  max_namelen,
>>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>>> out_no_address:
>>>   dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>>>   return -EINVAL;
>>> -
>>> -out_bad_auth:
>>> -    dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>>> -    return -EINVAL;
>>> }
>>> 
>>> static int
>>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>>>       data->rsize != nfss->rsize ||
>>>       data->wsize != nfss->wsize ||
>>>       data->retrans != nfss->client->cl_timeout->to_retries ||
>>> -        data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>>> +        data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>>>       data->acregmin != nfss->acregmin / HZ ||
>>>       data->acregmax != nfss->acregmax / HZ ||
>>>       data->acdirmin != nfss->acdirmin / HZ ||
>>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>>>   data->rsize = nfss->rsize;
>>>   data->wsize = nfss->wsize;
>>>   data->retrans = nfss->client->cl_timeout->to_retries;
>>> -    nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>>> +    data->selected_flavor = nfss->client->cl_auth->au_flavor;
>>> +    data->auth_info = nfss->auth_info;
>>>   data->acregmin = nfss->acregmin / HZ;
>>>   data->acregmax = nfss->acregmax / HZ;
>>>   data->acdirmin = nfss->acdirmin / HZ;
>>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>>>                      data->auth_flavours,
>>>                      sizeof(pseudoflavor)))
>>>               return -EFAULT;
>>> -            nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>>> +            args->selected_flavor = pseudoflavor;
>>>       } else
>>> -            nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +            args->selected_flavor = RPC_AUTH_UNIX;
>>> 
>>>       c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>>>       if (IS_ERR(c))
>>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>>> index f9c0a6c..b2c3b82 100644
>>> --- a/include/linux/nfs_fs_sb.h
>>> +++ b/include/linux/nfs_fs_sb.h
>>> @@ -149,6 +149,7 @@ struct nfs_server {
>>>   struct timespec        time_delta;    /* smallest time granularity */
>>>   unsigned long        mount_time;    /* when this fs was mounted */
>>>   dev_t            s_dev;        /* superblock dev numbers */
>>> +    struct nfs_auth_info    auth_info;    /* allowed auth flavors */
>>> 
>>> #ifdef CONFIG_NFS_FSCACHE
>>>   struct nfs_fscache_key    *fscache_key;    /* unique key for superblock */
>>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>>> index 49f52c8..488ce9d 100644
>>> --- a/include/linux/nfs_xdr.h
>>> +++ b/include/linux/nfs_xdr.h
>>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>>>   struct nfs_fattr        *new_fattr;
>>> };
>>> 
>>> +/* parsed sec= options */
>>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>>> +struct nfs_auth_info {
>>> +    unsigned int            flavor_len;
>>> +    rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>>> +};
>>> +
>>> /*
>>> * Argument struct for decode_entry function
>>> */
>>> -- 
>>> 1.7.12.4 (Apple Git-37)
>>> 
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>>> the body of a message to [e-mail]
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Anna Schumaker Oct. 14, 2013, 1:12 p.m. UTC | #7

On Fri 11 Oct 2013 05:01:04 PM EDT, J. Bruce Fields wrote:
> On Fri, Oct 11, 2013 at 02:44:22PM -0400, Weston Andros Adamson wrote:
>> This patch adds support for multiple security options which can be
>> specified using a colon-delimited list of security flavors (the same
>> syntax as nfsd's exports file).
>>
>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>> to mount a remote filesystem using krb5i, but can still cross
>> into krb5p-only exports.
>>
>> New mounts will try all security options before failing.  NFSv4.x
>> SECINFO results will be compared against the sec= flavors to
>> find the first flavor in both lists or if no match is found will
>> return EPERM.
>>
>> This patch cleans up some of the auth flavor logic by separating
>> the parsed mount options from the currently selected flavor and
>> sharing more code between the 'no sec= specified' and 'sec= specified'
>> code paths.
>>
>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>> reflect these changes.
>>
>> I wrote a script to verify that I haven't broken anything, it tests
>> all vers= and sec= combinations against a server with the exports:
>
> Is the script something that could be added to Anna's or my regular
> regression testing?

I looked over the script Friday and I don't think it'll be too 
difficult to work in to my Jenkins stuff :)

Anna

>
> --b.
>
>>
>>  /export/sys       *(sec=sys,rw,no_root_squash)
>>  /export/krb5a     *(sec=krb5,rw,no_root_squash)
>>  /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>>  /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>>  /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>>  /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>>
>> The script runs these tests against all exports, and the versions NFSv3,
>> v4.0, v4.1:
>>  - no sec= options
>>  - all single sec= options
>>  - all combinations of multiple sec= options
>>  - no sec= SECINFO (mount / then ls export dir, v4.x only)
>>  - single sec= SECINFO (mount / then ls export dir, v4.x only)
>>  - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>     v4.x only)
>>
>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>> ---
>>  fs/nfs/client.c           |   5 +-
>>  fs/nfs/internal.h         |   5 +-
>>  fs/nfs/nfs4_fs.h          |   1 -
>>  fs/nfs/nfs4client.c       |  10 ++-
>>  fs/nfs/nfs4namespace.c    |  21 +++--
>>  fs/nfs/nfs4proc.c         |  30 +++++---
>>  fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>>  include/linux/nfs_fs_sb.h |   1 +
>>  include/linux/nfs_xdr.h   |   7 ++
>>  9 files changed, 176 insertions(+), 94 deletions(-)
>>
>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>> index af03258..006fd52 100644
>> --- a/fs/nfs/client.c
>> +++ b/fs/nfs/client.c
>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>>  		goto error;
>>
>>  	server->port = data->nfs_server.port;
>> +	server->auth_info = data->auth_info;
>>
>> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>> +	error = nfs_init_server_rpcclient(server, &timeparms,
>> +					  data->selected_flavor);
>>  	if (error < 0)
>>  		goto error;
>>
>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>>  	target->acdirmax = source->acdirmax;
>>  	target->caps = source->caps;
>>  	target->options = source->options;
>> +	target->auth_info = source->auth_info;
>>  }
>>  EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>>
>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>> index 38da8c2..5c9cfe0 100644
>> --- a/fs/nfs/internal.h
>> +++ b/fs/nfs/internal.h
>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>>  	unsigned int		namlen;
>>  	unsigned int		options;
>>  	unsigned int		bsize;
>> -	unsigned int		auth_flavor_len;
>> -	rpc_authflavor_t	auth_flavors[1];
>> +	struct nfs_auth_info    auth_info;
>> +	rpc_authflavor_t        selected_flavor;
>>  	char			*client_address;
>>  	unsigned int		version;
>>  	unsigned int		minorversion;
>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>>  extern struct file_system_type nfs4_xdev_fs_type;
>>  extern struct file_system_type nfs4_referral_fs_type;
>>  #endif
>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>>  struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>>  			struct nfs_subversion *);
>>  void nfs_initialise_sb(struct super_block *);
>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>> index 28842ab..cffed27 100644
>> --- a/fs/nfs/nfs4_fs.h
>> +++ b/fs/nfs/nfs4_fs.h
>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>>  extern struct file_system_type nfs4_fs_type;
>>
>>  /* nfs4namespace.c */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>>  struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>>  struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>>  			       struct nfs_fh *, struct nfs_fattr *);
>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>> index 511cdce..b446314 100644
>> --- a/fs/nfs/nfs4client.c
>> +++ b/fs/nfs/nfs4client.c
>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>>  	/* Initialise the client representation from the mount data */
>>  	server->flags = data->flags;
>>  	server->options = data->options;
>> +	server->auth_info = data->auth_info;
>>
>> -	if (data->auth_flavor_len >= 1)
>> -		pseudoflavor = data->auth_flavors[0];
>> +	/* Use the first specified auth flavor. If this flavor isn't
>> +	 * allowed by the server, use the SECINFO path to try the
>> +	 * other specified flavors */
>> +	if (data->auth_info.flavor_len >= 1)
>> +		pseudoflavor = data->auth_info.flavors[0];
>>
>>  	/* Get a client record */
>>  	error = nfs4_set_client(server,
>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>>  	if (!server)
>>  		return ERR_PTR(-ENOMEM);
>>
>> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
>> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>>
>>  	/* set up the general RPC client */
>>  	error = nfs4_init_server(server, mount_info->parsed);
>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>> index 2288cd3..caaa7aa 100644
>> --- a/fs/nfs/nfs4namespace.c
>> +++ b/fs/nfs/nfs4namespace.c
>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>>
>>  /**
>>   * nfs_find_best_sec - Find a security mechanism supported locally
>> + * @server:  Nfs server structure
>>   * @flavors: List of security tuples returned by SECINFO procedure
>>   *
>>   * Return the pseudoflavor of the first security mechanism in
>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>> + * "flavors" that is locally supported and in the sec= mount
>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>>   * no matching flavor is found in the array.  The "flavors" array
>>   * is searched in the order returned from the server, per RFC 3530
>>   * recommendation.
>>   */
>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>> +					  struct nfs4_secinfo_flavors *flavors)
>>  {
>>  	rpc_authflavor_t pseudoflavor;
>>  	struct nfs4_secinfo4 *secinfo;
>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>  		case RPC_AUTH_GSS:
>>  			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>>  							&secinfo->flavor_info);
>> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>> +
>> +			/* make sure pseudoflavor matches sec= mount opt */
>> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>> +			    nfs_auth_info_match(&server->auth_info,
>> +						pseudoflavor))
>>  				return pseudoflavor;
>>  			break;
>>  		}
>>  	}
>>
>> +	/* if there were any sec= options then nothing matched */
>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> +		return -EPERM;
>> +
>>  	return RPC_AUTH_UNIX;
>>  }
>>
>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>>  		goto out;
>>  	}
>>
>> -	flavor = nfs_find_best_sec(flavors);
>> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>>
>>  out:
>>  	put_page(page);
>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>>
>>  	if (client->cl_auth->au_flavor != flavor)
>>  		flavor = client->cl_auth->au_flavor;
>> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>> +	else {
>>  		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>>  		if ((int)new >= 0)
>>  			flavor = new;
>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>> index d2b4845..a926a39 100644
>> --- a/fs/nfs/nfs4proc.c
>> +++ b/fs/nfs/nfs4proc.c
>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>  	int status = -EPERM;
>>  	size_t i;
>>
>> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> -			continue;
>> -		break;
>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>> +						server->auth_info.flavors[i]);
>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +				continue;
>> +			break;
>> +		}
>> +	} else {
>> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>> +						      flav_array[i]);
>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>> +				continue;
>> +			break;
>> +		}
>>  	}
>>
>>  	/*
>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>>  		status = nfs4_lookup_root(server, fhandle, info);
>>  		if (status != -NFS4ERR_WRONGSEC)
>>  			break;
>> -		/* Did user force a 'sec=' mount option? */
>> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
>> -			break;
>>  	default:
>>  		status = nfs4_do_find_root_sec(server, fhandle, info);
>>  	}
>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>>  			err = -EPERM;
>>  			if (client != *clnt)
>>  				goto out;
>> -			/* No security negotiation if the user specified 'sec=' */
>> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>> -				goto out;
>>  			client = nfs4_create_sec_client(client, dir, name);
>>  			if (IS_ERR(client))
>>  				return PTR_ERR(client);
>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>  			break;
>>  		}
>>
>> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
>> +			flavor = RPC_AUTH_MAXFLAVOR;
>> +
>>  		if (flavor != RPC_AUTH_MAXFLAVOR) {
>>  			err = nfs4_lookup_root_sec(server, fhandle,
>>  						   info, flavor);
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index a03b9c6..84cf276 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>>  	static const struct {
>>  		rpc_authflavor_t flavour;
>>  		const char *str;
>> -	} sec_flavours[] = {
>> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>> +		 * changes */
>>  		{ RPC_AUTH_NULL, "null" },
>>  		{ RPC_AUTH_UNIX, "sys" },
>>  		{ RPC_AUTH_GSS_KRB5, "krb5" },
>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>>  		data->mount_server.port	= NFS_UNSPEC_PORT;
>>  		data->nfs_server.port	= NFS_UNSPEC_PORT;
>>  		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
>> -		data->auth_flavor_len	= 0;
>> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
>>  		data->minorversion	= 0;
>>  		data->need_mount	= true;
>>  		data->net		= current->nsproxy->net_ns;
>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>>  	}
>>  }
>>
>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>> -		rpc_authflavor_t pseudoflavor)
>> +/*
>> + * Add 'flavor' to 'auth_info' if not already present.
>> + * Returns true if 'flavor' ends up in the list, false otherwise
>> + */
>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>> +			      rpc_authflavor_t flavor)
>>  {
>> -	data->auth_flavors[0] = pseudoflavor;
>> -	data->auth_flavor_len = 1;
>> +	unsigned int i;
>> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>> +					sizeof(auth_info->flavors[0]));
>> +
>> +	/* make sure this flavor isn't already in the list */
>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>> +		if (flavor == auth_info->flavors[i])
>> +			return true;
>> +	}
>> +
>> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
>> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>> +		return false;
>> +	}
>> +
>> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
>> +	return true;
>>  }
>>
>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>> +			 rpc_authflavor_t match)
>> +{
>> +	int i;
>> +
>> +	if (!auth_info->flavor_len)
>> +		return true;
>> +
>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>> +		if (auth_info->flavors[i] == match)
>> +			return true;
>> +	}
>> +	return false;
>> +}
>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>> +
>>  /*
>>   * Parse the value of the 'sec=' option.
>>   */
>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>>  {
>>  	substring_t args[MAX_OPT_ARGS];
>>  	rpc_authflavor_t pseudoflavor;
>> +	char *p;
>>
>>  	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>>
>> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
>> -	case Opt_sec_none:
>> -		pseudoflavor = RPC_AUTH_NULL;
>> -		break;
>> -	case Opt_sec_sys:
>> -		pseudoflavor = RPC_AUTH_UNIX;
>> -		break;
>> -	case Opt_sec_krb5:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
>> -		break;
>> -	case Opt_sec_krb5i:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> -		break;
>> -	case Opt_sec_krb5p:
>> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> -		break;
>> -	case Opt_sec_lkey:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
>> -		break;
>> -	case Opt_sec_lkeyi:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> -		break;
>> -	case Opt_sec_lkeyp:
>> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> -		break;
>> -	case Opt_sec_spkm:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
>> -		break;
>> -	case Opt_sec_spkmi:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> -		break;
>> -	case Opt_sec_spkmp:
>> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> -		break;
>> -	default:
>> -		return 0;
>> +	while ((p = strsep(&value, ":")) != NULL) {
>> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
>> +		case Opt_sec_none:
>> +			pseudoflavor = RPC_AUTH_NULL;
>> +			break;
>> +		case Opt_sec_sys:
>> +			pseudoflavor = RPC_AUTH_UNIX;
>> +			break;
>> +		case Opt_sec_krb5:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
>> +			break;
>> +		case Opt_sec_krb5i:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
>> +			break;
>> +		case Opt_sec_krb5p:
>> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
>> +			break;
>> +		case Opt_sec_lkey:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
>> +			break;
>> +		case Opt_sec_lkeyi:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
>> +			break;
>> +		case Opt_sec_lkeyp:
>> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
>> +			break;
>> +		case Opt_sec_spkm:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
>> +			break;
>> +		case Opt_sec_spkmi:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
>> +			break;
>> +		case Opt_sec_spkmp:
>> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
>> +			break;
>> +		default:
>> +			dfprintk(MOUNT,
>> +				 "NFS: sec= option '%s' not recognized\n", p);
>> +			return 0;
>> +		}
>> +
>> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>> +			return 0;
>>  	}
>>
>> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>> +	if (mnt->auth_info.flavor_len > 0) {
>> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
>> +	} else
>> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>> +
>>  	return 1;
>>  }
>>
>> @@ -1623,12 +1671,14 @@ out_security_failure:
>>  }
>>
>>  /*
>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>> + * Ensure that a specified authtype in args->auth_info is supported by
>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>> + * -EACCES if not.
>>   */
>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>>  			rpc_authflavor_t *server_authlist, unsigned int count)
>>  {
>> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>>  	unsigned int i;
>>
>>  	/*
>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>  	 * can be used.
>>  	 */
>>  	for (i = 0; i < count; i++) {
>> -		if (args->auth_flavors[0] == server_authlist[i] ||
>> -		    server_authlist[i] == RPC_AUTH_NULL)
>> +		flavor = server_authlist[i];
>> +
>> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
>> +		    flavor == RPC_AUTH_NULL)
>>  			goto out;
>>  	}
>>
>> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>> -		args->auth_flavors[0]);
>> +	dfprintk(MOUNT,
>> +		 "NFS: specified auth flavors not supported by server\n");
>>  	return -EACCES;
>>
>>  out:
>> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +	args->selected_flavor = flavor;
>> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>>  	return 0;
>>  }
>>
>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>  	 * Was a sec= authflavor specified in the options? First, verify
>>  	 * whether the server supports it, and then just try to use it if so.
>>  	 */
>> -	if (args->auth_flavor_len > 0) {
>> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
>> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
>> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>> +			 args->selected_flavor);
>>  		if (status)
>>  			return ERR_PTR(status);
>>  		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>  			/* Fallthrough */
>>  		}
>>  		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>> -		nfs_set_auth_parsed_mount_data(args, flavor);
>> +		args->selected_flavor = flavor;
>>  		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>  		if (!IS_ERR(server))
>>  			return server;
>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>
>>  	/* Last chance! Try AUTH_UNIX */
>>  	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +	args->selected_flavor = RPC_AUTH_UNIX;
>>  	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>  }
>>
>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>>  		args->bsize		= data->bsize;
>>
>>  		if (data->flags & NFS_MOUNT_SECFLAVOUR)
>> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>> +			args->selected_flavor = data->pseudoflavor;
>>  		else
>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>  		if (!args->nfs_server.hostname)
>>  			goto out_nomem;
>>
>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>>
>>  	nfs_set_port(sap, &args->nfs_server.port, port);
>>
>> -	if (args->auth_flavor_len > 1)
>> -		goto out_bad_auth;
>> -
>>  	return nfs_parse_devname(dev_name,
>>  				   &args->nfs_server.hostname,
>>  				   max_namelen,
>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>>  out_no_address:
>>  	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>>  	return -EINVAL;
>> -
>> -out_bad_auth:
>> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>> -	return -EINVAL;
>>  }
>>
>>  static int
>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>>  	    data->rsize != nfss->rsize ||
>>  	    data->wsize != nfss->wsize ||
>>  	    data->retrans != nfss->client->cl_timeout->to_retries ||
>> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>>  	    data->acregmin != nfss->acregmin / HZ ||
>>  	    data->acregmax != nfss->acregmax / HZ ||
>>  	    data->acdirmin != nfss->acdirmin / HZ ||
>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>>  	data->rsize = nfss->rsize;
>>  	data->wsize = nfss->wsize;
>>  	data->retrans = nfss->client->cl_timeout->to_retries;
>> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
>> +	data->auth_info = nfss->auth_info;
>>  	data->acregmin = nfss->acregmin / HZ;
>>  	data->acregmax = nfss->acregmax / HZ;
>>  	data->acdirmin = nfss->acdirmin / HZ;
>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>>  					   data->auth_flavours,
>>  					   sizeof(pseudoflavor)))
>>  				return -EFAULT;
>> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>> +			args->selected_flavor = pseudoflavor;
>>  		} else
>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>
>>  		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>>  		if (IS_ERR(c))
>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>> index f9c0a6c..b2c3b82 100644
>> --- a/include/linux/nfs_fs_sb.h
>> +++ b/include/linux/nfs_fs_sb.h
>> @@ -149,6 +149,7 @@ struct nfs_server {
>>  	struct timespec		time_delta;	/* smallest time granularity */
>>  	unsigned long		mount_time;	/* when this fs was mounted */
>>  	dev_t			s_dev;		/* superblock dev numbers */
>> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
>>
>>  #ifdef CONFIG_NFS_FSCACHE
>>  	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>> index 49f52c8..488ce9d 100644
>> --- a/include/linux/nfs_xdr.h
>> +++ b/include/linux/nfs_xdr.h
>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>>  	struct nfs_fattr		*new_fattr;
>>  };
>>
>> +/* parsed sec= options */
>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>> +struct nfs_auth_info {
>> +	unsigned int            flavor_len;
>> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>> +};
>> +
>>  /*
>>   * Argument struct for decode_entry function
>>   */
>> --
>> 1.7.12.4 (Apple Git-37)
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to [e-mail]
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 14, 2013, 3:11 p.m. UTC | #8

-dros

On Oct 14, 2013, at 9:12 AM, Anna Schumaker <[e-mail]> wrote:

> On Fri 11 Oct 2013 05:01:04 PM EDT, J. Bruce Fields wrote:
>> On Fri, Oct 11, 2013 at 02:44:22PM -0400, Weston Andros Adamson wrote:
>>> This patch adds support for multiple security options which can be
>>> specified using a colon-delimited list of security flavors (the same
>>> syntax as nfsd's exports file).
>>> 
>>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>>> to mount a remote filesystem using krb5i, but can still cross
>>> into krb5p-only exports.
>>> 
>>> New mounts will try all security options before failing.  NFSv4.x
>>> SECINFO results will be compared against the sec= flavors to
>>> find the first flavor in both lists or if no match is found will
>>> return EPERM.
>>> 
>>> This patch cleans up some of the auth flavor logic by separating
>>> the parsed mount options from the currently selected flavor and
>>> sharing more code between the 'no sec= specified' and 'sec= specified'
>>> code paths.
>>> 
>>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>>> reflect these changes.
>>> 
>>> I wrote a script to verify that I haven't broken anything, it tests
>>> all vers= and sec= combinations against a server with the exports:
>> 
>> Is the script something that could be added to Anna's or my regular
>> regression testing?
> 
> I looked over the script Friday and I don't think it'll be too 
> difficult to work in to my Jenkins stuff :)

I have a new copy of the script that allows (almost) everything to be passed in as an environment variable.

I'll hand that off to you later today.

-dros

> 
> Anna
> 
>> 
>> --b.
>> 
>>> 
>>> /export/sys       *(sec=sys,rw,no_root_squash)
>>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>>> 
>>> The script runs these tests against all exports, and the versions NFSv3,
>>> v4.0, v4.1:
>>> - no sec= options
>>> - all single sec= options
>>> - all combinations of multiple sec= options
>>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>>    v4.x only)
>>> 
>>> Signed-off-by: Weston Andros Adamson <[e-mail]>
>>> ---
>>> fs/nfs/client.c           |   5 +-
>>> fs/nfs/internal.h         |   5 +-
>>> fs/nfs/nfs4_fs.h          |   1 -
>>> fs/nfs/nfs4client.c       |  10 ++-
>>> fs/nfs/nfs4namespace.c    |  21 +++--
>>> fs/nfs/nfs4proc.c         |  30 +++++---
>>> fs/nfs/super.c            | 190 +++++++++++++++++++++++++++++-----------------
>>> include/linux/nfs_fs_sb.h |   1 +
>>> include/linux/nfs_xdr.h   |   7 ++
>>> 9 files changed, 176 insertions(+), 94 deletions(-)
>>> 
>>> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
>>> index af03258..006fd52 100644
>>> --- a/fs/nfs/client.c
>>> +++ b/fs/nfs/client.c
>>> @@ -786,8 +786,10 @@ static int nfs_init_server(struct nfs_server *server,
>>> 		goto error;
>>> 
>>> 	server->port = data->nfs_server.port;
>>> +	server->auth_info = data->auth_info;
>>> 
>>> -	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
>>> +	error = nfs_init_server_rpcclient(server, &timeparms,
>>> +					  data->selected_flavor);
>>> 	if (error < 0)
>>> 		goto error;
>>> 
>>> @@ -928,6 +930,7 @@ void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
>>> 	target->acdirmax = source->acdirmax;
>>> 	target->caps = source->caps;
>>> 	target->options = source->options;
>>> +	target->auth_info = source->auth_info;
>>> }
>>> EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
>>> 
>>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>>> index 38da8c2..5c9cfe0 100644
>>> --- a/fs/nfs/internal.h
>>> +++ b/fs/nfs/internal.h
>>> @@ -88,8 +88,8 @@ struct nfs_parsed_mount_data {
>>> 	unsigned int		namlen;
>>> 	unsigned int		options;
>>> 	unsigned int		bsize;
>>> -	unsigned int		auth_flavor_len;
>>> -	rpc_authflavor_t	auth_flavors[1];
>>> +	struct nfs_auth_info    auth_info;
>>> +	rpc_authflavor_t        selected_flavor;
>>> 	char			*client_address;
>>> 	unsigned int		version;
>>> 	unsigned int		minorversion;
>>> @@ -323,6 +323,7 @@ extern struct file_system_type nfs_xdev_fs_type;
>>> extern struct file_system_type nfs4_xdev_fs_type;
>>> extern struct file_system_type nfs4_referral_fs_type;
>>> #endif
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
>>> struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
>>> 			struct nfs_subversion *);
>>> void nfs_initialise_sb(struct super_block *);
>>> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
>>> index 28842ab..cffed27 100644
>>> --- a/fs/nfs/nfs4_fs.h
>>> +++ b/fs/nfs/nfs4_fs.h
>>> @@ -213,7 +213,6 @@ int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
>>> extern struct file_system_type nfs4_fs_type;
>>> 
>>> /* nfs4namespace.c */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
>>> struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
>>> struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
>>> 			       struct nfs_fh *, struct nfs_fattr *);
>>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>>> index 511cdce..b446314 100644
>>> --- a/fs/nfs/nfs4client.c
>>> +++ b/fs/nfs/nfs4client.c
>>> @@ -962,9 +962,13 @@ static int nfs4_init_server(struct nfs_server *server,
>>> 	/* Initialise the client representation from the mount data */
>>> 	server->flags = data->flags;
>>> 	server->options = data->options;
>>> +	server->auth_info = data->auth_info;
>>> 
>>> -	if (data->auth_flavor_len >= 1)
>>> -		pseudoflavor = data->auth_flavors[0];
>>> +	/* Use the first specified auth flavor. If this flavor isn't
>>> +	 * allowed by the server, use the SECINFO path to try the
>>> +	 * other specified flavors */
>>> +	if (data->auth_info.flavor_len >= 1)
>>> +		pseudoflavor = data->auth_info.flavors[0];
>>> 
>>> 	/* Get a client record */
>>> 	error = nfs4_set_client(server,
>>> @@ -1019,7 +1023,7 @@ struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
>>> 	if (!server)
>>> 		return ERR_PTR(-ENOMEM);
>>> 
>>> -	auth_probe = mount_info->parsed->auth_flavor_len < 1;
>>> +	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
>>> 
>>> 	/* set up the general RPC client */
>>> 	error = nfs4_init_server(server, mount_info->parsed);
>>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>>> index 2288cd3..caaa7aa 100644
>>> --- a/fs/nfs/nfs4namespace.c
>>> +++ b/fs/nfs/nfs4namespace.c
>>> @@ -137,15 +137,18 @@ static size_t nfs_parse_server_name(char *string, size_t len,
>>> 
>>> /**
>>>  * nfs_find_best_sec - Find a security mechanism supported locally
>>> + * @server:  Nfs server structure
>>>  * @flavors: List of security tuples returned by SECINFO procedure
>>>  *
>>>  * Return the pseudoflavor of the first security mechanism in
>>> - * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
>>> + * "flavors" that is locally supported and in the sec= mount
>>> + * options if any were specified.  Return RPC_AUTH_UNIX if
>>>  * no matching flavor is found in the array.  The "flavors" array
>>>  * is searched in the order returned from the server, per RFC 3530
>>>  * recommendation.
>>>  */
>>> -rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>> +static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
>>> +					  struct nfs4_secinfo_flavors *flavors)
>>> {
>>> 	rpc_authflavor_t pseudoflavor;
>>> 	struct nfs4_secinfo4 *secinfo;
>>> @@ -160,12 +163,20 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
>>> 		case RPC_AUTH_GSS:
>>> 			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
>>> 							&secinfo->flavor_info);
>>> -			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
>>> +
>>> +			/* make sure pseudoflavor matches sec= mount opt */
>>> +			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
>>> +			    nfs_auth_info_match(&server->auth_info,
>>> +						pseudoflavor))
>>> 				return pseudoflavor;
>>> 			break;
>>> 		}
>>> 	}
>>> 
>>> +	/* if there were any sec= options then nothing matched */
>>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> +		return -EPERM;
>>> +
>>> 	return RPC_AUTH_UNIX;
>>> }
>>> 
>>> @@ -187,7 +198,7 @@ static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
>>> 		goto out;
>>> 	}
>>> 
>>> -	flavor = nfs_find_best_sec(flavors);
>>> +	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
>>> 
>>> out:
>>> 	put_page(page);
>>> @@ -390,7 +401,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
>>> 
>>> 	if (client->cl_auth->au_flavor != flavor)
>>> 		flavor = client->cl_auth->au_flavor;
>>> -	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
>>> +	else {
>>> 		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
>>> 		if ((int)new >= 0)
>>> 			flavor = new;
>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>>> index d2b4845..a926a39 100644
>>> --- a/fs/nfs/nfs4proc.c
>>> +++ b/fs/nfs/nfs4proc.c
>>> @@ -2864,11 +2864,22 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 	int status = -EPERM;
>>> 	size_t i;
>>> 
>>> -	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> -		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
>>> -		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> -			continue;
>>> -		break;
>>> +	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +		for (i = 0; i < server->auth_info.flavor_len; i++) {
>>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +						server->auth_info.flavors[i]);
>>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +				continue;
>>> +			break;
>>> +		}
>>> +	} else {
>>> +		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
>>> +			status = nfs4_lookup_root_sec(server, fhandle, info,
>>> +						      flav_array[i]);
>>> +			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
>>> +				continue;
>>> +			break;
>>> +		}
>>> 	}
>>> 
>>> 	/*
>>> @@ -2910,9 +2921,6 @@ int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 		status = nfs4_lookup_root(server, fhandle, info);
>>> 		if (status != -NFS4ERR_WRONGSEC)
>>> 			break;
>>> -		/* Did user force a 'sec=' mount option? */
>>> -		if (server->flags & NFS_MOUNT_SECFLAVOUR)
>>> -			break;
>>> 	default:
>>> 		status = nfs4_do_find_root_sec(server, fhandle, info);
>>> 	}
>>> @@ -3165,9 +3173,6 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
>>> 			err = -EPERM;
>>> 			if (client != *clnt)
>>> 				goto out;
>>> -			/* No security negotiation if the user specified 'sec=' */
>>> -			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
>>> -				goto out;
>>> 			client = nfs4_create_sec_client(client, dir, name);
>>> 			if (IS_ERR(client))
>>> 				return PTR_ERR(client);
>>> @@ -7617,6 +7622,9 @@ nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
>>> 			break;
>>> 		}
>>> 
>>> +		if (!nfs_auth_info_match(&server->auth_info, flavor))
>>> +			flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>> 		if (flavor != RPC_AUTH_MAXFLAVOR) {
>>> 			err = nfs4_lookup_root_sec(server, fhandle,
>>> 						   info, flavor);
>>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>>> index a03b9c6..84cf276 100644
>>> --- a/fs/nfs/super.c
>>> +++ b/fs/nfs/super.c
>>> @@ -497,7 +497,9 @@ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
>>> 	static const struct {
>>> 		rpc_authflavor_t flavour;
>>> 		const char *str;
>>> -	} sec_flavours[] = {
>>> +	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
>>> +		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
>>> +		 * changes */
>>> 		{ RPC_AUTH_NULL, "null" },
>>> 		{ RPC_AUTH_UNIX, "sys" },
>>> 		{ RPC_AUTH_GSS_KRB5, "krb5" },
>>> @@ -923,8 +925,7 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
>>> 		data->mount_server.port	= NFS_UNSPEC_PORT;
>>> 		data->nfs_server.port	= NFS_UNSPEC_PORT;
>>> 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
>>> -		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
>>> -		data->auth_flavor_len	= 0;
>>> +		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
>>> 		data->minorversion	= 0;
>>> 		data->need_mount	= true;
>>> 		data->net		= current->nsproxy->net_ns;
>>> @@ -1019,13 +1020,48 @@ static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
>>> 	}
>>> }
>>> 
>>> -static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
>>> -		rpc_authflavor_t pseudoflavor)
>>> +/*
>>> + * Add 'flavor' to 'auth_info' if not already present.
>>> + * Returns true if 'flavor' ends up in the list, false otherwise
>>> + */
>>> +static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
>>> +			      rpc_authflavor_t flavor)
>>> {
>>> -	data->auth_flavors[0] = pseudoflavor;
>>> -	data->auth_flavor_len = 1;
>>> +	unsigned int i;
>>> +	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
>>> +					sizeof(auth_info->flavors[0]));
>>> +
>>> +	/* make sure this flavor isn't already in the list */
>>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>>> +		if (flavor == auth_info->flavors[i])
>>> +			return true;
>>> +	}
>>> +
>>> +	if (auth_info->flavor_len + 1 >= max_flavor_len) {
>>> +		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
>>> +		return false;
>>> +	}
>>> +
>>> +	auth_info->flavors[auth_info->flavor_len++] = flavor;
>>> +	return true;
>>> }
>>> 
>>> +bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
>>> +			 rpc_authflavor_t match)
>>> +{
>>> +	int i;
>>> +
>>> +	if (!auth_info->flavor_len)
>>> +		return true;
>>> +
>>> +	for (i = 0; i < auth_info->flavor_len; i++) {
>>> +		if (auth_info->flavors[i] == match)
>>> +			return true;
>>> +	}
>>> +	return false;
>>> +}
>>> +EXPORT_SYMBOL_GPL(nfs_auth_info_match);
>>> +
>>> /*
>>>  * Parse the value of the 'sec=' option.
>>>  */
>>> @@ -1034,49 +1070,61 @@ static int nfs_parse_security_flavors(char *value,
>>> {
>>> 	substring_t args[MAX_OPT_ARGS];
>>> 	rpc_authflavor_t pseudoflavor;
>>> +	char *p;
>>> 
>>> 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
>>> 
>>> -	switch (match_token(value, nfs_secflavor_tokens, args)) {
>>> -	case Opt_sec_none:
>>> -		pseudoflavor = RPC_AUTH_NULL;
>>> -		break;
>>> -	case Opt_sec_sys:
>>> -		pseudoflavor = RPC_AUTH_UNIX;
>>> -		break;
>>> -	case Opt_sec_krb5:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> -		break;
>>> -	case Opt_sec_krb5i:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> -		break;
>>> -	case Opt_sec_krb5p:
>>> -		pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> -		break;
>>> -	case Opt_sec_lkey:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> -		break;
>>> -	case Opt_sec_lkeyi:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> -		break;
>>> -	case Opt_sec_lkeyp:
>>> -		pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> -		break;
>>> -	case Opt_sec_spkm:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> -		break;
>>> -	case Opt_sec_spkmi:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> -		break;
>>> -	case Opt_sec_spkmp:
>>> -		pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> -		break;
>>> -	default:
>>> -		return 0;
>>> +	while ((p = strsep(&value, ":")) != NULL) {
>>> +		switch (match_token(p, nfs_secflavor_tokens, args)) {
>>> +		case Opt_sec_none:
>>> +			pseudoflavor = RPC_AUTH_NULL;
>>> +			break;
>>> +		case Opt_sec_sys:
>>> +			pseudoflavor = RPC_AUTH_UNIX;
>>> +			break;
>>> +		case Opt_sec_krb5:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5;
>>> +			break;
>>> +		case Opt_sec_krb5i:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5I;
>>> +			break;
>>> +		case Opt_sec_krb5p:
>>> +			pseudoflavor = RPC_AUTH_GSS_KRB5P;
>>> +			break;
>>> +		case Opt_sec_lkey:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEY;
>>> +			break;
>>> +		case Opt_sec_lkeyi:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEYI;
>>> +			break;
>>> +		case Opt_sec_lkeyp:
>>> +			pseudoflavor = RPC_AUTH_GSS_LKEYP;
>>> +			break;
>>> +		case Opt_sec_spkm:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKM;
>>> +			break;
>>> +		case Opt_sec_spkmi:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKMI;
>>> +			break;
>>> +		case Opt_sec_spkmp:
>>> +			pseudoflavor = RPC_AUTH_GSS_SPKMP;
>>> +			break;
>>> +		default:
>>> +			dfprintk(MOUNT,
>>> +				 "NFS: sec= option '%s' not recognized\n", p);
>>> +			return 0;
>>> +		}
>>> +
>>> +		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
>>> +			return 0;
>>> 	}
>>> 
>>> -	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> -	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
>>> +	if (mnt->auth_info.flavor_len > 0) {
>>> +		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
>>> +		mnt->selected_flavor = mnt->auth_info.flavors[0];
>>> +	} else
>>> +		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
>>> +
>>> 	return 1;
>>> }
>>> 
>>> @@ -1623,12 +1671,14 @@ out_security_failure:
>>> }
>>> 
>>> /*
>>> - * Ensure that the specified authtype in args->auth_flavors[0] is supported by
>>> - * the server. Returns 0 if it's ok, and -EACCES if not.
>>> + * Ensure that a specified authtype in args->auth_info is supported by
>>> + * the server. Returns 0 and sets args->selected_flavor if it's ok, and
>>> + * -EACCES if not.
>>>  */
>>> -static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>> +static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
>>> 			rpc_authflavor_t *server_authlist, unsigned int count)
>>> {
>>> +	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
>>> 	unsigned int i;
>>> 
>>> 	/*
>>> @@ -1640,17 +1690,20 @@ static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
>>> 	 * can be used.
>>> 	 */
>>> 	for (i = 0; i < count; i++) {
>>> -		if (args->auth_flavors[0] == server_authlist[i] ||
>>> -		    server_authlist[i] == RPC_AUTH_NULL)
>>> +		flavor = server_authlist[i];
>>> +
>>> +		if (nfs_auth_info_match(&args->auth_info, flavor) ||
>>> +		    flavor == RPC_AUTH_NULL)
>>> 			goto out;
>>> 	}
>>> 
>>> -	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
>>> -		args->auth_flavors[0]);
>>> +	dfprintk(MOUNT,
>>> +		 "NFS: specified auth flavors not supported by server\n");
>>> 	return -EACCES;
>>> 
>>> out:
>>> -	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +	args->selected_flavor = flavor;
>>> +	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
>>> 	return 0;
>>> }
>>> 
>>> @@ -1738,9 +1791,10 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 	 * Was a sec= authflavor specified in the options? First, verify
>>> 	 * whether the server supports it, and then just try to use it if so.
>>> 	 */
>>> -	if (args->auth_flavor_len > 0) {
>>> -		status = nfs_verify_authflavor(args, authlist, authlist_len);
>>> -		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
>>> +	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
>>> +		status = nfs_verify_authflavors(args, authlist, authlist_len);
>>> +		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
>>> +			 args->selected_flavor);
>>> 		if (status)
>>> 			return ERR_PTR(status);
>>> 		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> @@ -1769,7 +1823,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 			/* Fallthrough */
>>> 		}
>>> 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>>> -		nfs_set_auth_parsed_mount_data(args, flavor);
>>> +		args->selected_flavor = flavor;
>>> 		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> 		if (!IS_ERR(server))
>>> 			return server;
>>> @@ -1785,7 +1839,7 @@ static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
>>> 
>>> 	/* Last chance! Try AUTH_UNIX */
>>> 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
>>> -	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +	args->selected_flavor = RPC_AUTH_UNIX;
>>> 	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
>>> }
>>> 
>>> @@ -1972,9 +2026,9 @@ static int nfs23_validate_mount_data(void *options,
>>> 		args->bsize		= data->bsize;
>>> 
>>> 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
>>> -			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
>>> +			args->selected_flavor = data->pseudoflavor;
>>> 		else
>>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>> 		if (!args->nfs_server.hostname)
>>> 			goto out_nomem;
>>> 
>>> @@ -2108,9 +2162,6 @@ static int nfs_validate_text_mount_data(void *options,
>>> 
>>> 	nfs_set_port(sap, &args->nfs_server.port, port);
>>> 
>>> -	if (args->auth_flavor_len > 1)
>>> -		goto out_bad_auth;
>>> -
>>> 	return nfs_parse_devname(dev_name,
>>> 				   &args->nfs_server.hostname,
>>> 				   max_namelen,
>>> @@ -2130,10 +2181,6 @@ out_invalid_transport_udp:
>>> out_no_address:
>>> 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
>>> 	return -EINVAL;
>>> -
>>> -out_bad_auth:
>>> -	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
>>> -	return -EINVAL;
>>> }
>>> 
>>> static int
>>> @@ -2144,7 +2191,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
>>> 	    data->rsize != nfss->rsize ||
>>> 	    data->wsize != nfss->wsize ||
>>> 	    data->retrans != nfss->client->cl_timeout->to_retries ||
>>> -	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
>>> +	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
>>> 	    data->acregmin != nfss->acregmin / HZ ||
>>> 	    data->acregmax != nfss->acregmax / HZ ||
>>> 	    data->acdirmin != nfss->acdirmin / HZ ||
>>> @@ -2189,7 +2236,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
>>> 	data->rsize = nfss->rsize;
>>> 	data->wsize = nfss->wsize;
>>> 	data->retrans = nfss->client->cl_timeout->to_retries;
>>> -	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
>>> +	data->selected_flavor = nfss->client->cl_auth->au_flavor;
>>> +	data->auth_info = nfss->auth_info;
>>> 	data->acregmin = nfss->acregmin / HZ;
>>> 	data->acregmax = nfss->acregmax / HZ;
>>> 	data->acdirmin = nfss->acdirmin / HZ;
>>> @@ -2713,9 +2761,9 @@ static int nfs4_validate_mount_data(void *options,
>>> 					   data->auth_flavours,
>>> 					   sizeof(pseudoflavor)))
>>> 				return -EFAULT;
>>> -			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
>>> +			args->selected_flavor = pseudoflavor;
>>> 		} else
>>> -			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
>>> +			args->selected_flavor = RPC_AUTH_UNIX;
>>> 
>>> 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
>>> 		if (IS_ERR(c))
>>> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
>>> index f9c0a6c..b2c3b82 100644
>>> --- a/include/linux/nfs_fs_sb.h
>>> +++ b/include/linux/nfs_fs_sb.h
>>> @@ -149,6 +149,7 @@ struct nfs_server {
>>> 	struct timespec		time_delta;	/* smallest time granularity */
>>> 	unsigned long		mount_time;	/* when this fs was mounted */
>>> 	dev_t			s_dev;		/* superblock dev numbers */
>>> +	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
>>> 
>>> #ifdef CONFIG_NFS_FSCACHE
>>> 	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
>>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
>>> index 49f52c8..488ce9d 100644
>>> --- a/include/linux/nfs_xdr.h
>>> +++ b/include/linux/nfs_xdr.h
>>> @@ -591,6 +591,13 @@ struct nfs_renameres {
>>> 	struct nfs_fattr		*new_fattr;
>>> };
>>> 
>>> +/* parsed sec= options */
>>> +#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
>>> +struct nfs_auth_info {
>>> +	unsigned int            flavor_len;
>>> +	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
>>> +};
>>> +
>>> /*
>>>  * Argument struct for decode_entry function
>>>  */
>>> --
>>> 1.7.12.4 (Apple Git-37)
>>> 
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>>> the body of a message to [e-mail]
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to [e-mail]
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [e-mail]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Frank Filz Oct. 14, 2013, 3:18 p.m. UTC | #9

> >>> I wrote a script to verify that I haven't broken anything, it tests
> >>> all vers= and sec= combinations against a server with the exports:
> >>
> >> Is the script something that could be added to Anna's or my regular
> >> regression testing?
> >
> > I looked over the script Friday and I don't think it'll be too
> > difficult to work in to my Jenkins stuff :)
> 
> I have a new copy of the script that allows (almost) everything to be
passed
> in as an environment variable.
> 
> I'll hand that off to you later today.

Is this script something that would work well with Linux client against an
arbitrary server? We will eventually need to test the security negotiation
stuff with Ganesha.

Frank


--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 14, 2013, 3:23 p.m. UTC | #10

On Oct 14, 2013, at 11:18 AM, Frank Filz <[e-mail]> wrote:

>>>>> I wrote a script to verify that I haven't broken anything, it tests
>>>>> all vers= and sec= combinations against a server with the exports:
>>>> 
>>>> Is the script something that could be added to Anna's or my regular
>>>> regression testing?
>>> 
>>> I looked over the script Friday and I don't think it'll be too
>>> difficult to work in to my Jenkins stuff :)
>> 
>> I have a new copy of the script that allows (almost) everything to be
> passed
>> in as an environment variable.
>> 
>> I'll hand that off to you later today.
> 
> Is this script something that would work well with Linux client against an
> arbitrary server? We will eventually need to test the security negotiation
> stuff with Ganesha.
> 
> Frank
> 
> 

Yes, this script should work well for you. We'll make sure that it's easy to run as a standalone thing too.

-dros--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Frank Filz Oct. 14, 2013, 3:25 p.m. UTC | #11

> -----Original Message-----
> From: Weston Andros Adamson [mailto:[e-mail]]
> Sent: Monday, October 14, 2013 8:23 AM
> To: Frank Filz
> Cc: Anna Schumaker; J. Bruce Fields; Myklebust, Trond; <linux-
> [e-mail]>; Ganesha NFS List
> Subject: Re: [PATCH] NFS: Add support for multiple sec= mount options
> 
> On Oct 14, 2013, at 11:18 AM, Frank Filz <[e-mail]> wrote:
> 
> >>>>> I wrote a script to verify that I haven't broken anything, it
> >>>>> tests all vers= and sec= combinations against a server with the
> exports:
> >>>>
> >>>> Is the script something that could be added to Anna's or my regular
> >>>> regression testing?
> >>>
> >>> I looked over the script Friday and I don't think it'll be too
> >>> difficult to work in to my Jenkins stuff :)
> >>
> >> I have a new copy of the script that allows (almost) everything to be
> > passed
> >> in as an environment variable.
> >>
> >> I'll hand that off to you later today.
> >
> > Is this script something that would work well with Linux client
> > against an arbitrary server? We will eventually need to test the
> > security negotiation stuff with Ganesha.
> >
> > Frank
> >
> >
> 
> Yes, this script should work well for you. We'll make sure that it's easy
to run
> as a standalone thing too.

Cool, thanks.

Frank

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Weston Andros Adamson Oct. 16, 2013, 10:07 p.m. UTC | #12

-dros

On Oct 16, 2013, at 4:36 PM, "Myklebust, Trond" <[e-mail]> wrote:

> On Fri, 2013-10-11 at 14:44 -0400, Weston Andros Adamson wrote:
>> This patch adds support for multiple security options which can be
>> specified using a colon-delimited list of security flavors (the same
>> syntax as nfsd's exports file).
>> 
>> This is useful, for instance, when NFSv4.x mounts cross SECINFO
>> boundaries. With this patch a user can use "sec=krb5i,krb5p"
>> to mount a remote filesystem using krb5i, but can still cross
>> into krb5p-only exports.
>> 
>> New mounts will try all security options before failing.  NFSv4.x
>> SECINFO results will be compared against the sec= flavors to
>> find the first flavor in both lists or if no match is found will
>> return EPERM.
>> 
>> This patch cleans up some of the auth flavor logic by separating
>> the parsed mount options from the currently selected flavor and
>> sharing more code between the 'no sec= specified' and 'sec= specified'
>> code paths.
>> 
>> Along with this patch I'm posting a patch to nfs-util's nfs.man to
>> reflect these changes.
>> 
>> I wrote a script to verify that I haven't broken anything, it tests
>> all vers= and sec= combinations against a server with the exports:
>> 
>> /export/sys       *(sec=sys,rw,no_root_squash)
>> /export/krb5a     *(sec=krb5,rw,no_root_squash)
>> /export/krb5i     *(sec=krb5i,rw,no_root_squash)
>> /export/krb5p     *(sec=krb5p,rw,no_root_squash)
>> /export/krb5ip    *(sec=krb5i:krb5p,rw,no_root_squash)
>> /export/krb5aip   *(sec=krb5:krb5i:krb5p,rw,no_root_squash)
>> 
>> The script runs these tests against all exports, and the versions NFSv3,
>> v4.0, v4.1:
>> - no sec= options
>> - all single sec= options
>> - all combinations of multiple sec= options
>> - no sec= SECINFO (mount / then ls export dir, v4.x only)
>> - single sec= SECINFO (mount / then ls export dir, v4.x only)
>> - all combinations of multiple sec= SECINFO (mount / then ls export dir,
>>    v4.x only)
>> 
>> Signed-off-by: Weston Andros Adamson <[e-mail]>
> 
> Can you please split this up? It seems to me that there are at least 3
> patches here:
> 
>     1. Refactor code to introduce struct nfs_auth_info
>     2. Cache struct nfs_auth_info in struct nfs_server
>     3. Extend the mount code to allow multiple auth flavours in the
>        'sec=' mount options

Sounds good.

-dros

> 
> Thanks
>  Trond
> 
> -- 
> Trond Myklebust
> Linux NFS client maintainer
> 
> NetApp
> [e-mail]
> www.netapp.com

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index af03258..006fd52 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -786,8 +786,10 @@  static int nfs_init_server(struct nfs_server *server,
 		goto error;
 
 	server->port = data->nfs_server.port;
+	server->auth_info = data->auth_info;
 
-	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);
+	error = nfs_init_server_rpcclient(server, &timeparms,
+					  data->selected_flavor);
 	if (error < 0)
 		goto error;
 
@@ -928,6 +930,7 @@  void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *sour
 	target->acdirmax = source->acdirmax;
 	target->caps = source->caps;
 	target->options = source->options;
+	target->auth_info = source->auth_info;
 }
 EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
 
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 38da8c2..5c9cfe0 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -88,8 +88,8 @@  struct nfs_parsed_mount_data {
 	unsigned int		namlen;
 	unsigned int		options;
 	unsigned int		bsize;
-	unsigned int		auth_flavor_len;
-	rpc_authflavor_t	auth_flavors[1];
+	struct nfs_auth_info    auth_info;
+	rpc_authflavor_t        selected_flavor;
 	char			*client_address;
 	unsigned int		version;
 	unsigned int		minorversion;
@@ -323,6 +323,7 @@  extern struct file_system_type nfs_xdev_fs_type;
 extern struct file_system_type nfs4_xdev_fs_type;
 extern struct file_system_type nfs4_referral_fs_type;
 #endif
+bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);
 struct dentry *nfs_try_mount(int, const char *, struct nfs_mount_info *,
 			struct nfs_subversion *);
 void nfs_initialise_sb(struct super_block *);
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 28842ab..cffed27 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -213,7 +213,6 @@  int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
 extern struct file_system_type nfs4_fs_type;
 
 /* nfs4namespace.c */
-rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
 struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
 			       struct nfs_fh *, struct nfs_fattr *);
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 511cdce..b446314 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -962,9 +962,13 @@  static int nfs4_init_server(struct nfs_server *server,
 	/* Initialise the client representation from the mount data */
 	server->flags = data->flags;
 	server->options = data->options;
+	server->auth_info = data->auth_info;
 
-	if (data->auth_flavor_len >= 1)
-		pseudoflavor = data->auth_flavors[0];
+	/* Use the first specified auth flavor. If this flavor isn't
+	 * allowed by the server, use the SECINFO path to try the
+	 * other specified flavors */
+	if (data->auth_info.flavor_len >= 1)
+		pseudoflavor = data->auth_info.flavors[0];
 
 	/* Get a client record */
 	error = nfs4_set_client(server,
@@ -1019,7 +1023,7 @@  struct nfs_server *nfs4_create_server(struct nfs_mount_info *mount_info,
 	if (!server)
 		return ERR_PTR(-ENOMEM);
 
-	auth_probe = mount_info->parsed->auth_flavor_len < 1;
+	auth_probe = mount_info->parsed->auth_info.flavor_len < 1;
 
 	/* set up the general RPC client */
 	error = nfs4_init_server(server, mount_info->parsed);
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 2288cd3..caaa7aa 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -137,15 +137,18 @@  static size_t nfs_parse_server_name(char *string, size_t len,
 
 /**
  * nfs_find_best_sec - Find a security mechanism supported locally
+ * @server:  Nfs server structure
  * @flavors: List of security tuples returned by SECINFO procedure
  *
  * Return the pseudoflavor of the first security mechanism in
- * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
+ * "flavors" that is locally supported and in the sec= mount
+ * options if any were specified.  Return RPC_AUTH_UNIX if
  * no matching flavor is found in the array.  The "flavors" array
  * is searched in the order returned from the server, per RFC 3530
  * recommendation.
  */
-rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
+static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
+					  struct nfs4_secinfo_flavors *flavors)
 {
 	rpc_authflavor_t pseudoflavor;
 	struct nfs4_secinfo4 *secinfo;
@@ -160,12 +163,20 @@  rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
 		case RPC_AUTH_GSS:
 			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
 							&secinfo->flavor_info);
-			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
+
+			/* make sure pseudoflavor matches sec= mount opt */
+			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
+			    nfs_auth_info_match(&server->auth_info,
+						pseudoflavor))
 				return pseudoflavor;
 			break;
 		}
 	}
 
+	/* if there were any sec= options then nothing matched */
+	if (server->flags & NFS_MOUNT_SECFLAVOUR)
+		return -EPERM;
+
 	return RPC_AUTH_UNIX;
 }
 
@@ -187,7 +198,7 @@  static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr
 		goto out;
 	}
 
-	flavor = nfs_find_best_sec(flavors);
+	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
 
 out:
 	put_page(page);
@@ -390,7 +401,7 @@  struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
 
 	if (client->cl_auth->au_flavor != flavor)
 		flavor = client->cl_auth->au_flavor;
-	else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
+	else {
 		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
 		if ((int)new >= 0)
 			flavor = new;
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d2b4845..a926a39 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2864,11 +2864,22 @@  static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
 	int status = -EPERM;
 	size_t i;
 
-	for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
-		status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
-		if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
-			continue;
-		break;
+	if (server->flags & NFS_MOUNT_SECFLAVOUR) {
+		for (i = 0; i < server->auth_info.flavor_len; i++) {
+			status = nfs4_lookup_root_sec(server, fhandle, info,
+						server->auth_info.flavors[i]);
+			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
+				continue;
+			break;
+		}
+	} else {
+		for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
+			status = nfs4_lookup_root_sec(server, fhandle, info,
+						      flav_array[i]);
+			if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
+				continue;
+			break;
+		}
 	}
 
 	/*
@@ -2910,9 +2921,6 @@  int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
 		status = nfs4_lookup_root(server, fhandle, info);
 		if (status != -NFS4ERR_WRONGSEC)
 			break;
-		/* Did user force a 'sec=' mount option? */
-		if (server->flags & NFS_MOUNT_SECFLAVOUR)
-			break;
 	default:
 		status = nfs4_do_find_root_sec(server, fhandle, info);
 	}
@@ -3165,9 +3173,6 @@  static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
 			err = -EPERM;
 			if (client != *clnt)
 				goto out;
-			/* No security negotiation if the user specified 'sec=' */
-			if (NFS_SERVER(dir)->flags & NFS_MOUNT_SECFLAVOUR)
-				goto out;
 			client = nfs4_create_sec_client(client, dir, name);
 			if (IS_ERR(client))
 				return PTR_ERR(client);
@@ -7617,6 +7622,9 @@  nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
 			break;
 		}
 
+		if (!nfs_auth_info_match(&server->auth_info, flavor))
+			flavor = RPC_AUTH_MAXFLAVOR;
+
 		if (flavor != RPC_AUTH_MAXFLAVOR) {
 			err = nfs4_lookup_root_sec(server, fhandle,
 						   info, flavor);
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index a03b9c6..84cf276 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -497,7 +497,9 @@  static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
 	static const struct {
 		rpc_authflavor_t flavour;
 		const char *str;
-	} sec_flavours[] = {
+	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
+		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list
+		 * changes */
 		{ RPC_AUTH_NULL, "null" },
 		{ RPC_AUTH_UNIX, "sys" },
 		{ RPC_AUTH_GSS_KRB5, "krb5" },
@@ -923,8 +925,7 @@  static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
 		data->mount_server.port	= NFS_UNSPEC_PORT;
 		data->nfs_server.port	= NFS_UNSPEC_PORT;
 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
-		data->auth_flavors[0]	= RPC_AUTH_MAXFLAVOR;
-		data->auth_flavor_len	= 0;
+		data->selected_flavor	= RPC_AUTH_MAXFLAVOR;
 		data->minorversion	= 0;
 		data->need_mount	= true;
 		data->net		= current->nsproxy->net_ns;
@@ -1019,13 +1020,48 @@  static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
 	}
 }
 
-static void nfs_set_auth_parsed_mount_data(struct nfs_parsed_mount_data *data,
-		rpc_authflavor_t pseudoflavor)
+/*
+ * Add 'flavor' to 'auth_info' if not already present.
+ * Returns true if 'flavor' ends up in the list, false otherwise
+ */
+static bool nfs_auth_info_add(struct nfs_auth_info *auth_info,
+			      rpc_authflavor_t flavor)
 {
-	data->auth_flavors[0] = pseudoflavor;
-	data->auth_flavor_len = 1;
+	unsigned int i;
+	unsigned int max_flavor_len = (sizeof(auth_info->flavors) /
+					sizeof(auth_info->flavors[0]));
+
+	/* make sure this flavor isn't already in the list */
+	for (i = 0; i < auth_info->flavor_len; i++) {
+		if (flavor == auth_info->flavors[i])
+			return true;
+	}
+
+	if (auth_info->flavor_len + 1 >= max_flavor_len) {
+		dfprintk(MOUNT, "NFS: too many sec= flavors\n");
+		return false;
+	}
+
+	auth_info->flavors[auth_info->flavor_len++] = flavor;
+	return true;
 }
 
+bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
+			 rpc_authflavor_t match)
+{
+	int i;
+
+	if (!auth_info->flavor_len)
+		return true;
+
+	for (i = 0; i < auth_info->flavor_len; i++) {
+		if (auth_info->flavors[i] == match)
+			return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(nfs_auth_info_match);
+
 /*
  * Parse the value of the 'sec=' option.
  */
@@ -1034,49 +1070,61 @@  static int nfs_parse_security_flavors(char *value,
 {
 	substring_t args[MAX_OPT_ARGS];
 	rpc_authflavor_t pseudoflavor;
+	char *p;
 
 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
 
-	switch (match_token(value, nfs_secflavor_tokens, args)) {
-	case Opt_sec_none:
-		pseudoflavor = RPC_AUTH_NULL;
-		break;
-	case Opt_sec_sys:
-		pseudoflavor = RPC_AUTH_UNIX;
-		break;
-	case Opt_sec_krb5:
-		pseudoflavor = RPC_AUTH_GSS_KRB5;
-		break;
-	case Opt_sec_krb5i:
-		pseudoflavor = RPC_AUTH_GSS_KRB5I;
-		break;
-	case Opt_sec_krb5p:
-		pseudoflavor = RPC_AUTH_GSS_KRB5P;
-		break;
-	case Opt_sec_lkey:
-		pseudoflavor = RPC_AUTH_GSS_LKEY;
-		break;
-	case Opt_sec_lkeyi:
-		pseudoflavor = RPC_AUTH_GSS_LKEYI;
-		break;
-	case Opt_sec_lkeyp:
-		pseudoflavor = RPC_AUTH_GSS_LKEYP;
-		break;
-	case Opt_sec_spkm:
-		pseudoflavor = RPC_AUTH_GSS_SPKM;
-		break;
-	case Opt_sec_spkmi:
-		pseudoflavor = RPC_AUTH_GSS_SPKMI;
-		break;
-	case Opt_sec_spkmp:
-		pseudoflavor = RPC_AUTH_GSS_SPKMP;
-		break;
-	default:
-		return 0;
+	while ((p = strsep(&value, ":")) != NULL) {
+		switch (match_token(p, nfs_secflavor_tokens, args)) {
+		case Opt_sec_none:
+			pseudoflavor = RPC_AUTH_NULL;
+			break;
+		case Opt_sec_sys:
+			pseudoflavor = RPC_AUTH_UNIX;
+			break;
+		case Opt_sec_krb5:
+			pseudoflavor = RPC_AUTH_GSS_KRB5;
+			break;
+		case Opt_sec_krb5i:
+			pseudoflavor = RPC_AUTH_GSS_KRB5I;
+			break;
+		case Opt_sec_krb5p:
+			pseudoflavor = RPC_AUTH_GSS_KRB5P;
+			break;
+		case Opt_sec_lkey:
+			pseudoflavor = RPC_AUTH_GSS_LKEY;
+			break;
+		case Opt_sec_lkeyi:
+			pseudoflavor = RPC_AUTH_GSS_LKEYI;
+			break;
+		case Opt_sec_lkeyp:
+			pseudoflavor = RPC_AUTH_GSS_LKEYP;
+			break;
+		case Opt_sec_spkm:
+			pseudoflavor = RPC_AUTH_GSS_SPKM;
+			break;
+		case Opt_sec_spkmi:
+			pseudoflavor = RPC_AUTH_GSS_SPKMI;
+			break;
+		case Opt_sec_spkmp:
+			pseudoflavor = RPC_AUTH_GSS_SPKMP;
+			break;
+		default:
+			dfprintk(MOUNT,
+				 "NFS: sec= option '%s' not recognized\n", p);
+			return 0;
+		}
+
+		if (!nfs_auth_info_add(&mnt->auth_info, pseudoflavor))
+			return 0;
 	}
 
-	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
-	nfs_set_auth_parsed_mount_data(mnt, pseudoflavor);
+	if (mnt->auth_info.flavor_len > 0) {
+		mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+		mnt->selected_flavor = mnt->auth_info.flavors[0];
+	} else
+		mnt->selected_flavor = RPC_AUTH_MAXFLAVOR;
+
 	return 1;
 }
 
@@ -1623,12 +1671,14 @@  out_security_failure:
 }
 
 /*
- * Ensure that the specified authtype in args->auth_flavors[0] is supported by
- * the server. Returns 0 if it's ok, and -EACCES if not.
+ * Ensure that a specified authtype in args->auth_info is supported by
+ * the server. Returns 0 and sets args->selected_flavor if it's ok, and
+ * -EACCES if not.
  */
-static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
+static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
 			rpc_authflavor_t *server_authlist, unsigned int count)
 {
+	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
 	unsigned int i;
 
 	/*
@@ -1640,17 +1690,20 @@  static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
 	 * can be used.
 	 */
 	for (i = 0; i < count; i++) {
-		if (args->auth_flavors[0] == server_authlist[i] ||
-		    server_authlist[i] == RPC_AUTH_NULL)
+		flavor = server_authlist[i];
+
+		if (nfs_auth_info_match(&args->auth_info, flavor) ||
+		    flavor == RPC_AUTH_NULL)
 			goto out;
 	}
 
-	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
-		args->auth_flavors[0]);
+	dfprintk(MOUNT,
+		 "NFS: specified auth flavors not supported by server\n");
 	return -EACCES;
 
 out:
-	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
+	args->selected_flavor = flavor;
+	dfprintk(MOUNT, "NFS: using auth flavor %u\n", flavor);
 	return 0;
 }
 
@@ -1738,9 +1791,10 @@  static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
 	 * Was a sec= authflavor specified in the options? First, verify
 	 * whether the server supports it, and then just try to use it if so.
 	 */
-	if (args->auth_flavor_len > 0) {
-		status = nfs_verify_authflavor(args, authlist, authlist_len);
-		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
+	if (args->flags & NFS_MOUNT_SECFLAVOUR) {
+		status = nfs_verify_authflavors(args, authlist, authlist_len);
+		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
+			 args->selected_flavor);
 		if (status)
 			return ERR_PTR(status);
 		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
@@ -1769,7 +1823,7 @@  static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
 			/* Fallthrough */
 		}
 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
-		nfs_set_auth_parsed_mount_data(args, flavor);
+		args->selected_flavor = flavor;
 		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
 		if (!IS_ERR(server))
 			return server;
@@ -1785,7 +1839,7 @@  static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_inf
 
 	/* Last chance! Try AUTH_UNIX */
 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
-	nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
+	args->selected_flavor = RPC_AUTH_UNIX;
 	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
 }
 
@@ -1972,9 +2026,9 @@  static int nfs23_validate_mount_data(void *options,
 		args->bsize		= data->bsize;
 
 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
-			nfs_set_auth_parsed_mount_data(args, data->pseudoflavor);
+			args->selected_flavor = data->pseudoflavor;
 		else
-			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
+			args->selected_flavor = RPC_AUTH_UNIX;
 		if (!args->nfs_server.hostname)
 			goto out_nomem;
 
@@ -2108,9 +2162,6 @@  static int nfs_validate_text_mount_data(void *options,
 
 	nfs_set_port(sap, &args->nfs_server.port, port);
 
-	if (args->auth_flavor_len > 1)
-		goto out_bad_auth;
-
 	return nfs_parse_devname(dev_name,
 				   &args->nfs_server.hostname,
 				   max_namelen,
@@ -2130,10 +2181,6 @@  out_invalid_transport_udp:
 out_no_address:
 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
 	return -EINVAL;
-
-out_bad_auth:
-	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
-	return -EINVAL;
 }
 
 static int
@@ -2144,7 +2191,7 @@  nfs_compare_remount_data(struct nfs_server *nfss,
 	    data->rsize != nfss->rsize ||
 	    data->wsize != nfss->wsize ||
 	    data->retrans != nfss->client->cl_timeout->to_retries ||
-	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
+	    data->selected_flavor != nfss->client->cl_auth->au_flavor ||
 	    data->acregmin != nfss->acregmin / HZ ||
 	    data->acregmax != nfss->acregmax / HZ ||
 	    data->acdirmin != nfss->acdirmin / HZ ||
@@ -2189,7 +2236,8 @@  nfs_remount(struct super_block *sb, int *flags, char *raw_data)
 	data->rsize = nfss->rsize;
 	data->wsize = nfss->wsize;
 	data->retrans = nfss->client->cl_timeout->to_retries;
-	nfs_set_auth_parsed_mount_data(data, nfss->client->cl_auth->au_flavor);
+	data->selected_flavor = nfss->client->cl_auth->au_flavor;
+	data->auth_info = nfss->auth_info;
 	data->acregmin = nfss->acregmin / HZ;
 	data->acregmax = nfss->acregmax / HZ;
 	data->acdirmin = nfss->acdirmin / HZ;
@@ -2713,9 +2761,9 @@  static int nfs4_validate_mount_data(void *options,
 					   data->auth_flavours,
 					   sizeof(pseudoflavor)))
 				return -EFAULT;
-			nfs_set_auth_parsed_mount_data(args, pseudoflavor);
+			args->selected_flavor = pseudoflavor;
 		} else
-			nfs_set_auth_parsed_mount_data(args, RPC_AUTH_UNIX);
+			args->selected_flavor = RPC_AUTH_UNIX;
 
 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
 		if (IS_ERR(c))
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index f9c0a6c..b2c3b82 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -149,6 +149,7 @@  struct nfs_server {
 	struct timespec		time_delta;	/* smallest time granularity */
 	unsigned long		mount_time;	/* when this fs was mounted */
 	dev_t			s_dev;		/* superblock dev numbers */
+	struct nfs_auth_info	auth_info;	/* allowed auth flavors */
 
 #ifdef CONFIG_NFS_FSCACHE
 	struct nfs_fscache_key	*fscache_key;	/* unique key for superblock */
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 49f52c8..488ce9d 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -591,6 +591,13 @@  struct nfs_renameres {
 	struct nfs_fattr		*new_fattr;
 };
 
+/* parsed sec= options */
+#define NFS_AUTH_INFO_MAX_FLAVORS 12 /* see fs/nfs/super.c */
+struct nfs_auth_info {
+	unsigned int            flavor_len;
+	rpc_authflavor_t        flavors[NFS_AUTH_INFO_MAX_FLAVORS];
+};
+
 /*
  * Argument struct for decode_entry function
  */