[cifs] smb2 mounts with signing fail due to incorrect security mode bits check

Commit Message

Jeff Layton June 27, 2013, 11:40 a.m. UTC

On Thu, 27 Jun 2013 02:55:34 -0500
Steve French <[e-mail]> wrote:

> How about this patch to fix the problem that Shirish noted? It seemed
> simple to simply map the two SMB2 flags to the older style flags that
> we check in the sec_mode.
> 
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 2b312e4..8f0a46b 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -318,6 +318,23 @@ free_rsp_buf(int resp_buftype, void *rsp)
>  		cifs_buf_release(rsp);
>  }
> 
> +/* convert smb2 sec mode to older form so can be used for both smb2 and cifs */
> +static __u16
> +convert_sec_mode(__u16 smb2_sec_mode)
> +{
> +	u16 sec_mode = 0;
> +
> +	if ((smb2_sec_mode & SMB2_SEC_MODE_MASK) != smb2_sec_mode)
> +		cifs_dbg(VFS, "srv ret unknown sec_mode 0x%x\n", smb2_sec_mode);
> +
> +	if (smb2_sec_mode & SMB2_NEGOTIATE_SIGNING_ENABLED)
> +		sec_mode |= SECMODE_SIGN_ENABLED;
> +
> +	if (smb2_sec_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED)
> +		sec_mode |= SECMODE_SIGN_REQUIRED;
> +
> +	return sec_mode;
> +}
> 
>  /*
>   *
> @@ -416,8 +433,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>  	server->maxBuf = le32_to_cpu(rsp->MaxTransactSize);
>  	server->max_read = le32_to_cpu(rsp->MaxReadSize);
>  	server->max_write = le32_to_cpu(rsp->MaxWriteSize);
> -	/* BB Do we need to validate the SecurityMode? */
> -	server->sec_mode = le16_to_cpu(rsp->SecurityMode);
> +	server->sec_mode = convert_sec_mode(le16_to_cpu(rsp->SecurityMode));
>  	server->capabilities = le32_to_cpu(rsp->Capabilities);
>  	/* Internal types */
>  	server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;
> diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
> index f31043b..c7534ee 100644
> --- a/fs/cifs/smb2pdu.h
> +++ b/fs/cifs/smb2pdu.h
> @@ -176,6 +176,7 @@ struct smb2_negotiate_req {
>  /* SecurityMode flags */
>  #define	SMB2_NEGOTIATE_SIGNING_ENABLED	0x0001
>  #define SMB2_NEGOTIATE_SIGNING_REQUIRED	0x0002
> +#define SMB2_SEC_MODE_MASK		0x0003
>  /* Capabilities flags */
>  #define SMB2_GLOBAL_CAP_DFS		0x00000001
>  #define SMB2_GLOBAL_CAP_LEASING		0x00000002 /* Resp only New to SMB2.1 */
> 

I think it would be best to try and preserve the sec_mode field as-is...

Maybe something like this (untested) patch instead?

------------------------[snip]--------------------------

[PATCH] cifs: fix SMB2 signing enablement in cifs_enable_signing

Commit 9ddec56131 (cifs: move handling of signed connections into
separate function) broke signing on SMB2/3 connections. While the code
to enable signing on the connections was very similar between the two,
the bits that get set in the sec_mode are different.

Declare a couple of new smb_version_values fields and set them
appropriately for SMB1 and SMB2/3. Then change cifs_enable_signing to
use those instead.

Reported-by: Shirish Pargaonkar <[e-mail]>
Signed-off-by: Jeff Layton <[e-mail]>
---
 fs/cifs/cifsglob.h | 2 ++
 fs/cifs/cifssmb.c  | 4 ++--
 fs/cifs/smb1ops.c  | 2 ++
 fs/cifs/smb2ops.c  | 8 ++++++++
 4 files changed, 14 insertions(+), 2 deletions(-)

Patch

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b0f077e..e66b088 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -387,6 +387,8 @@  struct smb_version_values {
 	unsigned int	cap_nt_find;
 	unsigned int	cap_large_files;
 	unsigned int	oplock_read;
+	__u16		signing_enabled;
+	__u16		signing_required;
 };
 
 #define HEADER_SIZE(server) (server->vals->header_size)
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index a35aad2..bc7dfa8 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -407,8 +407,8 @@  decode_ext_sec_blob(struct cifs_ses *ses, NEGOTIATE_RSP *pSMBr)
 int
 cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
 {
-	bool srv_sign_required = server->sec_mode & SECMODE_SIGN_REQUIRED;
-	bool srv_sign_enabled = server->sec_mode & SECMODE_SIGN_ENABLED;
+	bool srv_sign_required = server->sec_mode & server->vals->signing_required;
+	bool srv_sign_enabled = server->sec_mode & server->vals->signing_enabled;
 	bool mnt_sign_enabled = global_secflags & CIFSSEC_MAY_SIGN;
 
 	/*
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index b28aabd..e813f04 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -957,4 +957,6 @@  struct smb_version_values smb1_values = {
 	.cap_nt_find = CAP_NT_SMBS | CAP_NT_FIND,
 	.cap_large_files = CAP_LARGE_FILES,
 	.oplock_read = OPLOCK_READ,
+	.signing_enabled = SECMODE_SIGN_ENABLED,
+	.signing_required = SECMODE_SIGN_REQUIRED,
 };
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 48fe7c4..e81c509 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -729,6 +729,8 @@  struct smb_version_values smb20_values = {
 	.cap_nt_find = SMB2_NT_FIND,
 	.cap_large_files = SMB2_LARGE_FILES,
 	.oplock_read = SMB2_OPLOCK_LEVEL_II,
+	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED,
+	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
 };
 
 struct smb_version_values smb21_values = {
@@ -747,6 +749,8 @@  struct smb_version_values smb21_values = {
 	.cap_nt_find = SMB2_NT_FIND,
 	.cap_large_files = SMB2_LARGE_FILES,
 	.oplock_read = SMB2_OPLOCK_LEVEL_II,
+	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED,
+	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
 };
 
 struct smb_version_values smb30_values = {
@@ -765,6 +769,8 @@  struct smb_version_values smb30_values = {
 	.cap_nt_find = SMB2_NT_FIND,
 	.cap_large_files = SMB2_LARGE_FILES,
 	.oplock_read = SMB2_OPLOCK_LEVEL_II,
+	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED,
+	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
 };
 
 struct smb_version_values smb302_values = {
@@ -783,4 +789,6 @@  struct smb_version_values smb302_values = {
 	.cap_nt_find = SMB2_NT_FIND,
 	.cap_large_files = SMB2_LARGE_FILES,
 	.oplock_read = SMB2_OPLOCK_LEVEL_II,
+	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED,
+	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
 };