From patchwork Sat Apr 2 18:24:48 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shirish Pargaonkar X-Patchwork-Id: 683841 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p32ILQbU030277 for ; Sat, 2 Apr 2011 18:21:27 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756275Ab1DBSVT (ORCPT ); Sat, 2 Apr 2011 14:21:19 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:55601 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756373Ab1DBSVS (ORCPT ); Sat, 2 Apr 2011 14:21:18 -0400 Received: by mail-iy0-f174.google.com with SMTP id 14so4599968iyb.19 for ; Sat, 02 Apr 2011 11:21:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:from:to:cc:subject:date:message-id:x-mailer; bh=KNg+PhaxSdJnOBVC5XJ1idkhtOC2rgnS9kUjH7HMsvw=; b=fBEvZPA7wuwoNcg8abok7KiSlizFvJF0C3IJbLDwVAV/xgt+35roGx2Bq5516dWkVy j0yVTWpxxrqh9qF62XhWYvwGa4Dwj32xsOh5H5HnJvd6veuzEN/amtJokG6hFeJHbUpT PGCnIrlFRVW00G/8Tv3SGcrBcfoRstnmzU0dA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer; b=eKaY93eXPUxIUfdlfOm69uI1q1BwuSSrDOE0+hfWAOV0JaAyrx6FphPIm533saT+Rm h2oypTjLUQAHo1AIpBCFMvF+uY4abLaPbXlCrpnL2mvZ9uf073qs5bN1bnABsWJATome LKg5mJZyAHTqQwaOsipw7R8jon7DPmGhCZuZU= Received: by 10.42.108.137 with SMTP id h9mr1580288icp.112.1301768478078; Sat, 02 Apr 2011 11:21:18 -0700 (PDT) Received: from localhost ([32.97.110.58]) by mx.google.com with ESMTPS id gy41sm2362442ibb.22.2011.04.02.11.21.16 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 02 Apr 2011 11:21:17 -0700 (PDT) From: shirishpargaonkar@gmail.com To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, Shirish Pargaonkar Subject: [PATCH 2/2] cifs: Invoke id mapping functions (try #12) Date: Sat, 2 Apr 2011 13:24:48 -0500 Message-Id: <1301768688-23867-1-git-send-email-shirishpargaonkar@gmail.com> X-Mailer: git-send-email 1.6.0.2 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Sat, 02 Apr 2011 18:21:27 +0000 (UTC) From: Shirish Pargaonkar rb tree search and insertion routines. A SID which needs to be mapped, is looked up in one of the rb trees depending whether SID is either owner or group SID. If found in the tree, a (mapped) id from that node is assigned to uid or gid as appropriate. If unmapped, an upcall is attempted to map the SID to an id. If upcall is successful, node is marked as mapped. If upcall fails, node stays marked as unmapped and a mapping is attempted again only after an arbitrary time period has passed. To map a SID, which can be either a Owner SID or a Group SID, key description starts with the string "os" or "gs" followed by SID converted to a string. Without "os" or "gs", cifs.upcall does not know whether SID needs to be mapped to either an uid or a gid. Nodes in rb tree as fields to prevent multiple upcalls for a SID. Adding and removing nodes is done within global locks. shrinker routine does not prune a node if mapping for that node is either pending or or node was recently created (before timeout period expires and node could be purged). The timeout period should be long enough at least for an upcall to return back to cifs. For now, cifs.upcall is only used to map a SID to an id (uid or gid) but it would be used to obtain an SID (string) for an id. Signed-off-by: Shirish Pargaonkar --- fs/cifs/cifsacl.c | 300 ++++++++++++++++++++++++++++++++++++++++++++++++----- fs/cifs/cifsacl.h | 24 +++++ 2 files changed, 300 insertions(+), 24 deletions(-) diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index c60bb90..b7489a0 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -54,7 +54,30 @@ static const struct cifs_sid sid_authusers = { /* group users */ static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} }; -static const struct cred *root_cred; +const struct cred *root_cred; + +static void +shrink_idmap_tree(struct rb_root *root, int nr_to_scan, int *nr_rem, + int *nr_del) +{ + struct rb_node *node; + struct rb_node *tmp; + struct cifs_sid_id *psidid; + + node = rb_first(root); + while (node) { + tmp = node; + node = rb_next(tmp); + psidid = rb_entry(tmp, struct cifs_sid_id, rbnode); + if (time_after(psidid->time + SID_MAP_EXPIRE, jiffies) || + (nr_to_scan == 0) || (*nr_del == nr_to_scan)) + ++(*nr_rem); + else { + rb_erase(tmp, root); + ++(*nr_del); + } + } +} /* * Run idmap cache shrinker. @@ -62,9 +85,21 @@ static const struct cred *root_cred; static int cifs_idmap_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask) { - /* Use a pruning scheme in a subsequent patch instead */ - cifs_destroy_idmaptrees(); - return 0; + int nr_del = 0; + int nr_rem = 0; + struct rb_root *root; + + root = &uidtree; + spin_lock(&siduidlock); + shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del); + spin_unlock(&siduidlock); + + root = &gidtree; + spin_lock(&sidgidlock); + shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del); + spin_unlock(&sidgidlock); + + return nr_rem; } static struct shrinker cifs_shrinker = { @@ -92,7 +127,6 @@ cifs_idmap_key_destroy(struct key *key) kfree(key->payload.data); } -static struct key_type cifs_idmap_key_type = { .name = "cifs.cifs_idmap", .instantiate = cifs_idmap_key_instantiate, @@ -101,6 +135,198 @@ struct key_type cifs_idmap_key_type = { .match = user_match, }; +static void +sid_to_str(struct cifs_sid *sidptr, char *sidstr) +{ + int i; + unsigned long saval; + char *strptr; + + strptr = sidstr; + + sprintf(strptr, "%s", "S"); + strptr = sidstr + strlen(sidstr); + + sprintf(strptr, "-%d", sidptr->revision); + strptr = sidstr + strlen(sidstr); + + for (i = 0; i < 6; ++i) { + if (sidptr->authority[i]) { + sprintf(strptr, "-%d", sidptr->authority[i]); + strptr = sidstr + strlen(sidstr); + } + } + + for (i = 0; i < sidptr->num_subauth; ++i) { + saval = le32_to_cpu(sidptr->sub_auth[i]); + sprintf(strptr, "-%ld", saval); + strptr = sidstr + strlen(sidstr); + } +} + +static void +id_rb_insert(struct rb_root *root, struct cifs_sid *sidptr, + struct cifs_sid_id **psidid, char *typestr) +{ + int rc; + char *strptr; + struct rb_node *node = root->rb_node; + struct rb_node *parent = NULL; + struct rb_node **linkto = &(root->rb_node); + struct cifs_sid_id *lsidid; + + while (node) { + lsidid = rb_entry(node, struct cifs_sid_id, rbnode); + parent = node; + rc = compare_sids(sidptr, &((lsidid)->sid)); + if (rc > 0) { + linkto = &(node->rb_left); + node = node->rb_left; + } else if (rc < 0) { + linkto = &(node->rb_right); + node = node->rb_right; + } + } + + memcpy(&(*psidid)->sid, sidptr, sizeof(struct cifs_sid)); + (*psidid)->time = jiffies; + (*psidid)->retry = jiffies - (SID_MAP_RETRY + 1); + + sprintf((*psidid)->sidstr, "%s", typestr); + strptr = (*psidid)->sidstr + strlen((*psidid)->sidstr); + sid_to_str(&(*psidid)->sid, strptr); + + clear_bit(SID_ID_PENDING, &(*psidid)->state); + clear_bit(SID_ID_MAPPED, &(*psidid)->state); + + rb_link_node(&(*psidid)->rbnode, parent, linkto); + rb_insert_color(&(*psidid)->rbnode, root); +} + +static struct cifs_sid_id * +id_rb_search(struct rb_root *root, struct cifs_sid *sidptr) +{ + int rc; + struct rb_node *node = root->rb_node; + struct rb_node *parent = NULL; + struct rb_node **linkto = &(root->rb_node); + struct cifs_sid_id *lsidid; + + while (node) { + lsidid = rb_entry(node, struct cifs_sid_id, rbnode); + parent = node; + rc = compare_sids(sidptr, &((lsidid)->sid)); + if (rc > 0) { + linkto = &(node->rb_left); + node = node->rb_left; + } else if (rc < 0) { + linkto = &(node->rb_right); + node = node->rb_right; + } else /* node found */ + return lsidid; + } + + return NULL; +} + +static int +sidid_pending_wait(void *unused) +{ + schedule(); + return signal_pending(current) ? -ERESTARTSYS : 0; +} + +static int +sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid, + struct cifs_fattr *fattr, uint sidtype) +{ + int rc; + unsigned long cid; + struct key *idkey; + const struct cred *saved_cred; + struct cifs_sid_id *psidid, *npsidid; + struct rb_root *cidtree; + spinlock_t *cidlock; + + if (sidtype == SIDOWNER) { + cid = cifs_sb->mnt_uid; /* default uid, in case upcall fails */ + cidlock = &siduidlock; + cidtree = &uidtree; + } else if (sidtype == SIDGROUP) { + cid = cifs_sb->mnt_gid; /* default gid, in case upcall fails */ + cidlock = &sidgidlock; + cidtree = &gidtree; + } else + return -ENOENT; + + spin_lock(cidlock); + psidid = id_rb_search(cidtree, psid); + spin_unlock(cidlock); + + if (!psidid) { /* node does not exist, allocate one & attempt adding */ + npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL); + if (!npsidid) + return -ENOMEM; + + npsidid->sidstr = kmalloc(SIDLEN, GFP_KERNEL); + if (!npsidid->sidstr) { + kfree(npsidid); + return -ENOMEM; + } + + spin_lock(cidlock); + psidid = id_rb_search(cidtree, psid); + if (psidid) { /* node happened to get inserted meanwhile */ + spin_unlock(cidlock); + kfree(npsidid->sidstr); + kfree(npsidid); + } else { + psidid = npsidid; + id_rb_insert(cidtree, psid, &psidid, + sidtype == SIDOWNER ? "os:" : "gs:"); + spin_unlock(cidlock); + } + } + + if (test_bit(SID_ID_MAPPED, &psidid->state)) + goto sid_to_id_out; /* SID mapped */ + if (time_after(psidid->retry + SID_MAP_RETRY, jiffies)) + goto sid_to_id_out; /* wait before re-attempting SID mapping */ + if (!test_and_set_bit(SID_ID_PENDING, &psidid->state)) { + saved_cred = override_creds(root_cred); + idkey = request_key(&cifs_idmap_key_type, psidid->sidstr, ""); + if (IS_ERR(idkey)) { + psidid->id = cid; + psidid->retry = jiffies; + cFYI(1, "%s: Can't map SID to an id", __func__); + } else { + psidid->id = *(unsigned long *)idkey->payload.value; + set_bit(SID_ID_MAPPED, &psidid->state); + key_put(idkey); + kfree(psidid->sidstr); + } + revert_creds(saved_cred); + clear_bit(SID_ID_PENDING, &psidid->state); + wake_up_bit(&psidid->state, SID_ID_PENDING); + } else { + rc = wait_on_bit(&psidid->state, SID_ID_PENDING, + sidid_pending_wait, TASK_INTERRUPTIBLE); + if (rc) { + cFYI(1, "%s: sidid_pending_wait interrupted %d", + __func__, rc); + return rc; + } + } + +sid_to_id_out: + if (sidtype == SIDOWNER) + fattr->cf_uid = psidid->id; + else + fattr->cf_gid = psidid->id; + + return 0; +} + int init_cifs_idmap(void) { @@ -242,16 +468,24 @@ int compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid) int num_subauth, num_sat, num_saw; if ((!ctsid) || (!cwsid)) - return 0; + return 1; /* compare the revision */ - if (ctsid->revision != cwsid->revision) - return 0; + if (ctsid->revision != cwsid->revision) { + if (ctsid->revision > cwsid->revision) + return 1; + else + return -1; + } /* compare all of the six auth values */ for (i = 0; i < 6; ++i) { - if (ctsid->authority[i] != cwsid->authority[i]) - return 0; + if (ctsid->authority[i] != cwsid->authority[i]) { + if (ctsid->authority[i] > cwsid->authority[i]) + return 1; + else + return -1; + } } /* compare all of the subauth values if any */ @@ -260,12 +494,16 @@ int compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid) num_subauth = num_sat < num_saw ? num_sat : num_saw; if (num_subauth) { for (i = 0; i < num_subauth; ++i) { - if (ctsid->sub_auth[i] != cwsid->sub_auth[i]) - return 0; + if (ctsid->sub_auth[i] != cwsid->sub_auth[i]) { + if (ctsid->sub_auth[i] > cwsid->sub_auth[i]) + return 1; + else + return -1; + } } } - return 1; /* sids compare/match */ + return 0; /* sids compare/match */ } @@ -520,22 +758,22 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, #ifdef CONFIG_CIFS_DEBUG2 dump_ace(ppace[i], end_of_acl); #endif - if (compare_sids(&(ppace[i]->sid), pownersid)) + if (compare_sids(&(ppace[i]->sid), pownersid) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &user_mask); - if (compare_sids(&(ppace[i]->sid), pgrpsid)) + if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &group_mask); - if (compare_sids(&(ppace[i]->sid), &sid_everyone)) + if (compare_sids(&(ppace[i]->sid), &sid_everyone) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &other_mask); - if (compare_sids(&(ppace[i]->sid), &sid_authusers)) + if (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, @@ -613,10 +851,10 @@ static int parse_sid(struct cifs_sid *psid, char *end_of_acl) /* Convert CIFS ACL to POSIX form */ -static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len, - struct cifs_fattr *fattr) +static int parse_sec_desc(struct cifs_sb_info *cifs_sb, + struct cifs_ntsd *pntsd, int acl_len, struct cifs_fattr *fattr) { - int rc; + int rc = 0; struct cifs_sid *owner_sid_ptr, *group_sid_ptr; struct cifs_acl *dacl_ptr; /* no need for SACL ptr */ char *end_of_acl = ((char *)pntsd) + acl_len; @@ -638,12 +876,26 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len, le32_to_cpu(pntsd->sacloffset), dacloffset); /* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */ rc = parse_sid(owner_sid_ptr, end_of_acl); - if (rc) + if (rc) { + cFYI(1, "%s: Error %d parsing Owner SID", __func__, rc); + return rc; + } + rc = sid_to_id(cifs_sb, owner_sid_ptr, fattr, SIDOWNER); + if (rc) { + cFYI(1, "%s: Error %d mapping Owner SID to uid", __func__, rc); return rc; + } rc = parse_sid(group_sid_ptr, end_of_acl); - if (rc) + if (rc) { + cFYI(1, "%s: Error %d mapping Owner SID to gid", __func__, rc); return rc; + } + rc = sid_to_id(cifs_sb, group_sid_ptr, fattr, SIDGROUP); + if (rc) { + cFYI(1, "%s: Error %d mapping Group SID to gid", __func__, rc); + return rc; + } if (dacloffset) parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr, @@ -658,7 +910,7 @@ static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len, memcpy((void *)(&(cifscred->gsid)), (void *)group_sid_ptr, sizeof(struct cifs_sid)); */ - return 0; + return rc; } @@ -865,7 +1117,7 @@ cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr, rc = PTR_ERR(pntsd); cERROR(1, "%s: error %d getting sec desc", __func__, rc); } else { - rc = parse_sec_desc(pntsd, acllen, fattr); + rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr); kfree(pntsd); if (rc) cERROR(1, "parse sec desc failed rc = %d", rc); diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h index 025e943..7f25b44 100644 --- a/fs/cifs/cifsacl.h +++ b/fs/cifs/cifsacl.h @@ -39,6 +39,15 @@ #define ACCESS_ALLOWED 0 #define ACCESS_DENIED 1 +#define SIDOWNER 1 +#define SIDGROUP 2 +#define SIDLEN 150 /* S- 1 revision- 6 authorities- max 5 sub authorities */ + +#define SID_ID_MAPPED 0 +#define SID_ID_PENDING 1 +#define SID_MAP_EXPIRE 1000 /* enough for an upcall to return? */ +#define SID_MAP_RETRY 1000 /* wait for next attempt to map sid */ + struct cifs_ntsd { __le16 revision; /* revision level */ __le16 type; @@ -74,6 +83,21 @@ struct cifs_wksid { char sidname[SIDNAMELENGTH]; } __attribute__((packed)); +struct cifs_sid_id { + unsigned long id; + unsigned long time; + unsigned long retry; + unsigned long state; + char *sidstr; + struct rb_node rbnode; + struct cifs_sid sid; +}; + +#ifdef __KERNEL__ +extern struct key_type cifs_idmap_key_type; +extern const struct cred *root_cred; +#endif /* KERNEL */ + extern int match_sid(struct cifs_sid *); extern int compare_sids(const struct cifs_sid *, const struct cifs_sid *);