diff options
Diffstat (limited to 'fs/cifs/cifsacl.c')
-rw-r--r-- | fs/cifs/cifsacl.c | 535 |
1 files changed, 94 insertions, 441 deletions
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index 42b3fe981a0..f4508ee4e80 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -44,128 +44,6 @@ static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} }; static 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 (nr_to_scan == 0 || *nr_del == nr_to_scan) - ++(*nr_rem); - else { - if (time_after(jiffies, psidid->time + SID_MAP_EXPIRE) - && psidid->refcount == 0) { - rb_erase(tmp, root); - ++(*nr_del); - } else - ++(*nr_rem); - } - } -} - -/* - * Run idmap cache shrinker. - */ -static int -cifs_idmap_shrinker(struct shrinker *shrink, struct shrink_control *sc) -{ - int nr_to_scan = sc->nr_to_scan; - 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); - - root = &siduidtree; - spin_lock(&uidsidlock); - shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del); - spin_unlock(&uidsidlock); - - root = &sidgidtree; - spin_lock(&gidsidlock); - shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del); - spin_unlock(&gidsidlock); - - return nr_rem; -} - -static void -sid_rb_insert(struct rb_root *root, unsigned long cid, - struct cifs_sid_id **psidid, char *typestr) -{ - 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; - if (cid > lsidid->id) { - linkto = &(node->rb_left); - node = node->rb_left; - } - if (cid < lsidid->id) { - linkto = &(node->rb_right); - node = node->rb_right; - } - } - - (*psidid)->id = cid; - (*psidid)->time = jiffies - (SID_MAP_RETRY + 1); - (*psidid)->refcount = 0; - - sprintf((*psidid)->sidstr, "%s", typestr); - strptr = (*psidid)->sidstr + strlen((*psidid)->sidstr); - sprintf(strptr, "%ld", cid); - - 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 * -sid_rb_search(struct rb_root *root, unsigned long cid) -{ - struct rb_node *node = root->rb_node; - struct cifs_sid_id *lsidid; - - while (node) { - lsidid = rb_entry(node, struct cifs_sid_id, rbnode); - if (cid > lsidid->id) - node = node->rb_left; - else if (cid < lsidid->id) - node = node->rb_right; - else /* node found */ - return lsidid; - } - - return NULL; -} - -static struct shrinker cifs_shrinker = { - .shrink = cifs_idmap_shrinker, - .seeks = DEFAULT_SEEKS, -}; - static int cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep) { @@ -195,30 +73,39 @@ static struct key_type cifs_idmap_key_type = { .match = user_match, }; -static void -sid_to_str(struct cifs_sid *sidptr, char *sidstr) +static char * +sid_to_key_str(struct cifs_sid *sidptr, unsigned int type) { - int i; + int i, len; unsigned int saval; - char *strptr; + char *sidstr, *strptr; - strptr = sidstr; + /* 3 bytes for prefix */ + sidstr = kmalloc(3 + SID_STRING_BASE_SIZE + + (SID_STRING_SUBAUTH_SIZE * sidptr->num_subauth), + GFP_KERNEL); + if (!sidstr) + return sidstr; - sprintf(strptr, "S-%hhu", sidptr->revision); - strptr = sidstr + strlen(sidstr); + strptr = sidstr; + len = sprintf(strptr, "%cs:S-%hhu", type == SIDOWNER ? 'o' : 'g', + sidptr->revision); + strptr += len; for (i = 0; i < NUM_AUTHS; ++i) { if (sidptr->authority[i]) { - sprintf(strptr, "-%hhu", sidptr->authority[i]); - strptr = sidstr + strlen(sidstr); + len = sprintf(strptr, "-%hhu", sidptr->authority[i]); + strptr += len; } } for (i = 0; i < sidptr->num_subauth; ++i) { saval = le32_to_cpu(sidptr->sub_auth[i]); - sprintf(strptr, "-%u", saval); - strptr = sidstr + strlen(sidstr); + len = sprintf(strptr, "-%u", saval); + strptr += len; } + + return sidstr; } /* @@ -284,184 +171,38 @@ cifs_copy_sid(struct cifs_sid *dst, const struct cifs_sid *src) dst->sub_auth[i] = src->sub_auth[i]; } -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; - } - } - - cifs_copy_sid(&(*psidid)->sid, sidptr); - (*psidid)->time = jiffies - (SID_MAP_RETRY + 1); - (*psidid)->refcount = 0; - - 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 cifs_sid_id *lsidid; - - while (node) { - lsidid = rb_entry(node, struct cifs_sid_id, rbnode); - rc = compare_sids(sidptr, &((lsidid)->sid)); - if (rc > 0) { - node = node->rb_left; - } else if (rc < 0) { - 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 -id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid) +id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid) { - int rc = 0; + int rc; struct key *sidkey; + char desc[3 + 10 + 1]; /* 3 byte prefix + 10 bytes for value + NULL */ const struct cred *saved_cred; - struct cifs_sid *lsid; - struct cifs_sid_id *psidid, *npsidid; - struct rb_root *cidtree; - spinlock_t *cidlock; - - if (sidtype == SIDOWNER) { - cidlock = &siduidlock; - cidtree = &uidtree; - } else if (sidtype == SIDGROUP) { - cidlock = &sidgidlock; - cidtree = &gidtree; - } else - return -EINVAL; - - spin_lock(cidlock); - psidid = sid_rb_search(cidtree, cid); - - if (!psidid) { /* node does not exist, allocate one & attempt adding */ - spin_unlock(cidlock); - npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL); - if (!npsidid) - return -ENOMEM; - - npsidid->sidstr = kmalloc(SID_STRING_MAX, GFP_KERNEL); - if (!npsidid->sidstr) { - kfree(npsidid); - return -ENOMEM; - } - - spin_lock(cidlock); - psidid = sid_rb_search(cidtree, cid); - if (psidid) { /* node happened to get inserted meanwhile */ - ++psidid->refcount; - spin_unlock(cidlock); - kfree(npsidid->sidstr); - kfree(npsidid); - } else { - psidid = npsidid; - sid_rb_insert(cidtree, cid, &psidid, - sidtype == SIDOWNER ? "oi:" : "gi:"); - ++psidid->refcount; - spin_unlock(cidlock); - } - } else { - ++psidid->refcount; - spin_unlock(cidlock); - } - /* - * If we are here, it is safe to access psidid and its fields - * since a reference was taken earlier while holding the spinlock. - * A reference on the node is put without holding the spinlock - * and it is OK to do so in this case, shrinker will not erase - * this node until all references are put and we do not access - * any fields of the node after a reference is put . - */ - if (test_bit(SID_ID_MAPPED, &psidid->state)) { - cifs_copy_sid(ssid, &psidid->sid); - psidid->time = jiffies; /* update ts for accessing */ - goto id_sid_out; - } + rc = snprintf(desc, sizeof(desc), "%ci:%u", + sidtype == SIDOWNER ? 'o' : 'g', cid); + if (rc >= sizeof(desc)) + return -EINVAL; - if (time_after(psidid->time + SID_MAP_RETRY, jiffies)) { + rc = 0; + saved_cred = override_creds(root_cred); + sidkey = request_key(&cifs_idmap_key_type, desc, ""); + if (IS_ERR(sidkey)) { rc = -EINVAL; - goto id_sid_out; - } - - if (!test_and_set_bit(SID_ID_PENDING, &psidid->state)) { - saved_cred = override_creds(root_cred); - sidkey = request_key(&cifs_idmap_key_type, psidid->sidstr, ""); - if (IS_ERR(sidkey)) { - rc = -EINVAL; - cFYI(1, "%s: Can't map and id to a SID", __func__); - } else if (sidkey->datalen < CIFS_SID_BASE_SIZE) { - rc = -EIO; - cFYI(1, "%s: Downcall contained malformed key " - "(datalen=%hu)", __func__, sidkey->datalen); - } else { - lsid = (struct cifs_sid *)sidkey->payload.data; - cifs_copy_sid(&psidid->sid, lsid); - cifs_copy_sid(ssid, &psidid->sid); - set_bit(SID_ID_MAPPED, &psidid->state); - key_put(sidkey); - kfree(psidid->sidstr); - } - psidid->time = jiffies; /* update ts for accessing */ - 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); - --psidid->refcount; - return rc; - } - if (test_bit(SID_ID_MAPPED, &psidid->state)) - cifs_copy_sid(ssid, &psidid->sid); - else - rc = -EINVAL; - } -id_sid_out: - --psidid->refcount; + cFYI(1, "%s: Can't map %cid %u to a SID", __func__, + sidtype == SIDOWNER ? 'u' : 'g', cid); + goto out_revert_creds; + } else if (sidkey->datalen < CIFS_SID_BASE_SIZE) { + rc = -EIO; + cFYI(1, "%s: Downcall contained malformed key " + "(datalen=%hu)", __func__, sidkey->datalen); + goto out_key_put; + } + cifs_copy_sid(ssid, (struct cifs_sid *)sidkey->payload.data); +out_key_put: + key_put(sidkey); +out_revert_creds: + revert_creds(saved_cred); return rc; } @@ -470,111 +211,66 @@ 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; + struct key *sidkey; + char *sidstr; 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); - - if (!psidid) { /* node does not exist, allocate one & attempt adding */ - spin_unlock(cidlock); - npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL); - if (!npsidid) - return -ENOMEM; - - npsidid->sidstr = kmalloc(SID_STRING_MAX, 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 */ - ++psidid->refcount; - spin_unlock(cidlock); - kfree(npsidid->sidstr); - kfree(npsidid); - } else { - psidid = npsidid; - id_rb_insert(cidtree, psid, &psidid, - sidtype == SIDOWNER ? "os:" : "gs:"); - ++psidid->refcount; - spin_unlock(cidlock); - } - } else { - ++psidid->refcount; - spin_unlock(cidlock); - } + uid_t fuid = cifs_sb->mnt_uid; + gid_t fgid = cifs_sb->mnt_gid; /* - * If we are here, it is safe to access psidid and its fields - * since a reference was taken earlier while holding the spinlock. - * A reference on the node is put without holding the spinlock - * and it is OK to do so in this case, shrinker will not erase - * this node until all references are put and we do not access - * any fields of the node after a reference is put . + * If we have too many subauthorities, then something is really wrong. + * Just return an error. */ - if (test_bit(SID_ID_MAPPED, &psidid->state)) { - cid = psidid->id; - psidid->time = jiffies; /* update ts for accessing */ - goto sid_to_id_out; + if (unlikely(psid->num_subauth > SID_MAX_SUB_AUTHORITIES)) { + cFYI(1, "%s: %u subauthorities is too many!", __func__, + psid->num_subauth); + return -EIO; } - if (time_after(psidid->time + SID_MAP_RETRY, jiffies)) - goto sid_to_id_out; - - 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)) - cFYI(1, "%s: Can't map SID to an id", __func__); - else { - cid = *(unsigned long *)idkey->payload.value; - psidid->id = cid; - set_bit(SID_ID_MAPPED, &psidid->state); - key_put(idkey); - kfree(psidid->sidstr); - } - revert_creds(saved_cred); - psidid->time = jiffies; /* update ts for accessing */ - 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); - --psidid->refcount; /* decremented without spinlock */ - return rc; - } - if (test_bit(SID_ID_MAPPED, &psidid->state)) - cid = psidid->id; + sidstr = sid_to_key_str(psid, sidtype); + if (!sidstr) + return -ENOMEM; + + saved_cred = override_creds(root_cred); + sidkey = request_key(&cifs_idmap_key_type, sidstr, ""); + if (IS_ERR(sidkey)) { + rc = -EINVAL; + cFYI(1, "%s: Can't map SID %s to a %cid", __func__, sidstr, + sidtype == SIDOWNER ? 'u' : 'g'); + goto out_revert_creds; + } + + /* + * FIXME: Here we assume that uid_t and gid_t are same size. It's + * probably a safe assumption but might be better to check based on + * sidtype. + */ + if (sidkey->datalen < sizeof(uid_t)) { + rc = -EIO; + cFYI(1, "%s: Downcall contained malformed key " + "(datalen=%hu)", __func__, sidkey->datalen); + goto out_key_put; } -sid_to_id_out: - --psidid->refcount; /* decremented without spinlock */ if (sidtype == SIDOWNER) - fattr->cf_uid = cid; + fuid = *(uid_t *)sidkey->payload.value; else - fattr->cf_gid = cid; + fgid = *(gid_t *)sidkey->payload.value; +out_key_put: + key_put(sidkey); +out_revert_creds: + revert_creds(saved_cred); + kfree(sidstr); + + /* + * Note that we return 0 here unconditionally. If the mapping + * fails then we just fall back to using the mnt_uid/mnt_gid. + */ + if (sidtype == SIDOWNER) + fattr->cf_uid = fuid; + else + fattr->cf_gid = fgid; return 0; } @@ -621,17 +317,6 @@ init_cifs_idmap(void) cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; root_cred = cred; - spin_lock_init(&siduidlock); - uidtree = RB_ROOT; - spin_lock_init(&sidgidlock); - gidtree = RB_ROOT; - - spin_lock_init(&uidsidlock); - siduidtree = RB_ROOT; - spin_lock_init(&gidsidlock); - sidgidtree = RB_ROOT; - register_shrinker(&cifs_shrinker); - cFYI(1, "cifs idmap keyring: %d", key_serial(keyring)); return 0; @@ -648,41 +333,9 @@ exit_cifs_idmap(void) key_revoke(root_cred->thread_keyring); unregister_key_type(&cifs_idmap_key_type); put_cred(root_cred); - unregister_shrinker(&cifs_shrinker); cFYI(1, "Unregistered %s key type", cifs_idmap_key_type.name); } -void -cifs_destroy_idmaptrees(void) -{ - struct rb_root *root; - struct rb_node *node; - - root = &uidtree; - spin_lock(&siduidlock); - while ((node = rb_first(root))) - rb_erase(node, root); - spin_unlock(&siduidlock); - - root = &gidtree; - spin_lock(&sidgidlock); - while ((node = rb_first(root))) - rb_erase(node, root); - spin_unlock(&sidgidlock); - - root = &siduidtree; - spin_lock(&uidsidlock); - while ((node = rb_first(root))) - rb_erase(node, root); - spin_unlock(&uidsidlock); - - root = &sidgidtree; - spin_lock(&gidsidlock); - while ((node = rb_first(root))) - rb_erase(node, root); - spin_unlock(&gidsidlock); -} - /* copy ntsd, owner sid, and group sid from a security descriptor to another */ static void copy_sec_desc(const struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd, __u32 sidsoffset) |