[PATCH] Keys: Add possessor permissions to keys [try #3]

[linux-3.10.git] / security / keys / keyring.c

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 9c208c756df8136cbaa0a06f5442af60c712ae6d..0639396dd441eabdc27418b66df7673a749419e8 100644 (file)
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -309,7 +309,7 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
        int ret;
 
        keyring = key_alloc(&key_type_keyring, description,
-                           uid, gid, KEY_USR_ALL, not_in_quota);
+                           uid, gid, KEY_POS_ALL | KEY_USR_ALL, not_in_quota);
 
        if (!IS_ERR(keyring)) {
                ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
@@ -333,12 +333,13 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
  * - we rely on RCU to prevent the keyring lists from disappearing on us
  * - we return -EAGAIN if we didn't find any matching key
  * - we return -ENOKEY if we only found negative matching keys
+ * - we propagate the possession attribute from the keyring ref to the key ref
  */
-struct key *keyring_search_aux(struct key *keyring,
-                              struct task_struct *context,
-                              struct key_type *type,
-                              const void *description,
-                              key_match_func_t match)
+key_ref_t keyring_search_aux(key_ref_t keyring_ref,
+                            struct task_struct *context,
+                            struct key_type *type,
+                            const void *description,
+                            key_match_func_t match)
 {
        struct {
                struct keyring_list *keylist;
@@ -347,29 +348,33 @@ struct key *keyring_search_aux(struct key *keyring,
 
        struct keyring_list *keylist;
        struct timespec now;
-       struct key *key;
+       unsigned long possessed;
+       struct key *keyring, *key;
+       key_ref_t key_ref;
        long err;
        int sp, kix;
 
+       keyring = key_ref_to_ptr(keyring_ref);
+       possessed = is_key_possessed(keyring_ref);
        key_check(keyring);
 
-       rcu_read_lock();
-
        /* top keyring must have search permission to begin the search */
-       key = ERR_PTR(-EACCES);
-       if (!key_task_permission(keyring, context, KEY_SEARCH))
+       key_ref = ERR_PTR(-EACCES);
+       if (!key_task_permission(keyring_ref, context, KEY_SEARCH))
                goto error;
 
-       key = ERR_PTR(-ENOTDIR);
+       key_ref = ERR_PTR(-ENOTDIR);
        if (keyring->type != &key_type_keyring)
                goto error;
 
+       rcu_read_lock();
+
        now = current_kernel_time();
        err = -EAGAIN;
        sp = 0;
 
        /* start processing a new keyring */
- descend:
+descend:
        if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
                goto not_this_keyring;
 
@@ -397,7 +402,8 @@ struct key *keyring_search_aux(struct key *keyring,
                        continue;
 
                /* key must have search permissions */
-               if (!key_task_permission(key, context, KEY_SEARCH))
+               if (!key_task_permission(make_key_ref(key, possessed),
+                                        context, KEY_SEARCH))
                        continue;
 
                /* we set a different error code if we find a negative key */
@@ -411,7 +417,7 @@ struct key *keyring_search_aux(struct key *keyring,
 
        /* search through the keyrings nested in this one */
        kix = 0;
- ascend:
+ascend:
        for (; kix < keylist->nkeys; kix++) {
                key = keylist->keys[kix];
                if (key->type != &key_type_keyring)
@@ -423,7 +429,8 @@ struct key *keyring_search_aux(struct key *keyring,
                if (sp >= KEYRING_SEARCH_MAX_DEPTH)
                        continue;
 
-               if (!key_task_permission(key, context, KEY_SEARCH))
+               if (!key_task_permission(make_key_ref(key, possessed),
+                                        context, KEY_SEARCH))
                        continue;
 
                /* stack the current position */
@@ -438,7 +445,7 @@ struct key *keyring_search_aux(struct key *keyring,
 
        /* the keyring we're looking at was disqualified or didn't contain a
         * matching key */
- not_this_keyring:
+not_this_keyring:
        if (sp > 0) {
                /* resume the processing of a keyring higher up in the tree */
                sp--;
@@ -447,16 +454,18 @@ struct key *keyring_search_aux(struct key *keyring,
                goto ascend;
        }
 
-       key = ERR_PTR(err);
-       goto error;
+       key_ref = ERR_PTR(err);
+       goto error_2;
 
        /* we found a viable match */
- found:
+found:
        atomic_inc(&key->usage);
        key_check(key);
- error:
+       key_ref = make_key_ref(key, possessed);
+error_2:
        rcu_read_unlock();
-       return key;
+error:
+       return key_ref;
 
 } /* end keyring_search_aux() */
 
@@ -469,9 +478,9 @@ struct key *keyring_search_aux(struct key *keyring,
  * - we return -EAGAIN if we didn't find any matching key
  * - we return -ENOKEY if we only found negative matching keys
  */
-struct key *keyring_search(struct key *keyring,
-                          struct key_type *type,
-                          const char *description)
+key_ref_t keyring_search(key_ref_t keyring,
+                        struct key_type *type,
+                        const char *description)
 {
        if (!type->match)
                return ERR_PTR(-ENOKEY);
@@ -488,15 +497,19 @@ EXPORT_SYMBOL(keyring_search);
  * search the given keyring only (no recursion)
  * - keyring must be locked by caller
  */
-struct key *__keyring_search_one(struct key *keyring,
-                                const struct key_type *ktype,
-                                const char *description,
-                                key_perm_t perm)
+key_ref_t __keyring_search_one(key_ref_t keyring_ref,
+                              const struct key_type *ktype,
+                              const char *description,
+                              key_perm_t perm)
 {
        struct keyring_list *klist;
-       struct key *key;
+       unsigned long possessed;
+       struct key *keyring, *key;
        int loop;
 
+       keyring = key_ref_to_ptr(keyring_ref);
+       possessed = is_key_possessed(keyring_ref);
+
        rcu_read_lock();
 
        klist = rcu_dereference(keyring->payload.subscriptions);
@@ -507,21 +520,21 @@ struct key *__keyring_search_one(struct key *keyring,
                        if (key->type == ktype &&
                            (!key->type->match ||
                             key->type->match(key, description)) &&
-                           key_permission(key, perm) &&
+                           key_permission(make_key_ref(key, possessed),
+                                          perm) &&
                            !test_bit(KEY_FLAG_REVOKED, &key->flags)
                            )
                                goto found;
                }
        }
 
-       key = ERR_PTR(-ENOKEY);
-       goto error;
+       rcu_read_unlock();
+       return ERR_PTR(-ENOKEY);
 
  found:
        atomic_inc(&key->usage);
- error:
        rcu_read_unlock();
-       return key;
+       return make_key_ref(key, possessed);
 
 } /* end __keyring_search_one() */
 
@@ -603,7 +616,8 @@ struct key *find_keyring_by_name(const char *name, key_serial_t bound)
                        if (strcmp(keyring->description, name) != 0)
                                continue;
 
-                       if (!key_permission(keyring, KEY_SEARCH))
+                       if (!key_permission(make_key_ref(keyring, 0),
+                                           KEY_SEARCH))
                                continue;
 
                        /* found a potential candidate, but we still need to