diff options
| author | David Howells <dhowells@redhat.com> | 2012-01-17 20:39:40 +0000 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2012-01-18 10:41:27 +1100 |
| commit | efde8b6e16f11e7d1681c68d86c7fd51053cada7 (patch) | |
| tree | 4fb5e80428c4f36c5da35ff3319cd71c1771451c /security/keys | |
| parent | 25add8cf99c9ec8b8dc0acd8b9241e963fc0d29c (diff) | |
KEYS: Add missing smp_rmb() primitives to the keyring search code
Add missing smp_rmb() primitives to the keyring search code.
When keyring payloads are appended to without replacement (thus using up spare
slots in the key pointer array), an smp_wmb() is issued between the pointer
assignment and the increment of the key count (nkeys).
There should be corresponding read barriers between the read of nkeys and
dereferences of keys[n] when n is dependent on the value of nkeys.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/gc.c | 4 | ||||
| -rw-r--r-- | security/keys/keyring.c | 22 |
2 files changed, 18 insertions, 8 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c index bf4d8da5a79..a42b45531aa 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -145,7 +145,9 @@ static void key_gc_keyring(struct key *keyring, time_t limit) if (!klist) goto unlock_dont_gc; - for (loop = klist->nkeys - 1; loop >= 0; loop--) { + loop = klist->nkeys; + smp_rmb(); + for (loop--; loop >= 0; loop--) { key = klist->keys[loop]; if (test_bit(KEY_FLAG_DEAD, &key->flags) || (key->expiry > 0 && key->expiry <= limit)) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 37a7f3b2885..d605f75292e 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -319,7 +319,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, struct key *keyring, *key; key_ref_t key_ref; long err; - int sp, kix; + int sp, nkeys, kix; keyring = key_ref_to_ptr(keyring_ref); possessed = is_key_possessed(keyring_ref); @@ -380,7 +380,9 @@ descend: goto not_this_keyring; /* iterate through the keys in this keyring first */ - for (kix = 0; kix < keylist->nkeys; kix++) { + nkeys = keylist->nkeys; + smp_rmb(); + for (kix = 0; kix < nkeys; kix++) { key = keylist->keys[kix]; kflags = key->flags; @@ -421,7 +423,9 @@ descend: /* search through the keyrings nested in this one */ kix = 0; ascend: - for (; kix < keylist->nkeys; kix++) { + nkeys = keylist->nkeys; + smp_rmb(); + for (; kix < nkeys; kix++) { key = keylist->keys[kix]; if (key->type != &key_type_keyring) continue; @@ -515,7 +519,7 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, struct keyring_list *klist; unsigned long possessed; struct key *keyring, *key; - int loop; + int nkeys, loop; keyring = key_ref_to_ptr(keyring_ref); possessed = is_key_possessed(keyring_ref); @@ -524,7 +528,9 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, klist = rcu_dereference(keyring->payload.subscriptions); if (klist) { - for (loop = 0; loop < klist->nkeys; loop++) { + nkeys = klist->nkeys; + smp_rmb(); + for (loop = 0; loop < nkeys ; loop++) { key = klist->keys[loop]; if (key->type == ktype && @@ -622,7 +628,7 @@ static int keyring_detect_cycle(struct key *A, struct key *B) struct keyring_list *keylist; struct key *subtree, *key; - int sp, kix, ret; + int sp, nkeys, kix, ret; rcu_read_lock(); @@ -645,7 +651,9 @@ descend: ascend: /* iterate through the remaining keys in this keyring */ - for (; kix < keylist->nkeys; kix++) { + nkeys = keylist->nkeys; + smp_rmb(); + for (; kix < nkeys; kix++) { key = keylist->keys[kix]; if (key == A) |