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KEYS: Add missing smp_rmb() primitives to the keyring search code

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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>
This commit is contained in:
David Howells
2012-01-17 20:39:40 +00:00
committed by James Morris
parent 25add8cf99
commit efde8b6e16
2 changed files with 18 additions and 8 deletions
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4
security/keys/gc.c
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@@ -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))