diff options
| author | David Howells <dhowells@redhat.com> | 2015-09-25 16:30:08 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-11-17 15:54:46 +0000 |
| commit | 650f6aa8c3c805bd41c4243aadbd63558f39fd32 (patch) | |
| tree | f7a391739bf8da9bf4347a3e14d36ae54888c163 | |
| parent | 3553e5d34d72a3aac5d967ec8b4d45a88340d679 (diff) | |
KEYS: Fix race between key destruction and finding a keyring by name
commit 94c4554ba07adbdde396748ee7ae01e86cf2d8d7 upstream.
There appears to be a race between:
(1) key_gc_unused_keys() which frees key->security and then calls
keyring_destroy() to unlink the name from the name list
(2) find_keyring_by_name() which calls key_permission(), thus accessing
key->security, on a key before checking to see whether the key usage is 0
(ie. the key is dead and might be cleaned up).
Fix this by calling ->destroy() before cleaning up the core key data -
including key->security.
Reported-by: Petr Matousek <pmatouse@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[carnil: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | security/keys/gc.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c index 2e2395d6bd16..207e9686c249 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -172,6 +172,10 @@ static noinline void key_gc_unused_key(struct key *key) { key_check(key); + /* Throw away the key data */ + if (key->type->destroy) + key->type->destroy(key); + security_key_free(key); /* deal with the user's key tracking and quota */ @@ -186,10 +190,6 @@ static noinline void key_gc_unused_key(struct key *key) if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) atomic_dec(&key->user->nikeys); - /* now throw away the key memory */ - if (key->type->destroy) - key->type->destroy(key); - key_user_put(key->user); kfree(key->description); |