diff options
| author |   David Howells <dhowells@redhat.com> | 2015-09-25 16:30:08 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2015-09-25 16:30:08 +0100 |
| commit | 94c4554ba07adbdde396748ee7ae01e86cf2d8d7 (patch) | |
| tree | 13cb745526d6c46d8d2f2c0dc30eba546f1f5857 /security/keys/gc.c | |
| parent | Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux (diff) | |
| download | linux-dev-94c4554ba07adbdde396748ee7ae01e86cf2d8d7.tar.xz linux-dev-94c4554ba07adbdde396748ee7ae01e86cf2d8d7.zip | |
KEYS: Fix race between key destruction and finding a keyring by name
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>
Diffstat (limited to 'security/keys/gc.c')
| -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 c7952375ac53..39eac1fd5706 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -134,6 +134,10 @@ static noinline void key_gc_unused_keys(struct list_head *keys) kdebug("- %u", key->serial); 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 */ @@ -148,10 +152,6 @@ static noinline void key_gc_unused_keys(struct list_head *keys) 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); |