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author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-29 14:39:01 -0600 |
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committer | Wolfgang Wiedmeyer <wolfgit@wiedmeyer.de> | 2016-03-18 01:51:05 +0100 |
commit | 48a12b57608cfc4f34bbbf744f6644f90e529370 (patch) | |
tree | 0cbfe06fecbeb7055de01b08c4c91d3bc48e8abd | |
parent | d576ad7a9bea9be74ed9c9f99eb31924ce26aba7 (diff) | |
download | kernel_samsung_smdk4412-48a12b57608cfc4f34bbbf744f6644f90e529370.zip kernel_samsung_smdk4412-48a12b57608cfc4f34bbbf744f6644f90e529370.tar.gz kernel_samsung_smdk4412-48a12b57608cfc4f34bbbf744f6644f90e529370.tar.bz2 |
KEYS: close race between key lookup and freeing
When a key is being garbage collected, it's key->user would get put before
the ->destroy() callback is called, where the key is removed from it's
respective tracking structures.
This leaves a key hanging in a semi-invalid state which leaves a window open
for a different task to try an access key->user. An example is
find_keyring_by_name() which would dereference key->user for a key that is
in the process of being garbage collected (where key->user was freed but
->destroy() wasn't called yet - so it's still present in the linked list).
This would cause either a panic, or corrupt memory.
Change-Id: I7856b7012d1bb668b15977ed16a4ee5f9c2882de
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r-- | security/keys/key.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/security/keys/key.c b/security/keys/key.c index f7f9d93..e1704f6 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -639,12 +639,12 @@ found_dead_key: if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) atomic_dec(&key->user->nikeys); - key_user_put(key->user); - /* now throw away the key memory */ if (key->type->destroy) key->type->destroy(key); + key_user_put(key->user); + kfree(key->description); #ifdef KEY_DEBUGGING |