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| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-29 14:39:01 -0600 |
|---|---|---|
| committer | Ziyan <jaraidaniel@gmail.com> | 2016-10-29 01:34:03 +0200 |
| commit | ba42a3d920ccbdf1c359abbdfe8af2a9398faf6e (patch) | |
| tree | a8e75283e3d41e92ad2438e096350403dc9bb822 /security | |
| parent | 9a1af4002291f2c5493a0ba0863fb2d873691d5a (diff) | |
| download | kernel_samsung_tuna-ba42a3d920ccbdf1c359abbdfe8af2a9398faf6e.zip kernel_samsung_tuna-ba42a3d920ccbdf1c359abbdfe8af2a9398faf6e.tar.gz kernel_samsung_tuna-ba42a3d920ccbdf1c359abbdfe8af2a9398faf6e.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>
Diffstat (limited to 'security')
| -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 4a4855d..d2765e4 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 |