diff options
author | David Howells <dhowells@redhat.com> | 2020-01-14 16:06:14 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-17 19:48:42 +0100 |
commit | 756f4d2ee8a5ad35b842227e7a269a8ad6128981 (patch) | |
tree | 83bfab782222ab01d24ef3e83909cf1c73f30a51 /kernel | |
parent | 6410050a09e84dd5bbe7624d6541769e5b92a78d (diff) |
keys: Fix request_key() cache
commit 8379bb84be757d5df2d818509faec5d66adb861d upstream.
When the key cached by request_key() and co. is cleaned up on exit(),
the code looks in the wrong task_struct, and so clears the wrong cache.
This leads to anomalies in key refcounting when doing, say, a kernel
build on an afs volume, that then trigger kasan to report a
use-after-free when the key is viewed in /proc/keys.
Fix this by making exit_creds() look in the passed-in task_struct rather
than in current (the task_struct cleanup code is deferred by RCU and
potentially run in another task).
Fixes: 7743c48e54ee ("keys: Cache result of request_key*() temporarily in task_struct")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cred.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 9ed51b70ed80..809a985b1793 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -175,8 +175,8 @@ void exit_creds(struct task_struct *tsk) put_cred(cred); #ifdef CONFIG_KEYS_REQUEST_CACHE - key_put(current->cached_requested_key); - current->cached_requested_key = NULL; + key_put(tsk->cached_requested_key); + tsk->cached_requested_key = NULL; #endif } |