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authorDavid Howells <dhowells@redhat.com>2020-01-14 19:06:14 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-14 20:40:06 +0300
commit8379bb84be757d5df2d818509faec5d66adb861d (patch)
tree4a5c150198cfdde4c07e4cfe55995c5cd51830df /kernel/cred.c
parent219d54332a09e8d8741c1e1982f5eae56099de85 (diff)
downloadlinux-8379bb84be757d5df2d818509faec5d66adb861d.tar.xz
keys: Fix request_key() cache
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>
Diffstat (limited to 'kernel/cred.c')
-rw-r--r--kernel/cred.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index c0a4c12d38b2..56395be1c2a8 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
}