This is a note to let you know that I've just added the patch titled
filelock: fix potential use-after-free in posix_lock_inode
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
filelock-fix-potential-use-after-free-in-posix_lock_.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8989764396ebaac847766289ffc2c78302dc40ba
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date: Tue Jul 2 18:44:48 2024 -0400
filelock: fix potential use-after-free in posix_lock_inode
[ Upstream commit 1b3ec4f7c03d4b07bad70697d7e2f4088d2cfe92 ]
Light Hsieh reported a KASAN UAF warning in trace_posix_lock_inode().
The request pointer had been changed earlier to point to a lock entry
that was added to the inode's list. However, before the tracepoint could
fire, another task raced in and freed that lock.
Fix this by moving the tracepoint inside the spinlock, which should
ensure that this doesn't happen.
Fixes: 74f6f5912693 ("locks: fix KASAN: use-after-free in trace_event_raw_event_filelock_lock")
Link: https://lore.kernel.org/linux-fsdevel/724ffb0a2962e912ea62bb0515deadf39c325112.camel@xxxxxxxxxx/
Reported-by: Light Hsieh (謝明燈) <Light.Hsieh@xxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240702-filelock-6-10-v1-1-96e766aadc98@xxxxxxxxxx
Reviewed-by: Alexander Aring <aahringo@xxxxxxxxxx>
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/locks.c b/fs/locks.c
index 77781b71bcaab..360c348ae6c8f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1392,9 +1392,9 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
locks_wake_up_blocks(left);
}
out:
+ trace_posix_lock_inode(inode, request, error);
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
- trace_posix_lock_inode(inode, request, error);
/*
* Free any unused locks.
*/
