This is a note to let you know that I've just added the patch titled
do_last(): don't let a bogus return value from ->open() et.al. to confuse us
to the 4.4-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:
do_last-don-t-let-a-bogus-return-value-from-open-et.al.-to-confuse-us.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c80567c82ae4814a41287618e315a60ecf513be6 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Sat, 27 Feb 2016 19:17:33 -0500
Subject: do_last(): don't let a bogus return value from ->open() et.al. to confuse us
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
commit c80567c82ae4814a41287618e315a60ecf513be6 upstream.
... into returning a positive to path_openat(), which would interpret that
as "symlink had been encountered" and proceed to corrupt memory, etc.
It can only happen due to a bug in some ->open() instance or in some LSM
hook, etc., so we report any such event *and* make sure it doesn't trick
us into further unpleasantness.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3210,6 +3210,10 @@ opened:
goto exit_fput;
}
out:
+ if (unlikely(error > 0)) {
+ WARN_ON(1);
+ error = -EINVAL;
+ }
if (got_write)
mnt_drop_write(nd->path.mnt);
path_put(&save_parent);
Patches currently in stable-queue which might be from viro@xxxxxxxxxxxxxxxxxx are
queue-4.4/make-sure-that-freeing-shmem-fast-symlinks-is-rcu-delayed.patch
queue-4.4/do_last-eloop-failure-exit-should-be-done-after-leaving-rcu-mode.patch
queue-4.4/bcache-fix-a-leak-in-bch_cached_dev_run.patch
queue-4.4/do_last-don-t-let-a-bogus-return-value-from-open-et.al.-to-confuse-us.patch
queue-4.4/locks-fix-unlock-when-fcntl_setlk-races-with-a-close.patch
queue-4.4/namei-d_inode-of-a-pinned-dentry-is-stable-only-for-positives.patch
queue-4.4/should_follow_link-validate-d_seq-after-having-decided-to-follow.patch
queue-4.4/uml-fix-hostfs-mknod.patch
queue-4.4/hpfs-don-t-truncate-the-file-when-delete-fails.patch
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