Patch "CIFS: Fix a possible memory corruption in push locks" has been added to the 4.8-stable tree

Patch "CIFS: Fix a possible memory corruption in push locks" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    CIFS: Fix a possible memory corruption in push locks

to the 4.8-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:
     cifs-fix-a-possible-memory-corruption-in-push-locks.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e3d240e9d505fc67f8f8735836df97a794bbd946 Mon Sep 17 00:00:00 2001
From: Pavel Shilovsky <pshilov@microsoft.com>
Date: Tue, 29 Nov 2016 16:14:43 -0800
Subject: CIFS: Fix a possible memory corruption in push locks

From: Pavel Shilovsky <pshilov@microsoft.com>

commit e3d240e9d505fc67f8f8735836df97a794bbd946 upstream.

If maxBuf is not 0 but less than a size of SMB2 lock structure
we can end up with a memory corruption.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/cifs/smb2file.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -260,7 +260,7 @@ smb2_push_mandatory_locks(struct cifsFil
 	 * and check it for zero before using.
 	 */
 	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
-	if (!max_buf) {
+	if (max_buf < sizeof(struct smb2_lock_element)) {
 		free_xid(xid);
 		return -EINVAL;
 	}


Patches currently in stable-queue which might be from pshilov@microsoft.com are

queue-4.8/cifs-fix-missing-nls-unload-in-smb2_reconnect.patch
queue-4.8/cifs-fix-a-possible-memory-corruption-in-push-locks.patch
queue-4.8/cifs-fix-a-possible-memory-corruption-during-reconnect.patch