[PATCH 3.16 073/370] CIFS: Fix a possible memory corruption in push locks

Ben Hutchings
2017-03-10T14:08:54Z

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: Ben Hutchings <ben@decadent.org.uk>
---
fs/cifs/smb2file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -241,7 +241,7 @@ 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;
}