CIFS: Fix a possible memory corruption in push locks
If maxBuf is not 0 but less than a size of SMB2 lock structure
we can end up with a memory corruption.
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index f9e766f..b2aff0c 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -260,7 +260,7 @@
* 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;
}