[PATCH 3.10 023/268] CIFS: Fix a possible memory corruption in push locks

Willy Tarreau
2017-06-19T18:34:47Z

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: Willy Tarreau <w@1wt.eu>
---
fs/cifs/smb2file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index d801f63..866caf1 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -266,7 +266,7 @@ smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
* 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;
}
--
2.8.0.rc2.1.gbe9624a