[PATCH 3.2 078/147] cifs: check MaxPathNameComponentLength != 0 before using it

[Ben Hutchings]

3.2.95-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ronnie Sahlberg <lsahl...@redhat.com>

commit f74bc7c6679200a4a83156bb89cbf6c229fe8ec0 upstream.

And fix tcon leak in error path.

Signed-off-by: Ronnie Sahlberg <lsahl...@redhat.com>
Signed-off-by: Steve French <smfre...@gmail.com>
Reviewed-by: David Disseldorp <dd...@samba.org>
[bwh: Backported to 3.2: cifs_tcon pointer is tcon, and there's no leak to fix]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -521,7 +521,8 @@ cifs_lookup(struct inode *parent_dir_ino
        oplock = pTcon->ses->server->oplocks ? REQ_OPLOCK : 0;
 
        /* Don't allow path components longer than the server max. */
-       if (unlikely(direntry->d_name.len >
+       if (unlikely(pTcon->fsAttrInfo.MaxPathNameComponentLength &&
+                    direntry->d_name.len >
                     
le32_to_cpu(pTcon->fsAttrInfo.MaxPathNameComponentLength))) {
                rc = -ENAMETOOLONG;
                goto lookup_out;