From 90d8668e4ac34a84c52dc5b078af9d982323502c Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Mon, 30 Oct 2017 13:28:03 +1100
Subject: [PATCH] cifs: check MaxPathNameComponentLength != 0 before using it

commit f74bc7c6679200a4a83156bb89cbf6c229fe8ec0 upstream.

And fix tcon leak in error path.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: David Disseldorp <ddiss@samba.org>
[bwh: Backported to 3.2: cifs_tcon pointer is tcon, and there's no leak to fix]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 fs/cifs/dir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index a1c99c4e7763b..22758b1c14261 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -521,7 +521,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	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;
-- 
2.47.2