From f74bc7c6679200a4a83156bb89cbf6c229fe8ec0 Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Mon, 30 Oct 2017 13:28:03 +1100
Subject: cifs: check MaxPathNameComponentLength != 0 before using it

From: Ronnie Sahlberg <lsahlber@redhat.com>

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/cifs/dir.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -193,7 +193,8 @@ check_name(struct dentry *direntry, stru
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	int i;
 
-	if (unlikely(direntry->d_name.len >
+	if (unlikely(tcon->fsAttrInfo.MaxPathNameComponentLength &&
+		     direntry->d_name.len >
 		     le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength)))
 		return -ENAMETOOLONG;
 
@@ -509,7 +510,7 @@ cifs_atomic_open(struct inode *inode, st
 
 	rc = check_name(direntry, tcon);
 	if (rc)
-		goto out_free_xid;
+		goto out;
 
 	server = tcon->ses->server;