[PATCH] cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty

From: Eugene Korenevsky <ekorenevsky@astralinux.ru>
To: linux-cifs@vger.kernel.org
Cc: Steve French <sfrench@samba.org>
Subject: [PATCH] cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty
Date: Thu, 30 Dec 2021 00:25:52 +0300	[thread overview]
Message-ID: <YczSYDk/eklOzc2e@himera.home> (raw)

alloc_path_with_tree_prefix() concatenates tree prefix and the path.
Windows CIFS client does not append separator after the tree prefix if
the path is empty. Let's do the same.

This fixes mounting DFS namespaces with names containing non-ASCII symbols.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215440
Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
---
 fs/cifs/smb2pdu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 8b3670388cda..88ea0163257c 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2527,8 +2527,13 @@ alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
 
 	cp = load_nls_default();
 	cifs_strtoUTF16(*out_path, treename, treename_len, cp);
-	UniStrcat(*out_path, sep);
-	UniStrcat(*out_path, path);
+
+	/* Do not append the separator if the path is empty */
+	if (path[0] != cpu_to_le16(0x0000)) {
+		UniStrcat(*out_path, sep);
+		UniStrcat(*out_path, path);
+	}
+
 	unload_nls(cp);
 
 	return 0;
-- 
2.30.2

