[CIFS] Fix memory overwrite when saving nativeFileSystem field during mount

CIFS can allocate a few bytes to little for the nativeFileSystem field
during tree connect response processing during mount.  This can result
in a "Redzone overwritten" message to be logged.

Signed-off-by: Sridhar Vinay <vinaysridhar@in.ibm.com>
Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index cd4ccc8..0de3b56 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3674,7 +3674,7 @@
 			    BCC(smb_buffer_response)) {
 				kfree(tcon->nativeFileSystem);
 				tcon->nativeFileSystem =
-				    kzalloc(length + 2, GFP_KERNEL);
+				    kzalloc(2*(length + 1), GFP_KERNEL);
 				if (tcon->nativeFileSystem)
 					cifs_strfromUCS_le(
 						tcon->nativeFileSystem,