1 files changed, 16 insertions, 1 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index f2e6ac29a8d6..4aa7a0f07d6e 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -178,9 +178,24 @@ smb2_check_message(char *buf, unsigned int length)
                 /* Windows 7 server returns 24 bytes more */
                 if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
                         return 0;
-                /* server can return one byte more */
+                /* server can return one byte more due to implied bcc[0] */
                 if (clc_len == 4 + len + 1)
                         return 0;
+
+                /*
+                 * MacOS server pads after SMB2.1 write response with 3 bytes
+                 * of junk. Other servers match RFC1001 len to actual
+                 * SMB2/SMB3 frame length (header + smb2 response specific data)
+                 * Log the server error (once), but allow it and continue
+                 * since the frame is parseable.
+                 */
+                if (clc_len < 4 /* RFC1001 header size */ + len) {
+                        printk_once(KERN_WARNING
+                                "SMB2 server sent bad RFC1001 len %d not %d\n",
+                                len, clc_len - 4);
+                        return 0;
+                }
+
                 return 1;
         }
         return 0;