[CIFS] Workaround MacOS server problem with SMB2.1 write

[karo-tx-linux.git] / fs / cifs / smb2misc.c

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index f2e6ac29a8d661b82f4ba1712dee36a842d6f7cd..4aa7a0f07d6eace61da47500bb6e83a5bd39e294 100644 (file)
--- 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;