Do not send ClientGUID on SMB2.02 dialect

commit 3c5f9be1 upstream.

ClientGUID must be zero for SMB2.02 dialect.  See section 2.2.3
of MS-SMB2. For SMB2.1 and later it must be non-zero.
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

fs/cifs/smb2pdu.c

@@ -375,7 +375,12 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 
 	req->Capabilities = cpu_to_le32(ses->server->vals->req_capabilities);
 
-	memcpy(req->ClientGUID, server->client_guid, SMB2_CLIENT_GUID_SIZE);
+	/* ClientGUID must be zero for SMB2.02 dialect */
+	if (ses->server->vals->protocol_id == SMB20_PROT_ID)
+		memset(req->ClientGUID, 0, SMB2_CLIENT_GUID_SIZE);
+	else
+		memcpy(req->ClientGUID, server->client_guid,
+			SMB2_CLIENT_GUID_SIZE);
 
 	iov[0].iov_base = (char *)req;
 	/* 4 for rfc1002 length field */