ksmbd: handle malformed smb1 message

If set_smb1_rsp_status() is not implemented, It will cause NULL pointer
dereferece error when client send malformed smb1 message.
This patch add set_smb1_rsp_status() to ignore malformed smb1 message.

Cc: stable@vger.kernel.org
Reported-by: Robert Morris <rtm@csail.mit.edu>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/smb_common.c

@@ -366,11 +366,22 @@ static int smb1_allocate_rsp_buf(struct ksmbd_work *work)
 	return 0;
 }
 
+/**
+ * set_smb1_rsp_status() - set error type in smb response header
+ * @work:	smb work containing smb response header
+ * @err:	error code to set in response
+ */
+static void set_smb1_rsp_status(struct ksmbd_work *work, __le32 err)
+{
+	work->send_no_response = 1;
+}
+
 static struct smb_version_ops smb1_server_ops = {
 	.get_cmd_val = get_smb1_cmd_val,
 	.init_rsp_hdr = init_smb1_rsp_hdr,
 	.allocate_rsp_buf = smb1_allocate_rsp_buf,
 	.check_user_session = smb1_check_user_session,
+	.set_rsp_status = set_smb1_rsp_status,
 };
 
 static int smb1_negotiate(struct ksmbd_work *work)