ru.org.linux.csrf.CSRFProtectionService.java Source code

Introduction

Here is the source code for ru.org.linux.csrf.CSRFProtectionService.java

Source

/*
 * Copyright 1998-2016 Linux.org.ru
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package ru.org.linux.csrf;

import com.google.common.base.Strings;
import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.validation.Errors;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.security.SecureRandom;

public class CSRFProtectionService {
    private static final Logger logger = LoggerFactory.getLogger(CSRFProtectionService.class);

    public static final String CSRF_COOKIE = "CSRF_TOKEN";
    public static final String CSRF_ATTRIBUTE = "csrfToken";
    private static final int TWO_YEARS = 60 * 60 * 24 * 31 * 24;
    public static final String CSRF_INPUT_NAME = "csrf";

    public static void generateCSRFCookie(HttpServletRequest request, HttpServletResponse response) {
        SecureRandom random = new SecureRandom();

        byte[] value = new byte[16];
        random.nextBytes(value);

        String token = new String(Base64.encodeBase64(value));

        Cookie cookie = new Cookie(CSRF_COOKIE, token);
        cookie.setMaxAge(TWO_YEARS);
        cookie.setPath("/");
        response.addCookie(cookie);

        request.setAttribute(CSRF_ATTRIBUTE, token);
    }

    /**
     * Check if user is authorized for request
     * @param request
     * @return true when ok, false when not authorized
     */
    public static boolean checkCSRF(HttpServletRequest request) {
        String cookieValue = (String) request.getAttribute(CSRF_ATTRIBUTE);

        if (Strings.isNullOrEmpty(cookieValue)) {
            logger.info("Missing CSRF cookie");
            return false;
        }

        String inputValue = request.getParameter(CSRF_INPUT_NAME);

        if (Strings.isNullOrEmpty(inputValue)) {
            logger.info("Missing CSRF input");
            return false;
        }

        boolean r = inputValue.trim().equals(cookieValue.trim());

        if (!r) {
            logger.info(String.format("Flood protection (CSRF cookie differs: cookie=%s param=%s) ip=%s url=%s",
                    cookieValue, inputValue, request.getRemoteAddr(), request.getRequestURI()));
        }

        return r;
    }

    public static void checkCSRF(HttpServletRequest request, Errors errors) {
        if (checkCSRF(request)) {
            return;
        }

        errors.reject(null, "? ?,   ");
    }
}