| // |
| // ======================================================================== |
| // Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd. |
| // ------------------------------------------------------------------------ |
| // All rights reserved. This program and the accompanying materials |
| // are made available under the terms of the Eclipse Public License v1.0 |
| // and Apache License v2.0 which accompanies this distribution. |
| // |
| // The Eclipse Public License is available at |
| // http://www.eclipse.org/legal/epl-v10.html |
| // |
| // The Apache License v2.0 is available at |
| // http://www.opensource.org/licenses/apache2.0.php |
| // |
| // You may elect to redistribute this code under either of these licenses. |
| // ======================================================================== |
| // |
| |
| package org.eclipse.jetty.servlets; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Enumeration; |
| import java.util.List; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterChain; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| import org.eclipse.jetty.util.log.Log; |
| import org.eclipse.jetty.util.log.Logger; |
| |
| /** |
| * <p>Implementation of the |
| * <a href="http://www.w3.org/TR/cors/">cross-origin resource sharing</a>.</p> |
| * <p>A typical example is to use this filter to allow cross-domain |
| * <a href="http://cometd.org">cometd</a> communication using the standard |
| * long polling transport instead of the JSONP transport (that is less |
| * efficient and less reactive to failures).</p> |
| * <p>This filter allows the following configuration parameters: |
| * <ul> |
| * <li><b>allowedOrigins</b>, a comma separated list of origins that are |
| * allowed to access the resources. Default value is <b>*</b>, meaning all |
| * origins.<br /> |
| * If an allowed origin contains one or more * characters (for example |
| * http://*.domain.com), then "*" characters are converted to ".*", "." |
| * characters are escaped to "\." and the resulting allowed origin |
| * interpreted as a regular expression.<br /> |
| * Allowed origins can therefore be more complex expressions such as |
| * https?://*.domain.[a-z]{3} that matches http or https, multiple subdomains |
| * and any 3 letter top-level domain (.com, .net, .org, etc.).</li> |
| * <li><b>allowedMethods</b>, a comma separated list of HTTP methods that |
| * are allowed to be used when accessing the resources. Default value is |
| * <b>GET,POST,HEAD</b></li> |
| * <li><b>allowedHeaders</b>, a comma separated list of HTTP headers that |
| * are allowed to be specified when accessing the resources. Default value |
| * is <b>X-Requested-With,Content-Type,Accept,Origin</b></li> |
| * <li><b>preflightMaxAge</b>, the number of seconds that preflight requests |
| * can be cached by the client. Default value is <b>1800</b> seconds, or 30 |
| * minutes</li> |
| * <li><b>allowCredentials</b>, a boolean indicating if the resource allows |
| * requests with credentials. Default value is <b>false</b></li> |
| * <li><b>exposeHeaders</b>, a comma separated list of HTTP headers that |
| * are allowed to be exposed on the client. Default value is the |
| * <b>empty list</b></li> |
| * <li><b>chainPreflight</b>, if true preflight requests are chained to their |
| * target resource for normal handling (as an OPTION request). Otherwise the |
| * filter will response to the preflight. Default is true.</li> |
| * </ul></p> |
| * <p>A typical configuration could be: |
| * <pre> |
| * <web-app ...> |
| * ... |
| * <filter> |
| * <filter-name>cross-origin</filter-name> |
| * <filter-class>org.eclipse.jetty.servlets.CrossOriginFilter</filter-class> |
| * </filter> |
| * <filter-mapping> |
| * <filter-name>cross-origin</filter-name> |
| * <url-pattern>/cometd/*</url-pattern> |
| * </filter-mapping> |
| * ... |
| * </web-app> |
| * </pre></p> |
| */ |
| public class CrossOriginFilter implements Filter |
| { |
| private static final Logger LOG = Log.getLogger(CrossOriginFilter.class); |
| |
| // Request headers |
| private static final String ORIGIN_HEADER = "Origin"; |
| public static final String ACCESS_CONTROL_REQUEST_METHOD_HEADER = "Access-Control-Request-Method"; |
| public static final String ACCESS_CONTROL_REQUEST_HEADERS_HEADER = "Access-Control-Request-Headers"; |
| // Response headers |
| public static final String ACCESS_CONTROL_ALLOW_ORIGIN_HEADER = "Access-Control-Allow-Origin"; |
| public static final String ACCESS_CONTROL_ALLOW_METHODS_HEADER = "Access-Control-Allow-Methods"; |
| public static final String ACCESS_CONTROL_ALLOW_HEADERS_HEADER = "Access-Control-Allow-Headers"; |
| public static final String ACCESS_CONTROL_MAX_AGE_HEADER = "Access-Control-Max-Age"; |
| public static final String ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER = "Access-Control-Allow-Credentials"; |
| public static final String ACCESS_CONTROL_EXPOSE_HEADERS_HEADER = "Access-Control-Expose-Headers"; |
| // Implementation constants |
| public static final String ALLOWED_ORIGINS_PARAM = "allowedOrigins"; |
| public static final String ALLOWED_METHODS_PARAM = "allowedMethods"; |
| public static final String ALLOWED_HEADERS_PARAM = "allowedHeaders"; |
| public static final String PREFLIGHT_MAX_AGE_PARAM = "preflightMaxAge"; |
| public static final String ALLOW_CREDENTIALS_PARAM = "allowCredentials"; |
| public static final String EXPOSED_HEADERS_PARAM = "exposedHeaders"; |
| public static final String OLD_CHAIN_PREFLIGHT_PARAM = "forwardPreflight"; |
| public static final String CHAIN_PREFLIGHT_PARAM = "chainPreflight"; |
| private static final String ANY_ORIGIN = "*"; |
| private static final List<String> SIMPLE_HTTP_METHODS = Arrays.asList("GET", "POST", "HEAD"); |
| |
| private boolean anyOriginAllowed; |
| private List<String> allowedOrigins = new ArrayList<String>(); |
| private List<String> allowedMethods = new ArrayList<String>(); |
| private List<String> allowedHeaders = new ArrayList<String>(); |
| private List<String> exposedHeaders = new ArrayList<String>(); |
| private int preflightMaxAge; |
| private boolean allowCredentials; |
| private boolean chainPreflight; |
| |
| public void init(FilterConfig config) throws ServletException |
| { |
| String allowedOriginsConfig = config.getInitParameter(ALLOWED_ORIGINS_PARAM); |
| if (allowedOriginsConfig == null) |
| allowedOriginsConfig = "*"; |
| String[] allowedOrigins = allowedOriginsConfig.split(","); |
| for (String allowedOrigin : allowedOrigins) |
| { |
| allowedOrigin = allowedOrigin.trim(); |
| if (allowedOrigin.length() > 0) |
| { |
| if (ANY_ORIGIN.equals(allowedOrigin)) |
| { |
| anyOriginAllowed = true; |
| this.allowedOrigins.clear(); |
| break; |
| } |
| else |
| { |
| this.allowedOrigins.add(allowedOrigin); |
| } |
| } |
| } |
| |
| String allowedMethodsConfig = config.getInitParameter(ALLOWED_METHODS_PARAM); |
| if (allowedMethodsConfig == null) |
| allowedMethodsConfig = "GET,POST,HEAD"; |
| allowedMethods.addAll(Arrays.asList(allowedMethodsConfig.split(","))); |
| |
| String allowedHeadersConfig = config.getInitParameter(ALLOWED_HEADERS_PARAM); |
| if (allowedHeadersConfig == null) |
| allowedHeadersConfig = "X-Requested-With,Content-Type,Accept,Origin"; |
| allowedHeaders.addAll(Arrays.asList(allowedHeadersConfig.split(","))); |
| |
| String preflightMaxAgeConfig = config.getInitParameter(PREFLIGHT_MAX_AGE_PARAM); |
| if (preflightMaxAgeConfig == null) |
| preflightMaxAgeConfig = "1800"; // Default is 30 minutes |
| try |
| { |
| preflightMaxAge = Integer.parseInt(preflightMaxAgeConfig); |
| } |
| catch (NumberFormatException x) |
| { |
| LOG.info("Cross-origin filter, could not parse '{}' parameter as integer: {}", PREFLIGHT_MAX_AGE_PARAM, preflightMaxAgeConfig); |
| } |
| |
| String allowedCredentialsConfig = config.getInitParameter(ALLOW_CREDENTIALS_PARAM); |
| if (allowedCredentialsConfig == null) |
| allowedCredentialsConfig = "true"; |
| allowCredentials = Boolean.parseBoolean(allowedCredentialsConfig); |
| |
| String exposedHeadersConfig = config.getInitParameter(EXPOSED_HEADERS_PARAM); |
| if (exposedHeadersConfig == null) |
| exposedHeadersConfig = ""; |
| exposedHeaders.addAll(Arrays.asList(exposedHeadersConfig.split(","))); |
| |
| String chainPreflightConfig = config.getInitParameter(OLD_CHAIN_PREFLIGHT_PARAM); |
| if (chainPreflightConfig!=null) // TODO remove this |
| LOG.warn("DEPRECATED CONFIGURATION: Use "+CHAIN_PREFLIGHT_PARAM+ " instead of "+OLD_CHAIN_PREFLIGHT_PARAM); |
| else |
| chainPreflightConfig = config.getInitParameter(CHAIN_PREFLIGHT_PARAM); |
| if (chainPreflightConfig == null) |
| chainPreflightConfig = "true"; |
| chainPreflight = Boolean.parseBoolean(chainPreflightConfig); |
| |
| if (LOG.isDebugEnabled()) |
| { |
| LOG.debug("Cross-origin filter configuration: " + |
| ALLOWED_ORIGINS_PARAM + " = " + allowedOriginsConfig + ", " + |
| ALLOWED_METHODS_PARAM + " = " + allowedMethodsConfig + ", " + |
| ALLOWED_HEADERS_PARAM + " = " + allowedHeadersConfig + ", " + |
| PREFLIGHT_MAX_AGE_PARAM + " = " + preflightMaxAgeConfig + ", " + |
| ALLOW_CREDENTIALS_PARAM + " = " + allowedCredentialsConfig + "," + |
| EXPOSED_HEADERS_PARAM + " = " + exposedHeadersConfig + "," + |
| CHAIN_PREFLIGHT_PARAM + " = " + chainPreflightConfig |
| ); |
| } |
| } |
| |
| public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException |
| { |
| handle((HttpServletRequest)request, (HttpServletResponse)response, chain); |
| } |
| |
| private void handle(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException |
| { |
| String origin = request.getHeader(ORIGIN_HEADER); |
| // Is it a cross origin request ? |
| if (origin != null && isEnabled(request)) |
| { |
| if (originMatches(origin)) |
| { |
| if (isSimpleRequest(request)) |
| { |
| LOG.debug("Cross-origin request to {} is a simple cross-origin request", request.getRequestURI()); |
| handleSimpleResponse(request, response, origin); |
| } |
| else if (isPreflightRequest(request)) |
| { |
| LOG.debug("Cross-origin request to {} is a preflight cross-origin request", request.getRequestURI()); |
| handlePreflightResponse(request, response, origin); |
| if (chainPreflight) |
| LOG.debug("Preflight cross-origin request to {} forwarded to application", request.getRequestURI()); |
| else |
| return; |
| } |
| else |
| { |
| LOG.debug("Cross-origin request to {} is a non-simple cross-origin request", request.getRequestURI()); |
| handleSimpleResponse(request, response, origin); |
| } |
| } |
| else |
| { |
| LOG.debug("Cross-origin request to " + request.getRequestURI() + " with origin " + origin + " does not match allowed origins " + allowedOrigins); |
| } |
| } |
| |
| chain.doFilter(request, response); |
| } |
| |
| protected boolean isEnabled(HttpServletRequest request) |
| { |
| // WebSocket clients such as Chrome 5 implement a version of the WebSocket |
| // protocol that does not accept extra response headers on the upgrade response |
| for (Enumeration connections = request.getHeaders("Connection"); connections.hasMoreElements();) |
| { |
| String connection = (String)connections.nextElement(); |
| if ("Upgrade".equalsIgnoreCase(connection)) |
| { |
| for (Enumeration upgrades = request.getHeaders("Upgrade"); upgrades.hasMoreElements();) |
| { |
| String upgrade = (String)upgrades.nextElement(); |
| if ("WebSocket".equalsIgnoreCase(upgrade)) |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| private boolean originMatches(String originList) |
| { |
| if (anyOriginAllowed) |
| return true; |
| |
| if (originList.trim().length() == 0) |
| return false; |
| |
| String[] origins = originList.split(" "); |
| for (String origin : origins) |
| { |
| if (origin.trim().length() == 0) |
| continue; |
| |
| for (String allowedOrigin : allowedOrigins) |
| { |
| if (allowedOrigin.contains("*")) |
| { |
| Matcher matcher = createMatcher(origin,allowedOrigin); |
| if (matcher.matches()) |
| return true; |
| } |
| else if (allowedOrigin.equals(origin)) |
| { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| private Matcher createMatcher(String origin, String allowedOrigin) |
| { |
| String regex = parseAllowedWildcardOriginToRegex(allowedOrigin); |
| Pattern pattern = Pattern.compile(regex); |
| return pattern.matcher(origin); |
| } |
| |
| private String parseAllowedWildcardOriginToRegex(String allowedOrigin) |
| { |
| String regex = allowedOrigin.replace(".","\\."); |
| return regex.replace("*",".*"); // we want to be greedy here to match multiple subdomains, thus we use .* |
| } |
| |
| private boolean isSimpleRequest(HttpServletRequest request) |
| { |
| String method = request.getMethod(); |
| if (SIMPLE_HTTP_METHODS.contains(method)) |
| { |
| // TODO: implement better detection of simple headers |
| // The specification says that for a request to be simple, custom request headers must be simple. |
| // Here for simplicity I just check if there is a Access-Control-Request-Method header, |
| // which is required for preflight requests |
| return request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER) == null; |
| } |
| return false; |
| } |
| |
| private boolean isPreflightRequest(HttpServletRequest request) |
| { |
| String method = request.getMethod(); |
| if (!"OPTIONS".equalsIgnoreCase(method)) |
| return false; |
| if (request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER) == null) |
| return false; |
| return true; |
| } |
| |
| private void handleSimpleResponse(HttpServletRequest request, HttpServletResponse response, String origin) |
| { |
| response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, origin); |
| if (allowCredentials) |
| response.setHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER, "true"); |
| if (!exposedHeaders.isEmpty()) |
| response.setHeader(ACCESS_CONTROL_EXPOSE_HEADERS_HEADER, commify(exposedHeaders)); |
| } |
| |
| private void handlePreflightResponse(HttpServletRequest request, HttpServletResponse response, String origin) |
| { |
| boolean methodAllowed = isMethodAllowed(request); |
| if (!methodAllowed) |
| return; |
| boolean headersAllowed = areHeadersAllowed(request); |
| if (!headersAllowed) |
| return; |
| response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, origin); |
| if (allowCredentials) |
| response.setHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER, "true"); |
| if (preflightMaxAge > 0) |
| response.setHeader(ACCESS_CONTROL_MAX_AGE_HEADER, String.valueOf(preflightMaxAge)); |
| response.setHeader(ACCESS_CONTROL_ALLOW_METHODS_HEADER, commify(allowedMethods)); |
| response.setHeader(ACCESS_CONTROL_ALLOW_HEADERS_HEADER, commify(allowedHeaders)); |
| } |
| |
| private boolean isMethodAllowed(HttpServletRequest request) |
| { |
| String accessControlRequestMethod = request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER); |
| LOG.debug("{} is {}", ACCESS_CONTROL_REQUEST_METHOD_HEADER, accessControlRequestMethod); |
| boolean result = false; |
| if (accessControlRequestMethod != null) |
| result = allowedMethods.contains(accessControlRequestMethod); |
| LOG.debug("Method {} is" + (result ? "" : " not") + " among allowed methods {}", accessControlRequestMethod, allowedMethods); |
| return result; |
| } |
| |
| private boolean areHeadersAllowed(HttpServletRequest request) |
| { |
| String accessControlRequestHeaders = request.getHeader(ACCESS_CONTROL_REQUEST_HEADERS_HEADER); |
| LOG.debug("{} is {}", ACCESS_CONTROL_REQUEST_HEADERS_HEADER, accessControlRequestHeaders); |
| boolean result = true; |
| if (accessControlRequestHeaders != null) |
| { |
| String[] headers = accessControlRequestHeaders.split(","); |
| for (String header : headers) |
| { |
| boolean headerAllowed = false; |
| for (String allowedHeader : allowedHeaders) |
| { |
| if (header.trim().equalsIgnoreCase(allowedHeader.trim())) |
| { |
| headerAllowed = true; |
| break; |
| } |
| } |
| if (!headerAllowed) |
| { |
| result = false; |
| break; |
| } |
| } |
| } |
| LOG.debug("Headers [{}] are" + (result ? "" : " not") + " among allowed headers {}", accessControlRequestHeaders, allowedHeaders); |
| return result; |
| } |
| |
| private String commify(List<String> strings) |
| { |
| StringBuilder builder = new StringBuilder(); |
| for (int i = 0; i < strings.size(); ++i) |
| { |
| if (i > 0) builder.append(","); |
| String string = strings.get(i); |
| builder.append(string); |
| } |
| return builder.toString(); |
| } |
| |
| public void destroy() |
| { |
| anyOriginAllowed = false; |
| allowedOrigins.clear(); |
| allowedMethods.clear(); |
| allowedHeaders.clear(); |
| preflightMaxAge = 0; |
| allowCredentials = false; |
| } |
| } |