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Implementing Header verification for REST API calls
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effrafax committed Jan 30, 2017
1 parent 78d822d commit 95f1b3e4307fb7d407ad0cb83869af2564a1aae8
Showing 8 changed files with 670 additions and 0 deletions.
@@ -133,4 +133,10 @@ ldap.bind.authenticator.enabled=false
user.manager.impl=jdo


# REST security settings

# REST base url is for avoiding CSRF attacks
# If it is not set or empty it tries to determine the base url automatically
rest.baseUrl=
# If true, requests without Origin or Referer Header are denied
rest.csrf.absentorigin.deny=true
@@ -0,0 +1,213 @@
package org.apache.archiva.redback.rest.services.interceptors;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/


import org.apache.archiva.redback.configuration.UserConfiguration;
import org.apache.cxf.jaxrs.utils.JAXRSUtils;
import org.apache.cxf.message.Message;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import javax.inject.Named;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

/**
* Created by Martin Stockhammer on 19.01.17.
*
* This interceptor tries to check if requests come from a valid origin and
* are not generated by another site on behalf of the real client.
*
* We are using some of the techniques mentioned in
* https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet
*
* Try to find Origin and Referer of the request.
* Match them to the target address, that may be either statically configured or is determined
* by the Host/X-Forwarded-For Header.
*
*
*/
@Provider
@Service( "requestValidationInterceptor#rest" )
public class RequestValidationInterceptor extends AbstractInterceptor implements ContainerRequestFilter {


private static final String X_FORWARDED_PROTO = "X-Forwarded-Proto";
private static final String X_FORWARDED_HOST = "X-Forwarded-Host";
private static final String ORIGIN = "Origin";
private static final String REFERER = "Referer";
private static final String CFG_REST_BASE_URL = "rest.baseUrl";
private static final String CFG_REST_CSRF_ABSENTORIGIN_DENY = "rest.csrffilter.absentorigin.deny";
private static final String CFG_REST_CSRF_ENABLED = "rest.csrffilter.enabled";

private final Logger log = LoggerFactory.getLogger( getClass() );

private boolean enabled = true;
private boolean useStaticUrl = false;
private boolean denyAbsentHeaders = true;
private URL baseUrl;
private HttpServletRequest httpRequest = null;

private UserConfiguration config;

@Inject
public RequestValidationInterceptor(@Named( value = "userConfiguration#default" )
UserConfiguration config) {
this.config = config;
}

@PostConstruct
public void init() {
String baseUrlStr = config.getString(CFG_REST_BASE_URL, "");
if (!"".equals(baseUrlStr.trim())) {
try {
baseUrl = new URL(baseUrlStr);
useStaticUrl = true;
} catch (MalformedURLException ex) {
log.error("Configured baseUrl (rest.baseUrl={}) is invalid. Message: {}", baseUrlStr, ex.getMessage());
}
} else {
useStaticUrl = false;
}
denyAbsentHeaders = config.getBoolean(CFG_REST_CSRF_ABSENTORIGIN_DENY,true);
enabled = config.getBoolean(CFG_REST_CSRF_ENABLED,true);
if (!enabled) {
log.info("CSRF Filter is disabled by configuration");
}
}

@Override
public void filter(ContainerRequestContext containerRequestContext) throws IOException {
if (enabled) {
HttpServletRequest request = getRequest();
URL targetUrl = getTargetUrl(request);
if (targetUrl == null) {
log.error("Could not verify target URL.");
containerRequestContext.abortWith(Response.status(Response.Status.FORBIDDEN).build());
}
if (!checkSourceRequestHeader(targetUrl, request)) {
log.warn("HTTP Header check failed. Assuming CSRF attack.");
containerRequestContext.abortWith(Response.status(Response.Status.FORBIDDEN).build());
}
}
}

private HttpServletRequest getRequest() {
if (httpRequest!=null) {
return httpRequest;
} else {
Message message = JAXRSUtils.getCurrentMessage();
return getHttpServletRequest(message);
}
}

private URL getTargetUrl(HttpServletRequest request) {
if (useStaticUrl) {
return baseUrl;
} else {
URL requestUrl;
try {
requestUrl = new URL(request.getRequestURL().toString());
} catch (MalformedURLException ex) {
log.error("Bad Request URL {}, Message: {}", request.getRequestURL(), ex.getMessage());
return null;
}
String xforwarded = request.getHeader(X_FORWARDED_HOST);
String xforwardedProto = request.getHeader(X_FORWARDED_PROTO);
if (xforwardedProto==null) {
xforwardedProto=requestUrl.getProtocol();
}
if (xforwarded!=null) {
try {
return new URL(xforwardedProto+"://"+xforwarded);
} catch (MalformedURLException ex) {
log.warn("X-Forwarded-Host Header is malformed: {}", ex.getMessage());
}
}
return requestUrl;
}
}

private int getPort(final URL url) {
return url.getPort() > 0 ? url.getPort() : url.getDefaultPort();
}

private boolean checkSourceRequestHeader(final URL targetUrl, final HttpServletRequest request) {
boolean headerFound=false;
String origin = request.getHeader(ORIGIN);
if (origin!=null) {
try {
URL originUrl = new URL(origin);
headerFound=true;
log.debug("Origin Header URL found: {}", originUrl);
if (!targetUrl.getProtocol().equals(originUrl.getProtocol())) {
log.warn("Origin Header Protocol does not match originUrl={}, targetUrl={}", originUrl, targetUrl);
return false;
}
if (!targetUrl.getHost().equals(originUrl.getHost())) {
log.warn("Origin Header Host does not match originUrl={}, targetUrl={}",originUrl,targetUrl);
return false;
}
int originPort = getPort(originUrl);
int targetPort = getPort(targetUrl);
if (targetPort != originPort) {
log.warn("Origin Header Port does not match originUrl={}, targetUrl={}",originUrl,targetUrl);
return false;
}
} catch (MalformedURLException ex) {
log.warn("Bad URL in Origin HTTP-Header: {}. Message: {}",origin, ex.getMessage());
return false;
}
}
String referer = request.getHeader(REFERER);
if (referer!=null) {
try {
URL refererUrl = new URL(referer);
headerFound=true;
log.debug("Referer Header URL found: {}",refererUrl);
if (!targetUrl.getHost().equals(refererUrl.getHost())) {
log.warn("Referer Header Host does not match refererUrl={}, targetUrl={}",refererUrl,targetUrl);
return false;
}
} catch (MalformedURLException ex) {
log.warn("Bad URL in Referer HTTP-Header: {}, Message: {}", referer, ex.getMessage());
return false;
}
}
if (!headerFound && denyAbsentHeaders) {
log.warn("Neither Origin nor Referer header found. Request is denied.");
return false;
}
return true;
}

public void setHttpRequest(HttpServletRequest request) {
this.httpRequest = request;
}
}
@@ -65,6 +65,7 @@
<ref bean="permissionInterceptor#rest"/>
<ref bean="redbackServiceExceptionMapper"/>
<ref bean="passwordRuleViolationExceptionMapper"/>
<ref bean="requestValidationInterceptor#rest" />
</jaxrs:providers>
</jaxrs:server>

@@ -175,6 +175,7 @@ protected UserService getUserService( String authzHeader )
{
WebClient.client( service ).header( "Authorization", authzHeader );
}
WebClient.client(service).header("Referer","http://localhost");
WebClient.client( service ).accept( MediaType.APPLICATION_JSON_TYPE );
WebClient.client( service ).type( MediaType.APPLICATION_JSON_TYPE );

@@ -196,6 +197,8 @@ protected RoleManagementService getRoleManagementService( String authzHeader )
{
WebClient.client( service ).header( "Authorization", authzHeader );
}
WebClient.client( service ).header("Referer","http://localhost/");


WebClient.client( service ).accept( MediaType.APPLICATION_JSON_TYPE );
WebClient.client( service ).type( MediaType.APPLICATION_JSON_TYPE );
@@ -216,6 +219,7 @@ protected LoginService getLoginService( String authzHeader )
{
WebClient.client( service ).header( "Authorization", authzHeader );
}
WebClient.client( service ).header("Referer","http://localhost/");

WebClient.client( service ).accept( MediaType.APPLICATION_JSON_TYPE );
WebClient.client( service ).type( MediaType.APPLICATION_JSON_TYPE );
@@ -238,6 +242,7 @@ protected LdapGroupMappingService getLdapGroupMappingService( String authzHeader
{
WebClient.client( service ).header( "Authorization", authzHeader );
}
WebClient.client( service ).header("Referer","http://localhost/");

WebClient.client( service ).accept( MediaType.APPLICATION_JSON_TYPE );
WebClient.client( service ).type( MediaType.APPLICATION_JSON_TYPE );

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