Cross-Site Request Forgery in Jenkins

@@ -7,6 +7,7 @@
  
 import hudson.util.MultipartFormDataParser;
 import jenkins.model.Jenkins;
+import jenkins.util.SystemProperties;
 import org.acegisecurity.providers.anonymous.AnonymousAuthenticationToken;
 import org.kohsuke.MetaInfServices;
 import org.kohsuke.accmod.Restricted;
@@ -15,7 +16,10 @@
 import org.kohsuke.stapler.interceptor.RequirePOST;
  
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Enumeration;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
  
@@ -26,6 +30,7 @@
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequestWrapper;
 import javax.servlet.http.HttpServletResponse;
  
 /**
@@ -58,6 +63,54 @@ public ForwardToView getForwardView() {
     public void init(FilterConfig filterConfig) throws ServletException {
     }
  
+    private static class Security1774ServletRequest extends HttpServletRequestWrapper {
+        public Security1774ServletRequest(HttpServletRequest request) {
+            super(request);
+        }
+ 
+        @Override
+        public String getPathInfo() {
+            // see Stapler#getServletPath
+            return canonicalPath(getRequestURI().substring(getContextPath().length()));
+        }
+ 
+ 
+        // Copied from Stapler#canonicalPath
+        private static String canonicalPath(String path) {
+            List<String> r = new ArrayList<String>(Arrays.asList(path.split("/+")));
+            for (int i=0; i<r.size(); ) {
+                if (r.get(i).length()==0 || r.get(i).equals(".")) {
+                    // empty token occurs for example, "".split("/+") is [""]
+                    r.remove(i);
+                } else
+                if (r.get(i).equals("..")) {
+                    // i==0 means this is a broken URI.
+                    r.remove(i);
+                    if (i>0) {
+                        r.remove(i-1);
+                        i--;
+                    }
+                } else {
+                    i++;
+                }
+            }
+ 
+            StringBuilder buf = new StringBuilder();
+            if (path.startsWith("/"))
+                buf.append('/');
+            boolean first = true;
+            for (String token : r) {
+                if (!first)     buf.append('/');
+                else            first = false;
+                buf.append(token);
+            }
+            // translation: if (path.endsWith("/") && !buf.endsWith("/"))
+            if (path.endsWith("/") && (buf.length()==0 || buf.charAt(buf.length()-1)!='/'))
+                buf.append('/');
+            return buf.toString();
+        }
+    }
+ 
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
         CrumbIssuer crumbIssuer = getCrumbIssuer();
         if (crumbIssuer == null || !(request instanceof HttpServletRequest)) {
@@ -69,8 +122,9 @@ public void doFilter(ServletRequest request, ServletResponse response, FilterCha
         HttpServletResponse httpResponse = (HttpServletResponse) response;
  
         if ("POST".equals(httpRequest.getMethod())) {
+            HttpServletRequest wrappedRequest = UNPROCESSED_PATHINFO ? httpRequest : new Security1774ServletRequest(httpRequest);
             for (CrumbExclusion e : CrumbExclusion.all()) {
-                if (e.process(httpRequest,httpResponse,chain))
+                if (e.process(wrappedRequest,httpResponse,chain))
                     return;
             }
  
@@ -136,5 +190,7 @@ protected static boolean isMultipart(HttpServletRequest request) {
     public void destroy() {
     }
  
+    static /* non-final for Groovy */ boolean UNPROCESSED_PATHINFO = SystemProperties.getBoolean(CrumbFilter.class.getName() + ".UNPROCESSED_PATHINFO");
+ 
     private static final Logger LOGGER = Logger.getLogger(CrumbFilter.class.getName());
 }

@@ -0,0 +1,120 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2020 CloudBees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
+package hudson.security.csrf;
+ 
+import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
+import com.gargoylesoftware.htmlunit.HttpMethod;
+import com.gargoylesoftware.htmlunit.WebRequest;
+ 
+import java.io.IOException;
+import java.net.URL;
+ 
+import hudson.ExtensionList;
+import hudson.model.UnprotectedRootAction;
+import jenkins.model.Jenkins;
+import static org.hamcrest.Matchers.containsString;
+ 
+import org.junit.Assert;
+import org.junit.Test;
+import static org.junit.Assert.*;
+import org.junit.Rule;
+import org.jvnet.hudson.test.Issue;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.MockAuthorizationStrategy;
+import org.jvnet.hudson.test.TestExtension;
+import org.kohsuke.stapler.verb.POST;
+ 
+import javax.annotation.CheckForNull;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+ 
+public class CrumbExclusionTest {
+ 
+    @Rule
+    public JenkinsRule r = new JenkinsRule();
+ 
+    @Issue("SECURITY-1774")
+    @Test
+    public void pathInfo() throws Exception {
+        r.jenkins.setSecurityRealm(r.createDummySecurityRealm());
+        r.jenkins.setAuthorizationStrategy(new MockAuthorizationStrategy().grant(Jenkins.ADMINISTER).everywhere().to("admin"));
+        for (String path : new String[] {/* control */ "scriptText", /* test */ "scriptText/..;/cli"}) {
+            try {
+                fail(path + " should have been rejected: " + r.createWebClient().login("admin").getPage(new WebRequest(new URL(r.getURL(), path + "?script=11*11"), HttpMethod.POST)).getWebResponse().getContentAsString());
+            } catch (FailingHttpStatusCodeException x) {
+                assertEquals("status code using " + path, 403, x.getStatusCode());
+                assertThat("error message using " + path, x.getResponse().getContentAsString(), containsString("No valid crumb was included in the request"));
+            }
+        }
+    }
+ 
+    @Test
+    public void regular() throws Exception {
+        r.createWebClient().getPage(new WebRequest(new URL(r.getURL(), "root/"), HttpMethod.POST));
+        Assert.assertTrue(ExtensionList.lookupSingleton(RootActionImpl.class).posted);
+    }
+ 
+    @TestExtension
+    public static class RootActionImpl implements UnprotectedRootAction {
+ 
+        public boolean posted = false;
+ 
+        @CheckForNull
+        public String getIconFileName() {
+            return null;
+        }
+ 
+        @CheckForNull
+        public String getDisplayName() {
+            return null;
+        }
+ 
+        @CheckForNull
+        public String getUrlName() {
+            return "root";
+        }
+ 
+        @POST
+        public void doIndex() {
+            posted = true;
+        }
+    }
+ 
+    @TestExtension
+    public static class CrumbExclusionImpl extends CrumbExclusion {
+ 
+        @Override
+        public boolean process(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
+            String pathInfo = request.getPathInfo();
+            if (pathInfo != null && pathInfo.startsWith("/root/")) {
+                chain.doFilter(request, response);
+                return true;
+            }
+            return false;
+        }
+    }
+}

@@ -0,0 +1,47 @@
+package jenkins.security;
+ 
+import jenkins.util.SystemProperties;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
+ 
+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 java.io.IOException;
+import java.util.logging.Logger;
+ 
+@Restricted(NoExternalUse.class)
+public class SuspiciousRequestFilter implements Filter {
+ 
+    /** System property name set to true or false to indicate whether or not semicolons should be allowed in URL paths. */
+    public static final String ALLOW_SEMICOLONS_IN_PATH = SuspiciousRequestFilter.class.getName() + ".allowSemicolonsInPath";
+    public static boolean allowSemicolonsInPath = SystemProperties.getBoolean(ALLOW_SEMICOLONS_IN_PATH, false);
+    private static final Logger LOGGER = Logger.getLogger(SuspiciousRequestFilter.class.getName());
+ 
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        HttpServletRequest httpRequest = (HttpServletRequest) request;
+        HttpServletResponse httpResponse = (HttpServletResponse) response;
+        if (!allowSemicolonsInPath && httpRequest.getRequestURI().contains(";")) {
+            LOGGER.warning(() -> "Denying HTTP " + httpRequest.getMethod() + " to " + httpRequest.getRequestURI() +
+                    " as it has an illegal semicolon in the path. This behavior can be overridden by setting the system property " +
+                    ALLOW_SEMICOLONS_IN_PATH + " to true. For more information, see https://jenkins.io/redirect/semicolons-in-urls");
+            httpResponse.sendError(HttpServletResponse.SC_BAD_REQUEST, "Semicolons are not allowed in the request URI");
+        } else {
+            chain.doFilter(request, response);
+        }
+    }
+ 
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+    }
+ 
+    @Override
+    public void destroy() {
+    }
+}

@@ -36,7 +36,10 @@
 import jenkins.model.Jenkins;
 import static org.hamcrest.Matchers.containsString;
  
+import jenkins.security.SuspiciousRequestFilter;
+import org.junit.AfterClass;
 import org.junit.Assert;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import static org.junit.Assert.*;
 import org.junit.Rule;
@@ -57,6 +60,16 @@ public class CrumbExclusionTest {
     @Rule
     public JenkinsRule r = new JenkinsRule();
  
+    @BeforeClass
+    public static void prepare() {
+        SuspiciousRequestFilter.allowSemicolonsInPath = true;
+    }
+ 
+    @AfterClass
+    public static void cleanup() {
+        SuspiciousRequestFilter.allowSemicolonsInPath = false;
+    }
+ 
     @Issue("SECURITY-1774")
     @Test
     public void pathInfo() throws Exception {

@@ -0,0 +1,102 @@
+package jenkins.security;
+ 
+import com.gargoylesoftware.htmlunit.WebRequest;
+import com.gargoylesoftware.htmlunit.WebResponse;
+import hudson.ExtensionList;
+import hudson.model.UnprotectedRootAction;
+import org.junit.Rule;
+import org.junit.Test;
+import org.jvnet.hudson.test.Issue;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.TestExtension;
+import org.kohsuke.stapler.QueryParameter;
+import org.kohsuke.stapler.verb.GET;
+ 
+import javax.annotation.CheckForNull;
+import javax.servlet.http.HttpServletResponse;
+import java.net.URL;
+ 
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+ 
+@Issue("SECURITY-1774")
+public class SuspiciousRequestFilterTest {
+ 
+    @Rule
+    public JenkinsRule j = new JenkinsRule();
+ 
+    private WebResponse get(String path) throws Exception {
+        return j.createWebClient()
+                .withThrowExceptionOnFailingStatusCode(false)
+                .getPage(new WebRequest(new URL(j.getURL(), path)))
+                .getWebResponse();
+    }
+ 
+    @Test
+    public void denySemicolonInRequestPathByDefault() throws Exception {
+        WebResponse response = get("foo/bar/..;/?baz=bruh");
+        assertThat(Foo.getInstance().baz, is(nullValue()));
+        assertThat(response.getStatusCode(), is(HttpServletResponse.SC_BAD_REQUEST));
+        assertThat(response.getContentAsString(), containsString("Semicolons are not allowed in the request URI"));
+    }
+ 
+    @Test
+    public void allowSemicolonsInRequestPathWhenEscapeHatchEnabled() throws Exception {
+        SuspiciousRequestFilter.allowSemicolonsInPath = true;
+        try {
+            WebResponse response = get("foo/bar/..;/..;/cli?baz=bruh");
+            assertThat(Foo.getInstance().baz, is("bruh"));
+            assertThat(response.getStatusCode(), is(HttpServletResponse.SC_OK));
+        } finally {
+            SuspiciousRequestFilter.allowSemicolonsInPath = false;
+        }
+    }
+ 
+    @Test
+    public void allowSemicolonsInQueryParameters() throws Exception {
+        WebResponse response = get("foo/bar?baz=foo;bar=baz");
+        assertThat(Foo.getInstance().baz, is("foo;bar=baz"));
+        assertThat(response.getStatusCode(), is(HttpServletResponse.SC_OK));
+    }
+ 
+    @TestExtension
+    public static class Foo implements UnprotectedRootAction {
+ 
+        private static Foo getInstance() {
+            return ExtensionList.lookupSingleton(Foo.class);
+        }
+ 
+        private String baz;
+ 
+        @CheckForNull
+        @Override
+        public String getIconFileName() {
+            return null;
+        }
+ 
+        @CheckForNull
+        @Override
+        public String getDisplayName() {
+            return "Pitied Foos";
+        }
+ 
+        @CheckForNull
+        @Override
+        public String getUrlName() {
+            return "foo";
+        }
+ 
+        @GET
+        public void doBar(@QueryParameter String baz) {
+            this.baz = baz;
+        }
+ 
+        @GET
+        public void doIndex(@QueryParameter String baz) {
+            this.baz = "index: " + baz;
+        }
+    }
+ 
+}

@@ -50,6 +50,11 @@ THE SOFTWARE.
     <url-pattern>/*</url-pattern>
   </servlet-mapping>
  
+  <filter>
+    <filter-name>suspicious-request-filter</filter-name>
+    <filter-class>jenkins.security.SuspiciousRequestFilter</filter-class>
+    <async-supported>true</async-supported>
+  </filter>
   <filter>
     <filter-name>diagnostic-name-filter</filter-name>
     <filter-class>org.kohsuke.stapler.DiagnosticThreadNameFilter</filter-class>
@@ -125,7 +130,11 @@ THE SOFTWARE.
     <url-pattern>*.png</url-pattern>
   </filter-mapping>
   -->
-  
+ 
+  <filter-mapping>
+    <filter-name>suspicious-request-filter</filter-name>
+    <url-pattern>/*</url-pattern>
+  </filter-mapping>
   <filter-mapping>
     <filter-name>diagnostic-name-filter</filter-name>
     <url-pattern>/*</url-pattern>