title: Ignoring SSL validation in Java
body: <p>I have to call an HTTP service hosted on web server with an invalid SSL certificate. In dev, I'm importing the certificate with <em>keytool</em> but the certificate will be different on each client install, so I can't just bundle it.</p>
  
  <p>Foreword: I <strong>DO</strong> know that skipping SSL validation is really ugly. In this specific case, I would not even need SSL and all other communications in the system are over simple HTTP. So I really don't care about MITM attacks or such. An attacker would not need to go as far as to break SSL because there is no SSL for the data. This is support for a legacy system over which I have no control.</p>
  
  <p>I'm using <code>HttpURLConnection</code> with an <code>SSLSocketFactory</code> that has a <code>NaiveTrustManager</code> and a <code>NaiveHostnameVerifier</code>. This works on some self-signed servers I tried but not on the customer's site. The error I'm getting is:</p>
  
  <pre><code>javax.net.ssl.SSLKeyException: [Security:090477]Certificate chain received from xxxxxxxxxx was not trusted causing SSL handshake failure.
      at com.certicom.tls.interfaceimpl.TLSConnectionImpl.fireException(Unknown Source)
      at com.certicom.tls.interfaceimpl.TLSConnectionImpl.fireAlertSent(Unknown Source)
      at com.certicom.tls.record.handshake.HandshakeHandler.fireAlert(Unknown Source)
      at com.certicom.tls.record.handshake.HandshakeHandler.fireAlert(Unknown Source)
      at com.certicom.tls.record.handshake.ClientStateReceivedServerHello.handle(Unknown Source)
      at com.certicom.tls.record.handshake.HandshakeHandler.handleHandshakeMessage(Unknown Source)
      at com.certicom.tls.record.handshake.HandshakeHandler.handleHandshakeMessages(Unknown Source)
      at com.certicom.tls.record.MessageInterpreter.interpretContent(Unknown Source)
      at com.certicom.tls.record.MessageInterpreter.decryptMessage(Unknown Source)
      at com.certicom.tls.record.ReadHandler.processRecord(Unknown Source)
      at com.certicom.tls.record.ReadHandler.readRecord(Unknown Source)
      at com.certicom.tls.record.ReadHandler.readUntilHandshakeComplete(Unknown Source)
      at com.certicom.tls.interfaceimpl.TLSConnectionImpl.completeHandshake(Unknown Source)
      at com.certicom.tls.record.WriteHandler.write(Unknown Source)
      at com.certicom.io.OutputSSLIOStreamWrapper.write(Unknown Source)
      at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
      at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
      at java.io.FilterOutputStream.flush(FilterOutputStream.java:123)
      at weblogic.net.http.HttpURLConnection.writeRequests(HttpURLConnection.java:154)
      at weblogic.net.http.HttpURLConnection.getInputStream(HttpURLConnection.java:358)
      at weblogic.net.http.SOAPHttpsURLConnection.getInputStream(SOAPHttpsURLConnection.java:37)
      at weblogic.net.http.HttpURLConnection.getResponseCode(HttpURLConnection.java:947)
      at (my own code)
  </code></pre>
  
  <p>My <code>SimpleSocketFactory</code> looks like:</p>
  
  <pre><code>public static final SSLSocketFactory getSocketFactory()
  {
      if ( sslSocketFactory == null ) {
          try {
              // get ssl context
              SSLContext sc = SSLContext.getInstance("SSL");
  
              // Create a trust manager that does not validate certificate chains
              TrustManager[] trustAllCerts = new TrustManager[]{
                  new NaiveTrustManager() {
                      public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                          log.debug("getAcceptedIssuers");
                          return new java.security.cert.X509Certificate[0];
                      }
                      public void checkClientTrusted(
                          java.security.cert.X509Certificate[] certs, String authType) {
                          log.debug("checkClientTrusted");
                      }
                      public void checkServerTrusted(
                          java.security.cert.X509Certificate[] certs, String authType) {
                          log.debug("checkServerTrusted");
                      }
                  }
              };
  
              sc.init(null, trustAllCerts, new java.security.SecureRandom());
              // EDIT: fixed the following line that was redeclaring SSLSocketFactory sslSocketFactory, returning null every time. Same result though.
              sslSocketFactory = sc.getSocketFactory();
  
              HttpsURLConnection.setDefaultSSLSocketFactory(sslSocketFactory);
              // EDIT: The following line has no effect
              //HttpsURLConnection.setDefaultHostnameVerifier(new NaiveHostNameVerifier());
  
          } catch (KeyManagementException e) {
              log.error ("No SSL algorithm support: " + e.getMessage(), e);
          } catch (NoSuchAlgorithmException e) {
              log.error ("Exception when setting up the Naive key management.", e);
          }
      }
      return sslSocketFactory;
  }
  </code></pre>
  
  <p>The <code>NaiveHostnameVerifier</code> has a way to limit the valid hosts but it's left null, so basically accepting anything:</p>
  
  <pre><code>public class NaiveHostnameVerifier implements HostnameVerifier {
      String[] patterns;
  
      public NaiveHostnameVerifier () {
          this.patterns=null;
      }
  
      public NaiveHostnameVerifier (String[] patterns) {
          this.patterns = patterns;
      }
  
      public boolean verify(String urlHostName,SSLSession session) {
          if (patterns==null || patterns.length==0) {
              return true;
          } else {
              for (String pattern : patterns) {
                  if (urlHostName.matches(pattern)) {
                      return true;
                  }
              }
              return false;
          }
      }
  }
  </code></pre>
  
  <p>The usage is like this:</p>
  
  <pre><code>    try {
          conn = (HttpURLConnection)url.openConnection();
          if (conn instanceof HttpsURLConnection) {
                  ((HttpsURLConnection)conn).setSSLSocketFactory(SimpleSSLSocketFactory.getSocketFactory());
                  // EDIT: added this line, the HV has to be set on connection, not on the factory.
                  ((HttpsURLConnection)conn).setHostnameVerifier(new NaiveHostnameVerifier());
          }
          conn.setDoInput(true);
          conn.setDoOutput(true);
          conn.setRequestMethod("POST");
          conn.setRequestProperty("Content-type","application/x-www-form-urlencoded");
          conn.connect();
  
          StringBuffer sbContent = new StringBuffer();
          // (snip)
          DataOutputStream stream = new DataOutputStream(conn.getOutputStream ());
          stream.writeBytes(sbContent.toString());
          stream.flush();
          stream.close();
      } catch (ClassCastException e) {
          log.error("The URL does not seem to point to a HTTP connection");
          return null;
      } catch (IOException e) {
          log.error("Error accessing the requested URL", e);
          return null;
      }
  </code></pre>
  
  <p>When I'm searching on the error message, most people just import the certificate in their store but again, I can't really do that because I don't know which certificate it'll be. My only alternative if this doesn't work is to make a tool that can download the certificate and add it in an easier way that cryptic command lines but I'd rather let my Java code just ignore the invalid certificate.</p>
  
  <p>Any idea ?</p>