rauch rauch - 1 month ago 17
Java Question

How to handle invalid SSL certificates with Apache HttpClient?

I know, there are many different questions and so many answers about this problem... But I can't understand...

I have: ubuntu-9.10-desktop-amd64 + NetBeans6.7.1 installed "as is" from off. rep.
I need connecting to some site over the HTTPS. For this I use Apache's HttpClient.

From tutorial I read:

"Once you have JSSE correctly installed, secure HTTP communication over SSL should be as

simple as plain HTTP communication." And some example:

HttpClient httpclient = new HttpClient();
GetMethod httpget = new GetMethod("https://www.verisign.com/");
try {
httpclient.executeMethod(httpget);
System.out.println(httpget.getStatusLine());
} finally {
httpget.releaseConnection();
}


By now, I write this:

HttpClient client = new HttpClient();

HttpMethod get = new GetMethod("https://mms.nw.ru");
//get.setDoAuthentication(true);

try {
int status = client.executeMethod(get);
System.out.println(status);

BufferedInputStream is = new BufferedInputStream(get.getResponseBodyAsStream());
int r=0;byte[] buf = new byte[10];
while((r = is.read(buf)) > 0) {
System.out.write(buf,0,r);
}

} catch(Exception ex) {
ex.printStackTrace();
}


As a result I have a set of errors:

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1627)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:204)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:198)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:994)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:142)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:533)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:471)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:904)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1132)
at sun.security.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:643)
at sun.security.ssl.AppOutputStream.write(AppOutputStream.java:78)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at org.apache.commons.httpclient.HttpConnection.flushRequestOutputStream(HttpConnection.java:828)
at org.apache.commons.httpclient.HttpMethodBase.writeRequest(HttpMethodBase.java:2116)
at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1096)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at simpleapachehttp.Main.main(Main.java:41)
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:302)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:205)
at sun.security.validator.Validator.validate(Validator.java:235)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:147)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:230)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:270)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:973)
... 17 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:191)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:255)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:297)
... 23 more


What have I to do to create simplest SSL connection?
(Probably without KeyManager and Trust manager etc. while.)

Answer

https://mms.nw.ru uses a self-signed certificate which obviously isn't contained in the default set of trust managers.

You'll need to one of the following:

  • Configure the SSLContext with a TrustManager that accepts any cert (see below)

  • Configure the SSLContext with an appropriate trust store that includes your cert

  • Add the cert for that site to the default java trust store.

Here is a sample program that creates a (mostly worthless) SSL Context that accepts any cert:

import java.net.URL;
import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class SSLTest {

    public static void main(String [] args) throws Exception {
        // configure the SSLContext with a TrustManager
        SSLContext ctx = SSLContext.getInstance("TLS");
        ctx.init(new KeyManager[0], new TrustManager[] {new DefaultTrustManager()}, new SecureRandom());
        SSLContext.setDefault(ctx);

        URL url = new URL("https://mms.nw.ru");
        HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
        conn.setHostnameVerifier(new HostnameVerifier() {
            @Override
            public boolean verify(String arg0, SSLSession arg1) {
                return true;
            }
        });
        System.out.println(conn.getResponseCode());
        conn.disconnect();
    }

    private static class DefaultTrustManager implements X509TrustManager {

        @Override
        public void checkClientTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {}

        @Override
        public void checkServerTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {}

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }
}