home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (AbstractVerifier.java)

This example source code file (AbstractVerifier.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java tags/keywords

abstractverifier, bad_country_2lds, cn, dns, io, ioexception, linkedlist, log, logging, net, nullpointerexception, or, ssl, sslexception, sslsession, string, stringbuffer, stringtokenizer, util, x509certificate

The AbstractVerifier.java example source code

/*
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.conn.ssl;

import org.apache.http.annotation.Immutable;

import org.apache.http.conn.util.InetAddressUtils;

import java.io.IOException;
import java.io.InputStream;
import java.security.cert.Certificate;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.StringTokenizer;
import java.util.logging.Logger;
import java.util.logging.Level;

import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;

/**
 * Abstract base class for all standard {@link X509HostnameVerifier} 
 * implementations.
 *
 * @since 4.0
 */
@Immutable
public abstract class AbstractVerifier implements X509HostnameVerifier {

    /**
     * This contains a list of 2nd-level domains that aren't allowed to
     * have wildcards when combined with country-codes.
     * For example: [*.co.uk].
     * <p/>
     * The [*.co.uk] problem is an interesting one.  Should we just hope
     * that CA's would never foolishly allow such a certificate to happen?
     * Looks like we're the only implementation guarding against this.
     * Firefox, Curl, Sun Java 1.4, 5, 6 don't bother with this check.
     */
    private final static String[] BAD_COUNTRY_2LDS =
          { "ac", "co", "com", "ed", "edu", "go", "gouv", "gov", "info",
            "lg", "ne", "net", "or", "org" };

    static {
        // Just in case developer forgot to manually sort the array.  :-)
        Arrays.sort(BAD_COUNTRY_2LDS);
    }

    public AbstractVerifier() {
        super();
    }

    public final void verify(String host, SSLSocket ssl)
          throws IOException {
        if(host == null) {
            throw new NullPointerException("host to verify is null");
        }

        SSLSession session = ssl.getSession();
        if(session == null) {
            // In our experience this only happens under IBM 1.4.x when
            // spurious (unrelated) certificates show up in the server'
            // chain.  Hopefully this will unearth the real problem:
            InputStream in = ssl.getInputStream();
            in.available();
            /*
              If you're looking at the 2 lines of code above because
              you're running into a problem, you probably have two
              options:

                #1.  Clean up the certificate chain that your server
                     is presenting (e.g. edit "/etc/apache2/server.crt"
                     or wherever it is your server's certificate chain
                     is defined).

                                           OR

                #2.   Upgrade to an IBM 1.5.x or greater JVM, or switch
                      to a non-IBM JVM.
            */

            // If ssl.getInputStream().available() didn't cause an
            // exception, maybe at least now the session is available?
            session = ssl.getSession();
            if(session == null) {
                // If it's still null, probably a startHandshake() will
                // unearth the real problem.
                ssl.startHandshake();

                // Okay, if we still haven't managed to cause an exception,
                // might as well go for the NPE.  Or maybe we're okay now?
                session = ssl.getSession();
            }
        }

        Certificate[] certs = session.getPeerCertificates();
        X509Certificate x509 = (X509Certificate) certs[0];
        verify(host, x509);
    }

    public final boolean verify(String host, SSLSession session) {
        try {
            Certificate[] certs = session.getPeerCertificates();
            X509Certificate x509 = (X509Certificate) certs[0];
            verify(host, x509);
            return true;
        }
        catch(SSLException e) {
            return false;
        }
    }

    public final void verify(String host, X509Certificate cert)
          throws SSLException {
        String[] cns = getCNs(cert);
        String[] subjectAlts = getSubjectAlts(cert, host);
        verify(host, cns, subjectAlts);
    }

    public final void verify(final String host, final String[] cns,
                             final String[] subjectAlts,
                             final boolean strictWithSubDomains)
          throws SSLException {

        // Build the list of names we're going to check.  Our DEFAULT and
        // STRICT implementations of the HostnameVerifier only use the
        // first CN provided.  All other CNs are ignored.
        // (Firefox, wget, curl, Sun Java 1.4, 5, 6 all work this way).
        LinkedList<String> names = new LinkedList();
        if(cns != null && cns.length > 0 && cns[0] != null) {
            names.add(cns[0]);
        }
        if(subjectAlts != null) {
            for (String subjectAlt : subjectAlts) {
                if (subjectAlt != null) {
                    names.add(subjectAlt);
                }
            }
        }

        if(names.isEmpty()) {
            String msg = "Certificate for <" + host + "> doesn't contain CN or DNS subjectAlt";
            throw new SSLException(msg);
        }

        // StringBuffer for building the error message.
        StringBuffer buf = new StringBuffer();

        // We're can be case-insensitive when comparing the host we used to
        // establish the socket to the hostname in the certificate.
        String hostName = host.trim().toLowerCase(Locale.ENGLISH);
        boolean match = false;
        for(Iterator<String> it = names.iterator(); it.hasNext();) {
            // Don't trim the CN, though!
            String cn = it.next();
            cn = cn.toLowerCase(Locale.ENGLISH);
            // Store CN in StringBuffer in case we need to report an error.
            buf.append(" <");
            buf.append(cn);
            buf.append('>');
            if(it.hasNext()) {
                buf.append(" OR");
            }

            // The CN better have at least two dots if it wants wildcard
            // action.  It also can't be [*.co.uk] or [*.co.jp] or
            // [*.org.uk], etc...
            boolean doWildcard = cn.startsWith("*.") &&
                                 cn.lastIndexOf('.') >= 0 &&
                                 acceptableCountryWildcard(cn) &&
                                 !isIPAddress(host);

            if(doWildcard) {
                match = hostName.endsWith(cn.substring(1));
                if(match && strictWithSubDomains) {
                    // If we're in strict mode, then [*.foo.com] is not
                    // allowed to match [a.b.foo.com]
                    match = countDots(hostName) == countDots(cn);
                }
            } else {
                match = hostName.equals(cn);
            }
            if(match) {
                break;
            }
        }
        if(!match) {
            throw new SSLException("hostname in certificate didn't match: <" + host + "> !=" + buf);
        }
    }

    public static boolean acceptableCountryWildcard(String cn) {
        int cnLen = cn.length();
        if(cnLen >= 7 && cnLen <= 9) {
            // Look for the '.' in the 3rd-last position:
            if(cn.charAt(cnLen - 3) == '.') {
                // Trim off the [*.] and the [.XX].
                String s = cn.substring(2, cnLen - 3);
                // And test against the sorted array of bad 2lds:
                int x = Arrays.binarySearch(BAD_COUNTRY_2LDS, s);
                return x < 0;
            }
        }
        return true;
    }

    public static String[] getCNs(X509Certificate cert) {
        LinkedList<String> cnList = new LinkedList();
        /*
          Sebastian Hauer's original StrictSSLProtocolSocketFactory used
          getName() and had the following comment:

                Parses a X.500 distinguished name for the value of the
                "Common Name" field.  This is done a bit sloppy right
                 now and should probably be done a bit more according to
                <code>RFC 2253.

           I've noticed that toString() seems to do a better job than
           getName() on these X500Principal objects, so I'm hoping that
           addresses Sebastian's concern.

           For example, getName() gives me this:
           1.2.840.113549.1.9.1=#16166a756c6975736461766965734063756362632e636f6d

           whereas toString() gives me this:
           EMAILADDRESS=juliusdavies@cucbc.com

           Looks like toString() even works with non-ascii domain names!
           I tested it with "花子.co.jp" and it worked fine.
        */
        String subjectPrincipal = cert.getSubjectX500Principal().toString();
        StringTokenizer st = new StringTokenizer(subjectPrincipal, ",");
        while(st.hasMoreTokens()) {
            String tok = st.nextToken();
            int x = tok.indexOf("CN=");
            if(x >= 0) {
                cnList.add(tok.substring(x + 3));
            }
        }
        if(!cnList.isEmpty()) {
            String[] cns = new String[cnList.size()];
            cnList.toArray(cns);
            return cns;
        } else {
            return null;
        }
    }

    /**
     * Extracts the array of SubjectAlt DNS or IP names from an X509Certificate.
     * Returns null if there aren't any.
     *
     * @param cert X509Certificate
     * @param hostname
     * @return Array of SubjectALT DNS or IP names stored in the certificate.
     */
    private static String[] getSubjectAlts(
            final X509Certificate cert, final String hostname) {
        int subjectType;
        if (isIPAddress(hostname)) {
            subjectType = 7;
        } else {
            subjectType = 2;
        }
        
        LinkedList<String> subjectAltList = new LinkedList();
        Collection<List c = null;
        try {
            c = cert.getSubjectAlternativeNames();
        }
        catch(CertificateParsingException cpe) {
            Logger.getLogger(AbstractVerifier.class.getName())
                    .log(Level.FINE, "Error parsing certificate.", cpe);
        }
        if(c != null) {
            for (List<?> aC : c) {
                List<?> list = aC;
                int type = ((Integer) list.get(0)).intValue();
                if (type == subjectType) {
                    String s = (String) list.get(1);
                    subjectAltList.add(s);
                }
            }
        }
        if(!subjectAltList.isEmpty()) {
            String[] subjectAlts = new String[subjectAltList.size()];
            subjectAltList.toArray(subjectAlts);
            return subjectAlts;
        } else {
            return null;
        }
    }

    /**
     * Extracts the array of SubjectAlt DNS names from an X509Certificate.
     * Returns null if there aren't any.
     * <p/>
     * Note:  Java doesn't appear able to extract international characters
     * from the SubjectAlts.  It can only extract international characters
     * from the CN field.
     * <p/>
     * (Or maybe the version of OpenSSL I'm using to test isn't storing the
     * international characters correctly in the SubjectAlts?).
     *
     * @param cert X509Certificate
     * @return Array of SubjectALT DNS names stored in the certificate.
     */
    public static String[] getDNSSubjectAlts(X509Certificate cert) {
        return getSubjectAlts(cert, null);
    }

    /**
     * Counts the number of dots "." in a string.
     * @param s  string to count dots from
     * @return  number of dots
     */
    public static int countDots(final String s) {
        int count = 0;
        for(int i = 0; i < s.length(); i++) {
            if(s.charAt(i) == '.') {
                count++;
            }
        }
        return count;
    }
    
    private static boolean isIPAddress(final String hostname) {
        return hostname != null && 
            (InetAddressUtils.isIPv4Address(hostname) || 
                    InetAddressUtils.isIPv6Address(hostname));
    }
    
}

Other Java examples (source code examples)

Here is a short list of links related to this Java AbstractVerifier.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.