/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/conn/ssl/AbstractVerifier.java $
* $Revision: 653041 $
* $Date: 2008-05-03 03:39:28 -0700 (Sat, 03 May 2008) $
*
* ====================================================================
* 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.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.
*
* @author Julius Davies
*/
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");
}
ssl.startHandshake();
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 = getDNSSubjectAlts(cert);
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<String>();
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) &&
!InetAddressUtils.isIPv4Address(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<String>();
/*
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</code>.
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 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) {
LinkedList<String> subjectAltList = new LinkedList<String>();
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 is 2, then we've got a dNSName
if (type == 2) {
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;
}
}
/**
* 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;
}
}