1 /*
2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/conn/ssl/AbstractVerifier.java $
3  * $Revision: 653041 $
4  * $Date: 2008-05-03 03:39:28 -0700 (Sat, 03 May 2008) $
5  *
6  * ====================================================================
7  * Licensed to the Apache Software Foundation (ASF) under one
8  * or more contributor license agreements.  See the NOTICE file
9  * distributed with this work for additional information
10  * regarding copyright ownership.  The ASF licenses this file
11  * to you under the Apache License, Version 2.0 (the
12  * "License"); you may not use this file except in compliance
13  * with the License.  You may obtain a copy of the License at
14  *
15  *   http://www.apache.org/licenses/LICENSE-2.0
16  *
17  * Unless required by applicable law or agreed to in writing,
18  * software distributed under the License is distributed on an
19  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20  * KIND, either express or implied.  See the License for the
21  * specific language governing permissions and limitations
22  * under the License.
23  * ====================================================================
24  *
25  * This software consists of voluntary contributions made by many
26  * individuals on behalf of the Apache Software Foundation.  For more
27  * information on the Apache Software Foundation, please see
28  * <http://www.apache.org/>.
29  *
30  */
31 
32 package org.apache.http.conn.ssl;
33 
34 import java.util.regex.Pattern;
35 
36 import java.io.IOException;
37 import java.security.cert.Certificate;
38 import java.security.cert.CertificateParsingException;
39 import java.security.cert.X509Certificate;
40 import java.util.Arrays;
41 import java.util.Collection;
42 import java.util.Iterator;
43 import java.util.LinkedList;
44 import java.util.List;
45 import java.util.Locale;
46 import java.util.logging.Logger;
47 import java.util.logging.Level;
48 
49 import javax.net.ssl.SSLException;
50 import javax.net.ssl.SSLSession;
51 import javax.net.ssl.SSLSocket;
52 
53 /**
54  * Abstract base class for all standard {@link X509HostnameVerifier}
55  * implementations.
56  *
57  * @author Julius Davies
58  *
59  * @deprecated Please use {@link java.net.URL#openConnection} instead.
60  *     Please visit <a href="http://android-developers.blogspot.com/2011/09/androids-http-clients.html">this webpage</a>
61  *     for further details.
62  */
63 @Deprecated
64 public abstract class AbstractVerifier implements X509HostnameVerifier {
65 
66     private static final Pattern IPV4_PATTERN = Pattern.compile(
67             "^(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}$");
68 
69     /**
70      * This contains a list of 2nd-level domains that aren't allowed to
71      * have wildcards when combined with country-codes.
72      * For example: [*.co.uk].
73      * <p/>
74      * The [*.co.uk] problem is an interesting one.  Should we just hope
75      * that CA's would never foolishly allow such a certificate to happen?
76      * Looks like we're the only implementation guarding against this.
77      * Firefox, Curl, Sun Java 1.4, 5, 6 don't bother with this check.
78      */
79     private final static String[] BAD_COUNTRY_2LDS =
80           { "ac", "co", "com", "ed", "edu", "go", "gouv", "gov", "info",
81             "lg", "ne", "net", "or", "org" };
82 
83     static {
84         // Just in case developer forgot to manually sort the array.  :-)
85         Arrays.sort(BAD_COUNTRY_2LDS);
86     }
87 
AbstractVerifier()88     public AbstractVerifier() {
89         super();
90     }
91 
verify(String host, SSLSocket ssl)92     public final void verify(String host, SSLSocket ssl)
93           throws IOException {
94         if(host == null) {
95             throw new NullPointerException("host to verify is null");
96         }
97 
98         SSLSession session = ssl.getSession();
99         Certificate[] certs = session.getPeerCertificates();
100         X509Certificate x509 = (X509Certificate) certs[0];
101         verify(host, x509);
102     }
103 
verify(String host, SSLSession session)104     public final boolean verify(String host, SSLSession session) {
105         try {
106             Certificate[] certs = session.getPeerCertificates();
107             X509Certificate x509 = (X509Certificate) certs[0];
108             verify(host, x509);
109             return true;
110         }
111         catch(SSLException e) {
112             return false;
113         }
114     }
115 
verify(String host, X509Certificate cert)116     public final void verify(String host, X509Certificate cert)
117           throws SSLException {
118         String[] cns = getCNs(cert);
119         String[] subjectAlts = getDNSSubjectAlts(cert);
120         verify(host, cns, subjectAlts);
121     }
122 
verify(final String host, final String[] cns, final String[] subjectAlts, final boolean strictWithSubDomains)123     public final void verify(final String host, final String[] cns,
124                              final String[] subjectAlts,
125                              final boolean strictWithSubDomains)
126           throws SSLException {
127 
128         // Build the list of names we're going to check.  Our DEFAULT and
129         // STRICT implementations of the HostnameVerifier only use the
130         // first CN provided.  All other CNs are ignored.
131         // (Firefox, wget, curl, Sun Java 1.4, 5, 6 all work this way).
132         LinkedList<String> names = new LinkedList<String>();
133         if(cns != null && cns.length > 0 && cns[0] != null) {
134             names.add(cns[0]);
135         }
136         if(subjectAlts != null) {
137             for (String subjectAlt : subjectAlts) {
138                 if (subjectAlt != null) {
139                     names.add(subjectAlt);
140                 }
141             }
142         }
143 
144         if(names.isEmpty()) {
145             String msg = "Certificate for <" + host + "> doesn't contain CN or DNS subjectAlt";
146             throw new SSLException(msg);
147         }
148 
149         // StringBuffer for building the error message.
150         StringBuffer buf = new StringBuffer();
151 
152         // We're can be case-insensitive when comparing the host we used to
153         // establish the socket to the hostname in the certificate.
154         String hostName = host.trim().toLowerCase(Locale.ENGLISH);
155         boolean match = false;
156         for(Iterator<String> it = names.iterator(); it.hasNext();) {
157             // Don't trim the CN, though!
158             String cn = it.next();
159             cn = cn.toLowerCase(Locale.ENGLISH);
160             // Store CN in StringBuffer in case we need to report an error.
161             buf.append(" <");
162             buf.append(cn);
163             buf.append('>');
164             if(it.hasNext()) {
165                 buf.append(" OR");
166             }
167 
168             // The CN better have at least two dots if it wants wildcard
169             // action.  It also can't be [*.co.uk] or [*.co.jp] or
170             // [*.org.uk], etc...
171             boolean doWildcard = cn.startsWith("*.") &&
172                                  cn.indexOf('.', 2) != -1 &&
173                                  acceptableCountryWildcard(cn) &&
174                                  !isIPv4Address(host);
175 
176             if(doWildcard) {
177                 match = hostName.endsWith(cn.substring(1));
178                 if(match && strictWithSubDomains) {
179                     // If we're in strict mode, then [*.foo.com] is not
180                     // allowed to match [a.b.foo.com]
181                     match = countDots(hostName) == countDots(cn);
182                 }
183             } else {
184                 match = hostName.equals(cn);
185             }
186             if(match) {
187                 break;
188             }
189         }
190         if(!match) {
191             throw new SSLException("hostname in certificate didn't match: <" + host + "> !=" + buf);
192         }
193     }
194 
acceptableCountryWildcard(String cn)195     public static boolean acceptableCountryWildcard(String cn) {
196         int cnLen = cn.length();
197         if(cnLen >= 7 && cnLen <= 9) {
198             // Look for the '.' in the 3rd-last position:
199             if(cn.charAt(cnLen - 3) == '.') {
200                 // Trim off the [*.] and the [.XX].
201                 String s = cn.substring(2, cnLen - 3);
202                 // And test against the sorted array of bad 2lds:
203                 int x = Arrays.binarySearch(BAD_COUNTRY_2LDS, s);
204                 return x < 0;
205             }
206         }
207         return true;
208     }
209 
getCNs(X509Certificate cert)210     public static String[] getCNs(X509Certificate cert) {
211         AndroidDistinguishedNameParser dnParser =
212                 new AndroidDistinguishedNameParser(cert.getSubjectX500Principal());
213         List<String> cnList = dnParser.getAllMostSpecificFirst("cn");
214 
215         if(!cnList.isEmpty()) {
216             String[] cns = new String[cnList.size()];
217             cnList.toArray(cns);
218             return cns;
219         } else {
220             return null;
221         }
222     }
223 
224 
225     /**
226      * Extracts the array of SubjectAlt DNS names from an X509Certificate.
227      * Returns null if there aren't any.
228      * <p/>
229      * Note:  Java doesn't appear able to extract international characters
230      * from the SubjectAlts.  It can only extract international characters
231      * from the CN field.
232      * <p/>
233      * (Or maybe the version of OpenSSL I'm using to test isn't storing the
234      * international characters correctly in the SubjectAlts?).
235      *
236      * @param cert X509Certificate
237      * @return Array of SubjectALT DNS names stored in the certificate.
238      */
getDNSSubjectAlts(X509Certificate cert)239     public static String[] getDNSSubjectAlts(X509Certificate cert) {
240         LinkedList<String> subjectAltList = new LinkedList<String>();
241         Collection<List<?>> c = null;
242         try {
243             c = cert.getSubjectAlternativeNames();
244         }
245         catch(CertificateParsingException cpe) {
246             Logger.getLogger(AbstractVerifier.class.getName())
247                     .log(Level.FINE, "Error parsing certificate.", cpe);
248         }
249         if(c != null) {
250             for (List<?> aC : c) {
251                 List<?> list = aC;
252                 int type = ((Integer) list.get(0)).intValue();
253                 // If type is 2, then we've got a dNSName
254                 if (type == 2) {
255                     String s = (String) list.get(1);
256                     subjectAltList.add(s);
257                 }
258             }
259         }
260         if(!subjectAltList.isEmpty()) {
261             String[] subjectAlts = new String[subjectAltList.size()];
262             subjectAltList.toArray(subjectAlts);
263             return subjectAlts;
264         } else {
265             return null;
266         }
267     }
268 
269     /**
270      * Counts the number of dots "." in a string.
271      * @param s  string to count dots from
272      * @return  number of dots
273      */
countDots(final String s)274     public static int countDots(final String s) {
275         int count = 0;
276         for(int i = 0; i < s.length(); i++) {
277             if(s.charAt(i) == '.') {
278                 count++;
279             }
280         }
281         return count;
282     }
283 
isIPv4Address(final String input)284     private static boolean isIPv4Address(final String input) {
285         return IPV4_PATTERN.matcher(input).matches();
286     }
287 }
288