Java tutorial
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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.http.conn.ssl; import java.io.IOException; import java.io.InputStream; import java.net.InetAddress; import java.net.UnknownHostException; 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 javax.net.ssl.SSLException; import javax.net.ssl.SSLSession; import javax.net.ssl.SSLSocket; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.annotation.Immutable; import org.apache.http.conn.util.InetAddressUtils; /** * 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); } private final Log log = LogFactory.getLog(getClass()); public AbstractVerifier() { super(); } public final void verify(final String host, final 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: final 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(); } } final Certificate[] certs = session.getPeerCertificates(); final X509Certificate x509 = (X509Certificate) certs[0]; verify(host, x509); } public final boolean verify(final String host, final SSLSession session) { try { final Certificate[] certs = session.getPeerCertificates(); final X509Certificate x509 = (X509Certificate) certs[0]; verify(host, x509); return true; } catch (final SSLException e) { return false; } } public final void verify(final String host, final X509Certificate cert) throws SSLException { final String[] cns = getCNs(cert); final 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). final LinkedList<String> names = new LinkedList<String>(); if (cns != null && cns.length > 0 && cns[0] != null) { names.add(cns[0]); } if (subjectAlts != null) { for (final String subjectAlt : subjectAlts) { if (subjectAlt != null) { names.add(subjectAlt); } } } if (names.isEmpty()) { final String msg = "Certificate for <" + host + "> doesn't contain CN or DNS subjectAlt"; throw new SSLException(msg); } // StringBuilder for building the error message. final StringBuilder buf = new StringBuilder(); // We're can be case-insensitive when comparing the host we used to // establish the socket to the hostname in the certificate. final String hostName = normaliseIPv6Address(host.trim().toLowerCase(Locale.US)); boolean match = false; for (final Iterator<String> it = names.iterator(); it.hasNext();) { // Don't trim the CN, though! String cn = it.next(); cn = cn.toLowerCase(Locale.US); // Store CN in StringBuilder 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... final String parts[] = cn.split("\\."); final boolean doWildcard = parts.length >= 3 && parts[0].endsWith("*") && validCountryWildcard(cn) && !isIPAddress(host); if (doWildcard) { final String firstpart = parts[0]; if (firstpart.length() > 1) { // e.g. server* final String prefix = firstpart.substring(0, firstpart.length() - 1); // e.g. server final String suffix = cn.substring(firstpart.length()); // skip wildcard part from cn final String hostSuffix = hostName.substring(prefix.length()); // skip wildcard part from host match = hostName.startsWith(prefix) && hostSuffix.endsWith(suffix); } else { 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(normaliseIPv6Address(cn)); } if (match) { break; } } if (!match) { throw new SSLException("hostname in certificate didn't match: <" + host + "> !=" + buf); } } /** * @deprecated (4.3.1) should not be a part of public APIs. */ @Deprecated public static boolean acceptableCountryWildcard(final String cn) { final String parts[] = cn.split("\\."); if (parts.length != 3 || parts[2].length() != 2) { return true; // it's not an attempt to wildcard a 2TLD within a country code } return Arrays.binarySearch(BAD_COUNTRY_2LDS, parts[1]) < 0; } boolean validCountryWildcard(final String cn) { final String parts[] = cn.split("\\."); if (parts.length != 3 || parts[2].length() != 2) { return true; // it's not an attempt to wildcard a 2TLD within a country code } return Arrays.binarySearch(BAD_COUNTRY_2LDS, parts[1]) < 0; } public static String[] getCNs(final X509Certificate cert) { final 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. */ final String subjectPrincipal = cert.getSubjectX500Principal().toString(); final StringTokenizer st = new StringTokenizer(subjectPrincipal, ",+"); while (st.hasMoreTokens()) { final String tok = st.nextToken().trim(); if (tok.length() > 3) { if (tok.substring(0, 3).equalsIgnoreCase("CN=")) { cnList.add(tok.substring(3)); } } } if (!cnList.isEmpty()) { final 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) { final int subjectType; if (isIPAddress(hostname)) { subjectType = 7; } else { subjectType = 2; } final LinkedList<String> subjectAltList = new LinkedList<String>(); Collection<List<?>> c = null; try { c = cert.getSubjectAlternativeNames(); } catch (final CertificateParsingException cpe) { } if (c != null) { for (final List<?> aC : c) { final List<?> list = aC; final int type = ((Integer) list.get(0)).intValue(); if (type == subjectType) { final String s = (String) list.get(1); subjectAltList.add(s); } } } if (!subjectAltList.isEmpty()) { final 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(final 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)); } /* * Check if hostname is IPv6, and if so, convert to standard format. */ private String normaliseIPv6Address(final String hostname) { if (hostname == null || !InetAddressUtils.isIPv6Address(hostname)) { return hostname; } try { final InetAddress inetAddress = InetAddress.getByName(hostname); return inetAddress.getHostAddress(); } catch (final UnknownHostException uhe) { // Should not happen, because we check for IPv6 address above log.error("Unexpected error converting " + hostname, uhe); return hostname; } } }