io.r2dbc.postgresql.client.DefaultHostnameVerifier Maven / Gradle / Ivy
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/*
* Copyright 2017-2020 the original author or authors.
*
* Licensed 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
*
* https://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.
*/
package io.r2dbc.postgresql.client;
import reactor.util.Logger;
import reactor.util.Loggers;
import reactor.util.annotation.Nullable;
import javax.naming.InvalidNameException;
import javax.naming.ldap.LdapName;
import javax.naming.ldap.Rdn;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;
import javax.security.auth.x500.X500Principal;
import java.net.IDN;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* Default hostname verifier.
*
* Considers wildcards and IPv6 addresses.
*/
public enum DefaultHostnameVerifier implements HostnameVerifier {
/**
* Singleton instance.
*/
INSTANCE;
private static final int TYPE_DNS_NAME = 2;
private static final int TYPE_IP_ADDRESS = 7;
static Comparator HOSTNAME_PATTERN_COMPARATOR = new Comparator() {
@Override
public int compare(String o1, String o2) {
// The more the dots the better: a.b.c.postgresql.org is more specific than postgresql.org
int d1 = countChars(o1, '.');
int d2 = countChars(o2, '.');
if (d1 != d2) {
return d1 > d2 ? 1 : -1;
}
// The less the stars the better: postgresql.org is more specific than *.*.postgresql.org
int s1 = countChars(o1, '*');
int s2 = countChars(o2, '*');
if (s1 != s2) {
return s1 < s2 ? 1 : -1;
}
// The longer the better: postgresql.org is more specific than sql.org
int l1 = o1.length();
int l2 = o2.length();
if (l1 != l2) {
return l1 > l2 ? 1 : -1;
}
return 0;
}
private int countChars(String value, char ch) {
int count = 0;
int pos = -1;
while (true) {
pos = value.indexOf(ch, pos + 1);
if (pos == -1) {
break;
}
count++;
}
return count;
}
};
private final Logger logger = Loggers.getLogger(this.getClass());
@Override
public boolean verify(String hostname, SSLSession session) {
X509Certificate[] peerCerts;
try {
peerCerts = (X509Certificate[]) session.getPeerCertificates();
} catch (SSLPeerUnverifiedException e) {
this.logger.warn("Unable to parse X509Certificate for hostname {}", hostname, e);
return false;
}
if (peerCerts == null || peerCerts.length == 0) {
this.logger.warn("No certificates found for hostname {}", hostname);
return false;
}
String canonicalHostname;
if (hostname.startsWith("[") && hostname.endsWith("]")) {
// IPv6 address like [2001:db8:0:1:1:1:1:1]
canonicalHostname = hostname.substring(1, hostname.length() - 1);
} else {
// This converts unicode domain name to ASCII
try {
canonicalHostname = IDN.toASCII(hostname);
this.logger.debug("Canonical host name for {} is {}", hostname, canonicalHostname);
} catch (IllegalArgumentException e) {
// e.g. hostname is invalid
this.logger.warn("Hostname {} is invalid", hostname, e);
return false;
}
}
X509Certificate serverCert = peerCerts[0];
// Check for Subject Alternative Names (see RFC 6125)
Collection> subjectAltNames;
try {
subjectAltNames = serverCert.getSubjectAlternativeNames();
if (subjectAltNames == null) {
subjectAltNames = Collections.emptyList();
}
} catch (CertificateParsingException e) {
this.logger.warn("Unable to parse certificates for hostname {}", hostname, e);
return false;
}
boolean anyDnsSan = false;
/*
* Each item in the SAN collection is a 2-element list.
* See {@link X509Certificate#getSubjectAlternativeNames}
* The first element in each list is a number indicating the type of entry.
*/
for (List sanItem : subjectAltNames) {
if (sanItem.size() != 2) {
continue;
}
Integer sanType = (Integer) sanItem.get(0);
if (sanType == null) {
// just in case
continue;
}
if (sanType != TYPE_IP_ADDRESS && sanType != TYPE_DNS_NAME) {
continue;
}
String san = (String) sanItem.get(1);
if (sanType == TYPE_IP_ADDRESS && san.startsWith("*")) {
// Wildcards should not be present in the IP Address field
continue;
}
anyDnsSan |= sanType == TYPE_DNS_NAME;
if (verifyHostName(canonicalHostname, san)) {
this.logger.debug("Server name validation pass for {}, subjectAltName {}", hostname, san);
return true;
}
}
if (anyDnsSan) {
/*
* RFC2818, section 3.1 (I bet you won't recheck :)
* If a subjectAltName extension of type dNSName is present, that MUST
* be used as the identity. Otherwise, the (most specific) Common Name
* field in the Subject field of the certificate MUST be used. Although
* the use of the Common Name is existing practice, it is deprecated and
* Certification Authorities are encouraged to use the dNSName instead.
*/
this.logger.debug("Server name validation failed: certificate for host {} dNSName entries subjectAltName, but none of them match. Assuming server name validation failed", hostname);
return false;
}
// Last attempt: no DNS Subject Alternative Name entries detected, try common name
LdapName DN;
try {
DN = new LdapName(serverCert.getSubjectX500Principal().getName(X500Principal.RFC2253));
} catch (InvalidNameException e) {
this.logger.warn("Server name validation failed: unable to extract common name from X509Certificate for hostname {}", hostname, e);
return false;
}
List commonNames = new ArrayList(1);
for (Rdn rdn : DN.getRdns()) {
if ("CN".equals(rdn.getType())) {
commonNames.add((String) rdn.getValue());
}
}
if (commonNames.isEmpty()) {
this.logger.warn("Server name validation failed: certificate for hostname {} has no DNS subjectAltNames, and it CommonName is missing as well", hostname);
return false;
}
if (commonNames.size() > 1) {
/*
* RFC2818, section 3.1
* If a subjectAltName extension of type dNSName is present, that MUST
* be used as the identity. Otherwise, the (most specific) Common Name
* field in the Subject field of the certificate MUST be used
*
* The sort is from less specific to most specific.
*/
commonNames.sort(HOSTNAME_PATTERN_COMPARATOR);
}
String commonName = commonNames.get(commonNames.size() - 1);
boolean result = verifyHostName(canonicalHostname, commonName);
if (!result) {
this.logger.warn("Server name validation failed: hostname {} does not match common name {}", hostname, commonName);
}
return result;
}
public boolean verifyHostName(@Nullable String hostname, @Nullable String pattern) {
if (hostname == null || pattern == null) {
return false;
}
int lastStar = pattern.lastIndexOf('*');
if (lastStar == -1) {
// No wildcard => just compare hostnames
return hostname.equalsIgnoreCase(pattern);
}
if (lastStar > 0) {
// Wildcards like foo*.com are not supported yet
return false;
}
if (pattern.indexOf('.') == -1) {
// Wildcard certificates should contain at least one dot
return false;
}
// pattern starts with *, so hostname should be at least (pattern.length-1) long
if (hostname.length() < pattern.length() - 1) {
return false;
}
// Use case insensitive comparison
final boolean ignoreCase = true;
// Below code is "hostname.endsWithIgnoreCase(pattern.withoutFirstStar())"
// E.g. hostname==sub.host.com; pattern==*.host.com
// We need to start the offset of ".host.com" in hostname
// For this we take hostname.length() - pattern.length()
// and +1 is required since pattern is known to start with *
int toffset = hostname.length() - pattern.length() + 1;
// Wildcard covers just one domain level
// a.b.c.com should not be covered by *.c.com
if (hostname.lastIndexOf('.', toffset - 1) >= 0) {
// If there's a dot in between 0..toffset
return false;
}
return hostname.regionMatches(ignoreCase, toffset,
pattern, 1, pattern.length() - 1);
}
}