okhttp3.internal.tls.BasicCertificateChainCleaner Maven / Gradle / Ivy
/*
* Copyright (C) 2016 Square, Inc.
*
* 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
*
* 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.
*/
package okhttp3.internal.tls;
import java.security.GeneralSecurityException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.Iterator;
import java.util.List;
import javax.net.ssl.SSLPeerUnverifiedException;
/**
* A certificate chain cleaner that uses a set of trusted root certificates to build the trusted
* chain. This class duplicates the clean chain building performed during the TLS handshake. We
* prefer other mechanisms where they exist, such as with
* {@code okhttp3.internal.platform.AndroidPlatform.AndroidCertificateChainCleaner}.
*
* This class includes code from Conscrypt's {@code
* TrustManagerImpl} and {@code TrustedCertificateIndex}.
*/
public final class BasicCertificateChainCleaner extends CertificateChainCleaner {
/** The maximum number of signers in a chain. We use 9 for consistency with OpenSSL. */
private static final int MAX_SIGNERS = 9;
private final TrustRootIndex trustRootIndex;
public BasicCertificateChainCleaner(TrustRootIndex trustRootIndex) {
this.trustRootIndex = trustRootIndex;
}
/**
* Returns a cleaned chain for {@code chain}.
*
*
This method throws if the complete chain to a trusted CA certificate cannot be constructed.
* This is unexpected unless the trust root index in this class has a different trust manager than
* what was used to establish {@code chain}.
*/
@Override public List clean(List chain, String hostname)
throws SSLPeerUnverifiedException {
Deque queue = new ArrayDeque<>(chain);
List result = new ArrayList<>();
result.add(queue.removeFirst());
boolean foundTrustedCertificate = false;
followIssuerChain:
for (int c = 0; c < MAX_SIGNERS; c++) {
X509Certificate toVerify = (X509Certificate) result.get(result.size() - 1);
// If this cert has been signed by a trusted cert, use that. Add the trusted certificate to
// the end of the chain unless it's already present. (That would happen if the first
// certificate in the chain is itself a self-signed and trusted CA certificate.)
X509Certificate trustedCert = trustRootIndex.findByIssuerAndSignature(toVerify);
if (trustedCert != null) {
if (result.size() > 1 || !toVerify.equals(trustedCert)) {
result.add(trustedCert);
}
if (verifySignature(trustedCert, trustedCert)) {
return result; // The self-signed cert is a root CA. We're done.
}
foundTrustedCertificate = true;
continue;
}
// Search for the certificate in the chain that signed this certificate. This is typically
// the next element in the chain, but it could be any element.
for (Iterator i = queue.iterator(); i.hasNext(); ) {
X509Certificate signingCert = (X509Certificate) i.next();
if (verifySignature(toVerify, signingCert)) {
i.remove();
result.add(signingCert);
continue followIssuerChain;
}
}
// We've reached the end of the chain. If any cert in the chain is trusted, we're done.
if (foundTrustedCertificate) {
return result;
}
// The last link isn't trusted. Fail.
throw new SSLPeerUnverifiedException(
"Failed to find a trusted cert that signed " + toVerify);
}
throw new SSLPeerUnverifiedException("Certificate chain too long: " + result);
}
/** Returns true if {@code toVerify} was signed by {@code signingCert}'s public key. */
private boolean verifySignature(X509Certificate toVerify, X509Certificate signingCert) {
if (!toVerify.getIssuerDN().equals(signingCert.getSubjectDN())) return false;
try {
toVerify.verify(signingCert.getPublicKey());
return true;
} catch (GeneralSecurityException verifyFailed) {
return false;
}
}
@Override public int hashCode() {
return trustRootIndex.hashCode();
}
@Override public boolean equals(Object other) {
if (other == this) return true;
return other instanceof BasicCertificateChainCleaner
&& ((BasicCertificateChainCleaner) other).trustRootIndex.equals(trustRootIndex);
}
}