/*
* 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.
*/
/**
* @author Boris Kuznetsov
* @version $Revision$
*/
package org.apache.harmony.security.utils;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Principal;
import java.security.Signature;
import java.security.cert.Certificate;
import java.security.cert.CertificateEncodingException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import javax.security.auth.x500.X500Principal;
import org.apache.harmony.security.asn1.ASN1OctetString;
import org.apache.harmony.security.asn1.BerInputStream;
import org.apache.harmony.security.pkcs7.ContentInfo;
import org.apache.harmony.security.pkcs7.SignedData;
import org.apache.harmony.security.pkcs7.SignerInfo;
import org.apache.harmony.security.x501.AttributeTypeAndValue;
public class JarUtils {
// as defined in PKCS #9: Selected Attribute Types:
// http://www.ietf.org/rfc/rfc2985.txt
private static final int[] MESSAGE_DIGEST_OID =
new int[] {1, 2, 840, 113549, 1, 9, 4};
/**
* This method handle all the work with PKCS7, ASN1 encoding, signature verifying,
* and certification path building.
* See also PKCS #7: Cryptographic Message Syntax Standard:
* http://www.ietf.org/rfc/rfc2315.txt
* @param signature - the input stream of signature file to be verified
* @param signatureBlock - the input stream of corresponding signature block file
* @return array of certificates used to verify the signature file
* @throws IOException - if some errors occurs during reading from the stream
* @throws GeneralSecurityException - if signature verification process fails
*/
public static Certificate[] verifySignature(InputStream signature, InputStream
signatureBlock) throws IOException, GeneralSecurityException {
BerInputStream bis = new BerInputStream(signatureBlock);
ContentInfo info = (ContentInfo)ContentInfo.ASN1.decode(bis);
SignedData signedData = info.getSignedData();
if (signedData == null) {
throw new IOException("No SignedData found");
}
Collection<org.apache.harmony.security.x509.Certificate> encCerts
= signedData.getCertificates();
if (encCerts.isEmpty()) {
return null;
}
X509Certificate[] certs = new X509Certificate[encCerts.size()];
CertificateFactory cf = CertificateFactory.getInstance("X.509");
int i = 0;
for (org.apache.harmony.security.x509.Certificate encCert : encCerts) {
final byte[] encoded = encCert.getEncoded();
final InputStream is = new ByteArrayInputStream(encoded);
certs[i++] = new VerbatimX509Certificate((X509Certificate) cf.generateCertificate(is),
encoded);
}
List<SignerInfo> sigInfos = signedData.getSignerInfos();
SignerInfo sigInfo;
if (!sigInfos.isEmpty()) {
sigInfo = sigInfos.get(0);
} else {
return null;
}
// Issuer
X500Principal issuer = sigInfo.getIssuer();
// Certificate serial number
BigInteger snum = sigInfo.getSerialNumber();
// Locate the certificate
int issuerSertIndex = 0;
for (i = 0; i < certs.length; i++) {
if (issuer.equals(certs[i].getIssuerDN()) &&
snum.equals(certs[i].getSerialNumber())) {
issuerSertIndex = i;
break;
}
}
if (i == certs.length) { // No issuer certificate found
return null;
}
if (certs[issuerSertIndex].hasUnsupportedCriticalExtension()) {
throw new SecurityException("Can not recognize a critical extension");
}
// Get Signature instance
final String daOid = sigInfo.getDigestAlgorithm();
final String daName = sigInfo.getDigestAlgorithmName();
final String deaOid = sigInfo.getDigestEncryptionAlgorithm();
final String deaName = sigInfo.getDigestEncryptionAlgorithmName();
String alg = null;
Signature sig = null;
if (daOid != null && deaOid != null) {
alg = daOid + "with" + deaOid;
try {
sig = Signature.getInstance(alg);
} catch (NoSuchAlgorithmException e) {
}
// Try to convert to names instead of OID.
if (sig == null && daName != null && deaName != null) {
alg = daName + "with" + deaName;
try {
sig = Signature.getInstance(alg);
} catch (NoSuchAlgorithmException e) {
}
}
}
if (sig == null && deaOid != null) {
alg = deaOid;
try {
sig = Signature.getInstance(alg);
} catch (NoSuchAlgorithmException e) {
}
if (sig == null) {
alg = deaName;
try {
sig = Signature.getInstance(alg);
} catch (NoSuchAlgorithmException e) {
}
}
}
// We couldn't find a valid Signature type.
if (sig == null) {
return null;
}
sig.initVerify(certs[issuerSertIndex]);
// If the authenticatedAttributes field of SignerInfo contains more than zero attributes,
// compute the message digest on the ASN.1 DER encoding of the Attributes value.
// Otherwise, compute the message digest on the data.
List<AttributeTypeAndValue> atr = sigInfo.getAuthenticatedAttributes();
byte[] sfBytes = new byte[signature.available()];
signature.read(sfBytes);
if (atr == null) {
sig.update(sfBytes);
} else {
sig.update(sigInfo.getEncodedAuthenticatedAttributes());
// If the authenticatedAttributes field contains the message-digest attribute,
// verify that it equals the computed digest of the signature file
byte[] existingDigest = null;
for (AttributeTypeAndValue a : atr) {
if (Arrays.equals(a.getType().getOid(), MESSAGE_DIGEST_OID)) {
if (existingDigest != null) {
throw new SecurityException("Too many MessageDigest attributes");
}
Collection<?> entries = a.getValue().getValues(ASN1OctetString.getInstance());
if (entries.size() != 1) {
throw new SecurityException("Too many values for MessageDigest attribute");
}
existingDigest = (byte[]) entries.iterator().next();
}
}
// RFC 3852 section 9.2: it authAttrs is present, it must have a
// message digest entry.
if (existingDigest == null) {
throw new SecurityException("Missing MessageDigest in Authenticated Attributes");
}
MessageDigest md = null;
if (daOid != null) {
md = MessageDigest.getInstance(daOid);
}
if (md == null && daName != null) {
md = MessageDigest.getInstance(daName);
}
if (md == null) {
return null;
}
byte[] computedDigest = md.digest(sfBytes);
if (!Arrays.equals(existingDigest, computedDigest)) {
throw new SecurityException("Incorrect MD");
}
}
if (!sig.verify(sigInfo.getEncryptedDigest())) {
throw new SecurityException("Incorrect signature");
}
return createChain(certs[issuerSertIndex], certs);
}
private static X509Certificate[] createChain(X509Certificate signer,
X509Certificate[] candidates) {
Principal issuer = signer.getIssuerDN();
// Signer is self-signed
if (signer.getSubjectDN().equals(issuer)) {
return new X509Certificate[] { signer };
}
ArrayList<X509Certificate> chain = new ArrayList<X509Certificate>(candidates.length + 1);
chain.add(0, signer);
X509Certificate issuerCert;
int count = 1;
while (true) {
issuerCert = findCert(issuer, candidates);
if (issuerCert == null) {
break;
}
chain.add(issuerCert);
count++;
/* Prevent growing infinitely if there is a loop */
if (count > candidates.length) {
break;
}
issuer = issuerCert.getIssuerDN();
if (issuerCert.getSubjectDN().equals(issuer)) {
break;
}
}
return chain.toArray(new X509Certificate[count]);
}
private static X509Certificate findCert(Principal issuer, X509Certificate[] candidates) {
for (int i = 0; i < candidates.length; i++) {
if (issuer.equals(candidates[i].getSubjectDN())) {
return candidates[i];
}
}
return null;
}
/**
* For legacy reasons we need to return exactly the original encoded
* certificate bytes, instead of letting the underlying implementation have
* a shot at re-encoding the data.
*/
private static class VerbatimX509Certificate extends WrappedX509Certificate {
private byte[] encodedVerbatim;
public VerbatimX509Certificate(X509Certificate wrapped, byte[] encodedVerbatim) {
super(wrapped);
this.encodedVerbatim = encodedVerbatim;
}
@Override
public byte[] getEncoded() throws CertificateEncodingException {
return encodedVerbatim;
}
}
}