/*
*
* This file is part of the iText (R) project.
Copyright (c) 1998-2017 iText Group NV
* Authors: Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
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* Boston, MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
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* or manipulated using iText.
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the iText software without
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package com.itextpdf.text.pdf.security;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.KeyStoreException;
import java.security.cert.CRL;
import java.security.cert.Certificate;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509CRL;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.List;
import org.bouncycastle.asn1.ocsp.OCSPObjectIdentifiers;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.cert.ocsp.BasicOCSPResp;
import org.bouncycastle.cert.ocsp.CertificateStatus;
import org.bouncycastle.cert.ocsp.OCSPException;
import org.bouncycastle.cert.ocsp.SingleResp;
import org.bouncycastle.operator.ContentVerifierProvider;
import org.bouncycastle.operator.OperatorCreationException;
import org.bouncycastle.operator.bc.BcDigestCalculatorProvider;
import org.bouncycastle.operator.jcajce.JcaContentVerifierProviderBuilder;
import com.itextpdf.text.log.Logger;
import com.itextpdf.text.log.LoggerFactory;
/**
* Class that allows you to verify a certificate against
* one or more OCSP responses.
*/
public class OCSPVerifier extends RootStoreVerifier {
/** The Logger instance */
protected final static Logger LOGGER = LoggerFactory.getLogger(OCSPVerifier.class);
protected final static String id_kp_OCSPSigning = "1.3.6.1.5.5.7.3.9";
/** The list of OCSP responses. */
protected List<BasicOCSPResp> ocsps;
/**
* Creates an OCSPVerifier instance.
* @param verifier the next verifier in the chain
* @param ocsps a list of OCSP responses
*/
public OCSPVerifier(CertificateVerifier verifier, List<BasicOCSPResp> ocsps) {
super(verifier);
this.ocsps = ocsps;
}
/**
* Verifies if a a valid OCSP response is found for the certificate.
* If this method returns false, it doesn't mean the certificate isn't valid.
* It means we couldn't verify it against any OCSP response that was available.
* @param signCert the certificate that needs to be checked
* @param issuerCert its issuer
* @return a list of <code>VerificationOK</code> objects.
* The list will be empty if the certificate couldn't be verified.
* @see com.itextpdf.text.pdf.security.RootStoreVerifier#verify(java.security.cert.X509Certificate, java.security.cert.X509Certificate, java.util.Date)
*/
public List<VerificationOK> verify(X509Certificate signCert,
X509Certificate issuerCert, Date signDate)
throws GeneralSecurityException, IOException {
List<VerificationOK> result = new ArrayList<VerificationOK>();
int validOCSPsFound = 0;
// first check in the list of OCSP responses that was provided
if (ocsps != null) {
for (BasicOCSPResp ocspResp : ocsps) {
if (verify(ocspResp, signCert, issuerCert, signDate))
validOCSPsFound++;
}
}
// then check online if allowed
boolean online = false;
if (onlineCheckingAllowed && validOCSPsFound == 0) {
if (verify(getOcspResponse(signCert, issuerCert), signCert, issuerCert, signDate)) {
validOCSPsFound++;
online = true;
}
}
// show how many valid OCSP responses were found
LOGGER.info("Valid OCSPs found: " + validOCSPsFound);
if (validOCSPsFound > 0)
result.add(new VerificationOK(signCert, this.getClass(), "Valid OCSPs Found: " + validOCSPsFound + (online ? " (online)" : "")));
if (verifier != null)
result.addAll(verifier.verify(signCert, issuerCert, signDate));
// verify using the previous verifier in the chain (if any)
return result;
}
/**
* Verifies a certificate against a single OCSP response
* @param ocspResp the OCSP response
* @param signCert the certificate that needs to be checked
* @param issuerCert the certificate of CA
* @param signDate sign date
* @return {@code true}, in case successful check, otherwise false.
* @throws GeneralSecurityException
* @throws IOException
*/
public boolean verify(BasicOCSPResp ocspResp, X509Certificate signCert, X509Certificate issuerCert, Date signDate) throws GeneralSecurityException, IOException {
if (ocspResp == null)
return false;
// Getting the responses
SingleResp[] resp = ocspResp.getResponses();
for (int i = 0; i < resp.length; i++) {
// check if the serial number corresponds
if (!signCert.getSerialNumber().equals(resp[i].getCertID().getSerialNumber())) {
continue;
}
// check if the issuer matches
try {
if (issuerCert == null) issuerCert = signCert;
if (!resp[i].getCertID().matchesIssuer(new X509CertificateHolder(issuerCert.getEncoded()), new BcDigestCalculatorProvider())) {
LOGGER.info("OCSP: Issuers doesn't match.");
continue;
}
} catch (OCSPException e) {
continue;
}
// check if the OCSP response was valid at the time of signing
Date nextUpdate = resp[i].getNextUpdate();
if (nextUpdate == null) {
nextUpdate = new Date(resp[i].getThisUpdate().getTime() + 180000l);
LOGGER.info(String.format("No 'next update' for OCSP Response; assuming %s", nextUpdate));
}
if (signDate.after(nextUpdate)) {
LOGGER.info(String.format("OCSP no longer valid: %s after %s", signDate, nextUpdate));
continue;
}
// check the status of the certificate
Object status = resp[i].getCertStatus();
if (status == CertificateStatus.GOOD) {
// check if the OCSP response was genuine
isValidResponse(ocspResp, issuerCert);
return true;
}
}
return false;
}
/**
* Verifies if an OCSP response is genuine
* If it doesn't verify against the issuer certificate and response's certificates, it may verify
* using a trusted anchor or cert.
* @param ocspResp the OCSP response
* @param issuerCert the issuer certificate
* @throws GeneralSecurityException
* @throws IOException
*/
public void isValidResponse(BasicOCSPResp ocspResp, X509Certificate issuerCert) throws GeneralSecurityException, IOException {
//OCSP response might be signed by the issuer certificate or
//the Authorized OCSP responder certificate containing the id-kp-OCSPSigning extended key usage extension
X509Certificate responderCert = null;
//first check if the issuer certificate signed the response
//since it is expected to be the most common case
if (isSignatureValid(ocspResp, issuerCert)) {
responderCert = issuerCert;
}
//if the issuer certificate didn't sign the ocsp response, look for authorized ocsp responses
// from properties or from certificate chain received with response
if (responderCert == null) {
if (ocspResp.getCerts() != null) {
//look for existence of Authorized OCSP responder inside the cert chain in ocsp response
X509CertificateHolder[] certs = ocspResp.getCerts();
for (X509CertificateHolder cert : certs) {
X509Certificate tempCert;
try {
tempCert = new JcaX509CertificateConverter().getCertificate(cert);
} catch (Exception ex) {
continue;
}
List<String> keyPurposes = null;
try {
keyPurposes = tempCert.getExtendedKeyUsage();
if ((keyPurposes != null) && keyPurposes.contains(id_kp_OCSPSigning) && isSignatureValid(ocspResp, tempCert)) {
responderCert = tempCert;
break;
}
} catch (CertificateParsingException ignored) {
}
}
// Certificate signing the ocsp response is not found in ocsp response's certificate chain received
// and is not signed by the issuer certificate.
if (responderCert == null) {
throw new VerificationException(issuerCert, "OCSP response could not be verified");
}
} else {
//certificate chain is not present in response received
//try to verify using rootStore
if (rootStore != null) {
try {
for (Enumeration<String> aliases = rootStore.aliases(); aliases.hasMoreElements(); ) {
String alias = aliases.nextElement();
try {
if (!rootStore.isCertificateEntry(alias))
continue;
X509Certificate anchor = (X509Certificate) rootStore.getCertificate(alias);
if (isSignatureValid(ocspResp, anchor)) {
responderCert = anchor;
break;
}
} catch (GeneralSecurityException ignored) {
}
}
} catch (KeyStoreException e) {
responderCert = null;
}
}
// OCSP Response does not contain certificate chain, and response is not signed by any
// of the rootStore or the issuer certificate.
if (responderCert == null) {
throw new VerificationException(issuerCert, "OCSP response could not be verified");
}
}
}
//check "This certificate MUST be issued directly by the CA that issued the certificate in question".
responderCert.verify(issuerCert.getPublicKey());
// validating ocsp signers certificate
// Check if responders certificate has id-pkix-ocsp-nocheck extension,
// in which case we do not validate (perform revocation check on) ocsp certs for lifetime of certificate
if (responderCert.getExtensionValue(OCSPObjectIdentifiers.id_pkix_ocsp_nocheck.getId()) == null) {
CRL crl;
try {
crl = CertificateUtil.getCRL(responderCert);
} catch (Exception ignored) {
crl = null;
}
if (crl != null && crl instanceof X509CRL) {
CRLVerifier crlVerifier = new CRLVerifier(null, null);
crlVerifier.setRootStore(rootStore);
crlVerifier.setOnlineCheckingAllowed(onlineCheckingAllowed);
crlVerifier.verify((X509CRL)crl, responderCert, issuerCert, new Date());
return;
}
}
//check if lifetime of certificate is ok
responderCert.checkValidity();
}
/**
* Verifies if the response is valid.
* If it doesn't verify against the issuer certificate and response's certificates, it may verify
* using a trusted anchor or cert.
* NOTE. Use {@code isValidResponse()} instead.
* @param ocspResp the response object
* @param issuerCert the issuer certificate
* @return true if the response can be trusted
*/
@Deprecated
public boolean verifyResponse(BasicOCSPResp ocspResp, X509Certificate issuerCert) {
try {
isValidResponse(ocspResp, issuerCert);
return true;
} catch (Exception e) {
return false;
}
}
/**
* Checks if an OCSP response is genuine
* @param ocspResp the OCSP response
* @param responderCert the responder certificate
* @return true if the OCSP response verifies against the responder certificate
*/
public boolean isSignatureValid(BasicOCSPResp ocspResp, Certificate responderCert) {
try {
ContentVerifierProvider verifierProvider = new JcaContentVerifierProviderBuilder()
.setProvider("BC").build(responderCert.getPublicKey());
return ocspResp.isSignatureValid(verifierProvider);
} catch (OperatorCreationException e) {
return false;
} catch (OCSPException e) {
return false;
}
}
/**
* Gets an OCSP response online and returns it if the status is GOOD
* (without further checking).
* @param signCert the signing certificate
* @param issuerCert the issuer certificate
* @return an OCSP response
*/
public BasicOCSPResp getOcspResponse(X509Certificate signCert, X509Certificate issuerCert) {
if (signCert == null && issuerCert == null) {
return null;
}
OcspClientBouncyCastle ocsp = new OcspClientBouncyCastle();
BasicOCSPResp ocspResp = ocsp.getBasicOCSPResp(signCert, issuerCert, null);
if (ocspResp == null) {
return null;
}
SingleResp[] resp = ocspResp.getResponses();
for (int i = 0; i < resp.length; i++) {
Object status = resp[i].getCertStatus();
if (status == CertificateStatus.GOOD) {
return ocspResp;
}
}
return null;
}
}