Java tutorial
/* * $Id: ffbafb2283b3cd687debb34095ca24318b387dc8 $ * * This file is part of the iText (R) project. * Copyright (c) 1998-2015 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): * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT * OF THIRD PARTY RIGHTS * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU Affero General Public License for more details. * You should have received a copy of the GNU Affero General Public License * along with this program; if not, see http://www.gnu.org/licenses or write to * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * Boston, MA, 02110-1301 USA, or download the license from the following URL: * http://itextpdf.com/terms-of-use/ * * The interactive user interfaces in modified source and object code versions * of this program must display Appropriate Legal Notices, as required under * Section 5 of the GNU Affero General Public License. * * In accordance with Section 7(b) of the GNU Affero General Public License, * a covered work must retain the producer line in every PDF that is created * 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 * disclosing the source code of your own applications. * These activities include: offering paid services to customers as an ASP, * serving PDFs on the fly in a web application, shipping iText with a closed * source product. * * For more information, please contact iText Software Corp. at this * address: sales@itextpdf.com */ package com.itextpdf.text.pdf.security; import java.io.IOException; import java.security.GeneralSecurityException; import java.security.cert.Certificate; import java.security.cert.X509Certificate; import java.util.ArrayList; import java.util.Date; import java.util.Enumeration; import java.util.List; 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); /** 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 serialNumber the serial number of the certificate that needs to be checked * @param issuerCert * @param signDate * @return * @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 * @param ocspResp the OCSP response * @param issuerCert the issuer certificate * @throws GeneralSecurityException * @throws IOException */ public void isValidResponse(BasicOCSPResp ocspResp, X509Certificate issuerCert) throws GeneralSecurityException, IOException { // by default the OCSP responder certificate is the issuer certificate X509Certificate responderCert = issuerCert; // check if there's a responder certificate X509CertificateHolder[] certHolders = ocspResp.getCerts(); if (certHolders.length > 0) { responderCert = new JcaX509CertificateConverter().setProvider("BC").getCertificate(certHolders[0]); try { responderCert.verify(issuerCert.getPublicKey()); } catch (GeneralSecurityException e) { if (super.verify(responderCert, issuerCert, null).size() == 0) throw new VerificationException(responderCert, "Responder certificate couldn't be verified"); } } // verify if the signature of the response is valid if (!verifyResponse(ocspResp, responderCert)) throw new VerificationException(responderCert, "OCSP response could not be verified"); } /** * Verifies if the signature of the response is valid. * If it doesn't verify against the responder certificate, it may verify * using a trusted anchor. * @param ocspResp the response object * @param responderCert the certificate that may be used to sign the response * @return true if the response can be trusted */ public boolean verifyResponse(BasicOCSPResp ocspResp, X509Certificate responderCert) { // testing using the responder certificate if (isSignatureValid(ocspResp, responderCert)) return true; // testing using trusted anchors if (rootStore == null) return false; try { // loop over the certificates in the root store 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)) return true; } catch (GeneralSecurityException e) { continue; } } } catch (GeneralSecurityException e) { return false; } 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; } }