/*
* $Id: CertificateUtil.java 5190 2012-06-18 10:46:23Z blowagie $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2012 1T3XT BVBA
* Authors: Bruno Lowagie, Paulo Soares, et al.
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package com.itextpdf.text.pdf.security;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.cert.CRL;
import java.security.cert.CRLException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERIA5String;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.x509.CRLDistPoint;
import org.bouncycastle.asn1.x509.DistributionPoint;
import org.bouncycastle.asn1.x509.DistributionPointName;
import org.bouncycastle.asn1.x509.Extension;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.GeneralNames;
/**
* This class contains a series of static methods that
* allow you to retrieve information from a Certificate.
*/
public class CertificateUtil {
// Certificate Revocation Lists
/**
* Gets a CRL from a certificate
* @param certificate
* @return the CRL or null if there's no CRL available
* @throws CertificateException
* @throws CRLException
* @throws IOException
*/
public static CRL getCRL(X509Certificate certificate) throws CertificateException, CRLException, IOException {
return CertificateUtil.getCRL(CertificateUtil.getCRLURL(certificate));
}
/**
* Gets the URL of the Certificate Revocation List for a Certificate
* @param certificate the Certificate
* @return the String where you can check if the certificate was revoked
* @throws CertificateParsingException
* @throws IOException
*/
public static String getCRLURL(X509Certificate certificate) throws CertificateParsingException {
ASN1Primitive obj;
try {
obj = getExtensionValue(certificate, Extension.cRLDistributionPoints.getId());
} catch (IOException e) {
obj = null;
}
if (obj == null) {
return null;
}
CRLDistPoint dist = CRLDistPoint.getInstance(obj);
DistributionPoint[] dists = dist.getDistributionPoints();
for (DistributionPoint p : dists) {
DistributionPointName distributionPointName = p.getDistributionPoint();
if (DistributionPointName.FULL_NAME != distributionPointName.getType()) {
continue;
}
GeneralNames generalNames = (GeneralNames)distributionPointName.getName();
GeneralName[] names = generalNames.getNames();
for (GeneralName name : names) {
if (name.getTagNo() != GeneralName.uniformResourceIdentifier) {
continue;
}
DERIA5String derStr = DERIA5String.getInstance((ASN1TaggedObject)name.toASN1Primitive(), false);
return derStr.getString();
}
}
return null;
}
/**
* Gets the CRL object using a CRL URL.
* @param url the URL where to get the CRL
* @return a CRL object
* @throws IOException
* @throws CertificateException
* @throws CRLException
*/
public static CRL getCRL(String url) throws IOException, CertificateException, CRLException {
if (url == null)
return null;
InputStream is = new URL(url).openStream();
CertificateFactory cf = CertificateFactory.getInstance("X.509");
return (CRL)cf.generateCRL(is);
}
// Online Certificate Status Protocol
/**
* Retrieves the OCSP URL from the given certificate.
* @param certificate the certificate
* @return the URL or null
* @throws IOException
*/
public static String getOCSPURL(X509Certificate certificate) {
ASN1Primitive obj;
try {
obj = getExtensionValue(certificate, Extension.authorityInfoAccess.getId());
if (obj == null) {
return null;
}
ASN1Sequence AccessDescriptions = (ASN1Sequence) obj;
for (int i = 0; i < AccessDescriptions.size(); i++) {
ASN1Sequence AccessDescription = (ASN1Sequence) AccessDescriptions.getObjectAt(i);
if ( AccessDescription.size() != 2 ) {
continue;
}
else if (AccessDescription.getObjectAt(0) instanceof ASN1ObjectIdentifier) {
ASN1ObjectIdentifier id = (ASN1ObjectIdentifier)AccessDescription.getObjectAt(0);
if (SecurityIDs.ID_OCSP.equals(id.getId())) {
ASN1Primitive description = (ASN1Primitive)AccessDescription.getObjectAt(1);
String AccessLocation = getStringFromGeneralName(description);
if (AccessLocation == null) {
return "" ;
}
else {
return AccessLocation ;
}
}
}
}
} catch (IOException e) {
return null;
}
return null;
}
// Time Stamp Authority
/**
* Gets the URL of the TSA if it's available on the certificate
* @param certificate a certificate
* @return a TSA URL
* @throws IOException
*/
public static String getTSAURL(X509Certificate certificate) {
byte der[] = certificate.getExtensionValue(SecurityIDs.ID_TSA);
if(der == null)
return null;
ASN1Primitive asn1obj;
try {
asn1obj = ASN1Primitive.fromByteArray(der);
DEROctetString octets = (DEROctetString)asn1obj;
asn1obj = ASN1Primitive.fromByteArray(octets.getOctets());
ASN1Sequence asn1seq = ASN1Sequence.getInstance(asn1obj);
return getStringFromGeneralName(asn1seq.getObjectAt(1).toASN1Primitive());
} catch (IOException e) {
return null;
}
}
// helper methods
/**
* @param certificate the certificate from which we need the ExtensionValue
* @param oid the Object Identifier value for the extension.
* @return the extension value as an ASN1Primitive object
* @throws IOException
*/
private static ASN1Primitive getExtensionValue(X509Certificate certificate, String oid) throws IOException {
byte[] bytes = certificate.getExtensionValue(oid);
if (bytes == null) {
return null;
}
ASN1InputStream aIn = new ASN1InputStream(new ByteArrayInputStream(bytes));
ASN1OctetString octs = (ASN1OctetString) aIn.readObject();
aIn = new ASN1InputStream(new ByteArrayInputStream(octs.getOctets()));
return aIn.readObject();
}
/**
* Gets a String from an ASN1Primitive
* @param names the ASN1Primitive
* @return a human-readable String
* @throws IOException
*/
private static String getStringFromGeneralName(ASN1Primitive names) throws IOException {
ASN1TaggedObject taggedObject = (ASN1TaggedObject) names ;
return new String(ASN1OctetString.getInstance(taggedObject, false).getOctets(), "ISO-8859-1");
}
}