/*
* $Id: 6e6f2a26db82b38176ed5b6772463c655230f3c4 $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2016 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 com.itextpdf.text.DocumentException;
import com.itextpdf.text.io.RASInputStream;
import com.itextpdf.text.io.RandomAccessSource;
import com.itextpdf.text.io.RandomAccessSourceFactory;
import com.itextpdf.text.io.StreamUtil;
import com.itextpdf.text.log.Logger;
import com.itextpdf.text.log.LoggerFactory;
import com.itextpdf.text.pdf.AcroFields;
import com.itextpdf.text.pdf.ByteBuffer;
import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfDate;
import com.itextpdf.text.pdf.PdfDeveloperExtension;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfSignature;
import com.itextpdf.text.pdf.PdfSignatureAppearance;
import com.itextpdf.text.pdf.PdfString;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.HashMap;
/**
* Class that signs your PDF.
* @author Paulo Soares
*/
public class MakeSignature {
/** The Logger instance. */
private static final Logger LOGGER = LoggerFactory.getLogger(MakeSignature.class);
public enum CryptoStandard {
CMS, CADES
}
/**
* Signs the document using the detached mode, CMS or CAdES equivalent.
* @param sap the PdfSignatureAppearance
* @param externalSignature the interface providing the actual signing
* @param chain the certificate chain
* @param crlList the CRL list
* @param ocspClient the OCSP client
* @param tsaClient the Timestamp client
* @param externalDigest an implementation that provides the digest
* @param estimatedSize the reserved size for the signature. It will be estimated if 0
* @param sigtype Either Signature.CMS or Signature.CADES
* @throws DocumentException
* @throws IOException
* @throws GeneralSecurityException
* @throws NoSuchAlgorithmException
* @throws Exception
*/
public static void signDetached(PdfSignatureAppearance sap, ExternalDigest externalDigest, ExternalSignature externalSignature, Certificate[] chain, Collection<CrlClient> crlList, OcspClient ocspClient,
TSAClient tsaClient, int estimatedSize, CryptoStandard sigtype) throws IOException, DocumentException, GeneralSecurityException {
Collection<byte[]> crlBytes = null;
int i = 0;
while (crlBytes == null && i < chain.length)
crlBytes = processCrl(chain[i++], crlList);
if (estimatedSize == 0) {
estimatedSize = 8192;
if (crlBytes != null) {
for (byte[] element : crlBytes) {
estimatedSize += element.length + 10;
}
}
if (ocspClient != null)
estimatedSize += 4192;
if (tsaClient != null)
estimatedSize += 4192;
}
sap.setCertificate(chain[0]);
if (sigtype == CryptoStandard.CADES) {
sap.addDeveloperExtension(PdfDeveloperExtension.ESIC_1_7_EXTENSIONLEVEL2);
}
PdfSignature dic = new PdfSignature(PdfName.ADOBE_PPKLITE, sigtype == CryptoStandard.CADES ? PdfName.ETSI_CADES_DETACHED : PdfName.ADBE_PKCS7_DETACHED);
dic.setReason(sap.getReason());
dic.setLocation(sap.getLocation());
dic.setSignatureCreator(sap.getSignatureCreator());
dic.setContact(sap.getContact());
dic.setDate(new PdfDate(sap.getSignDate())); // time-stamp will over-rule this
sap.setCryptoDictionary(dic);
HashMap<PdfName, Integer> exc = new HashMap<PdfName, Integer>();
exc.put(PdfName.CONTENTS, new Integer(estimatedSize * 2 + 2));
sap.preClose(exc);
String hashAlgorithm = externalSignature.getHashAlgorithm();
PdfPKCS7 sgn = new PdfPKCS7(null, chain, hashAlgorithm, null, externalDigest, false);
InputStream data = sap.getRangeStream();
byte hash[] = DigestAlgorithms.digest(data, externalDigest.getMessageDigest(hashAlgorithm));
byte[] ocsp = null;
if (chain.length >= 2 && ocspClient != null) {
ocsp = ocspClient.getEncoded((X509Certificate) chain[0], (X509Certificate) chain[1], null);
}
byte[] sh = sgn.getAuthenticatedAttributeBytes(hash, ocsp, crlBytes, sigtype);
byte[] extSignature = externalSignature.sign(sh);
sgn.setExternalDigest(extSignature, null, externalSignature.getEncryptionAlgorithm());
byte[] encodedSig = sgn.getEncodedPKCS7(hash, tsaClient, ocsp, crlBytes, sigtype);
if (estimatedSize < encodedSig.length)
throw new IOException("Not enough space");
byte[] paddedSig = new byte[estimatedSize];
System.arraycopy(encodedSig, 0, paddedSig, 0, encodedSig.length);
PdfDictionary dic2 = new PdfDictionary();
dic2.put(PdfName.CONTENTS, new PdfString(paddedSig).setHexWriting(true));
sap.close(dic2);
}
/**
* Processes a CRL list.
* @param cert a Certificate if one of the CrlList implementations needs to retrieve the CRL URL from it.
* @param crlList a list of CrlClient implementations
* @return a collection of CRL bytes that can be embedded in a PDF.
*/
public static Collection<byte[]> processCrl(Certificate cert, Collection<CrlClient> crlList) {
if (crlList == null)
return null;
ArrayList<byte[]> crlBytes = new ArrayList<byte[]>();
for (CrlClient cc : crlList) {
if (cc == null)
continue;
LOGGER.info("Processing " + cc.getClass().getName());
Collection<byte[]> b = cc.getEncoded((X509Certificate)cert, null);
if (b == null)
continue;
crlBytes.addAll(b);
}
if (crlBytes.isEmpty())
return null;
else
return crlBytes;
}
/**
* Sign the document using an external container, usually a PKCS7. The signature is fully composed
* externally, iText will just put the container inside the document.
* @param sap the PdfSignatureAppearance
* @param externalSignatureContainer the interface providing the actual signing
* @param estimatedSize the reserved size for the signature
* @throws GeneralSecurityException
* @throws IOException
* @throws DocumentException
*/
public static void signExternalContainer(PdfSignatureAppearance sap, ExternalSignatureContainer externalSignatureContainer, int estimatedSize) throws GeneralSecurityException, IOException, DocumentException {
PdfSignature dic = new PdfSignature(null, null);
dic.setReason(sap.getReason());
dic.setLocation(sap.getLocation());
dic.setSignatureCreator(sap.getSignatureCreator());
dic.setContact(sap.getContact());
dic.setDate(new PdfDate(sap.getSignDate())); // time-stamp will over-rule this
externalSignatureContainer.modifySigningDictionary(dic);
sap.setCryptoDictionary(dic);
HashMap<PdfName, Integer> exc = new HashMap<PdfName, Integer>();
exc.put(PdfName.CONTENTS, new Integer(estimatedSize * 2 + 2));
sap.preClose(exc);
InputStream data = sap.getRangeStream();
byte[] encodedSig = externalSignatureContainer.sign(data);
if (estimatedSize < encodedSig.length)
throw new IOException("Not enough space");
byte[] paddedSig = new byte[estimatedSize];
System.arraycopy(encodedSig, 0, paddedSig, 0, encodedSig.length);
PdfDictionary dic2 = new PdfDictionary();
dic2.put(PdfName.CONTENTS, new PdfString(paddedSig).setHexWriting(true));
sap.close(dic2);
}
/**
* Signs a PDF where space was already reserved.
* @param reader the original PDF
* @param fieldName the field to sign. It must be the last field
* @param outs the output PDF
* @param externalSignatureContainer the signature container doing the actual signing. Only the
* method ExternalSignatureContainer.sign is used
* @throws DocumentException
* @throws IOException
* @throws GeneralSecurityException
*/
public static void signDeferred(PdfReader reader, String fieldName, OutputStream outs, ExternalSignatureContainer externalSignatureContainer) throws DocumentException, IOException, GeneralSecurityException {
AcroFields af = reader.getAcroFields();
PdfDictionary v = af.getSignatureDictionary(fieldName);
if (v == null)
throw new DocumentException("No field");
if (!af.signatureCoversWholeDocument(fieldName))
throw new DocumentException("Not the last signature");
PdfArray b = v.getAsArray(PdfName.BYTERANGE);
long[] gaps = b.asLongArray();
if (b.size() != 4 || gaps[0] != 0)
throw new DocumentException("Single exclusion space supported");
RandomAccessSource readerSource = reader.getSafeFile().createSourceView();
InputStream rg = new RASInputStream(new RandomAccessSourceFactory().createRanged(readerSource, gaps));
byte[] signedContent = externalSignatureContainer.sign(rg);
int spaceAvailable = (int)(gaps[2] - gaps[1]) - 2;
if ((spaceAvailable & 1) != 0)
throw new DocumentException("Gap is not a multiple of 2");
spaceAvailable /= 2;
if (spaceAvailable < signedContent.length)
throw new DocumentException("Not enough space");
StreamUtil.CopyBytes(readerSource, 0, gaps[1] + 1, outs);
ByteBuffer bb = new ByteBuffer(spaceAvailable * 2);
for (byte bi : signedContent) {
bb.appendHex(bi);
}
int remain = (spaceAvailable - signedContent.length) * 2;
for (int k = 0; k < remain; ++k) {
bb.append((byte)48);
}
bb.writeTo(outs);
StreamUtil.CopyBytes(readerSource, gaps[2] - 1, gaps[3] + 1, outs);
}
}