eu.europa.esig.dss.pades.validation.PDFDocumentValidator.java Source code

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Here is the source code for eu.europa.esig.dss.pades.validation.PDFDocumentValidator.java

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/**
 * DSS - Digital Signature Services
 * Copyright (C) 2015 European Commission, provided under the CEF programme
 *
 * This file is part of the "DSS - Digital Signature Services" project.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package eu.europa.esig.dss.pades.validation;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang.StringUtils;
import org.apache.pdfbox.io.IOUtils;
import org.bouncycastle.util.encoders.Base64;

import eu.europa.esig.dss.DSSDocument;
import eu.europa.esig.dss.DSSException;
import eu.europa.esig.dss.DSSUtils;
import eu.europa.esig.dss.InMemoryDocument;
import eu.europa.esig.dss.cades.validation.CAdESSignature;
import eu.europa.esig.dss.pdf.PDFSignatureService;
import eu.europa.esig.dss.pdf.PdfObjFactory;
import eu.europa.esig.dss.pdf.PdfSignatureInfo;
import eu.europa.esig.dss.pdf.PdfSignatureValidationCallback;
import eu.europa.esig.dss.validation.AdvancedSignature;
import eu.europa.esig.dss.validation.SignedDocumentValidator;

/**
 * Validation of PDF document.
 *
 */
public class PDFDocumentValidator extends SignedDocumentValidator {

    final PDFSignatureService pdfSignatureService;
    private static final String BASE64_REGEX = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$";

    /**
     * Default constructor used with reflexion (see SignedDocumentValidator)
     */
    private PDFDocumentValidator() {
        super(null);
        pdfSignatureService = null;
    }

    /**
     * The default constructor for PDFDocumentValidator.
     */
    public PDFDocumentValidator(final DSSDocument document) {
        super(new PAdESSignatureScopeFinder());
        this.document = document;
        pdfSignatureService = PdfObjFactory.getInstance().newPAdESSignatureService();
    }

    @Override
    public boolean isSupported(DSSDocument dssDocument) {
        int headerLength = 500;
        byte[] preamble = new byte[headerLength];
        DSSUtils.readToArray(dssDocument, headerLength, preamble);
        String preambleString = new String(preamble);
        if (preambleString.startsWith("%PDF-")) {
            return true;
        }
        return false;
    }

    @Override
    public List<AdvancedSignature> getSignatures() {

        final List<AdvancedSignature> signatures = new ArrayList<AdvancedSignature>();
        pdfSignatureService.validateSignatures(validationCertPool, document, new PdfSignatureValidationCallback() {

            @Override
            public void validate(final PdfSignatureInfo pdfSignatureInfo) {
                try {
                    if (pdfSignatureInfo.getCades() != null) {

                        final PAdESSignature padesSignature = new PAdESSignature(document, pdfSignatureInfo,
                                validationCertPool);
                        padesSignature.setProvidedSigningCertificateToken(providedSigningCertificateToken);
                        signatures.add(padesSignature);
                    }
                } catch (Exception e) {
                    throw new DSSException(e);
                }
            }
        });
        return signatures;
    }

    @Override
    public DSSDocument getOriginalDocument(String signatureId) throws DSSException {
        if (StringUtils.isBlank(signatureId)) {
            throw new NullPointerException("signatureId");
        }
        List<AdvancedSignature> signatures = getSignatures();
        for (AdvancedSignature signature : signatures) {
            PAdESSignature padesSignature = (PAdESSignature) signature;
            if (padesSignature.getId().equals(signatureId)) {
                CAdESSignature cadesSignature = padesSignature.getCAdESSignature();
                DSSDocument inMemoryDocument = null;
                DSSDocument firstDocument = null;
                for (DSSDocument document : cadesSignature.getDetachedContents()) {
                    byte[] content;
                    try {
                        content = IOUtils.toByteArray(document.openStream());
                    } catch (IOException e) {
                        throw new DSSException(e);
                    }
                    content = isBase64Encoded(content) ? Base64.decode(content) : content;
                    if (firstDocument == null) {
                        firstDocument = new InMemoryDocument(content);
                        inMemoryDocument = firstDocument;
                    } else {
                        DSSDocument doc = new InMemoryDocument(content);
                        inMemoryDocument.setNextDocument(document);
                        inMemoryDocument = document;
                    }
                }
                return firstDocument;
            }
        }
        throw new DSSException("The signature with the given id was not found!");
    }

    private boolean isBase64Encoded(byte[] array) {
        return isBase64Encoded(new String(array));
    }

    private boolean isBase64Encoded(String text) {
        Pattern pattern = Pattern.compile(BASE64_REGEX);
        Matcher matcher = pattern.matcher(text);
        return matcher.matches();
    }

}