org.dcache.gridsite.BouncyCastleCredentialDelegation.java Source code

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/* dCache - http://www.dcache.org/
 *
 * Copyright (C) 2014-2015 Deutsches Elektronen-Synchrotron
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * 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/>.
 */
package org.dcache.gridsite;

import eu.emi.security.authn.x509.X509Credential;
import eu.emi.security.authn.x509.impl.KeyAndCertCredential;
import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1StreamParser;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERPrintableString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.DERSet;
import org.bouncycastle.asn1.x509.X509CertificateStructure;
import org.bouncycastle.asn1.x509.X509Name;
import org.bouncycastle.jce.PKCS10CertificationRequest;
import org.bouncycastle.jce.provider.X509CertificateObject;
import org.bouncycastle.openssl.PEMWriter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.security.auth.x500.X500Principal;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.KeyPair;
import java.security.KeyStoreException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.List;
import java.util.stream.Stream;

import org.dcache.delegation.gridsite2.DelegationException;

/**
 * An in-progress credential delegation that uses BouncyCastle.
 */
public class BouncyCastleCredentialDelegation implements CredentialDelegation {
    private static final Logger LOG = LoggerFactory.getLogger(BouncyCastleCredentialDelegation.class);

    private final DelegationIdentity _id;
    private final Collection<X509Certificate> _certificates;
    private final X509Certificate _first;
    private final String _pemRequest;

    protected final KeyPair _keyPair;

    BouncyCastleCredentialDelegation(KeyPair keypair, DelegationIdentity id,
            Collection<X509Certificate> certificates) throws DelegationException {
        _id = id;
        _certificates = certificates;
        _first = certificates.iterator().next();
        _keyPair = keypair;

        try {
            _pemRequest = pemEncode(createRequest(_first, keypair));
        } catch (GeneralSecurityException e) {
            LOG.error("Failed to create CSR: {}", e.toString());
            throw new DelegationException("cannot create certificate-signing" + " request: " + e.getMessage());
        } catch (IOException e) {
            LOG.error("Failed to convert CSR to PEM: {}", e.toString());
            throw new DelegationException("cannot PEM-encode certificate-" + "signing request: " + e.getMessage());
        }
    }

    private static PKCS10CertificationRequest createRequest(X509Certificate cert, KeyPair keyPair)
            throws GeneralSecurityException {
        return new PKCS10CertificationRequest(cert.getSigAlgName(), buildProxyDN(cert.getSubjectX500Principal()),
                keyPair.getPublic(), null, keyPair.getPrivate());
    }

    private static X509Name buildProxyDN(X500Principal principal) throws GeneralSecurityException {
        ASN1StreamParser parser = new ASN1StreamParser(principal.getEncoded());

        DERSequence seq;
        try {
            ASN1Encodable object = parser.readObject().getDERObject();
            if (!(object instanceof DERSequence)) {
                throw new IOException("not a DER-encoded ASN.1 sequence");
            }
            seq = (DERSequence) object;
        } catch (IOException e) {
            throw new GeneralSecurityException("failed to parse DN: " + e.getMessage());
        }

        List<ASN1Encodable> rdn = new ArrayList<>(seq.size() + 1);
        for (Enumeration e = seq.getObjects(); e.hasMoreElements();) {
            rdn.add((ASN1Encodable) e.nextElement());
        }

        DERSequence atv = new DERSequence(new ASN1Object[] { X509Name.CN, new DERPrintableString("proxy") });
        rdn.add(new DERSet(atv));

        ASN1Encodable[] rdnArray = rdn.toArray(new ASN1Encodable[rdn.size()]);
        return new X509Name(new DERSequence(rdnArray));
    }

    private static X509Certificate loadCertificate(InputStream in) throws IOException, GeneralSecurityException {
        DERObject certInfo = new ASN1InputStream(in).readObject();
        ASN1Sequence seq = ASN1Sequence.getInstance(certInfo);
        return new X509CertificateObject(new X509CertificateStructure(seq));
    }

    private static String pemEncode(Object item) throws IOException {
        StringWriter writer = new StringWriter();
        try (PEMWriter pem = new PEMWriter(writer)) {
            pem.writeObject(item);
        }
        return writer.toString();
    }

    @Override
    public String getCertificateSigningRequest() {
        return _pemRequest;
    }

    @Override
    public DelegationIdentity getId() {
        return _id;
    }

    @Override
    public X509Credential acceptCertificate(String encodedCertificate) throws DelegationException {
        X509Certificate certificate;

        try {
            certificate = pemDecodeCertificate(encodedCertificate);
        } catch (CertificateException e) {
            LOG.debug("Bad certificate: {}", e.getMessage());
            throw new DelegationException("Supplied certificate is " + "unacceptable: " + e.getMessage());
        }

        X509Certificate[] newCertificates = Stream.concat(Stream.of(certificate), _certificates.stream())
                .map(BouncyCastleCredentialDelegation::asBcCertificate).toArray(X509Certificate[]::new);
        try {
            return new KeyAndCertCredential(_keyPair.getPrivate(), newCertificates);
        } catch (KeyStoreException e) {
            LOG.error("Failed to create delegated credential: {}", e.getMessage());
            throw new DelegationException("Unable to create delegated credential: " + e.getMessage());
        }
    }

    private static X509Certificate asBcCertificate(X509Certificate c) {
        if (c instanceof X509CertificateObject) {
            return c;
        } else {
            try (ByteArrayInputStream in = new ByteArrayInputStream(c.getEncoded())) {
                return loadCertificate(in);
            } catch (GeneralSecurityException | IOException e) {
                throw new RuntimeException("failed to convert certificate: " + e.getMessage());
            }
        }
    }

    private static X509Certificate pemDecodeCertificate(String encoded) throws CertificateException {
        byte[] data;

        try {
            data = encoded.getBytes("UTF-8");
        } catch (UnsupportedEncodingException ignored) {
            throw new RuntimeException("UTF-8 not supported");
        }
        InputStream in = new ByteArrayInputStream(data, 0, data.length);

        CertificateFactory cf;
        try {
            cf = CertificateFactory.getInstance("X.509");
        } catch (CertificateException e) {
            throw new RuntimeException("Failed to find CertificateFactory" + " for X.509: " + e.getMessage());
        }

        return (X509Certificate) cf.generateCertificate(in);
    }
}