cc.arduino.plugins.unowifi.certs.WiFi101Certificate.java Source code

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Here is the source code for cc.arduino.plugins.unowifi.certs.WiFi101Certificate.java

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/*
 * This file is part of WiFi101 Updater Arduino-IDE Plugin.
 * Copyright 2016 Arduino LLC (http://www.arduino.cc/)
 *
 * Arduino is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
package cc.arduino.plugins.unowifi.certs;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPublicKey;
import java.util.Arrays;
import java.util.Date;

import javax.xml.bind.DatatypeConverter;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1OutputStream;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.DERPrintableString;
import org.bouncycastle.asn1.DLSequence;
import org.bouncycastle.asn1.DLSet;
import org.bouncycastle.asn1.x509.Time;

public class WiFi101Certificate {

    byte data[];
    String subject;
    String hash;

    public WiFi101Certificate(X509Certificate x509) throws Exception, NoSuchAlgorithmException, IOException {
        String algo = x509.getPublicKey().getAlgorithm();
        if (!algo.equals("RSA") || !(x509.getPublicKey() instanceof RSAPublicKey))
            throw new Exception("SSL Certificate must have an RSA Public Key");
        RSAPublicKey publicKey = (RSAPublicKey) x509.getPublicKey();

        byte[] publicExponent = publicKey.getPublicExponent().toByteArray();
        byte[] publicExponentLen = shortToBytes(publicExponent.length);
        byte[] publicModulus = publicKey.getModulus().toByteArray();
        if (publicModulus.length == 257 || publicModulus[0] == 0) {
            publicModulus = Arrays.copyOfRange(publicModulus, 1, publicModulus.length);
        }
        byte[] publicModulusLen = shortToBytes(publicModulus.length);
        byte[] name1hash = getSubjectValueHash(x509);
        byte[] notBefore = encodeTimestamp(x509.getNotBefore());
        byte[] notAfter = encodeTimestamp(x509.getNotAfter());

        ByteArrayOutputStream res = new ByteArrayOutputStream();
        res.write(name1hash);
        res.write(publicModulusLen);
        res.write(publicExponentLen);
        res.write(notBefore);
        res.write(notAfter);
        res.write(publicModulus);
        res.write(publicExponent);
        while (res.size() % 4 != 0)
            res.write(0xFF);
        data = res.toByteArray();

        byte[] digest = MessageDigest.getInstance("SHA-1").digest(data);
        hash = DatatypeConverter.printHexBinary(digest).substring(0, 6);
    }

    @Override
    public String toString() {
        return "(" + hash + ")";
    }

    private static byte[] shortToBytes(int x) {
        // little endian
        byte ret[] = new byte[2];
        ret[0] = (byte) x;
        ret[1] = (byte) (x >> 8);
        return ret;
    }

    private static byte[] encodeTimestamp(Date notBefore) throws IOException {
        ByteArrayOutputStream encoded = new ByteArrayOutputStream();
        ASN1OutputStream asn1 = new ASN1OutputStream(encoded);
        asn1.writeObject(new Time(notBefore));
        return Arrays.copyOfRange(encoded.toByteArray(), 2, 22);
    }

    private static byte[] getSubjectValueHash(X509Certificate x509) throws NoSuchAlgorithmException, IOException {
        MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
        ASN1InputStream ais = new ASN1InputStream(x509.getSubjectX500Principal().getEncoded());
        while (ais.available() > 0) {
            ASN1Primitive obj = ais.readObject();
            sha1.update(extractPrintableString(obj));
        }
        ais.close();
        return sha1.digest();
    }

    private static byte[] extractPrintableString(ASN1Encodable obj) throws IOException {
        if (obj instanceof DERPrintableString) {
            DERPrintableString s = (DERPrintableString) obj;
            // System.out.println("'" + s.getString() + "'");
            return s.getString().getBytes();
        }
        ByteArrayOutputStream res = new ByteArrayOutputStream();
        if (obj instanceof DLSequence) {
            DLSequence s = (DLSequence) obj;
            for (int i = 0; i < s.size(); i++) {
                res.write(extractPrintableString(s.getObjectAt(i)));
            }
        }
        if (obj instanceof DLSet) {
            DLSet s = (DLSet) obj;
            for (int i = 0; i < s.size(); i++) {
                res.write(extractPrintableString(s.getObjectAt(i)));
            }
        }
        return res.toByteArray();
    }

    public byte[] getEncoded() {
        return data.clone();
    }
}