org.bouncycastle.tls.TlsPSKKeyExchange Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of bctls-fips Show documentation
The Bouncy Castle Java APIs for the TLS, including a JSSE provider. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.
There is a newer version: 2.0.19
Show newest version
package org.bouncycastle.tls;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.bouncycastle.tls.crypto.TlsAgreement;
import org.bouncycastle.tls.crypto.TlsCertificate;
import org.bouncycastle.tls.crypto.TlsCryptoParameters;
import org.bouncycastle.tls.crypto.TlsDHConfig;
import org.bouncycastle.tls.crypto.TlsECConfig;
import org.bouncycastle.tls.crypto.TlsSecret;
import org.bouncycastle.util.Arrays;

/**
 * (D)TLS PSK key exchange (RFC 4279).
 */
public class TlsPSKKeyExchange
    extends AbstractTlsKeyExchange
{
    private static int checkKeyExchange(int keyExchange)
    {
        switch (keyExchange)
        {
        case KeyExchangeAlgorithm.DHE_PSK:
        case KeyExchangeAlgorithm.ECDHE_PSK:
        case KeyExchangeAlgorithm.PSK:
        case KeyExchangeAlgorithm.RSA_PSK:
            return keyExchange;
        default:
            throw new IllegalArgumentException("unsupported key exchange algorithm");
        }
    }

    protected TlsPSKIdentity pskIdentity;
    protected TlsPSKIdentityManager pskIdentityManager;
    protected TlsDHGroupVerifier dhGroupVerifier;

    protected byte[] psk_identity_hint = null;
    protected byte[] psk = null;

    protected TlsDHConfig dhConfig;
    protected TlsECConfig ecConfig;
    protected TlsAgreement agreement;

    protected TlsCredentialedDecryptor serverCredentials = null;
    protected TlsCertificate serverCertificate;
    protected TlsSecret preMasterSecret;

    public TlsPSKKeyExchange(int keyExchange, TlsPSKIdentity pskIdentity, TlsDHGroupVerifier dhGroupVerifier)
    {
        this(keyExchange, pskIdentity, null, dhGroupVerifier, null, null);
    }

    public TlsPSKKeyExchange(int keyExchange, TlsPSKIdentityManager pskIdentityManager,
        TlsDHConfig dhConfig, TlsECConfig ecConfig)
    {
        this(keyExchange, null, pskIdentityManager, null, dhConfig, ecConfig);
    }

    private TlsPSKKeyExchange(int keyExchange, TlsPSKIdentity pskIdentity, TlsPSKIdentityManager pskIdentityManager,
        TlsDHGroupVerifier dhGroupVerifier, TlsDHConfig dhConfig, TlsECConfig ecConfig)
    {
        super(checkKeyExchange(keyExchange));

        this.pskIdentity = pskIdentity;
        this.pskIdentityManager = pskIdentityManager;
        this.dhGroupVerifier = dhGroupVerifier;
        this.dhConfig = dhConfig;
        this.ecConfig = ecConfig;
    }

    public void skipServerCredentials() throws IOException
    {
        if (keyExchange == KeyExchangeAlgorithm.RSA_PSK)
        {
            throw new TlsFatalAlert(AlertDescription.internal_error);
        }
    }

    public void processServerCredentials(TlsCredentials serverCredentials) throws IOException
    {
        if (keyExchange != KeyExchangeAlgorithm.RSA_PSK)
        {
            throw new TlsFatalAlert(AlertDescription.internal_error);
        }

        this.serverCredentials = TlsUtils.requireDecryptorCredentials(serverCredentials);
    }

    public void processServerCertificate(Certificate serverCertificate) throws IOException
    {
        if (keyExchange != KeyExchangeAlgorithm.RSA_PSK)
        {
            throw new TlsFatalAlert(AlertDescription.unexpected_message);
        }

        this.serverCertificate = serverCertificate.getCertificateAt(0).useInRole(ConnectionEnd.server, keyExchange);
    }

    public byte[] generateServerKeyExchange() throws IOException
    {
        this.psk_identity_hint = pskIdentityManager.getHint();

        if (this.psk_identity_hint == null && !requiresServerKeyExchange())
        {
            return null;
        }

        ByteArrayOutputStream buf = new ByteArrayOutputStream();

        if (this.psk_identity_hint == null)
        {
            TlsUtils.writeOpaque16(TlsUtils.EMPTY_BYTES, buf);
        }
        else
        {
            TlsUtils.writeOpaque16(this.psk_identity_hint, buf);
        }

        if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
        {
            if (this.dhConfig == null)
            {
                throw new TlsFatalAlert(AlertDescription.internal_error);
            }

            TlsDHUtils.writeDHConfig(dhConfig, buf);

            this.agreement = context.getCrypto().createDHDomain(dhConfig).createDH();

            generateEphemeralDH(buf);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.ECDHE_PSK)
        {
            if (this.ecConfig == null)
            {
                throw new TlsFatalAlert(AlertDescription.internal_error);
            }

            TlsECCUtils.writeECConfig(ecConfig, buf);

            this.agreement = context.getCrypto().createECDomain(ecConfig).createECDH();

            generateEphemeralECDH(buf);
        }

        return buf.toByteArray();
    }

    public boolean requiresServerKeyExchange()
    {
        switch (keyExchange)
        {
        case KeyExchangeAlgorithm.DHE_PSK:
        case KeyExchangeAlgorithm.ECDHE_PSK:
            return true;
        default:
            return false;
        }
    }

    public void processServerKeyExchange(InputStream input) throws IOException
    {
        this.psk_identity_hint = TlsUtils.readOpaque16(input);

        if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
        {
            this.dhConfig = TlsDHUtils.receiveDHConfig(context, dhGroupVerifier, input);

            byte[] y = TlsUtils.readOpaque16(input, 1);

            this.agreement = context.getCrypto().createDHDomain(dhConfig).createDH();

            processEphemeralDH(y);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.ECDHE_PSK)
        {
            this.ecConfig = TlsECCUtils.receiveECDHConfig(context, input);

            byte[] point = TlsUtils.readOpaque8(input, 1);

            this.agreement = context.getCrypto().createECDomain(ecConfig).createECDH();

            processEphemeralECDH(point);
        }
    }

    public void processClientCredentials(TlsCredentials clientCredentials) throws IOException
    {
        throw new TlsFatalAlert(AlertDescription.internal_error);
    }

    public void generateClientKeyExchange(OutputStream output) throws IOException
    {
        if (psk_identity_hint == null)
        {
            pskIdentity.skipIdentityHint();
        }
        else
        {
            pskIdentity.notifyIdentityHint(psk_identity_hint);
        }

        byte[] psk_identity = pskIdentity.getPSKIdentity();
        if (psk_identity == null)
        {
            throw new TlsFatalAlert(AlertDescription.internal_error);
        }

        this.psk = pskIdentity.getPSK();
        if (psk == null)
        {
            throw new TlsFatalAlert(AlertDescription.internal_error);
        }

        TlsUtils.writeOpaque16(psk_identity, output);

        context.getSecurityParametersHandshake().pskIdentity = Arrays.clone(psk_identity);

        if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
        {
            generateEphemeralDH(output);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.ECDHE_PSK)
        {
            generateEphemeralECDH(output);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.RSA_PSK)
        {
            this.preMasterSecret = TlsRSAUtils.generateEncryptedPreMasterSecret(context, serverCertificate, output);
        }
    }

    public void processClientKeyExchange(InputStream input) throws IOException
    {
        byte[] psk_identity = TlsUtils.readOpaque16(input);

        this.psk = pskIdentityManager.getPSK(psk_identity);
        if (psk == null)
        {
            throw new TlsFatalAlert(AlertDescription.unknown_psk_identity);
        }

        context.getSecurityParametersHandshake().pskIdentity = psk_identity;

        if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
        {
            byte[] y = TlsUtils.readOpaque16(input, 1);

            processEphemeralDH(y);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.ECDHE_PSK)
        {
            byte[] point = TlsUtils.readOpaque8(input, 1);

            processEphemeralECDH(point);
        }
        else if (this.keyExchange == KeyExchangeAlgorithm.RSA_PSK)
        {
            byte[] encryptedPreMasterSecret = TlsUtils.readOpaque16(input);

            this.preMasterSecret = serverCredentials.decrypt(new TlsCryptoParameters(context), encryptedPreMasterSecret);
        }
    }

    public TlsSecret generatePreMasterSecret() throws IOException
    {
        byte[] other_secret = generateOtherSecret(psk.length);

        ByteArrayOutputStream buf = new ByteArrayOutputStream(4 + other_secret.length + psk.length);
        TlsUtils.writeOpaque16(other_secret, buf);
        TlsUtils.writeOpaque16(psk, buf);

        Arrays.fill(psk, (byte)0);
        this.psk = null;

        return context.getCrypto().createSecret(buf.toByteArray());
    }

    protected void generateEphemeralDH(OutputStream output) throws IOException
    {
        byte[] y = agreement.generateEphemeral();
        TlsUtils.writeOpaque16(y, output);
    }

    protected void generateEphemeralECDH(OutputStream output) throws IOException
    {
        byte[] point = agreement.generateEphemeral();
        TlsUtils.writeOpaque8(point, output);
    }

    protected byte[] generateOtherSecret(int pskLength) throws IOException
    {
        if (this.keyExchange == KeyExchangeAlgorithm.PSK)
        {
            return new byte[pskLength];
        }

        if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK
            || this.keyExchange == KeyExchangeAlgorithm.ECDHE_PSK)
        {
            if (agreement != null)
            {
                return agreement.calculateSecret().extract();
            }
        }

        if (this.keyExchange == KeyExchangeAlgorithm.RSA_PSK)
        {
            if (preMasterSecret != null)
            {
                return this.preMasterSecret.extract();
            }
        }

        throw new TlsFatalAlert(AlertDescription.internal_error);
    }

    protected void processEphemeralDH(byte[] y) throws IOException
    {
        this.agreement.receivePeerValue(y);
    }

    protected void processEphemeralECDH(byte[] point) throws IOException
    {
        TlsECCUtils.checkPointEncoding(ecConfig.getNamedGroup(), point);

        this.agreement.receivePeerValue(point);
    }
}