src/main/java/eu/siacs/conversations/crypto/sasl/ScramPlusMechanism.java


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package eu.siacs.conversations.crypto.sasl;

import org.conscrypt.Conscrypt;

import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocket;

import eu.siacs.conversations.entities.Account;

abstract class ScramPlusMechanism extends ScramMechanism {

    private static final String EXPORTER_LABEL = "EXPORTER-Channel-Binding";

    ScramPlusMechanism(Account account, ChannelBinding channelBinding) {
        super(account, channelBinding);
    }

    @Override
    protected byte[] getChannelBindingData(final SSLSocket sslSocket)
            throws AuthenticationException {
        if (sslSocket == null) {
            throw new AuthenticationException("Channel binding attempt on non secure socket");
        }
        if (this.channelBinding == ChannelBinding.TLS_EXPORTER) {
            final byte[] keyingMaterial;
            try {
                keyingMaterial =
                        Conscrypt.exportKeyingMaterial(sslSocket, EXPORTER_LABEL, new byte[0], 32);
            } catch (final SSLException e) {
                throw new AuthenticationException("Could not export keying material");
            }
            if (keyingMaterial == null) {
                throw new AuthenticationException(
                        "Could not export keying material. Socket not ready");
            }
            return keyingMaterial;
        } else if (this.channelBinding == ChannelBinding.TLS_UNIQUE) {
            final byte[] unique = Conscrypt.getTlsUnique(sslSocket);
            if (unique == null) {
                throw new AuthenticationException(
                        "Could not retrieve tls unique. Socket not ready");
            }
            return unique;
        } else {
            throw new AuthenticationException(
                    String.format("%s is not a valid channel binding", ChannelBinding.NONE));
        }
    }
}