java/io/netty/internal/tcnative/CertificateRequestedCallback.java

/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.internal.tcnative;

/**
 * Is called during handshake and hooked into openssl via {@code SSL_CTX_set_client_cert_cb}.
 *
 * IMPORTANT: Implementations of this interface should be static as it is stored as a global reference via JNI. This
 *            means if you use an inner / anonymous class to implement this and also depend on the finalizer of the
 *            class to free up the SSLContext the finalizer will never run as the object is never GC, due the hard
 *            reference to the enclosing class. This will most likely result in a memory leak.
 */
public interface CertificateRequestedCallback {

    /**
     * The types contained in the {@code keyTypeBytes} array.
     */
    // Extracted from https://github.com/openssl/openssl/blob/master/include/openssl/tls1.h
    byte TLS_CT_RSA_SIGN = 1;
    byte TLS_CT_DSS_SIGN = 2;
    byte TLS_CT_RSA_FIXED_DH = 3;
    byte TLS_CT_DSS_FIXED_DH = 4;
    byte TLS_CT_ECDSA_SIGN = 64;
    byte TLS_CT_RSA_FIXED_ECDH = 65;
    byte TLS_CT_ECDSA_FIXED_ECDH = 66;

    /**
     * Called during cert selection.
     *
     * @param ssl                       the SSL instance
     * @param keyTypeBytes              an array of the key types.
     * @param asn1DerEncodedPrincipals  the principals
     * @return material to use or {@code null} if non should be used. The ownership of all native memory goes over to
     *                  tcnative at this point.
     *
     */
    KeyMaterial requested(long ssl, byte[] keyTypeBytes, byte[][] asn1DerEncodedPrincipals);

    /**
     * Holds the material to use. Tcnative is responsible releasing native memory used by the wrapped native objects.
     */
    // Non-final so we can extend from this later ond cache these easily in Netty.
    class KeyMaterial {

        private final long certificateChain;
        private final long privateKey;

        public KeyMaterial(long certificateChain, long privateKey) {
            this.certificateChain = certificateChain;
            this.privateKey = privateKey;
        }

        /**
         * Returns a {@code EVP_PKEY} pointer
         *
         * @return the {@code EVP_PKEY} pointer
         */
        public final long privateKey() {
            return privateKey;
        }

        /**
         * Returns a x509 chain ({@code STACK_OF(X509)} pointer)
         *
         * @return thex509 chain ({@code STACK_OF(X509)} pointer)
         */
        public final long certificateChain() {
            return certificateChain;
        }
    }
}