// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// Licensed 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

//

//     https://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.

#include <openssl/ssl.h>

#include <assert.h>

#include <string.h>

#include <openssl/err.h>

#include "../crypto/internal.h"

#include "internal.h"

BSSL_NAMESPACE_BEGIN

static void tls_on_handshake_complete(SSL *ssl) {

  // The handshake should have released its final message.

  assert(!ssl->s3->has_message);

  // During the handshake, |hs_buf| is retained. Release if it there is no

  // excess in it. There should not be any excess because the handshake logic

  // rejects unprocessed data after each Finished message. Note this means we do

  // not allow a TLS 1.2 HelloRequest to be packed into the same record as

  // Finished. (Schannel also rejects this.)

  assert(!ssl->s3->hs_buf || ssl->s3->hs_buf->length == 0);

  if (ssl->s3->hs_buf && ssl->s3->hs_buf->length == 0) {

    ssl->s3->hs_buf.reset();

  }

}

static bool tls_set_read_state(SSL *ssl, ssl_encryption_level_t level,

                               UniquePtr<SSLAEADContext> aead_ctx,

                               Span<const uint8_t> traffic_secret) {

  // Cipher changes are forbidden if the current epoch has leftover data.

  if (tls_has_unprocessed_handshake_data(ssl)) {

    OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);

    ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);

    return false;

  }

  if (SSL_is_quic(ssl)) {

    if ((ssl->s3->hs == nullptr || !ssl->s3->hs->hints_requested) &&

        !ssl->quic_method->set_read_secret(ssl, level, aead_ctx->cipher(),

                                           traffic_secret.data(),

                                           traffic_secret.size())) {

      return false;

    }

    // QUIC only uses |ssl| for handshake messages, which never use early data

    // keys, so we return without installing anything. This avoids needing to

    // have two secrets active at once in 0-RTT.

    if (level == ssl_encryption_early_data) {

      return true;

    }

    ssl->s3->quic_read_level = level;

  }

  ssl->s3->read_sequence = 0;

  ssl->s3->aead_read_ctx = std::move(aead_ctx);

  return true;

}

static bool tls_set_write_state(SSL *ssl, ssl_encryption_level_t level,

                                UniquePtr<SSLAEADContext> aead_ctx,

                                Span<const uint8_t> traffic_secret) {

  if (!tls_flush_pending_hs_data(ssl)) {

    return false;

  }

  if (SSL_is_quic(ssl)) {

    if ((ssl->s3->hs == nullptr || !ssl->s3->hs->hints_requested) &&

        !ssl->quic_method->set_write_secret(ssl, level, aead_ctx->cipher(),

                                            traffic_secret.data(),

                                            traffic_secret.size())) {

      return false;

    }

    // QUIC only uses |ssl| for handshake messages, which never use early data

    // keys, so we return without installing anything. This avoids needing to

    // have two secrets active at once in 0-RTT.

    if (level == ssl_encryption_early_data) {

      return true;

    }

    ssl->s3->quic_write_level = level;

  }

  ssl->s3->write_sequence = 0;

  ssl->s3->aead_write_ctx = std::move(aead_ctx);

  return true;

}

static void tls_finish_flight(SSL *ssl) {

  // We don't track whether a flight is complete in TLS and instead always flush

  // every queued message in |tls_flush|, whether the flight is complete or not.

}

static void tls_schedule_ack(SSL *ssl) {

  // TLS does not use ACKs.

}

static const SSL_PROTOCOL_METHOD kTLSProtocolMethod = {

    false /* is_dtls */,

    tls_new,

    tls_free,

    tls_get_message,

    tls_next_message,

    tls_has_unprocessed_handshake_data,

    tls_open_handshake,

    tls_open_change_cipher_spec,

    tls_open_app_data,

    tls_write_app_data,

    tls_dispatch_alert,

    tls_init_message,

    tls_finish_message,

    tls_add_message,

    tls_add_change_cipher_spec,

    tls_finish_flight,

    tls_schedule_ack,

    tls_flush,

    tls_on_handshake_complete,

    tls_set_read_state,

    tls_set_write_state,

};

static bool ssl_noop_x509_check_client_CA_names(

    STACK_OF(CRYPTO_BUFFER) *names) {

  return true;

}

static void ssl_noop_x509_clear(CERT *cert) {}

static void ssl_noop_x509_free(CERT *cert) {}

static void ssl_noop_x509_dup(CERT *new_cert, const CERT *cert) {}

static void ssl_noop_x509_flush_cached_leaf(CERT *cert) {}

static void ssl_noop_x509_flush_cached_chain(CERT *cert) {}

static bool ssl_noop_x509_session_cache_objects(SSL_SESSION *sess) {

  return true;

}

static bool ssl_noop_x509_session_dup(SSL_SESSION *new_session,

                                      const SSL_SESSION *session) {

  return true;

}

static void ssl_noop_x509_session_clear(SSL_SESSION *session) {}

static bool ssl_noop_x509_session_verify_cert_chain(SSL_SESSION *session,

                                                    SSL_HANDSHAKE *hs,

                                                    uint8_t *out_alert) {

  return false;

}

static void ssl_noop_x509_hs_flush_cached_ca_names(SSL_HANDSHAKE *hs) {}

static bool ssl_noop_x509_ssl_new(SSL_HANDSHAKE *hs) { return true; }

static void ssl_noop_x509_ssl_config_free(SSL_CONFIG *cfg) {}

static void ssl_noop_x509_ssl_flush_cached_client_CA(SSL_CONFIG *cfg) {}

static bool ssl_noop_x509_ssl_auto_chain_if_needed(SSL_HANDSHAKE *hs) {

  return true;

}

static bool ssl_noop_x509_ssl_ctx_new(SSL_CTX *ctx) { return true; }

static void ssl_noop_x509_ssl_ctx_free(SSL_CTX *ctx) {}

static void ssl_noop_x509_ssl_ctx_flush_cached_client_CA(SSL_CTX *ctx) {}

const SSL_X509_METHOD ssl_noop_x509_method = {

    ssl_noop_x509_check_client_CA_names,

    ssl_noop_x509_clear,

    ssl_noop_x509_free,

    ssl_noop_x509_dup,

    ssl_noop_x509_flush_cached_chain,

    ssl_noop_x509_flush_cached_leaf,

    ssl_noop_x509_session_cache_objects,

    ssl_noop_x509_session_dup,

    ssl_noop_x509_session_clear,

    ssl_noop_x509_session_verify_cert_chain,

    ssl_noop_x509_hs_flush_cached_ca_names,

    ssl_noop_x509_ssl_new,

    ssl_noop_x509_ssl_config_free,

    ssl_noop_x509_ssl_flush_cached_client_CA,

    ssl_noop_x509_ssl_auto_chain_if_needed,

    ssl_noop_x509_ssl_ctx_new,

    ssl_noop_x509_ssl_ctx_free,

    ssl_noop_x509_ssl_ctx_flush_cached_client_CA,

};

BSSL_NAMESPACE_END

using namespace bssl;

const SSL_METHOD *TLS_method(void) {

  static const SSL_METHOD kMethod = {

      0,

      &kTLSProtocolMethod,

      &ssl_crypto_x509_method,

  };

  return &kMethod;

}

const SSL_METHOD *SSLv23_method(void) { return TLS_method(); }

const SSL_METHOD *TLS_with_buffers_method(void) {

  static const SSL_METHOD kMethod = {

      0,

      &kTLSProtocolMethod,

      &ssl_noop_x509_method,

  };

  return &kMethod;

}

// Legacy version-locked methods.

const SSL_METHOD *TLSv1_2_method(void) {

  static const SSL_METHOD kMethod = {

      TLS1_2_VERSION,

      &kTLSProtocolMethod,

      &ssl_crypto_x509_method,

  };

  return &kMethod;

}

const SSL_METHOD *TLSv1_1_method(void) {

  static const SSL_METHOD kMethod = {

      TLS1_1_VERSION,

      &kTLSProtocolMethod,

      &ssl_crypto_x509_method,

  };

  return &kMethod;

}

const SSL_METHOD *TLSv1_method(void) {

  static const SSL_METHOD kMethod = {

      TLS1_VERSION,

      &kTLSProtocolMethod,

      &ssl_crypto_x509_method,

  };

  return &kMethod;

}

// Legacy side-specific methods.

const SSL_METHOD *TLSv1_2_server_method(void) { return TLSv1_2_method(); }

const SSL_METHOD *TLSv1_1_server_method(void) { return TLSv1_1_method(); }

const SSL_METHOD *TLSv1_server_method(void) { return TLSv1_method(); }

const SSL_METHOD *TLSv1_2_client_method(void) { return TLSv1_2_method(); }

const SSL_METHOD *TLSv1_1_client_method(void) { return TLSv1_1_method(); }

const SSL_METHOD *TLSv1_client_method(void) { return TLSv1_method(); }

const SSL_METHOD *SSLv23_server_method(void) { return SSLv23_method(); }

const SSL_METHOD *SSLv23_client_method(void) { return SSLv23_method(); }

const SSL_METHOD *TLS_server_method(void) { return TLS_method(); }

const SSL_METHOD *TLS_client_method(void) { return TLS_method(); }