text: /* Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.
   */
  
  /*                      _             _
   *  _ __ ___   ___   __| |    ___ ___| |  mod_ssl
   * | '_ ` _ \ / _ \ / _` |   / __/ __| |  Apache Interface to OpenSSL
   * | | | | | | (_) | (_| |   \__ \__ \ |
   * |_| |_| |_|\___/ \__,_|___|___/___/_|
   *                      |_____|
   *  mod_ssl.c
   *  Apache API interface structures
   */
  
  #include "ssl_private.h"
  #include "mod_ssl.h"
  #include "mod_ssl_openssl.h"
  #include "util_md5.h"
  #include "util_mutex.h"
  #include "ap_provider.h"
  #include "http_config.h"
  
  #include "mod_proxy.h" /* for proxy_hook_section_post_config() */
  
  #include <assert.h>
  
  #if HAVE_VALGRIND
  #include <valgrind.h>
  int ssl_running_on_valgrind = 0;
  #endif
  
  #if HAVE_OPENSSL_INIT_SSL || (OPENSSL_VERSION_NUMBER >= 0x10100000L && \
                                !defined(LIBRESSL_VERSION_NUMBER))
  /* Openssl v1.1+ handles all termination automatically from
   * OPENSSL_init_ssl().  No manual initialization is required. */
  #else
  /* For older OpenSSL releases, "manual" initialization and cleanup are
   * required. */
  #define NEED_MANUAL_OPENSSL_INIT
  /* Will be set to true if mod_ssl is built statically into httpd. */
  static int modssl_running_statically = 0;
  #endif
  
  APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ssl, SSL, int, pre_handshake,
                                      (conn_rec *c,SSL *ssl,int is_proxy),
                                      (c,ssl,is_proxy), OK, DECLINED);
  
  /*
   *  the table of configuration directives we provide
   */
  
  #define SSL_CMD_ALL(name, args, desc) \
          AP_INIT_##args("SSL"#name, ssl_cmd_SSL##name, \
                         NULL, RSRC_CONF|OR_AUTHCFG, desc),
  
  #define SSL_CMD_SRV(name, args, desc) \
          AP_INIT_##args("SSL"#name, ssl_cmd_SSL##name, \
                         NULL, RSRC_CONF, desc),
  
  #define SSL_CMD_PXY(name, args, desc) \
          AP_INIT_##args("SSL"#name, ssl_cmd_SSL##name, \
                         NULL, RSRC_CONF|PROXY_CONF, desc),
  
  #define SSL_CMD_DIR(name, type, args, desc) \
          AP_INIT_##args("SSL"#name, ssl_cmd_SSL##name, \
                         NULL, OR_##type, desc),
  
  #define AP_END_CMD { NULL }
  
  static const command_rec ssl_config_cmds[] = {
      /*
       * Global (main-server) context configuration directives
       */
      SSL_CMD_SRV(PassPhraseDialog, TAKE1,
                  "SSL dialog mechanism for the pass phrase query "
                  "('builtin', '|/path/to/pipe_program', "
                  "or 'exec:/path/to/cgi_program')")
      SSL_CMD_SRV(SessionCache, TAKE1,
                  "SSL Session Cache storage "
                  "('none', 'nonenotnull', 'dbm:/path/to/file')")
  #if defined(HAVE_OPENSSL_ENGINE_H) && defined(HAVE_ENGINE_INIT)
      SSL_CMD_SRV(CryptoDevice, TAKE1,
                  "SSL external Crypto Device usage "
                  "('builtin', '...')")
  #endif
      SSL_CMD_SRV(RandomSeed, TAKE23,
                  "SSL Pseudo Random Number Generator (PRNG) seeding source "
                  "('startup|connect builtin|file:/path|exec:/path [bytes]')")
  
      /*
       * Per-server context configuration directives
       */
      SSL_CMD_SRV(Engine, TAKE1,
                  "SSL switch for the protocol engine "
                  "('on', 'off')")
      SSL_CMD_SRV(FIPS, FLAG,
                  "Enable FIPS-140 mode "
                  "(`on', `off')")
      SSL_CMD_ALL(CipherSuite, TAKE12,
                  "Colon-delimited list of permitted SSL Ciphers, optional preceded "
                  "by protocol identifier ('XXX:...:XXX' - see manual)")
      SSL_CMD_SRV(CertificateFile, TAKE1,
                  "SSL Server Certificate file "
                  "('/path/to/file' - PEM or DER encoded)")
      SSL_CMD_SRV(CertificateKeyFile, TAKE1,
                  "SSL Server Private Key file "
                  "('/path/to/file' - PEM or DER encoded)")
      SSL_CMD_SRV(CertificateChainFile, TAKE1,
                  "SSL Server CA Certificate Chain file "
                  "('/path/to/file' - PEM encoded)")
  #ifdef HAVE_TLS_SESSION_TICKETS
      SSL_CMD_SRV(SessionTicketKeyFile, TAKE1,
                  "TLS session ticket encryption/decryption key file (RFC 5077) "
                  "('/path/to/file' - file with 48 bytes of random data)")
  #endif
      SSL_CMD_ALL(CACertificatePath, TAKE1,
                  "SSL CA Certificate path "
                  "('/path/to/dir' - contains PEM encoded files)")
      SSL_CMD_ALL(CACertificateFile, TAKE1,
                  "SSL CA Certificate file "
                  "('/path/to/file' - PEM encoded)")
      SSL_CMD_SRV(CADNRequestPath, TAKE1,
                  "SSL CA Distinguished Name path "
                  "('/path/to/dir' - symlink hashes to PEM of acceptable CA names to request)")
      SSL_CMD_SRV(CADNRequestFile, TAKE1,
                  "SSL CA Distinguished Name file "
                  "('/path/to/file' - PEM encoded to derive acceptable CA names to request)")
      SSL_CMD_SRV(CARevocationPath, TAKE1,
                  "SSL CA Certificate Revocation List (CRL) path "
                  "('/path/to/dir' - contains PEM encoded files)")
      SSL_CMD_SRV(CARevocationFile, TAKE1,
                  "SSL CA Certificate Revocation List (CRL) file "
                  "('/path/to/file' - PEM encoded)")
      SSL_CMD_SRV(CARevocationCheck, RAW_ARGS,
                  "SSL CA Certificate Revocation List (CRL) checking mode")
      SSL_CMD_ALL(VerifyClient, TAKE1,
                  "SSL Client verify type "
                  "('none', 'optional', 'require', 'optional_no_ca')")
      SSL_CMD_ALL(VerifyDepth, TAKE1,
                  "SSL Client verify depth "
                  "('N' - number of intermediate certificates)")
      SSL_CMD_SRV(SessionCacheTimeout, TAKE1,
                  "SSL Session Cache object lifetime "
                  "('N' - number of seconds)")
  #ifdef OPENSSL_NO_SSL3
  #define SSLv3_PROTO_PREFIX ""
  #else
  #define SSLv3_PROTO_PREFIX "SSLv3|"
  #endif
  #ifdef HAVE_TLSV1_X
  #define SSL_PROTOCOLS SSLv3_PROTO_PREFIX "TLSv1|TLSv1.1|TLSv1.2"
  #else
  #define SSL_PROTOCOLS SSLv3_PROTO_PREFIX "TLSv1"
  #endif
      SSL_CMD_SRV(Protocol, RAW_ARGS,
                  "Enable or disable various SSL protocols "
                  "('[+-][" SSL_PROTOCOLS "] ...' - see manual)")
      SSL_CMD_SRV(HonorCipherOrder, FLAG,
                  "Use the server's cipher ordering preference")
      SSL_CMD_SRV(Compression, FLAG,
                  "Enable SSL level compression "
                  "(`on', `off')")
      SSL_CMD_SRV(SessionTickets, FLAG,
                  "Enable or disable TLS session tickets"
                  "(`on', `off')")
      SSL_CMD_SRV(InsecureRenegotiation, FLAG,
                  "Enable support for insecure renegotiation")
      SSL_CMD_ALL(UserName, TAKE1,
                  "Set user name to SSL variable value")
      SSL_CMD_SRV(StrictSNIVHostCheck, FLAG,
                  "Strict SNI virtual host checking")
  
  #ifdef HAVE_SRP
      SSL_CMD_SRV(SRPVerifierFile, TAKE1,
                  "SRP verifier file "
                  "('/path/to/file' - created by srptool)")
      SSL_CMD_SRV(SRPUnknownUserSeed, TAKE1,
                  "SRP seed for unknown users (to avoid leaking a user's existence) "
                  "('some secret text')")
  #endif
  
      /*
       * Proxy configuration for remote SSL connections
       */
      SSL_CMD_PXY(ProxyEngine, FLAG,
                  "SSL switch for the proxy protocol engine "
                  "('on', 'off')")
      SSL_CMD_PXY(ProxyProtocol, RAW_ARGS,
                 "SSL Proxy: enable or disable SSL protocol flavors "
                  "('[+-][" SSL_PROTOCOLS "] ...' - see manual)")
      SSL_CMD_PXY(ProxyCipherSuite, TAKE12,
                 "SSL Proxy: colon-delimited list of permitted SSL ciphers "
                 ", optionally preceded by protocol specifier ('XXX:...:XXX' - see manual)")
      SSL_CMD_PXY(ProxyVerify, TAKE1,
                 "SSL Proxy: whether to verify the remote certificate "
                 "('on' or 'off')")
      SSL_CMD_PXY(ProxyVerifyDepth, TAKE1,
                 "SSL Proxy: maximum certificate verification depth "
                 "('N' - number of intermediate certificates)")
      SSL_CMD_PXY(ProxyCACertificateFile, TAKE1,
                 "SSL Proxy: file containing server certificates "
                 "('/path/to/file' - PEM encoded certificates)")
      SSL_CMD_PXY(ProxyCACertificatePath, TAKE1,
                 "SSL Proxy: directory containing server certificates "
                 "('/path/to/dir' - contains PEM encoded certificates)")
      SSL_CMD_PXY(ProxyCARevocationPath, TAKE1,
                  "SSL Proxy: CA Certificate Revocation List (CRL) path "
                  "('/path/to/dir' - contains PEM encoded files)")
      SSL_CMD_PXY(ProxyCARevocationFile, TAKE1,
                  "SSL Proxy: CA Certificate Revocation List (CRL) file "
                  "('/path/to/file' - PEM encoded)")
      SSL_CMD_PXY(ProxyCARevocationCheck, RAW_ARGS,
                  "SSL Proxy: CA Certificate Revocation List (CRL) checking mode")
      SSL_CMD_PXY(ProxyMachineCertificateFile, TAKE1,
                 "SSL Proxy: file containing client certificates "
                 "('/path/to/file' - PEM encoded certificates)")
      SSL_CMD_PXY(ProxyMachineCertificatePath, TAKE1,
                 "SSL Proxy: directory containing client certificates "
                 "('/path/to/dir' - contains PEM encoded certificates)")
      SSL_CMD_PXY(ProxyMachineCertificateChainFile, TAKE1,
                 "SSL Proxy: file containing issuing certificates "
                 "of the client certificate "
                 "(`/path/to/file' - PEM encoded certificates)")
      SSL_CMD_PXY(ProxyCheckPeerExpire, FLAG,
                  "SSL Proxy: check the peer certificate's expiration date")
      SSL_CMD_PXY(ProxyCheckPeerCN, FLAG,
                  "SSL Proxy: check the peer certificate's CN")
      SSL_CMD_PXY(ProxyCheckPeerName, FLAG,
                  "SSL Proxy: check the peer certificate's name "
                  "(must be present in subjectAltName extension or CN")
  
      /*
       * Per-directory context configuration directives
       */
      SSL_CMD_DIR(Options, OPTIONS, RAW_ARGS,
                 "Set one or more options to configure the SSL engine"
                 "('[+-]option[=value] ...' - see manual)")
      SSL_CMD_DIR(RequireSSL, AUTHCFG, NO_ARGS,
                 "Require the SSL protocol for the per-directory context "
                 "(no arguments)")
      SSL_CMD_DIR(Require, AUTHCFG, RAW_ARGS,
                 "Require a boolean expression to evaluate to true for granting access"
                 "(arbitrary complex boolean expression - see manual)")
      SSL_CMD_DIR(RenegBufferSize, AUTHCFG, TAKE1,
                  "Configure the amount of memory that will be used for buffering the "
                  "request body if a per-location SSL renegotiation is required due to "
                  "changed access control requirements")
  
      SSL_CMD_SRV(OCSPEnable, RAW_ARGS,
                 "Enable use of OCSP to verify certificate revocation mode ('on', 'leaf', 'off')")
      SSL_CMD_SRV(OCSPDefaultResponder, TAKE1,
                 "URL of the default OCSP Responder")
      SSL_CMD_SRV(OCSPOverrideResponder, FLAG,
                 "Force use of the default responder URL ('on', 'off')")
      SSL_CMD_SRV(OCSPResponseTimeSkew, TAKE1,
                  "Maximum time difference in OCSP responses")
      SSL_CMD_SRV(OCSPResponseMaxAge, TAKE1,
                  "Maximum age of OCSP responses")
      SSL_CMD_SRV(OCSPResponderTimeout, TAKE1,
                  "OCSP responder query timeout")
      SSL_CMD_SRV(OCSPUseRequestNonce, FLAG,
                  "Whether OCSP queries use a nonce or not ('on', 'off')")
      SSL_CMD_SRV(OCSPProxyURL, TAKE1,
                  "Proxy URL to use for OCSP requests")
  
  /* Define OCSP Responder Certificate Verification Directive */
      SSL_CMD_SRV(OCSPNoVerify, FLAG,
                  "Do not verify OCSP Responder certificate ('on', 'off')")
  /* Define OCSP Responder File Configuration Directive */
      SSL_CMD_SRV(OCSPResponderCertificateFile, TAKE1,
                 "Trusted OCSP responder certificates"
                 "(`/path/to/file' - PEM encoded certificates)")
  
  #ifdef HAVE_OCSP_STAPLING
      /*
       * OCSP Stapling options
       */
      SSL_CMD_SRV(StaplingCache, TAKE1,
                  "SSL Stapling Response Cache storage "
                  "(`dbm:/path/to/file')")
      SSL_CMD_SRV(UseStapling, FLAG,
                  "SSL switch for the OCSP Stapling protocol " "(`on', `off')")
      SSL_CMD_SRV(StaplingResponseTimeSkew, TAKE1,
                  "SSL stapling option for maximum time difference in OCSP responses")
      SSL_CMD_SRV(StaplingResponderTimeout, TAKE1,
                  "SSL stapling option for OCSP responder timeout")
      SSL_CMD_SRV(StaplingResponseMaxAge, TAKE1,
                  "SSL stapling option for maximum age of OCSP responses")
      SSL_CMD_SRV(StaplingStandardCacheTimeout, TAKE1,
                  "SSL stapling option for normal OCSP Response Cache Lifetime")
      SSL_CMD_SRV(StaplingReturnResponderErrors, FLAG,
                  "SSL stapling switch to return Status Errors Back to Client"
                  "(`on', `off')")
      SSL_CMD_SRV(StaplingFakeTryLater, FLAG,
                  "SSL stapling switch to send tryLater response to client on error "
                  "(`on', `off')")
      SSL_CMD_SRV(StaplingErrorCacheTimeout, TAKE1,
                  "SSL stapling option for OCSP Response Error Cache Lifetime")
      SSL_CMD_SRV(StaplingForceURL, TAKE1,
                  "SSL stapling option to Force the OCSP Stapling URL")
  #endif
  
  #ifdef HAVE_SSL_CONF_CMD
      SSL_CMD_SRV(OpenSSLConfCmd, TAKE2,
                  "OpenSSL configuration command")
  #endif
  
      /* Deprecated directives. */
      AP_INIT_RAW_ARGS("SSLLog", ap_set_deprecated, NULL, OR_ALL,
        "SSLLog directive is no longer supported - use ErrorLog."),
      AP_INIT_RAW_ARGS("SSLLogLevel", ap_set_deprecated, NULL, OR_ALL,
        "SSLLogLevel directive is no longer supported - use LogLevel."),
  
      AP_INIT_TAKE1("SSLPolicy", ssl_cmd_SSLPolicyApply, NULL, RSRC_CONF, 
                  "Apply the SSL* (not the SSLProxy*) settings from the policy with the given name."),
      AP_END_CMD
  };
  
  #ifdef NEED_MANUAL_OPENSSL_INIT
  static int modssl_is_prelinked(void)
  {
      apr_size_t i = 0;
      const module *mod;
      while ((mod = ap_prelinked_modules[i++])) {
          if (strcmp(mod->name, "mod_ssl.c") == 0) {
              return 1;
          }
      }
      return 0;
  }
  
  /* Termination below is for legacy Openssl versions v1.0.x and
   * older. */
  static apr_status_t ssl_cleanup_pre_config(void *data)
  {
      /* Corresponds to OBJ_create()s */
      OBJ_cleanup();
      /* Corresponds to OPENSSL_load_builtin_modules() */
      CONF_modules_free();
      /* Corresponds to SSL_library_init: */
      EVP_cleanup();
  #if HAVE_ENGINE_LOAD_BUILTIN_ENGINES
      ENGINE_cleanup();
  #endif
  #if OPENSSL_VERSION_NUMBER >= 0x1000200fL
  #ifndef OPENSSL_NO_COMP
      SSL_COMP_free_compression_methods();
  #endif
  #endif
  
      /* Usually needed per thread, but this parent process is single-threaded */
  #if MODSSL_USE_OPENSSL_PRE_1_1_API
  #if OPENSSL_VERSION_NUMBER >= 0x1000000fL
      ERR_remove_thread_state(NULL);
  #else
      ERR_remove_state(0);
  #endif
  #endif
  
      /* Don't call ERR_free_strings in earlier versions, ERR_load_*_strings only
       * actually loaded the error strings once per process due to static
       * variable abuse in OpenSSL. */
  #if (OPENSSL_VERSION_NUMBER >= 0x00090805f)
      ERR_free_strings();
  #endif
  
      /* Also don't call CRYPTO_cleanup_all_ex_data when linked statically here;
       * any registered ex_data indices may have been cached in static variables
       * in OpenSSL; removing them may cause havoc.  Notably, with OpenSSL
       * versions >= 0.9.8f, COMP_CTX cleanups would not be run, which
       * could result in a per-connection memory leak (!). */
      if (!modssl_running_statically) {
          CRYPTO_cleanup_all_ex_data();
      }
  
      /*
       * TODO: determine somewhere we can safely shove out diagnostics
       *       (when enabled) at this late stage in the game:
       * CRYPTO_mem_leaks_fp(stderr);
       */
  
      return APR_SUCCESS;
  }
  #endif /* NEED_MANUAL_OPENSSL_INIT */
  
  static int ssl_hook_pre_config(apr_pool_t *pconf,
                                 apr_pool_t *plog,
                                 apr_pool_t *ptemp)
  {
  #if HAVE_VALGRIND
      ssl_running_on_valgrind = RUNNING_ON_VALGRIND;
  #endif
  
  #ifndef NEED_MANUAL_OPENSSL_INIT
      /* Openssl v1.1+ handles all initialisation automatically, apart
       * from hints as to how we want to use the library.
       *
       * We tell openssl we want to include engine support.
       */
      OPENSSL_init_ssl(OPENSSL_INIT_ENGINE_ALL_BUILTIN, NULL);
  
  #else
      /* Configuration below is for legacy versions Openssl v1.0 and
       * older.
       */
      modssl_running_statically = modssl_is_prelinked();
  
  #if APR_HAS_THREADS && MODSSL_USE_OPENSSL_PRE_1_1_API
      ssl_util_thread_id_setup(pconf);
  #endif
  #if MODSSL_USE_OPENSSL_PRE_1_1_API || defined(LIBRESSL_VERSION_NUMBER)
      (void)CRYPTO_malloc_init();
  #else
      OPENSSL_malloc_init();
  #endif
      ERR_load_crypto_strings();
      SSL_load_error_strings();
      SSL_library_init();
  #if HAVE_ENGINE_LOAD_BUILTIN_ENGINES
      ENGINE_load_builtin_engines();
  #endif
      OpenSSL_add_all_algorithms();
      OPENSSL_load_builtin_modules();
  #endif /* NEED_MANUAL_OPENSSL_INIT */
  
      if (OBJ_txt2nid("id-on-dnsSRV") == NID_undef) {
          (void)OBJ_create("1.3.6.1.5.5.7.8.7", "id-on-dnsSRV",
                           "SRVName otherName form");
      }
  
      /* Start w/o errors (e.g. OBJ_txt2nid() above) */
      ERR_clear_error();
  
  
  #ifdef NEED_MANUAL_OPENSSL_INIT
      /*
       * Let us cleanup the ssl library when the module is unloaded
       */
      apr_pool_cleanup_register(pconf, NULL, ssl_cleanup_pre_config,
                                             apr_pool_cleanup_null);
  #endif
  
      /* Register to handle mod_status status page generation */
      ssl_scache_status_register(pconf);
  
      /* Register mutex type names so they can be configured with Mutex */
      ap_mutex_register(pconf, SSL_CACHE_MUTEX_TYPE, NULL, APR_LOCK_DEFAULT, 0);
  #ifdef HAVE_OCSP_STAPLING
      ap_mutex_register(pconf, SSL_STAPLING_CACHE_MUTEX_TYPE, NULL,
                        APR_LOCK_DEFAULT, 0);
      ap_mutex_register(pconf, SSL_STAPLING_REFRESH_MUTEX_TYPE, NULL,
                        APR_LOCK_DEFAULT, 0);
  #endif
  
      return OK;
  }
  
  static SSLConnRec *ssl_init_connection_ctx(conn_rec *c,
                                             ap_conf_vector_t *per_dir_config,
                                             int reinit)
  {
      SSLConnRec *sslconn = myConnConfig(c);
      int need_setup = 0;
  
      /* mod_proxy's (r->)per_dir_config has the lifetime of the request, thus
       * it uses ssl_engine_set() to reset sslconn->dc when reusing SSL backend
       * connections, so we must fall through here. But in the case where we are
       * called from ssl_init_ssl_connection() with no per_dir_config (which also
       * includes mod_proxy's later run_pre_connection call), sslconn->dc should
       * be preserved if it's already set.
       */
      if (!sslconn) {
          sslconn = apr_pcalloc(c->pool, sizeof(*sslconn));
          need_setup = 1;
      }
      else if (!reinit) {
          return sslconn;
      }
  
      /* Reinit dc in any case because it may be r->per_dir_config scoped
       * and thus a caller like mod_proxy needs to update it per request.
       */
      if (per_dir_config) {
          sslconn->dc = ap_get_module_config(per_dir_config, &ssl_module);
      }
      else {
          sslconn->dc = ap_get_module_config(c->base_server->lookup_defaults,
                                             &ssl_module);
      }
  
      if (need_setup) {
          sslconn->server = c->base_server;
          sslconn->verify_depth = UNSET;
          if (c->outgoing) {
              sslconn->cipher_suite = sslconn->dc->proxy->auth.cipher_suite;
          }
          else {
              SSLSrvConfigRec *sc = mySrvConfig(c->base_server);
              sslconn->cipher_suite = sc->server->auth.cipher_suite;
          }
  
          myConnConfigSet(c, sslconn);
      }
  
      return sslconn;
  }
  
  static int ssl_engine_status(conn_rec *c, SSLConnRec *sslconn)
  {
      if (c->master) {
          return DECLINED;
      }
      if (sslconn) {
          /* This connection has already been configured. Check what applies. */
          if (sslconn->disabled) {
              return SUSPENDED;
          }
          if (c->outgoing) {
              if (!sslconn->dc->proxy_enabled) {
                  return DECLINED;
              }
          }
          else {
              if (mySrvConfig(sslconn->server)->enabled != SSL_ENABLED_TRUE) {
                  return DECLINED;
              }
          }
      }
      else {
          /* we decline by default for outgoing connections and for incoming
           * where the base_server is not enabled. */
          if (c->outgoing || mySrvConfig(c->base_server)->enabled != SSL_ENABLED_TRUE) {
              return DECLINED;
          }
      }
      return OK;
  }
  
  static int ssl_hook_ssl_bind_outgoing(conn_rec *c,
                                   ap_conf_vector_t *per_dir_config,
                                   int enable_ssl)
  {
      SSLConnRec *sslconn;
      int status;
  
      sslconn = ssl_init_connection_ctx(c, per_dir_config, 1);
      status = ssl_engine_status(c, sslconn);
      if (enable_ssl) {
          if (status != OK) {
              SSLSrvConfigRec *sc = mySrvConfig(sslconn->server);
              sslconn->disabled = 1;
              ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(10272)
                            "SSL Proxy requested for %s but not enabled for us.",
                            sc->vhost_id);
          }
          else {
              sslconn->disabled = 0;
              return OK;
          }
      }
      else {
          sslconn->disabled = 1;
      }
      return DECLINED;
  }
  
  #if defined(SSL_MAX_SID_CTX_LENGTH) && (APR_MD5_DIGESTSIZE * 2) > SSL_MAX_SID_CTX_LENGTH
  #error APR digest length x2 exceeds SSL_MAX_SID_CTX_LENGTH
  #endif
  
  int ssl_init_ssl_connection(conn_rec *c, request_rec *r)
  {
      SSLSrvConfigRec *sc;
      SSL *ssl;
      SSLConnRec *sslconn;
      int rc;
      modssl_ctx_t *mctx;
      server_rec *server;
  
      /*
       * Create or retrieve SSL context
       */
      sslconn = ssl_init_connection_ctx(c, r ? r->per_dir_config : NULL, 0);
      server = sslconn->server;
      sc = mySrvConfig(server);
  
      /*
       * Seed the Pseudo Random Number Generator (PRNG)
       */
      ssl_rand_seed(server, c->pool, SSL_RSCTX_CONNECT,
                    c->outgoing ? "Proxy: " : "Server: ");
  
      mctx = myConnCtxConfig(c, sc);
  
      /*
       * Create a new SSL connection with the configured server SSL context and
       * attach this to the socket. Additionally we register this attachment
       * so we can detach later.
       */
      if (!(sslconn->ssl = ssl = SSL_new(mctx->ssl_ctx))) {
          ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c, APLOGNO(01962)
                        "Unable to create a new SSL connection from the SSL "
                        "context");
          ssl_log_ssl_error(SSLLOG_MARK, APLOG_ERR, server);
  
          c->aborted = 1;
  
          return DECLINED; /* XXX */
      }
  
      rc = ssl_run_pre_handshake(c, ssl, c->outgoing ? 1 : 0);
      if (rc != OK && rc != DECLINED) {
          return rc;
      }
  
      if (!SSL_set_session_id_context(ssl, sc->vhost_md5, APR_MD5_DIGESTSIZE*2)) {
          ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c, APLOGNO(01963)
                        "Unable to set session id context to '%s'",
                        sc->vhost_md5);
          ssl_log_ssl_error(SSLLOG_MARK, APLOG_ERR, server);
  
          c->aborted = 1;
  
          return DECLINED; /* XXX */
      }
  
      SSL_set_app_data(ssl, c);
      modssl_set_app_data2(ssl, NULL); /* will be request_rec */
  
      SSL_set_verify_result(ssl, X509_V_OK);
  
      return ssl_io_filter_init(c, r, ssl);
  }
  
  static const char *ssl_hook_http_scheme(const request_rec *r)
  {
      return modssl_request_is_tls(r, NULL) ? "https" : NULL;
  }
  
  static apr_port_t ssl_hook_default_port(const request_rec *r)
  {
      return modssl_request_is_tls(r, NULL) ? 443 : 0;
  }
  
  static int ssl_hook_pre_connection(conn_rec *c, void *csd)
  {
      SSLSrvConfigRec *sc;
      SSLConnRec *sslconn = myConnConfig(c);
  
      /*
       * Immediately stop processing if SSL is disabled for this connection
       */
      if (ssl_engine_status(c, sslconn) != OK) {
          return DECLINED;
      }
  
      if (sslconn) {
          sc = mySrvConfig(sslconn->server);
      }
      else {
          sc = mySrvConfig(c->base_server);
      }
  
      /*
       * Remember the connection information for
       * later access inside callback functions
       */
  
      ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, c, APLOGNO(01964)
                    "Connection to child %ld established "
                    "(server %s)", c->id, sc->vhost_id);
  
      return ssl_init_ssl_connection(c, NULL);
  }
  
  static int ssl_hook_process_connection(conn_rec* c)
  {
      SSLConnRec *sslconn = myConnConfig(c);
  
      if (sslconn && !sslconn->disabled) {
          /* On an active SSL connection, let the input filters initialize
           * themselves which triggers the handshake, which again triggers
           * all kinds of useful things such as SNI and ALPN.
           */
          apr_bucket_brigade* temp;
          apr_status_t rv;
  
          temp = apr_brigade_create(c->pool, c->bucket_alloc);
          rv = ap_get_brigade(c->input_filters, temp,
                              AP_MODE_INIT, APR_BLOCK_READ, 0);
          apr_brigade_destroy(temp);
  
          if (APR_SUCCESS != APR_SUCCESS) {
              if (c->cs) {
                  c->cs->state = CONN_STATE_LINGER;
              }
              ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, c, APLOGNO(10373)
                            "SSL handshake was not completed, "
                            "closing connection");
              return OK;
          }
      }
      
      return DECLINED;
  }
  
  /*
   *  the module registration phase
   */
  
  static void ssl_register_hooks(apr_pool_t *p)
  {
      /* ssl_hook_ReadReq needs to use the BrowserMatch settings so must
       * run after mod_setenvif's post_read_request hook. */
      static const char *pre_prr[] = { "mod_setenvif.c", NULL };
      /* The ssl_init_Module post_config hook should run before mod_proxy's
       * for the ssl proxy main configs to be merged with vhosts' before being
       * themselves merged with mod_proxy's in proxy_hook_section_post_config.
       */
      static const char *b_pc[] = { "mod_proxy.c", NULL};
  
  
      ssl_io_filter_register(p);
  
      ap_hook_pre_connection(ssl_hook_pre_connection,NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_process_connection(ssl_hook_process_connection, 
                                                     NULL, NULL, APR_HOOK_MIDDLE);
      ap_hook_test_config   (ssl_hook_ConfigTest,    NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_post_config   (ssl_init_Module,        NULL,b_pc, APR_HOOK_MIDDLE);
      ap_hook_http_scheme   (ssl_hook_http_scheme,   NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_default_port  (ssl_hook_default_port,  NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_pre_config    (ssl_hook_pre_config,    NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_child_init    (ssl_init_Child,         NULL,NULL, APR_HOOK_MIDDLE);
      ap_hook_post_read_request(ssl_hook_ReadReq, pre_prr,NULL, APR_HOOK_MIDDLE);
      ap_hook_check_access  (ssl_hook_Access,        NULL,NULL, APR_HOOK_MIDDLE,
                             AP_AUTH_INTERNAL_PER_CONF);
      ap_hook_check_authn   (ssl_hook_UserCheck,     NULL,NULL, APR_HOOK_FIRST,
                             AP_AUTH_INTERNAL_PER_CONF);
      ap_hook_check_authz   (ssl_hook_Auth,          NULL,NULL, APR_HOOK_MIDDLE,
                             AP_AUTH_INTERNAL_PER_CONF);
      ap_hook_fixups        (ssl_hook_Fixup,         NULL,NULL, APR_HOOK_MIDDLE);
  
      APR_OPTIONAL_HOOK(proxy, section_post_config,
                        ssl_proxy_section_post_config, NULL, NULL,
                        APR_HOOK_MIDDLE);
  
      ssl_var_register(p);
      ap_hook_ssl_bind_outgoing  (ssl_hook_ssl_bind_outgoing, NULL, NULL, APR_HOOK_MIDDLE);
  
      ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "ssl",
                                AUTHZ_PROVIDER_VERSION,
                                &ssl_authz_provider_require_ssl,
                                AP_AUTH_INTERNAL_PER_CONF);
  
      ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "ssl-verify-client",
                                AUTHZ_PROVIDER_VERSION,
                                &ssl_authz_provider_verify_client,
                                AP_AUTH_INTERNAL_PER_CONF);
  }
  
  module AP_MODULE_DECLARE_DATA ssl_module = {
      STANDARD20_MODULE_STUFF,
      ssl_config_perdir_create,   /* create per-dir    config structures */
      ssl_config_perdir_merge,    /* merge  per-dir    config structures */
      ssl_config_server_create,   /* create per-server config structures */
      ssl_config_server_merge,    /* merge  per-server config structures */
      ssl_config_cmds,            /* table of configuration directives   */
      ssl_register_hooks          /* register hooks */
  #if defined(AP_MODULE_HAS_FLAGS)
     ,AP_MODULE_FLAG_ALWAYS_MERGE /* flags */
  #endif
  };
  