text: 
  /*
   * Copyright (C) Igor Sysoev
   * Copyright (C) Nginx, Inc.
   */
  
  
  #include <ngx_config.h>
  #include <ngx_core.h>
  #include <ngx_event.h>
  
  
  typedef struct {
      ngx_uint_t  engine;   /* unsigned  engine:1; */
  } ngx_openssl_conf_t;
  
  
  static int ngx_http_ssl_verify_callback(int ok, X509_STORE_CTX *x509_store);
  static void ngx_ssl_info_callback(const ngx_ssl_conn_t *ssl_conn, int where,
      int ret);
  static void ngx_ssl_handshake_handler(ngx_event_t *ev);
  static ngx_int_t ngx_ssl_handle_recv(ngx_connection_t *c, int n);
  static void ngx_ssl_write_handler(ngx_event_t *wev);
  static void ngx_ssl_read_handler(ngx_event_t *rev);
  static void ngx_ssl_shutdown_handler(ngx_event_t *ev);
  static void ngx_ssl_connection_error(ngx_connection_t *c, int sslerr,
      ngx_err_t err, char *text);
  static void ngx_ssl_clear_error(ngx_log_t *log);
  
  ngx_int_t ngx_ssl_session_cache_init(ngx_shm_zone_t *shm_zone, void *data);
  static int ngx_ssl_new_session(ngx_ssl_conn_t *ssl_conn,
      ngx_ssl_session_t *sess);
  static ngx_ssl_session_t *ngx_ssl_get_cached_session(ngx_ssl_conn_t *ssl_conn,
      u_char *id, int len, int *copy);
  static void ngx_ssl_remove_session(SSL_CTX *ssl, ngx_ssl_session_t *sess);
  static void ngx_ssl_expire_sessions(ngx_ssl_session_cache_t *cache,
      ngx_slab_pool_t *shpool, ngx_uint_t n);
  static void ngx_ssl_session_rbtree_insert_value(ngx_rbtree_node_t *temp,
      ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
  
  static void *ngx_openssl_create_conf(ngx_cycle_t *cycle);
  static char *ngx_openssl_engine(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
  static void ngx_openssl_exit(ngx_cycle_t *cycle);
  
  
  static ngx_command_t  ngx_openssl_commands[] = {
  
      { ngx_string("ssl_engine"),
        NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
        ngx_openssl_engine,
        0,
        0,
        NULL },
  
        ngx_null_command
  };
  
  
  static ngx_core_module_t  ngx_openssl_module_ctx = {
      ngx_string("openssl"),
      ngx_openssl_create_conf,
      NULL
  };
  
  
  ngx_module_t  ngx_openssl_module = {
      NGX_MODULE_V1,
      &ngx_openssl_module_ctx,               /* module context */
      ngx_openssl_commands,                  /* module directives */
      NGX_CORE_MODULE,                       /* module type */
      NULL,                                  /* init master */
      NULL,                                  /* init module */
      NULL,                                  /* init process */
      NULL,                                  /* init thread */
      NULL,                                  /* exit thread */
      NULL,                                  /* exit process */
      ngx_openssl_exit,                      /* exit master */
      NGX_MODULE_V1_PADDING
  };
  
  
  int  ngx_ssl_connection_index;
  int  ngx_ssl_server_conf_index;
  int  ngx_ssl_session_cache_index;
  
  
  ngx_int_t
  ngx_ssl_init(ngx_log_t *log)
  {
      OPENSSL_config(NULL);
  
      SSL_library_init();
      SSL_load_error_strings();
  
      OpenSSL_add_all_algorithms();
  
      ngx_ssl_connection_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
  
      if (ngx_ssl_connection_index == -1) {
          ngx_ssl_error(NGX_LOG_ALERT, log, 0, "SSL_get_ex_new_index() failed");
          return NGX_ERROR;
      }
  
      ngx_ssl_server_conf_index = SSL_CTX_get_ex_new_index(0, NULL, NULL, NULL,
                                                           NULL);
      if (ngx_ssl_server_conf_index == -1) {
          ngx_ssl_error(NGX_LOG_ALERT, log, 0,
                        "SSL_CTX_get_ex_new_index() failed");
          return NGX_ERROR;
      }
  
      ngx_ssl_session_cache_index = SSL_CTX_get_ex_new_index(0, NULL, NULL, NULL,
                                                             NULL);
      if (ngx_ssl_session_cache_index == -1) {
          ngx_ssl_error(NGX_LOG_ALERT, log, 0,
                        "SSL_CTX_get_ex_new_index() failed");
          return NGX_ERROR;
      }
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_create(ngx_ssl_t *ssl, ngx_uint_t protocols, void *data)
  {
      ssl->ctx = SSL_CTX_new(SSLv23_method());
  
      if (ssl->ctx == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, "SSL_CTX_new() failed");
          return NGX_ERROR;
      }
  
      if (SSL_CTX_set_ex_data(ssl->ctx, ngx_ssl_server_conf_index, data) == 0) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_CTX_set_ex_data() failed");
          return NGX_ERROR;
      }
  
      /* client side options */
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_MICROSOFT_SESS_ID_BUG);
      SSL_CTX_set_options(ssl->ctx, SSL_OP_NETSCAPE_CHALLENGE_BUG);
  
      /* server side options */
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG);
      SSL_CTX_set_options(ssl->ctx, SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER);
  
      /* this option allow a potential SSL 2.0 rollback (CAN-2005-2969) */
      SSL_CTX_set_options(ssl->ctx, SSL_OP_MSIE_SSLV2_RSA_PADDING);
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_SSLEAY_080_CLIENT_DH_BUG);
      SSL_CTX_set_options(ssl->ctx, SSL_OP_TLS_D5_BUG);
      SSL_CTX_set_options(ssl->ctx, SSL_OP_TLS_BLOCK_PADDING_BUG);
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS);
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_SINGLE_DH_USE);
  
      if (!(protocols & NGX_SSL_SSLv2)) {
          SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_SSLv2);
      }
      if (!(protocols & NGX_SSL_SSLv3)) {
          SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_SSLv3);
      }
      if (!(protocols & NGX_SSL_TLSv1)) {
          SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_TLSv1);
      }
  #ifdef SSL_OP_NO_TLSv1_1
      if (!(protocols & NGX_SSL_TLSv1_1)) {
          SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_TLSv1_1);
      }
  #endif
  #ifdef SSL_OP_NO_TLSv1_2
      if (!(protocols & NGX_SSL_TLSv1_2)) {
          SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_TLSv1_2);
      }
  #endif
  
  #ifdef SSL_OP_NO_COMPRESSION
      SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_COMPRESSION);
  #endif
  
  #ifdef SSL_MODE_RELEASE_BUFFERS
      SSL_CTX_set_mode(ssl->ctx, SSL_MODE_RELEASE_BUFFERS);
  #endif
  
      SSL_CTX_set_read_ahead(ssl->ctx, 1);
  
      SSL_CTX_set_info_callback(ssl->ctx, ngx_ssl_info_callback);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
      ngx_str_t *key)
  {
      if (ngx_conf_full_name(cf->cycle, cert, 1) != NGX_OK) {
          return NGX_ERROR;
      }
  
      if (SSL_CTX_use_certificate_chain_file(ssl->ctx, (char *) cert->data)
          == 0)
      {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_CTX_use_certificate_chain_file(\"%s\") failed",
                        cert->data);
          return NGX_ERROR;
      }
  
      if (ngx_conf_full_name(cf->cycle, key, 1) != NGX_OK) {
          return NGX_ERROR;
      }
  
      if (SSL_CTX_use_PrivateKey_file(ssl->ctx, (char *) key->data,
                                      SSL_FILETYPE_PEM)
          == 0)
      {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_CTX_use_PrivateKey_file(\"%s\") failed", key->data);
          return NGX_ERROR;
      }
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_client_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
      ngx_int_t depth)
  {
      STACK_OF(X509_NAME)  *list;
  
      SSL_CTX_set_verify(ssl->ctx, SSL_VERIFY_PEER, ngx_http_ssl_verify_callback);
  
      SSL_CTX_set_verify_depth(ssl->ctx, depth);
  
      if (cert->len == 0) {
          return NGX_OK;
      }
  
      if (ngx_conf_full_name(cf->cycle, cert, 1) != NGX_OK) {
          return NGX_ERROR;
      }
  
      if (SSL_CTX_load_verify_locations(ssl->ctx, (char *) cert->data, NULL)
          == 0)
      {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_CTX_load_verify_locations(\"%s\") failed",
                        cert->data);
          return NGX_ERROR;
      }
  
      list = SSL_load_client_CA_file((char *) cert->data);
  
      if (list == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_load_client_CA_file(\"%s\") failed", cert->data);
          return NGX_ERROR;
      }
  
      /*
       * before 0.9.7h and 0.9.8 SSL_load_client_CA_file()
       * always leaved an error in the error queue
       */
  
      ERR_clear_error();
  
      SSL_CTX_set_client_CA_list(ssl->ctx, list);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_crl(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *crl)
  {
      X509_STORE   *store;
      X509_LOOKUP  *lookup;
  
      if (crl->len == 0) {
          return NGX_OK;
      }
  
      if (ngx_conf_full_name(cf->cycle, crl, 1) != NGX_OK) {
          return NGX_ERROR;
      }
  
      store = SSL_CTX_get_cert_store(ssl->ctx);
  
      if (store == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "SSL_CTX_get_cert_store() failed");
          return NGX_ERROR;
      }
  
      lookup = X509_STORE_add_lookup(store, X509_LOOKUP_file());
  
      if (lookup == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "X509_STORE_add_lookup() failed");
          return NGX_ERROR;
      }
  
      if (X509_LOOKUP_load_file(lookup, (char *) crl->data, X509_FILETYPE_PEM)
          == 0)
      {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "X509_LOOKUP_load_file(\"%s\") failed", crl->data);
          return NGX_ERROR;
      }
  
      X509_STORE_set_flags(store,
                           X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
  
      return NGX_OK;
  }
  
  
  static int
  ngx_http_ssl_verify_callback(int ok, X509_STORE_CTX *x509_store)
  {
  #if (NGX_DEBUG)
      char              *subject, *issuer;
      int                err, depth;
      X509              *cert;
      X509_NAME         *sname, *iname;
      ngx_connection_t  *c;
      ngx_ssl_conn_t    *ssl_conn;
  
      ssl_conn = X509_STORE_CTX_get_ex_data(x509_store,
                                            SSL_get_ex_data_X509_STORE_CTX_idx());
  
      c = ngx_ssl_get_connection(ssl_conn);
  
      cert = X509_STORE_CTX_get_current_cert(x509_store);
      err = X509_STORE_CTX_get_error(x509_store);
      depth = X509_STORE_CTX_get_error_depth(x509_store);
  
      sname = X509_get_subject_name(cert);
      subject = sname ? X509_NAME_oneline(sname, NULL, 0) : "(none)";
  
      iname = X509_get_issuer_name(cert);
      issuer = iname ? X509_NAME_oneline(iname, NULL, 0) : "(none)";
  
      ngx_log_debug5(NGX_LOG_DEBUG_EVENT, c->log, 0,
                     "verify:%d, error:%d, depth:%d, "
                     "subject:\"%s\",issuer: \"%s\"",
                     ok, err, depth, subject, issuer);
  
      if (sname) {
          OPENSSL_free(subject);
      }
  
      if (iname) {
          OPENSSL_free(issuer);
      }
  #endif
  
      return 1;
  }
  
  
  static void
  ngx_ssl_info_callback(const ngx_ssl_conn_t *ssl_conn, int where, int ret)
  {
      ngx_connection_t  *c;
  
      if (where & SSL_CB_HANDSHAKE_START) {
          c = ngx_ssl_get_connection((ngx_ssl_conn_t *) ssl_conn);
  
          if (c->ssl->handshaked) {
              c->ssl->renegotiation = 1;
              ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL renegotiation");
          }
      }
  }
  
  
  RSA *
  ngx_ssl_rsa512_key_callback(SSL *ssl, int is_export, int key_length)
  {
      static RSA  *key;
  
      if (key_length == 512) {
          if (key == NULL) {
              key = RSA_generate_key(512, RSA_F4, NULL, NULL);
          }
      }
  
      return key;
  }
  
  
  ngx_int_t
  ngx_ssl_dhparam(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *file)
  {
      DH   *dh;
      BIO  *bio;
  
      /*
       * -----BEGIN DH PARAMETERS-----
       * MIGHAoGBALu8LcrYRnSQfEP89YDpz9vZWKP1aLQtSwju1OsPs1BMbAMCducQgAxc
       * y7qokiYUxb7spWWl/fHSh6K8BJvmd4Bg6RqSp1fjBI9osHb302zI8pul34HcLKcl
       * 7OZicMyaUDXYzs7vnqAnSmOrHlj6/UmI0PZdFGdX2gcd8EXP4WubAgEC
       * -----END DH PARAMETERS-----
       */
  
      static unsigned char dh1024_p[] = {
          0xBB, 0xBC, 0x2D, 0xCA, 0xD8, 0x46, 0x74, 0x90, 0x7C, 0x43, 0xFC, 0xF5,
          0x80, 0xE9, 0xCF, 0xDB, 0xD9, 0x58, 0xA3, 0xF5, 0x68, 0xB4, 0x2D, 0x4B,
          0x08, 0xEE, 0xD4, 0xEB, 0x0F, 0xB3, 0x50, 0x4C, 0x6C, 0x03, 0x02, 0x76,
          0xE7, 0x10, 0x80, 0x0C, 0x5C, 0xCB, 0xBA, 0xA8, 0x92, 0x26, 0x14, 0xC5,
          0xBE, 0xEC, 0xA5, 0x65, 0xA5, 0xFD, 0xF1, 0xD2, 0x87, 0xA2, 0xBC, 0x04,
          0x9B, 0xE6, 0x77, 0x80, 0x60, 0xE9, 0x1A, 0x92, 0xA7, 0x57, 0xE3, 0x04,
          0x8F, 0x68, 0xB0, 0x76, 0xF7, 0xD3, 0x6C, 0xC8, 0xF2, 0x9B, 0xA5, 0xDF,
          0x81, 0xDC, 0x2C, 0xA7, 0x25, 0xEC, 0xE6, 0x62, 0x70, 0xCC, 0x9A, 0x50,
          0x35, 0xD8, 0xCE, 0xCE, 0xEF, 0x9E, 0xA0, 0x27, 0x4A, 0x63, 0xAB, 0x1E,
          0x58, 0xFA, 0xFD, 0x49, 0x88, 0xD0, 0xF6, 0x5D, 0x14, 0x67, 0x57, 0xDA,
          0x07, 0x1D, 0xF0, 0x45, 0xCF, 0xE1, 0x6B, 0x9B
      };
  
      static unsigned char dh1024_g[] = { 0x02 };
  
  
      if (file->len == 0) {
  
          dh = DH_new();
          if (dh == NULL) {
              ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, "DH_new() failed");
              return NGX_ERROR;
          }
  
          dh->p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
          dh->g = BN_bin2bn(dh1024_g, sizeof(dh1024_g), NULL);
  
          if (dh->p == NULL || dh->g == NULL) {
              ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, "BN_bin2bn() failed");
              DH_free(dh);
              return NGX_ERROR;
          }
  
          SSL_CTX_set_tmp_dh(ssl->ctx, dh);
  
          DH_free(dh);
  
          return NGX_OK;
      }
  
      if (ngx_conf_full_name(cf->cycle, file, 1) != NGX_OK) {
          return NGX_ERROR;
      }
  
      bio = BIO_new_file((char *) file->data, "r");
      if (bio == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "BIO_new_file(\"%s\") failed", file->data);
          return NGX_ERROR;
      }
  
      dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
      if (dh == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "PEM_read_bio_DHparams(\"%s\") failed", file->data);
          BIO_free(bio);
          return NGX_ERROR;
      }
  
      SSL_CTX_set_tmp_dh(ssl->ctx, dh);
  
      DH_free(dh);
      BIO_free(bio);
  
      return NGX_OK;
  }
  
  ngx_int_t
  ngx_ssl_ecdh_curve(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *name)
  {
  #if OPENSSL_VERSION_NUMBER >= 0x0090800fL
  #ifndef OPENSSL_NO_ECDH
      int      nid;
      EC_KEY  *ecdh;
  
      /*
       * Elliptic-Curve Diffie-Hellman parameters are either "named curves"
       * from RFC 4492 section 5.1.1, or explicitely described curves over
       * binary fields. OpenSSL only supports the "named curves", which provide
       * maximum interoperability.
       */
  
      nid = OBJ_sn2nid((const char *) name->data);
      if (nid == 0) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "Unknown curve name \"%s\"", name->data);
          return NGX_ERROR;
      }
  
      ecdh = EC_KEY_new_by_curve_name(nid);
      if (ecdh == NULL) {
          ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                        "Unable to create curve \"%s\"", name->data);
          return NGX_ERROR;
      }
  
      SSL_CTX_set_tmp_ecdh(ssl->ctx, ecdh);
  
      SSL_CTX_set_options(ssl->ctx, SSL_OP_SINGLE_ECDH_USE);
  
      EC_KEY_free(ecdh);
  #endif
  #endif
  
      return NGX_OK;
  }
  
  ngx_int_t
  ngx_ssl_create_connection(ngx_ssl_t *ssl, ngx_connection_t *c, ngx_uint_t flags)
  {
      ngx_ssl_connection_t  *sc;
  
      sc = ngx_pcalloc(c->pool, sizeof(ngx_ssl_connection_t));
      if (sc == NULL) {
          return NGX_ERROR;
      }
  
      sc->buffer = ((flags & NGX_SSL_BUFFER) != 0);
  
      sc->connection = SSL_new(ssl->ctx);
  
      if (sc->connection == NULL) {
          ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_new() failed");
          return NGX_ERROR;
      }
  
      if (SSL_set_fd(sc->connection, c->fd) == 0) {
          ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_fd() failed");
          return NGX_ERROR;
      }
  
      if (flags & NGX_SSL_CLIENT) {
          SSL_set_connect_state(sc->connection);
  
      } else {
          SSL_set_accept_state(sc->connection);
      }
  
      if (SSL_set_ex_data(sc->connection, ngx_ssl_connection_index, c) == 0) {
          ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_ex_data() failed");
          return NGX_ERROR;
      }
  
      c->ssl = sc;
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_set_session(ngx_connection_t *c, ngx_ssl_session_t *session)
  {
      if (session) {
          if (SSL_set_session(c->ssl->connection, session) == 0) {
              ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_session() failed");
              return NGX_ERROR;
          }
      }
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_handshake(ngx_connection_t *c)
  {
      int        n, sslerr;
      ngx_err_t  err;
  
      ngx_ssl_clear_error(c->log);
  
      n = SSL_do_handshake(c->ssl->connection);
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_do_handshake: %d", n);
  
      if (n == 1) {
  
          if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
  #if (NGX_DEBUG)
          {
          char         buf[129], *s, *d;
  #if OPENSSL_VERSION_NUMBER >= 0x10000000L
          const
  #endif
          SSL_CIPHER  *cipher;
  
          cipher = SSL_get_current_cipher(c->ssl->connection);
  
          if (cipher) {
              SSL_CIPHER_description(cipher, &buf[1], 128);
  
              for (s = &buf[1], d = buf; *s; s++) {
                  if (*s == ' ' && *d == ' ') {
                      continue;
                  }
  
                  if (*s == LF || *s == CR) {
                      continue;
                  }
  
                  *++d = *s;
              }
  
              if (*d != ' ') {
                  d++;
              }
  
              *d = '\0';
  
              ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
                             "SSL: %s, cipher: \"%s\"",
                             SSL_get_version(c->ssl->connection), &buf[1]);
  
              if (SSL_session_reused(c->ssl->connection)) {
                  ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
                                 "SSL reused session");
              }
  
          } else {
              ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
                             "SSL no shared ciphers");
          }
          }
  #endif
  
          c->ssl->handshaked = 1;
  
          c->recv = ngx_ssl_recv;
          c->send = ngx_ssl_write;
          c->recv_chain = ngx_ssl_recv_chain;
          c->send_chain = ngx_ssl_send_chain;
  
          /* initial handshake done, disable renegotiation (CVE-2009-3555) */
          if (c->ssl->connection->s3) {
              c->ssl->connection->s3->flags |= SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS;
          }
  
          return NGX_OK;
      }
  
      sslerr = SSL_get_error(c->ssl->connection, n);
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);
  
      if (sslerr == SSL_ERROR_WANT_READ) {
          c->read->ready = 0;
          c->read->handler = ngx_ssl_handshake_handler;
          c->write->handler = ngx_ssl_handshake_handler;
  
          if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          return NGX_AGAIN;
      }
  
      if (sslerr == SSL_ERROR_WANT_WRITE) {
          c->write->ready = 0;
          c->read->handler = ngx_ssl_handshake_handler;
          c->write->handler = ngx_ssl_handshake_handler;
  
          if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          return NGX_AGAIN;
      }
  
      err = (sslerr == SSL_ERROR_SYSCALL) ? ngx_errno : 0;
  
      c->ssl->no_wait_shutdown = 1;
      c->ssl->no_send_shutdown = 1;
      c->read->eof = 1;
  
      if (sslerr == SSL_ERROR_ZERO_RETURN || ERR_peek_error() == 0) {
          ngx_log_error(NGX_LOG_INFO, c->log, err,
                        "peer closed connection in SSL handshake");
  
          return NGX_ERROR;
      }
  
      c->read->error = 1;
  
      ngx_ssl_connection_error(c, sslerr, err, "SSL_do_handshake() failed");
  
      return NGX_ERROR;
  }
  
  
  static void
  ngx_ssl_handshake_handler(ngx_event_t *ev)
  {
      ngx_connection_t  *c;
  
      c = ev->data;
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                     "SSL handshake handler: %d", ev->write);
  
      if (ev->timedout) {
          c->ssl->handler(c);
          return;
      }
  
      if (ngx_ssl_handshake(c) == NGX_AGAIN) {
          return;
      }
  
      c->ssl->handler(c);
  }
  
  
  ssize_t
  ngx_ssl_recv_chain(ngx_connection_t *c, ngx_chain_t *cl)
  {
      u_char     *last;
      ssize_t     n, bytes;
      ngx_buf_t  *b;
  
      bytes = 0;
  
      b = cl->buf;
      last = b->last;
  
      for ( ;; ) {
  
          n = ngx_ssl_recv(c, last, b->end - last);
  
          if (n > 0) {
              last += n;
              bytes += n;
  
              if (last == b->end) {
                  cl = cl->next;
  
                  if (cl == NULL) {
                      return bytes;
                  }
  
                  b = cl->buf;
                  last = b->last;
              }
  
              continue;
          }
  
          if (bytes) {
  
              if (n == 0 || n == NGX_ERROR) {
                  c->read->ready = 1;
              }
  
              return bytes;
          }
  
          return n;
      }
  }
  
  
  ssize_t
  ngx_ssl_recv(ngx_connection_t *c, u_char *buf, size_t size)
  {
      int  n, bytes;
  
      if (c->ssl->last == NGX_ERROR) {
          c->read->error = 1;
          return NGX_ERROR;
      }
  
      if (c->ssl->last == NGX_DONE) {
          c->read->ready = 0;
          c->read->eof = 1;
          return 0;
      }
  
      bytes = 0;
  
      ngx_ssl_clear_error(c->log);
  
      /*
       * SSL_read() may return data in parts, so try to read
       * until SSL_read() would return no data
       */
  
      for ( ;; ) {
  
          n = SSL_read(c->ssl->connection, buf, size);
  
          ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_read: %d", n);
  
          if (n > 0) {
              bytes += n;
          }
  
          c->ssl->last = ngx_ssl_handle_recv(c, n);
  
          if (c->ssl->last == NGX_OK) {
  
              size -= n;
  
              if (size == 0) {
                  return bytes;
              }
  
              buf += n;
  
              continue;
          }
  
          if (bytes) {
              return bytes;
          }
  
          switch (c->ssl->last) {
  
          case NGX_DONE:
              c->read->ready = 0;
              c->read->eof = 1;
              return 0;
  
          case NGX_ERROR:
              c->read->error = 1;
  
              /* fall through */
  
          case NGX_AGAIN:
              return c->ssl->last;
          }
      }
  }
  
  
  static ngx_int_t
  ngx_ssl_handle_recv(ngx_connection_t *c, int n)
  {
      int        sslerr;
      ngx_err_t  err;
  
      if (c->ssl->renegotiation) {
          /*
           * disable renegotiation (CVE-2009-3555):
           * OpenSSL (at least up to 0.9.8l) does not handle disabled
           * renegotiation gracefully, so drop connection here
           */
  
          ngx_log_error(NGX_LOG_NOTICE, c->log, 0, "SSL renegotiation disabled");
  
          while (ERR_peek_error()) {
              ngx_ssl_error(NGX_LOG_DEBUG, c->log, 0,
                            "ignoring stale global SSL error");
          }
  
          ERR_clear_error();
  
          c->ssl->no_wait_shutdown = 1;
          c->ssl->no_send_shutdown = 1;
  
          return NGX_ERROR;
      }
  
      if (n > 0) {
  
          if (c->ssl->saved_write_handler) {
  
              c->write->handler = c->ssl->saved_write_handler;
              c->ssl->saved_write_handler = NULL;
              c->write->ready = 1;
  
              if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
                  return NGX_ERROR;
              }
  
              ngx_post_event(c->write, &ngx_posted_events);
          }
  
          return NGX_OK;
      }
  
      sslerr = SSL_get_error(c->ssl->connection, n);
  
      err = (sslerr == SSL_ERROR_SYSCALL) ? ngx_errno : 0;
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);
  
      if (sslerr == SSL_ERROR_WANT_READ) {
          c->read->ready = 0;
          return NGX_AGAIN;
      }
  
      if (sslerr == SSL_ERROR_WANT_WRITE) {
  
          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                        "peer started SSL renegotiation");
  
          c->write->ready = 0;
  
          if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          /*
           * we do not set the timer because there is already the read event timer
           */
  
          if (c->ssl->saved_write_handler == NULL) {
              c->ssl->saved_write_handler = c->write->handler;
              c->write->handler = ngx_ssl_write_handler;
          }
  
          return NGX_AGAIN;
      }
  
      c->ssl->no_wait_shutdown = 1;
      c->ssl->no_send_shutdown = 1;
  
      if (sslerr == SSL_ERROR_ZERO_RETURN || ERR_peek_error() == 0) {
          ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
                         "peer shutdown SSL cleanly");
          return NGX_DONE;
      }
  
      ngx_ssl_connection_error(c, sslerr, err, "SSL_read() failed");
  
      return NGX_ERROR;
  }
  
  
  static void
  ngx_ssl_write_handler(ngx_event_t *wev)
  {
      ngx_connection_t  *c;
  
      c = wev->data;
  
      c->read->handler(c->read);
  }
  
  
  /*
   * OpenSSL has no SSL_writev() so we copy several bufs into our 16K buffer
   * before the SSL_write() call to decrease a SSL overhead.
   *
   * Besides for protocols such as HTTP it is possible to always buffer
   * the output to decrease a SSL overhead some more.
   */
  
  ngx_chain_t *
  ngx_ssl_send_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
  {
      int          n;
      ngx_uint_t   flush;
      ssize_t      send, size;
      ngx_buf_t   *buf;
  
      if (!c->ssl->buffer) {
  
          while (in) {
              if (ngx_buf_special(in->buf)) {
                  in = in->next;
                  continue;
              }
  
              n = ngx_ssl_write(c, in->buf->pos, in->buf->last - in->buf->pos);
  
              if (n == NGX_ERROR) {
                  return NGX_CHAIN_ERROR;
              }
  
              if (n == NGX_AGAIN) {
                  c->buffered |= NGX_SSL_BUFFERED;
                  return in;
              }
  
              in->buf->pos += n;
  
              if (in->buf->pos == in->buf->last) {
                  in = in->next;
              }
          }
  
          return in;
      }
  
  
      /* the maximum limit size is the maximum int32_t value - the page size */
  
      if (limit == 0 || limit > (off_t) (NGX_MAX_INT32_VALUE - ngx_pagesize)) {
          limit = NGX_MAX_INT32_VALUE - ngx_pagesize;
      }
  
      buf = c->ssl->buf;
  
      if (buf == NULL) {
          buf = ngx_create_temp_buf(c->pool, NGX_SSL_BUFSIZE);
          if (buf == NULL) {
              return NGX_CHAIN_ERROR;
          }
  
          c->ssl->buf = buf;
      }
  
      if (buf->start == NULL) {
          buf->start = ngx_palloc(c->pool, NGX_SSL_BUFSIZE);
          if (buf->start == NULL) {
              return NGX_CHAIN_ERROR;
          }
  
          buf->pos = buf->start;
          buf->last = buf->start;
          buf->end = buf->start + NGX_SSL_BUFSIZE;
      }
  
      send = 0;
      flush = (in == NULL) ? 1 : 0;
  
      for ( ;; ) {
  
          while (in && buf->last < buf->end && send < limit) {
              if (in->buf->last_buf || in->buf->flush) {
                  flush = 1;
              }
  
              if (ngx_buf_special(in->buf)) {
                  in = in->next;
                  continue;
              }
  
              size = in->buf->last - in->buf->pos;
  
              if (size > buf->end - buf->last) {
                  size = buf->end - buf->last;
              }
  
              if (send + size > limit) {
                  size = (ssize_t) (limit - send);
                  flush = 1;
              }
  
              ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                             "SSL buf copy: %d", size);
  
              ngx_memcpy(buf->last, in->buf->pos, size);
  
              buf->last += size;
              in->buf->pos += size;
              send += size;
  
              if (in->buf->pos == in->buf->last) {
                  in = in->next;
              }
          }
  
          size = buf->last - buf->pos;
  
          if (!flush && buf->last < buf->end && c->ssl->buffer) {
              break;
          }
  
          n = ngx_ssl_write(c, buf->pos, size);
  
          if (n == NGX_ERROR) {
              return NGX_CHAIN_ERROR;
          }
  
          if (n == NGX_AGAIN) {
              c->buffered |= NGX_SSL_BUFFERED;
              return in;
          }
  
          buf->pos += n;
          c->sent += n;
  
          if (n < size) {
              break;
          }
  
          if (buf->pos == buf->last) {
              buf->pos = buf->start;
              buf->last = buf->start;
          }
  
          if (in == NULL || send == limit) {
              break;
          }
      }
  
      if (buf->pos < buf->last) {
          c->buffered |= NGX_SSL_BUFFERED;
  
      } else {
          c->buffered &= ~NGX_SSL_BUFFERED;
      }
  
      return in;
  }
  
  
  ssize_t
  ngx_ssl_write(ngx_connection_t *c, u_char *data, size_t size)
  {
      int        n, sslerr;
      ngx_err_t  err;
  
      ngx_ssl_clear_error(c->log);
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL to write: %d", size);
  
      n = SSL_write(c->ssl->connection, data, size);
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_write: %d", n);
  
      if (n > 0) {
  
          if (c->ssl->saved_read_handler) {
  
              c->read->handler = c->ssl->saved_read_handler;
              c->ssl->saved_read_handler = NULL;
              c->read->ready = 1;
  
              if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
                  return NGX_ERROR;
              }
  
              ngx_post_event(c->read, &ngx_posted_events);
          }
  
          return n;
      }
  
      sslerr = SSL_get_error(c->ssl->connection, n);
  
      err = (sslerr == SSL_ERROR_SYSCALL) ? ngx_errno : 0;
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);
  
      if (sslerr == SSL_ERROR_WANT_WRITE) {
          c->write->ready = 0;
          return NGX_AGAIN;
      }
  
      if (sslerr == SSL_ERROR_WANT_READ) {
  
          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                        "peer started SSL renegotiation");
  
          c->read->ready = 0;
  
          if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          /*
           * we do not set the timer because there is already
           * the write event timer
           */
  
          if (c->ssl->saved_read_handler == NULL) {
              c->ssl->saved_read_handler = c->read->handler;
              c->read->handler = ngx_ssl_read_handler;
          }
  
          return NGX_AGAIN;
      }
  
      c->ssl->no_wait_shutdown = 1;
      c->ssl->no_send_shutdown = 1;
      c->write->error = 1;
  
      ngx_ssl_connection_error(c, sslerr, err, "SSL_write() failed");
  
      return NGX_ERROR;
  }
  
  
  static void
  ngx_ssl_read_handler(ngx_event_t *rev)
  {
      ngx_connection_t  *c;
  
      c = rev->data;
  
      c->write->handler(c->write);
  }
  
  
  void
  ngx_ssl_free_buffer(ngx_connection_t *c)
  {
      if (c->ssl->buf && c->ssl->buf->start) {
          if (ngx_pfree(c->pool, c->ssl->buf->start) == NGX_OK) {
              c->ssl->buf->start = NULL;
          }
      }
  }
  
  
  ngx_int_t
  ngx_ssl_shutdown(ngx_connection_t *c)
  {
      int        n, sslerr, mode;
      ngx_err_t  err;
  
      if (c->timedout) {
          mode = SSL_RECEIVED_SHUTDOWN|SSL_SENT_SHUTDOWN;
          SSL_set_quiet_shutdown(c->ssl->connection, 1);
  
      } else {
          mode = SSL_get_shutdown(c->ssl->connection);
  
          if (c->ssl->no_wait_shutdown) {
              mode |= SSL_RECEIVED_SHUTDOWN;
          }
  
          if (c->ssl->no_send_shutdown) {
              mode |= SSL_SENT_SHUTDOWN;
          }
  
          if (c->ssl->no_wait_shutdown && c->ssl->no_send_shutdown) {
              SSL_set_quiet_shutdown(c->ssl->connection, 1);
          }
      }
  
      SSL_set_shutdown(c->ssl->connection, mode);
  
      ngx_ssl_clear_error(c->log);
  
      n = SSL_shutdown(c->ssl->connection);
  
      ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_shutdown: %d", n);
  
      sslerr = 0;
  
      /* SSL_shutdown() never returns -1, on error it returns 0 */
  
      if (n != 1 && ERR_peek_error()) {
          sslerr = SSL_get_error(c->ssl->connection, n);
  
          ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
                         "SSL_get_error: %d", sslerr);
      }
  
      if (n == 1 || sslerr == 0 || sslerr == SSL_ERROR_ZERO_RETURN) {
          SSL_free(c->ssl->connection);
          c->ssl = NULL;
  
          return NGX_OK;
      }
  
      if (sslerr == SSL_ERROR_WANT_READ || sslerr == SSL_ERROR_WANT_WRITE) {
          c->read->handler = ngx_ssl_shutdown_handler;
          c->write->handler = ngx_ssl_shutdown_handler;
  
          if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
              return NGX_ERROR;
          }
  
          if (sslerr == SSL_ERROR_WANT_READ) {
              ngx_add_timer(c->read, 30000);
          }
  
          return NGX_AGAIN;
      }
  
      err = (sslerr == SSL_ERROR_SYSCALL) ? ngx_errno : 0;
  
      ngx_ssl_connection_error(c, sslerr, err, "SSL_shutdown() failed");
  
      SSL_free(c->ssl->connection);
      c->ssl = NULL;
  
      return NGX_ERROR;
  }
  
  
  static void
  ngx_ssl_shutdown_handler(ngx_event_t *ev)
  {
      ngx_connection_t           *c;
      ngx_connection_handler_pt   handler;
  
      c = ev->data;
      handler = c->ssl->handler;
  
      if (ev->timedout) {
          c->timedout = 1;
      }
  
      ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, 0, "SSL shutdown handler");
  
      if (ngx_ssl_shutdown(c) == NGX_AGAIN) {
          return;
      }
  
      handler(c);
  }
  
  
  static void
  ngx_ssl_connection_error(ngx_connection_t *c, int sslerr, ngx_err_t err,
      char *text)
  {
      int         n;
      ngx_uint_t  level;
  
      level = NGX_LOG_CRIT;
  
      if (sslerr == SSL_ERROR_SYSCALL) {
  
          if (err == NGX_ECONNRESET
              || err == NGX_EPIPE
              || err == NGX_ENOTCONN
              || err == NGX_ETIMEDOUT
              || err == NGX_ECONNREFUSED
              || err == NGX_ENETDOWN
              || err == NGX_ENETUNREACH
              || err == NGX_EHOSTDOWN
              || err == NGX_EHOSTUNREACH)
          {
              switch (c->log_error) {
  
              case NGX_ERROR_IGNORE_ECONNRESET:
              case NGX_ERROR_INFO:
                  level = NGX_LOG_INFO;
                  break;
  
              case NGX_ERROR_ERR:
                  level = NGX_LOG_ERR;
                  break;
  
              default:
                  break;
              }
          }
  
      } else if (sslerr == SSL_ERROR_SSL) {
  
          n = ERR_GET_REASON(ERR_peek_error());
  
              /* handshake failures */
          if (n == SSL_R_BAD_CHANGE_CIPHER_SPEC                        /*  103 */
              || n == SSL_R_BLOCK_CIPHER_PAD_IS_WRONG                  /*  129 */
              || n == SSL_R_DIGEST_CHECK_FAILED                        /*  149 */
              || n == SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST              /*  151 */
              || n == SSL_R_EXCESSIVE_MESSAGE_SIZE                     /*  152 */
              || n == SSL_R_LENGTH_MISMATCH                            /*  159 */
              || n == SSL_R_NO_CIPHERS_PASSED                          /*  182 */
              || n == SSL_R_NO_CIPHERS_SPECIFIED                       /*  183 */
              || n == SSL_R_NO_COMPRESSION_SPECIFIED                   /*  187 */
              || n == SSL_R_NO_SHARED_CIPHER                           /*  193 */
              || n == SSL_R_RECORD_LENGTH_MISMATCH                     /*  213 */
  #ifdef SSL_R_PARSE_TLSEXT
              || n == SSL_R_PARSE_TLSEXT                               /*  227 */
  #endif
              || n == SSL_R_UNEXPECTED_MESSAGE                         /*  244 */
              || n == SSL_R_UNEXPECTED_RECORD                          /*  245 */
              || n == SSL_R_UNKNOWN_ALERT_TYPE                         /*  246 */
              || n == SSL_R_UNKNOWN_PROTOCOL                           /*  252 */
              || n == SSL_R_WRONG_VERSION_NUMBER                       /*  267 */
              || n == SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC        /*  281 */
  #ifdef SSL_R_RENEGOTIATE_EXT_TOO_LONG
              || n == SSL_R_RENEGOTIATE_EXT_TOO_LONG                   /*  335 */
              || n == SSL_R_RENEGOTIATION_ENCODING_ERR                 /*  336 */
              || n == SSL_R_RENEGOTIATION_MISMATCH                     /*  337 */
  #endif
  #ifdef SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED
              || n == SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED       /*  338 */
  #endif
  #ifdef SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING
              || n == SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING           /*  345 */
  #endif
              || n == 1000 /* SSL_R_SSLV3_ALERT_CLOSE_NOTIFY */
              || n == SSL_R_SSLV3_ALERT_UNEXPECTED_MESSAGE             /* 1010 */
              || n == SSL_R_SSLV3_ALERT_BAD_RECORD_MAC                 /* 1020 */
              || n == SSL_R_TLSV1_ALERT_DECRYPTION_FAILED              /* 1021 */
              || n == SSL_R_TLSV1_ALERT_RECORD_OVERFLOW                /* 1022 */
              || n == SSL_R_SSLV3_ALERT_DECOMPRESSION_FAILURE          /* 1030 */
              || n == SSL_R_SSLV3_ALERT_HANDSHAKE_FAILURE              /* 1040 */
              || n == SSL_R_SSLV3_ALERT_NO_CERTIFICATE                 /* 1041 */
              || n == SSL_R_SSLV3_ALERT_BAD_CERTIFICATE                /* 1042 */
              || n == SSL_R_SSLV3_ALERT_UNSUPPORTED_CERTIFICATE        /* 1043 */
              || n == SSL_R_SSLV3_ALERT_CERTIFICATE_REVOKED            /* 1044 */
              || n == SSL_R_SSLV3_ALERT_CERTIFICATE_EXPIRED            /* 1045 */
              || n == SSL_R_SSLV3_ALERT_CERTIFICATE_UNKNOWN            /* 1046 */
              || n == SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER              /* 1047 */
              || n == SSL_R_TLSV1_ALERT_UNKNOWN_CA                     /* 1048 */
              || n == SSL_R_TLSV1_ALERT_ACCESS_DENIED                  /* 1049 */
              || n == SSL_R_TLSV1_ALERT_DECODE_ERROR                   /* 1050 */
              || n == SSL_R_TLSV1_ALERT_DECRYPT_ERROR                  /* 1051 */
              || n == SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION             /* 1060 */
              || n == SSL_R_TLSV1_ALERT_PROTOCOL_VERSION               /* 1070 */
              || n == SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY          /* 1071 */
              || n == SSL_R_TLSV1_ALERT_INTERNAL_ERROR                 /* 1080 */
              || n == SSL_R_TLSV1_ALERT_USER_CANCELLED                 /* 1090 */
              || n == SSL_R_TLSV1_ALERT_NO_RENEGOTIATION)              /* 1100 */
          {
              switch (c->log_error) {
  
              case NGX_ERROR_IGNORE_ECONNRESET:
              case NGX_ERROR_INFO:
                  level = NGX_LOG_INFO;
                  break;
  
              case NGX_ERROR_ERR:
                  level = NGX_LOG_ERR;
                  break;
  
              default:
                  break;
              }
          }
      }
  
      ngx_ssl_error(level, c->log, err, text);
  }
  
  
  static void
  ngx_ssl_clear_error(ngx_log_t *log)
  {
      while (ERR_peek_error()) {
          ngx_ssl_error(NGX_LOG_ALERT, log, 0, "ignoring stale global SSL error");
      }
  
      ERR_clear_error();
  }
  
  
  void ngx_cdecl
  ngx_ssl_error(ngx_uint_t level, ngx_log_t *log, ngx_err_t err, char *fmt, ...)
  {
      u_long    n;
      va_list   args;
      u_char   *p, *last;
      u_char    errstr[NGX_MAX_CONF_ERRSTR];
  
      last = errstr + NGX_MAX_CONF_ERRSTR;
  
      va_start(args, fmt);
      p = ngx_vslprintf(errstr, last - 1, fmt, args);
      va_end(args);
  
      p = ngx_cpystrn(p, (u_char *) " (SSL:", last - p);
  
      for ( ;; ) {
  
          n = ERR_get_error();
  
          if (n == 0) {
              break;
          }
  
          if (p >= last) {
              continue;
          }
  
          *p++ = ' ';
  
          ERR_error_string_n(n, (char *) p, last - p);
  
          while (p < last && *p) {
              p++;
          }
      }
  
      ngx_log_error(level, log, err, "%s)", errstr);
  }
  
  
  ngx_int_t
  ngx_ssl_session_cache(ngx_ssl_t *ssl, ngx_str_t *sess_ctx,
      ssize_t builtin_session_cache, ngx_shm_zone_t *shm_zone, time_t timeout)
  {
      long  cache_mode;
  
      if (builtin_session_cache == NGX_SSL_NO_SCACHE) {
          SSL_CTX_set_session_cache_mode(ssl->ctx, SSL_SESS_CACHE_OFF);
          return NGX_OK;
      }
  
      SSL_CTX_set_session_id_context(ssl->ctx, sess_ctx->data, sess_ctx->len);
  
      if (builtin_session_cache == NGX_SSL_NONE_SCACHE) {
  
          /*
           * If the server explicitly says that it does not support
           * session reuse (see SSL_SESS_CACHE_OFF above), then
           * Outlook Express fails to upload a sent email to
           * the Sent Items folder on the IMAP server via a separate IMAP
           * connection in the background. Therefore we have a special
           * mode (SSL_SESS_CACHE_SERVER|SSL_SESS_CACHE_NO_INTERNAL_STORE)
           * where the server pretends that it supports session reuse,
           * but it does not actually store any session.
           */
  
          SSL_CTX_set_session_cache_mode(ssl->ctx,
                                         SSL_SESS_CACHE_SERVER
                                         |SSL_SESS_CACHE_NO_AUTO_CLEAR
                                         |SSL_SESS_CACHE_NO_INTERNAL_STORE);
  
          SSL_CTX_sess_set_cache_size(ssl->ctx, 1);
  
          return NGX_OK;
      }
  
      cache_mode = SSL_SESS_CACHE_SERVER;
  
      if (shm_zone && builtin_session_cache == NGX_SSL_NO_BUILTIN_SCACHE) {
          cache_mode |= SSL_SESS_CACHE_NO_INTERNAL;
      }
  
      SSL_CTX_set_session_cache_mode(ssl->ctx, cache_mode);
  
      if (builtin_session_cache != NGX_SSL_NO_BUILTIN_SCACHE) {
  
          if (builtin_session_cache != NGX_SSL_DFLT_BUILTIN_SCACHE) {
              SSL_CTX_sess_set_cache_size(ssl->ctx, builtin_session_cache);
          }
      }
  
      SSL_CTX_set_timeout(ssl->ctx, (long) timeout);
  
      if (shm_zone) {
          SSL_CTX_sess_set_new_cb(ssl->ctx, ngx_ssl_new_session);
          SSL_CTX_sess_set_get_cb(ssl->ctx, ngx_ssl_get_cached_session);
          SSL_CTX_sess_set_remove_cb(ssl->ctx, ngx_ssl_remove_session);
  
          if (SSL_CTX_set_ex_data(ssl->ctx, ngx_ssl_session_cache_index, shm_zone)
              == 0)
          {
              ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                            "SSL_CTX_set_ex_data() failed");
              return NGX_ERROR;
          }
      }
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_session_cache_init(ngx_shm_zone_t *shm_zone, void *data)
  {
      size_t                    len;
      ngx_slab_pool_t          *shpool;
      ngx_ssl_session_cache_t  *cache;
  
      if (data) {
          shm_zone->data = data;
          return NGX_OK;
      }
  
      if (shm_zone->shm.exists) {
          shm_zone->data = data;
          return NGX_OK;
      }
  
      shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
  
      cache = ngx_slab_alloc(shpool, sizeof(ngx_ssl_session_cache_t));
      if (cache == NULL) {
          return NGX_ERROR;
      }
  
      shpool->data = cache;
      shm_zone->data = cache;
  
      ngx_rbtree_init(&cache->session_rbtree, &cache->sentinel,
                      ngx_ssl_session_rbtree_insert_value);
  
      ngx_queue_init(&cache->expire_queue);
  
      len = sizeof(" in SSL session shared cache \"\"") + shm_zone->shm.name.len;
  
      shpool->log_ctx = ngx_slab_alloc(shpool, len);
      if (shpool->log_ctx == NULL) {
          return NGX_ERROR;
      }
  
      ngx_sprintf(shpool->log_ctx, " in SSL session shared cache \"%V\"%Z",
                  &shm_zone->shm.name);
  
      return NGX_OK;
  }
  
  
  /*
   * The length of the session id is 16 bytes for SSLv2 sessions and
   * between 1 and 32 bytes for SSLv3/TLSv1, typically 32 bytes.
   * It seems that the typical length of the external ASN1 representation
   * of a session is 118 or 119 bytes for SSLv3/TSLv1.
   *
   * Thus on 32-bit platforms we allocate separately an rbtree node,
   * a session id, and an ASN1 representation, they take accordingly
   * 64, 32, and 128 bytes.
   *
   * On 64-bit platforms we allocate separately an rbtree node + session_id,
   * and an ASN1 representation, they take accordingly 128 and 128 bytes.
   *
   * OpenSSL's i2d_SSL_SESSION() and d2i_SSL_SESSION are slow,
   * so they are outside the code locked by shared pool mutex
   */
  
  static int
  ngx_ssl_new_session(ngx_ssl_conn_t *ssl_conn, ngx_ssl_session_t *sess)
  {
      int                       len;
      u_char                   *p, *id, *cached_sess;
      uint32_t                  hash;
      SSL_CTX                  *ssl_ctx;
      ngx_shm_zone_t           *shm_zone;
      ngx_connection_t         *c;
      ngx_slab_pool_t          *shpool;
      ngx_ssl_sess_id_t        *sess_id;
      ngx_ssl_session_cache_t  *cache;
      u_char                    buf[NGX_SSL_MAX_SESSION_SIZE];
  
      len = i2d_SSL_SESSION(sess, NULL);
  
      /* do not cache too big session */
  
      if (len > (int) NGX_SSL_MAX_SESSION_SIZE) {
          return 0;
      }
  
      p = buf;
      i2d_SSL_SESSION(sess, &p);
  
      c = ngx_ssl_get_connection(ssl_conn);
  
      ssl_ctx = SSL_get_SSL_CTX(ssl_conn);
      shm_zone = SSL_CTX_get_ex_data(ssl_ctx, ngx_ssl_session_cache_index);
  
      cache = shm_zone->data;
      shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
  
      ngx_shmtx_lock(&shpool->mutex);
  
      /* drop one or two expired sessions */
      ngx_ssl_expire_sessions(cache, shpool, 1);
  
      cached_sess = ngx_slab_alloc_locked(shpool, len);
  
      if (cached_sess == NULL) {
  
          /* drop the oldest non-expired session and try once more */
  
          ngx_ssl_expire_sessions(cache, shpool, 0);
  
          cached_sess = ngx_slab_alloc_locked(shpool, len);
  
          if (cached_sess == NULL) {
              sess_id = NULL;
              goto failed;
          }
      }
  
      sess_id = ngx_slab_alloc_locked(shpool, sizeof(ngx_ssl_sess_id_t));
      if (sess_id == NULL) {
          goto failed;
      }
  
  #if (NGX_PTR_SIZE == 8)
  
      id = sess_id->sess_id;
  
  #else
  
      id = ngx_slab_alloc_locked(shpool, sess->session_id_length);
      if (id == NULL) {
          goto failed;
      }
  
  #endif
  
      ngx_memcpy(cached_sess, buf, len);
  
      ngx_memcpy(id, sess->session_id, sess->session_id_length);
  
      hash = ngx_crc32_short(sess->session_id, sess->session_id_length);
  
      ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
                     "ssl new session: %08XD:%d:%d",
                     hash, sess->session_id_length, len);
  
      sess_id->node.key = hash;
      sess_id->node.data = (u_char) sess->session_id_length;
      sess_id->id = id;
      sess_id->len = len;
      sess_id->session = cached_sess;
  
      sess_id->expire = ngx_time() + SSL_CTX_get_timeout(ssl_ctx);
  
      ngx_queue_insert_head(&cache->expire_queue, &sess_id->queue);
  
      ngx_rbtree_insert(&cache->session_rbtree, &sess_id->node);
  
      ngx_shmtx_unlock(&shpool->mutex);
  
      return 0;
  
  failed:
  
      if (cached_sess) {
          ngx_slab_free_locked(shpool, cached_sess);
      }
  
      if (sess_id) {
          ngx_slab_free_locked(shpool, sess_id);
      }
  
      ngx_shmtx_unlock(&shpool->mutex);
  
      ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                    "could not add new SSL session to the session cache");
  
      return 0;
  }
  
  
  static ngx_ssl_session_t *
  ngx_ssl_get_cached_session(ngx_ssl_conn_t *ssl_conn, u_char *id, int len,
      int *copy)
  {
  #if OPENSSL_VERSION_NUMBER >= 0x0090707fL
      const
  #endif
      u_char                   *p;
      uint32_t                  hash;
      ngx_int_t                 rc;
      ngx_shm_zone_t           *shm_zone;
      ngx_slab_pool_t          *shpool;
      ngx_rbtree_node_t        *node, *sentinel;
      ngx_ssl_session_t        *sess;
      ngx_ssl_sess_id_t        *sess_id;
      ngx_ssl_session_cache_t  *cache;
      u_char                    buf[NGX_SSL_MAX_SESSION_SIZE];
  #if (NGX_DEBUG)
      ngx_connection_t         *c;
  #endif
  
      hash = ngx_crc32_short(id, (size_t) len);
      *copy = 0;
  
  #if (NGX_DEBUG)
      c = ngx_ssl_get_connection(ssl_conn);
  
      ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
                     "ssl get session: %08XD:%d", hash, len);
  #endif
  
      shm_zone = SSL_CTX_get_ex_data(SSL_get_SSL_CTX(ssl_conn),
                                     ngx_ssl_session_cache_index);
  
      cache = shm_zone->data;
  
      sess = NULL;
  
      shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
  
      ngx_shmtx_lock(&shpool->mutex);
  
      node = cache->session_rbtree.root;
      sentinel = cache->session_rbtree.sentinel;
  
      while (node != sentinel) {
  
          if (hash < node->key) {
              node = node->left;
              continue;
          }
  
          if (hash > node->key) {
              node = node->right;
              continue;
          }
  
          /* hash == node->key */
  
          sess_id = (ngx_ssl_sess_id_t *) node;
  
          rc = ngx_memn2cmp(id, sess_id->id, (size_t) len, (size_t) node->data);
  
          if (rc == 0) {
  
              if (sess_id->expire > ngx_time()) {
                  ngx_memcpy(buf, sess_id->session, sess_id->len);
  
                  ngx_shmtx_unlock(&shpool->mutex);
  
                  p = buf;
                  sess = d2i_SSL_SESSION(NULL, &p, sess_id->len);
  
                  return sess;
              }
  
              ngx_queue_remove(&sess_id->queue);
  
              ngx_rbtree_delete(&cache->session_rbtree, node);
  
              ngx_slab_free_locked(shpool, sess_id->session);
  #if (NGX_PTR_SIZE == 4)
              ngx_slab_free_locked(shpool, sess_id->id);
  #endif
              ngx_slab_free_locked(shpool, sess_id);
  
              sess = NULL;
  
              goto done;
          }
  
          node = (rc < 0) ? node->left : node->right;
      }
  
  done:
  
      ngx_shmtx_unlock(&shpool->mutex);
  
      return sess;
  }
  
  
  void
  ngx_ssl_remove_cached_session(SSL_CTX *ssl, ngx_ssl_session_t *sess)
  {
       SSL_CTX_remove_session(ssl, sess);
  
       ngx_ssl_remove_session(ssl, sess);
  }
  
  
  static void
  ngx_ssl_remove_session(SSL_CTX *ssl, ngx_ssl_session_t *sess)
  {
      size_t                    len;
      u_char                   *id;
      uint32_t                  hash;
      ngx_int_t                 rc;
      ngx_shm_zone_t           *shm_zone;
      ngx_slab_pool_t          *shpool;
      ngx_rbtree_node_t        *node, *sentinel;
      ngx_ssl_sess_id_t        *sess_id;
      ngx_ssl_session_cache_t  *cache;
  
      shm_zone = SSL_CTX_get_ex_data(ssl, ngx_ssl_session_cache_index);
  
      if (shm_zone == NULL) {
          return;
      }
  
      cache = shm_zone->data;
  
      id = sess->session_id;
      len = (size_t) sess->session_id_length;
  
      hash = ngx_crc32_short(id, len);
  
      ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ngx_cycle->log, 0,
                     "ssl remove session: %08XD:%uz", hash, len);
  
      shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
  
      ngx_shmtx_lock(&shpool->mutex);
  
      node = cache->session_rbtree.root;
      sentinel = cache->session_rbtree.sentinel;
  
      while (node != sentinel) {
  
          if (hash < node->key) {
              node = node->left;
              continue;
          }
  
          if (hash > node->key) {
              node = node->right;
              continue;
          }
  
          /* hash == node->key */
  
          sess_id = (ngx_ssl_sess_id_t *) node;
  
          rc = ngx_memn2cmp(id, sess_id->id, len, (size_t) node->data);
  
          if (rc == 0) {
  
              ngx_queue_remove(&sess_id->queue);
  
              ngx_rbtree_delete(&cache->session_rbtree, node);
  
              ngx_slab_free_locked(shpool, sess_id->session);
  #if (NGX_PTR_SIZE == 4)
              ngx_slab_free_locked(shpool, sess_id->id);
  #endif
              ngx_slab_free_locked(shpool, sess_id);
  
              goto done;
          }
  
          node = (rc < 0) ? node->left : node->right;
      }
  
  done:
  
      ngx_shmtx_unlock(&shpool->mutex);
  }
  
  
  static void
  ngx_ssl_expire_sessions(ngx_ssl_session_cache_t *cache,
      ngx_slab_pool_t *shpool, ngx_uint_t n)
  {
      time_t              now;
      ngx_queue_t        *q;
      ngx_ssl_sess_id_t  *sess_id;
  
      now = ngx_time();
  
      while (n < 3) {
  
          if (ngx_queue_empty(&cache->expire_queue)) {
              return;
          }
  
          q = ngx_queue_last(&cache->expire_queue);
  
          sess_id = ngx_queue_data(q, ngx_ssl_sess_id_t, queue);
  
          if (n++ != 0 && sess_id->expire > now) {
              return;
          }
  
          ngx_queue_remove(q);
  
          ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ngx_cycle->log, 0,
                         "expire session: %08Xi", sess_id->node.key);
  
          ngx_rbtree_delete(&cache->session_rbtree, &sess_id->node);
  
          ngx_slab_free_locked(shpool, sess_id->session);
  #if (NGX_PTR_SIZE == 4)
          ngx_slab_free_locked(shpool, sess_id->id);
  #endif
          ngx_slab_free_locked(shpool, sess_id);
      }
  }
  
  
  static void
  ngx_ssl_session_rbtree_insert_value(ngx_rbtree_node_t *temp,
      ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
  {
      ngx_rbtree_node_t  **p;
      ngx_ssl_sess_id_t   *sess_id, *sess_id_temp;
  
      for ( ;; ) {
  
          if (node->key < temp->key) {
  
              p = &temp->left;
  
          } else if (node->key > temp->key) {
  
              p = &temp->right;
  
          } else { /* node->key == temp->key */
  
              sess_id = (ngx_ssl_sess_id_t *) node;
              sess_id_temp = (ngx_ssl_sess_id_t *) temp;
  
              p = (ngx_memn2cmp(sess_id->id, sess_id_temp->id,
                                (size_t) node->data, (size_t) temp->data)
                   < 0) ? &temp->left : &temp->right;
          }
  
          if (*p == sentinel) {
              break;
          }
  
          temp = *p;
      }
  
      *p = node;
      node->parent = temp;
      node->left = sentinel;
      node->right = sentinel;
      ngx_rbt_red(node);
  }
  
  
  void
  ngx_ssl_cleanup_ctx(void *data)
  {
      ngx_ssl_t  *ssl = data;
  
      SSL_CTX_free(ssl->ctx);
  }
  
  
  ngx_int_t
  ngx_ssl_get_protocol(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      s->data = (u_char *) SSL_get_version(c->ssl->connection);
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_cipher_name(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      s->data = (u_char *) SSL_get_cipher_name(c->ssl->connection);
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_session_id(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      int           len;
      u_char       *p, *buf;
      SSL_SESSION  *sess;
  
      sess = SSL_get0_session(c->ssl->connection);
  
      len = i2d_SSL_SESSION(sess, NULL);
  
      buf = ngx_alloc(len, c->log);
      if (buf == NULL) {
          return NGX_ERROR;
      }
  
      s->len = 2 * len;
      s->data = ngx_pnalloc(pool, 2 * len);
      if (s->data == NULL) {
          ngx_free(buf);
          return NGX_ERROR;
      }
  
      p = buf;
      i2d_SSL_SESSION(sess, &p);
  
      ngx_hex_dump(s->data, buf, len);
  
      ngx_free(buf);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_raw_certificate(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      size_t   len;
      BIO     *bio;
      X509    *cert;
  
      s->len = 0;
  
      cert = SSL_get_peer_certificate(c->ssl->connection);
      if (cert == NULL) {
          return NGX_OK;
      }
  
      bio = BIO_new(BIO_s_mem());
      if (bio == NULL) {
          ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "BIO_new() failed");
          X509_free(cert);
          return NGX_ERROR;
      }
  
      if (PEM_write_bio_X509(bio, cert) == 0) {
          ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "PEM_write_bio_X509() failed");
          goto failed;
      }
  
      len = BIO_pending(bio);
      s->len = len;
  
      s->data = ngx_pnalloc(pool, len);
      if (s->data == NULL) {
          goto failed;
      }
  
      BIO_read(bio, s->data, len);
  
      BIO_free(bio);
      X509_free(cert);
  
      return NGX_OK;
  
  failed:
  
      BIO_free(bio);
      X509_free(cert);
  
      return NGX_ERROR;
  }
  
  
  ngx_int_t
  ngx_ssl_get_certificate(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      u_char      *p;
      size_t       len;
      ngx_uint_t   i;
      ngx_str_t    cert;
  
      if (ngx_ssl_get_raw_certificate(c, pool, &cert) != NGX_OK) {
          return NGX_ERROR;
      }
  
      if (cert.len == 0) {
          s->len = 0;
          return NGX_OK;
      }
  
      len = cert.len - 1;
  
      for (i = 0; i < cert.len - 1; i++) {
          if (cert.data[i] == LF) {
              len++;
          }
      }
  
      s->len = len;
      s->data = ngx_pnalloc(pool, len);
      if (s->data == NULL) {
          return NGX_ERROR;
      }
  
      p = s->data;
  
      for (i = 0; i < cert.len - 1; i++) {
          *p++ = cert.data[i];
          if (cert.data[i] == LF) {
              *p++ = '\t';
          }
      }
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_subject_dn(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      char       *p;
      size_t      len;
      X509       *cert;
      X509_NAME  *name;
  
      s->len = 0;
  
      cert = SSL_get_peer_certificate(c->ssl->connection);
      if (cert == NULL) {
          return NGX_OK;
      }
  
      name = X509_get_subject_name(cert);
      if (name == NULL) {
          X509_free(cert);
          return NGX_ERROR;
      }
  
      p = X509_NAME_oneline(name, NULL, 0);
  
      for (len = 0; p[len]; len++) { /* void */ }
  
      s->len = len;
      s->data = ngx_pnalloc(pool, len);
      if (s->data == NULL) {
          OPENSSL_free(p);
          X509_free(cert);
          return NGX_ERROR;
      }
  
      ngx_memcpy(s->data, p, len);
  
      OPENSSL_free(p);
      X509_free(cert);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_issuer_dn(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      char       *p;
      size_t      len;
      X509       *cert;
      X509_NAME  *name;
  
      s->len = 0;
  
      cert = SSL_get_peer_certificate(c->ssl->connection);
      if (cert == NULL) {
          return NGX_OK;
      }
  
      name = X509_get_issuer_name(cert);
      if (name == NULL) {
          X509_free(cert);
          return NGX_ERROR;
      }
  
      p = X509_NAME_oneline(name, NULL, 0);
  
      for (len = 0; p[len]; len++) { /* void */ }
  
      s->len = len;
      s->data = ngx_pnalloc(pool, len);
      if (s->data == NULL) {
          OPENSSL_free(p);
          X509_free(cert);
          return NGX_ERROR;
      }
  
      ngx_memcpy(s->data, p, len);
  
      OPENSSL_free(p);
      X509_free(cert);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_serial_number(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      size_t   len;
      X509    *cert;
      BIO     *bio;
  
      s->len = 0;
  
      cert = SSL_get_peer_certificate(c->ssl->connection);
      if (cert == NULL) {
          return NGX_OK;
      }
  
      bio = BIO_new(BIO_s_mem());
      if (bio == NULL) {
          X509_free(cert);
          return NGX_ERROR;
      }
  
      i2a_ASN1_INTEGER(bio, X509_get_serialNumber(cert));
      len = BIO_pending(bio);
  
      s->len = len;
      s->data = ngx_pnalloc(pool, len);
      if (s->data == NULL) {
          BIO_free(bio);
          X509_free(cert);
          return NGX_ERROR;
      }
  
      BIO_read(bio, s->data, len);
      BIO_free(bio);
      X509_free(cert);
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_ssl_get_client_verify(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
  {
      X509  *cert;
  
      if (SSL_get_verify_result(c->ssl->connection) != X509_V_OK) {
          ngx_str_set(s, "FAILED");
          return NGX_OK;
      }
  
      cert = SSL_get_peer_certificate(c->ssl->connection);
  
      if (cert) {
          ngx_str_set(s, "SUCCESS");
  
      } else {
          ngx_str_set(s, "NONE");
      }
  
      X509_free(cert);
  
      return NGX_OK;
  }
  
  
  static void *
  ngx_openssl_create_conf(ngx_cycle_t *cycle)
  {
      ngx_openssl_conf_t  *oscf;
  
      oscf = ngx_pcalloc(cycle->pool, sizeof(ngx_openssl_conf_t));
      if (oscf == NULL) {
          return NULL;
      }
  
      /*
       * set by ngx_pcalloc():
       *
       *     oscf->engine = 0;
       */
  
      return oscf;
  }
  
  
  static char *
  ngx_openssl_engine(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
  {
      ngx_openssl_conf_t *oscf = conf;
  
      ENGINE     *engine;
      ngx_str_t  *value;
  
      if (oscf->engine) {
          return "is duplicate";
      }
  
      oscf->engine = 1;
  
      value = cf->args->elts;
  
      engine = ENGINE_by_id((const char *) value[1].data);
  
      if (engine == NULL) {
          ngx_ssl_error(NGX_LOG_WARN, cf->log, 0,
                        "ENGINE_by_id(\"%V\") failed", &value[1]);
          return NGX_CONF_ERROR;
      }
  
      if (ENGINE_set_default(engine, ENGINE_METHOD_ALL) == 0) {
          ngx_ssl_error(NGX_LOG_WARN, cf->log, 0,
                        "ENGINE_set_default(\"%V\", ENGINE_METHOD_ALL) failed",
                        &value[1]);
  
          ENGINE_free(engine);
  
          return NGX_CONF_ERROR;
      }
  
      ENGINE_free(engine);
  
      return NGX_CONF_OK;
  }
  
  
  static void
  ngx_openssl_exit(ngx_cycle_t *cycle)
  {
      EVP_cleanup();
      ENGINE_cleanup();
  }
  