lighttpd1.4/src/mod_openssl.c

#include "first.h"

#include <errno.h>
#include <string.h>
#include <unistd.h>

#ifndef USE_OPENSSL_KERBEROS
#ifndef OPENSSL_NO_KRB5
#define OPENSSL_NO_KRB5
#endif
#endif

#include <openssl/ssl.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#ifndef OPENSSL_NO_DH
#include <openssl/dh.h>
#endif

#if ! defined OPENSSL_NO_TLSEXT && ! defined SSL_CTRL_SET_TLSEXT_HOSTNAME
#define OPENSSL_NO_TLSEXT
#endif

#if OPENSSL_VERSION_NUMBER >= 0x0090800fL
#ifndef OPENSSL_NO_ECDH
#include <openssl/ecdh.h>
#endif
#endif

#include "base.h"
#include "http_header.h"
#include "log.h"
#include "plugin.h"

typedef struct {
    SSL_CTX *ssl_ctx; /* not patched */
    /* SNI per host: with COMP_SERVER_SOCKET, COMP_HTTP_SCHEME, COMP_HTTP_HOST */
    EVP_PKEY *ssl_pemfile_pkey;
    X509 *ssl_pemfile_x509;
    STACK_OF(X509_NAME) *ssl_ca_file_cert_names;

    unsigned short ssl_verifyclient;
    unsigned short ssl_verifyclient_enforce;
    unsigned short ssl_verifyclient_depth;
    unsigned short ssl_verifyclient_export_cert;
    buffer *ssl_verifyclient_username;

    unsigned short ssl_disable_client_renegotiation;
    unsigned short ssl_read_ahead;
    unsigned short ssl_log_noise;

    /*(used only during startup; not patched)*/
    unsigned short ssl_enabled; /* only interesting for setting up listening sockets. don't use at runtime */
    unsigned short ssl_honor_cipher_order; /* determine SSL cipher in server-preferred order, not client-order */
    unsigned short ssl_empty_fragments; /* whether to not set SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS */
    unsigned short ssl_use_sslv2;
    unsigned short ssl_use_sslv3;
    buffer *ssl_pemfile;
    buffer *ssl_ca_file;
    buffer *ssl_ca_crl_file;
    buffer *ssl_ca_dn_file;
    buffer *ssl_cipher_list;
    buffer *ssl_dh_file;
    buffer *ssl_ec_curve;
    array *ssl_conf_cmd;
} plugin_config;

typedef struct {
    PLUGIN_DATA;
    plugin_config **config_storage;
} plugin_data;

static int ssl_is_init;
/* need assigned p->id for deep access of module handler_ctx for connection
 *   i.e. handler_ctx *hctx = con->plugin_ctx[plugin_data_singleton->id]; */
static plugin_data *plugin_data_singleton;
#define LOCAL_SEND_BUFSIZE (64 * 1024)
static char *local_send_buffer;

typedef struct {
    SSL *ssl;
    connection *con;
    int renegotiations; /* count of SSL_CB_HANDSHAKE_START */
    int request_env_patched;
    plugin_config conf;
    server *srv;
} handler_ctx;


static handler_ctx *
handler_ctx_init (void)
{
    handler_ctx *hctx = calloc(1, sizeof(*hctx));
    force_assert(hctx);
    return hctx;
}


static void
handler_ctx_free (handler_ctx *hctx)
{
    if (hctx->ssl) SSL_free(hctx->ssl);
    free(hctx);
}


INIT_FUNC(mod_openssl_init)
{
    plugin_data_singleton = (plugin_data *)calloc(1, sizeof(plugin_data));
    return plugin_data_singleton;
}


FREE_FUNC(mod_openssl_free)
{
    plugin_data *p = p_d;
    if (!p) return HANDLER_GO_ON;

    if (p->config_storage) {
        for (size_t i = 0; i < srv->config_context->used; ++i) {
            plugin_config *s = p->config_storage[i];
            int copy;
            if (NULL == s) continue;
            copy = s->ssl_enabled && buffer_string_is_empty(s->ssl_pemfile);
            buffer_free(s->ssl_pemfile);
            buffer_free(s->ssl_ca_file);
            buffer_free(s->ssl_ca_crl_file);
            buffer_free(s->ssl_ca_dn_file);
            buffer_free(s->ssl_cipher_list);
            buffer_free(s->ssl_dh_file);
            buffer_free(s->ssl_ec_curve);
            buffer_free(s->ssl_verifyclient_username);
            array_free(s->ssl_conf_cmd);

            if (copy) continue;
            SSL_CTX_free(s->ssl_ctx);
            EVP_PKEY_free(s->ssl_pemfile_pkey);
            X509_free(s->ssl_pemfile_x509);
            if (NULL != s->ssl_ca_file_cert_names)
                sk_X509_NAME_pop_free(s->ssl_ca_file_cert_names,X509_NAME_free);
        }
        for (size_t i = 0; i < srv->config_context->used; ++i) {
            plugin_config *s = p->config_storage[i];
            if (NULL == s) continue;

            free(s);
        }
        free(p->config_storage);
    }

    if (ssl_is_init) {
      #if OPENSSL_VERSION_NUMBER >= 0x10100000L \
       && !defined(LIBRESSL_VERSION_NUMBER)
        /*(OpenSSL libraries handle thread init and deinit)
         * https://github.com/openssl/openssl/pull/1048 */
      #else
        CRYPTO_cleanup_all_ex_data();
        ERR_free_strings();
       #if OPENSSL_VERSION_NUMBER >= 0x10000000L
        ERR_remove_thread_state(NULL);
       #else
        ERR_remove_state(0);
       #endif
        EVP_cleanup();
      #endif

        free(local_send_buffer);
    }

    free(p);

    return HANDLER_GO_ON;
}


static int
safer_X509_NAME_oneline(X509_NAME *name, char *buf, size_t sz)
{
    BIO *bio = BIO_new(BIO_s_mem());
    if (bio) {
        int len = X509_NAME_print_ex(bio, name, 0, XN_FLAG_ONELINE);
        BIO_gets(bio, buf, (int)sz); /*(may be truncated if len >= sz)*/
        BIO_free(bio);
        return len; /*return value has similar semantics to that of snprintf()*/
    }
    else {
        buf[0] = '\0';
        return -1;
    }
}


static void
ssl_info_callback (const SSL *ssl, int where, int ret)
{
    UNUSED(ret);

    if (0 != (where & SSL_CB_HANDSHAKE_START)) {
        handler_ctx *hctx = (handler_ctx *) SSL_get_app_data(ssl);
        if (hctx->renegotiations >= 0) ++hctx->renegotiations;
    }
  #ifdef TLS1_3_VERSION
    /* https://github.com/openssl/openssl/issues/5721
     * "TLSv1.3 unexpected InfoCallback after handshake completed" */
    if (0 != (where & SSL_CB_HANDSHAKE_DONE)) {
        /* SSL_version() is valid after initial handshake completed */
        if (SSL_version(ssl) >= TLS1_3_VERSION) {
            /* https://wiki.openssl.org/index.php/TLS1.3
             * "Renegotiation is not possible in a TLSv1.3 connection" */
            handler_ctx *hctx = (handler_ctx *) SSL_get_app_data(ssl);
            hctx->renegotiations = -1;
        }
    }
  #endif
}

/* https://wiki.openssl.org/index.php/Manual:SSL_CTX_set_verify(3)#EXAMPLES */
static int
verify_callback(int preverify_ok, X509_STORE_CTX *ctx)
{
    char buf[256];
    X509 *err_cert;
    int err, depth;
    SSL *ssl;
    handler_ctx *hctx;
    server *srv;

    err = X509_STORE_CTX_get_error(ctx);
    depth = X509_STORE_CTX_get_error_depth(ctx);

    /*
     * Retrieve the pointer to the SSL of the connection currently treated
     * and the application specific data stored into the SSL object.
     */
    ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
    hctx = (handler_ctx *) SSL_get_app_data(ssl);
    srv = hctx->srv;

    /*
     * Catch a too long certificate chain. The depth limit set using
     * SSL_CTX_set_verify_depth() is by purpose set to "limit+1" so
     * that whenever the "depth>verify_depth" condition is met, we
     * have violated the limit and want to log this error condition.
     * We must do it here, because the CHAIN_TOO_LONG error would not
     * be found explicitly; only errors introduced by cutting off the
     * additional certificates would be logged.
     */
    if (depth > hctx->conf.ssl_verifyclient_depth) {
        preverify_ok = 0;
        err = X509_V_ERR_CERT_CHAIN_TOO_LONG;
        X509_STORE_CTX_set_error(ctx, err);
    }

    if (preverify_ok && 0 == depth
        && !buffer_string_is_empty(hctx->conf.ssl_ca_dn_file)
        && !buffer_string_is_empty(hctx->conf.ssl_ca_file)) {
        /* verify that client cert is issued by CA in ssl.ca-dn-file
         * if both ssl.ca-dn-file and ssl.ca-file were configured */
        STACK_OF(X509_NAME) * const names = hctx->conf.ssl_ca_file_cert_names;
        X509_NAME *issuer;
      #if OPENSSL_VERSION_NUMBER >= 0x10002000L
        err_cert = X509_STORE_CTX_get_current_cert(ctx);
      #else
        err_cert = ctx->current_cert;
      #endif
        if (NULL == err_cert) return !hctx->conf.ssl_verifyclient_enforce;
        issuer = X509_get_issuer_name(err_cert);
      #if 0 /*(?desirable/undesirable to have ssl_ca_file_cert_names sorted?)*/
        if (-1 != sk_X509_NAME_find(names, issuer))
            return preverify_ok; /* match */
      #else
        for (int i = 0, len = sk_X509_NAME_num(names); i < len; ++i) {
            if (0 == X509_NAME_cmp(sk_X509_NAME_value(names, i), issuer))
                return preverify_ok; /* match */
        }
      #endif

        preverify_ok = 0;
        err = X509_V_ERR_CERT_REJECTED;
        X509_STORE_CTX_set_error(ctx, err);
    }

    if (preverify_ok) {
        return preverify_ok;
    }

  #if OPENSSL_VERSION_NUMBER >= 0x10002000L
    err_cert = X509_STORE_CTX_get_current_cert(ctx);
  #else
    err_cert = ctx->current_cert;
  #endif
    if (NULL == err_cert) return !hctx->conf.ssl_verifyclient_enforce;
    safer_X509_NAME_oneline(X509_get_subject_name(err_cert),buf,sizeof(buf));
    log_error_write(srv, __FILE__, __LINE__, "SDSSSDSS",
                        "SSL: verify error:num=", err, ":",
                        X509_verify_cert_error_string(err), ":depth=", depth,
                        ":subject=", buf);

    /*
     * At this point, err contains the last verification error. We can use
     * it for something special
     */
    if (!preverify_ok && (err == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY ||
                          err == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT)) {
        safer_X509_NAME_oneline(X509_get_issuer_name(err_cert),buf,sizeof(buf));
        log_error_write(srv, __FILE__, __LINE__, "SS", "SSL: issuer=", buf);
    }

    return !hctx->conf.ssl_verifyclient_enforce;
}

#ifndef OPENSSL_NO_TLSEXT
static int mod_openssl_patch_connection (server *srv, connection *con, handler_ctx *hctx);

static int
network_ssl_servername_callback (SSL *ssl, int *al, server *srv)
{
    const char *servername;
    handler_ctx *hctx = (handler_ctx *) SSL_get_app_data(ssl);
    connection *con = hctx->con;
    UNUSED(al);

    buffer_copy_string(con->uri.scheme, "https");

    servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
    if (NULL == servername) {
#if 0
        /* this "error" just means the client didn't support it */
        log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                "failed to get TLS server name");
#endif
        return SSL_TLSEXT_ERR_NOACK;
    }
    /* use SNI to patch mod_openssl config and then reset COMP_HTTP_HOST */
    buffer_copy_string(con->uri.authority, servername);
    buffer_to_lower(con->uri.authority);

    con->conditional_is_valid[COMP_HTTP_SCHEME] = 1;
    con->conditional_is_valid[COMP_HTTP_HOST] = 1;
    mod_openssl_patch_connection(srv, con, hctx);
    /* reset COMP_HTTP_HOST so that conditions re-run after request hdrs read */
    /*(done in response.c:config_cond_cache_reset() after request hdrs read)*/
    /*config_cond_cache_reset_item(con, COMP_HTTP_HOST);*/
    /*buffer_reset(con->uri.authority);*/

    if (NULL == hctx->conf.ssl_pemfile_x509
        || NULL == hctx->conf.ssl_pemfile_pkey) {
        /* x509/pkey available <=> pemfile was set <=> pemfile got patched:
         * so this should never happen, unless you nest $SERVER["socket"] */
        log_error_write(srv, __FILE__, __LINE__, "ssb", "SSL:",
                        "no certificate/private key for TLS server name",
                        con->uri.authority);
        return SSL_TLSEXT_ERR_ALERT_FATAL;
    }

    /* first set certificate!
     * setting private key checks whether certificate matches it */
    if (1 != SSL_use_certificate(ssl, hctx->conf.ssl_pemfile_x509)) {
        log_error_write(srv, __FILE__, __LINE__, "ssb:s", "SSL:",
                        "failed to set certificate for TLS server name",
                        con->uri.authority,
                        ERR_error_string(ERR_get_error(), NULL));
        return SSL_TLSEXT_ERR_ALERT_FATAL;
    }

    if (1 != SSL_use_PrivateKey(ssl, hctx->conf.ssl_pemfile_pkey)) {
        log_error_write(srv, __FILE__, __LINE__, "ssb:s", "SSL:",
                        "failed to set private key for TLS server name",
                        con->uri.authority,
                        ERR_error_string(ERR_get_error(), NULL));
        return SSL_TLSEXT_ERR_ALERT_FATAL;
    }

    if (hctx->conf.ssl_verifyclient) {
        int mode;
        if (NULL == hctx->conf.ssl_ca_file_cert_names) {
            log_error_write(srv, __FILE__, __LINE__, "ssb:s", "SSL:",
                            "can't verify client without ssl.ca-file "
                            "or ssl.ca-dn-file for TLS server name",
                            con->uri.authority,
                            ERR_error_string(ERR_get_error(), NULL));
            return SSL_TLSEXT_ERR_ALERT_FATAL;
        }

        SSL_set_client_CA_list(
          ssl, SSL_dup_CA_list(hctx->conf.ssl_ca_file_cert_names));
        /* forcing verification here is really not that useful
         * -- a client could just connect without SNI */
        mode = SSL_VERIFY_PEER;
        if (hctx->conf.ssl_verifyclient_enforce) {
            mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
        }
        SSL_set_verify(ssl, mode, verify_callback);
        SSL_set_verify_depth(ssl, hctx->conf.ssl_verifyclient_depth + 1);
    } else {
        SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
    }

    return SSL_TLSEXT_ERR_OK;
}
#endif


static X509 *
x509_load_pem_file (server *srv, const char *file)
{
    BIO *in;
    X509 *x = NULL;

    in = BIO_new(BIO_s_file());
    if (NULL == in) {
        log_error_write(srv, __FILE__, __LINE__, "S",
                        "SSL: BIO_new(BIO_s_file()) failed");
        goto error;
    }

    if (BIO_read_filename(in,file) <= 0) {
        log_error_write(srv, __FILE__, __LINE__, "SSS",
                        "SSL: BIO_read_filename('", file,"') failed");
        goto error;
    }

    x = PEM_read_bio_X509(in, NULL, NULL, NULL);
    if (NULL == x) {
        log_error_write(srv, __FILE__, __LINE__, "SSS",
                        "SSL: couldn't read X509 certificate from '", file,"'");
        goto error;
    }

    BIO_free(in);
    return x;

error:
    if (NULL != in) BIO_free(in);
    return NULL;
}


static EVP_PKEY *
evp_pkey_load_pem_file (server *srv, const char *file)
{
    BIO *in;
    EVP_PKEY *x = NULL;

    in = BIO_new(BIO_s_file());
    if (NULL == in) {
        log_error_write(srv, __FILE__, __LINE__, "s",
                        "SSL: BIO_new(BIO_s_file()) failed");
        goto error;
    }

    if (BIO_read_filename(in,file) <= 0) {
        log_error_write(srv, __FILE__, __LINE__, "SSS",
                        "SSL: BIO_read_filename('", file,"') failed");
        goto error;
    }

    x = PEM_read_bio_PrivateKey(in, NULL, NULL, NULL);
    if (NULL == x) {
        log_error_write(srv, __FILE__, __LINE__, "SSS",
                        "SSL: couldn't read private key from '", file,"'");
        goto error;
    }

    BIO_free(in);
    return x;

error:
    if (NULL != in) BIO_free(in);
    return NULL;
}


static int
network_openssl_load_pemfile (server *srv, plugin_config *s, size_t ndx)
{
  #ifdef OPENSSL_NO_TLSEXT
    data_config *dc = (data_config *)srv->config_context->data[ndx];
    if ((ndx > 0 && (COMP_SERVER_SOCKET != dc->comp
                     || dc->cond != CONFIG_COND_EQ)) || !s->ssl_enabled) {
        log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                        "ssl.pemfile only works in SSL socket binding context "
                        "as openssl version does not support TLS extensions");
        return -1;
    }
  #else
    UNUSED(ndx);
  #endif

    s->ssl_pemfile_x509 = x509_load_pem_file(srv, s->ssl_pemfile->ptr);
    if (NULL == s->ssl_pemfile_x509) return -1;
    s->ssl_pemfile_pkey = evp_pkey_load_pem_file(srv, s->ssl_pemfile->ptr);
    if (NULL == s->ssl_pemfile_pkey) return -1;

    if (!X509_check_private_key(s->ssl_pemfile_x509, s->ssl_pemfile_pkey)) {
        log_error_write(srv, __FILE__, __LINE__, "sssb", "SSL:",
                        "Private key does not match the certificate public key,"
                        " reason:", ERR_error_string(ERR_get_error(), NULL),
                        s->ssl_pemfile);
        return -1;
    }

    return 0;
}


static int
network_openssl_ssl_conf_cmd (server *srv, plugin_config *s)
{
  #ifdef SSL_CONF_FLAG_CMDLINE

    int rc = 0;
    data_string *ds;
    SSL_CONF_CTX * const cctx = SSL_CONF_CTX_new();
    SSL_CONF_CTX_set_ssl_ctx(cctx, s->ssl_ctx);
    SSL_CONF_CTX_set_flags(cctx, SSL_CONF_FLAG_FILE
                               | SSL_CONF_FLAG_SERVER
                               | SSL_CONF_FLAG_SHOW_ERRORS
                               | SSL_CONF_FLAG_CERTIFICATE);

    /* always disable null and export ciphers */
    ds = (data_string *)
      array_get_element_klen(s->ssl_conf_cmd,
                             CONST_STR_LEN("CipherString"));
    if (NULL != ds) {
        buffer_append_string_len(ds->value,
                                 CONST_STR_LEN(":!aNULL:!eNULL:!EXP"));
    }

    for (size_t i = 0; i < s->ssl_conf_cmd->used; ++i) {
        ds = (data_string *)s->ssl_conf_cmd->data[i];
        ERR_clear_error();
        if (SSL_CONF_cmd(cctx, ds->key->ptr, ds->value->ptr) <= 0) {
            log_error_write(srv, __FILE__, __LINE__, "ssbbss", "SSL:",
                            "SSL_CONF_cmd", ds->key, ds->value, ":",
                            ERR_error_string(ERR_get_error(), NULL));
            rc = -1;
            break;
        }
    }

    if (0 == rc && 1 != SSL_CONF_CTX_finish(cctx)) {
        log_error_write(srv, __FILE__, __LINE__, "sss", "SSL:",
                        "SSL_CONF_CTX_finish():",
                        ERR_error_string(ERR_get_error(), NULL));
        rc = -1;
    }

    SSL_CONF_CTX_free(cctx);
    return rc;

  #else

    UNUSED(s);
    log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                    "ssl.openssl.ssl-conf-cmd not available; ignored");
    return 0;

  #endif
}


static int
network_init_ssl (server *srv, void *p_d)
{
    plugin_data *p = p_d;

  #ifndef OPENSSL_NO_DH
   /* 1024-bit MODP Group with 160-bit prime order subgroup (RFC5114)
    * -----BEGIN DH PARAMETERS-----
    * MIIBDAKBgQCxC4+WoIDgHd6S3l6uXVTsUsmfvPsGo8aaap3KUtI7YWBz4oZ1oj0Y
    * mDjvHi7mUsAT7LSuqQYRIySXXDzUm4O/rMvdfZDEvXCYSI6cIZpzck7/1vrlZEc4
    * +qMaT/VbzMChUa9fDci0vUW/N982XBpl5oz9p21NpwjfH7K8LkpDcQKBgQCk0cvV
    * w/00EmdlpELvuZkF+BBN0lisUH/WQGz/FCZtMSZv6h5cQVZLd35pD1UE8hMWAhe0
    * sBuIal6RVH+eJ0n01/vX07mpLuGQnQ0iY/gKdqaiTAh6CR9THb8KAWm2oorWYqTR
    * jnOvoy13nVkY0IvIhY9Nzvl8KiSFXm7rIrOy5QICAKA=
    * -----END DH PARAMETERS-----
    */

    static const unsigned char dh1024_p[]={
        0xB1,0x0B,0x8F,0x96,0xA0,0x80,0xE0,0x1D,0xDE,0x92,0xDE,0x5E,
        0xAE,0x5D,0x54,0xEC,0x52,0xC9,0x9F,0xBC,0xFB,0x06,0xA3,0xC6,
        0x9A,0x6A,0x9D,0xCA,0x52,0xD2,0x3B,0x61,0x60,0x73,0xE2,0x86,
        0x75,0xA2,0x3D,0x18,0x98,0x38,0xEF,0x1E,0x2E,0xE6,0x52,0xC0,
        0x13,0xEC,0xB4,0xAE,0xA9,0x06,0x11,0x23,0x24,0x97,0x5C,0x3C,
        0xD4,0x9B,0x83,0xBF,0xAC,0xCB,0xDD,0x7D,0x90,0xC4,0xBD,0x70,
        0x98,0x48,0x8E,0x9C,0x21,0x9A,0x73,0x72,0x4E,0xFF,0xD6,0xFA,
        0xE5,0x64,0x47,0x38,0xFA,0xA3,0x1A,0x4F,0xF5,0x5B,0xCC,0xC0,
        0xA1,0x51,0xAF,0x5F,0x0D,0xC8,0xB4,0xBD,0x45,0xBF,0x37,0xDF,
        0x36,0x5C,0x1A,0x65,0xE6,0x8C,0xFD,0xA7,0x6D,0x4D,0xA7,0x08,
        0xDF,0x1F,0xB2,0xBC,0x2E,0x4A,0x43,0x71,
    };

    static const unsigned char dh1024_g[]={
        0xA4,0xD1,0xCB,0xD5,0xC3,0xFD,0x34,0x12,0x67,0x65,0xA4,0x42,
        0xEF,0xB9,0x99,0x05,0xF8,0x10,0x4D,0xD2,0x58,0xAC,0x50,0x7F,
        0xD6,0x40,0x6C,0xFF,0x14,0x26,0x6D,0x31,0x26,0x6F,0xEA,0x1E,
        0x5C,0x41,0x56,0x4B,0x77,0x7E,0x69,0x0F,0x55,0x04,0xF2,0x13,
        0x16,0x02,0x17,0xB4,0xB0,0x1B,0x88,0x6A,0x5E,0x91,0x54,0x7F,
        0x9E,0x27,0x49,0xF4,0xD7,0xFB,0xD7,0xD3,0xB9,0xA9,0x2E,0xE1,
        0x90,0x9D,0x0D,0x22,0x63,0xF8,0x0A,0x76,0xA6,0xA2,0x4C,0x08,
        0x7A,0x09,0x1F,0x53,0x1D,0xBF,0x0A,0x01,0x69,0xB6,0xA2,0x8A,
        0xD6,0x62,0xA4,0xD1,0x8E,0x73,0xAF,0xA3,0x2D,0x77,0x9D,0x59,
        0x18,0xD0,0x8B,0xC8,0x85,0x8F,0x4D,0xCE,0xF9,0x7C,0x2A,0x24,
        0x85,0x5E,0x6E,0xEB,0x22,0xB3,0xB2,0xE5,
    };
  #endif

    /* load SSL certificates */
    for (size_t i = 0; i < srv->config_context->used; ++i) {
        plugin_config *s = p->config_storage[i];
      #ifndef SSL_OP_NO_COMPRESSION
      #define SSL_OP_NO_COMPRESSION 0
      #endif
      #ifndef SSL_MODE_RELEASE_BUFFERS    /* OpenSSL >= 1.0.0 */
      #define SSL_MODE_RELEASE_BUFFERS 0
      #endif
        long ssloptions = SSL_OP_ALL
                        | SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
                        | SSL_OP_NO_COMPRESSION;

        if (s->ssl_enabled) {
            if (buffer_string_is_empty(s->ssl_pemfile)) {
                /* inherit ssl settings from global scope
                 * (if only ssl.engine = "enable" and no other ssl.* settings)*/
                if (0 != i && p->config_storage[0]->ssl_enabled) {
                    s->ssl_ctx = p->config_storage[0]->ssl_ctx;
                    continue;
                }
                /* PEM file is require */
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "ssl.pemfile has to be set "
                                "when ssl.engine = \"enable\"");
                return -1;
            }
        }

        if (buffer_string_is_empty(s->ssl_pemfile)
            && buffer_string_is_empty(s->ssl_ca_dn_file)
            && buffer_string_is_empty(s->ssl_ca_file)) continue;

        if (ssl_is_init == 0) {
          #if OPENSSL_VERSION_NUMBER >= 0x10100000L \
           && !defined(LIBRESSL_VERSION_NUMBER)
            OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS
                            |OPENSSL_INIT_LOAD_CRYPTO_STRINGS,NULL);
            OPENSSL_init_crypto(OPENSSL_INIT_ADD_ALL_CIPHERS
                               |OPENSSL_INIT_ADD_ALL_DIGESTS
                               |OPENSSL_INIT_LOAD_CONFIG, NULL);
          #else
            SSL_load_error_strings();
            SSL_library_init();
            OpenSSL_add_all_algorithms();
          #endif
            ssl_is_init = 1;

            if (0 == RAND_status()) {
                log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                                "not enough entropy in the pool");
                return -1;
            }

            local_send_buffer = malloc(LOCAL_SEND_BUFSIZE);
            force_assert(NULL != local_send_buffer);
        }

        if (!buffer_string_is_empty(s->ssl_pemfile)) {
          #ifdef OPENSSL_NO_TLSEXT
            data_config *dc = (data_config *)srv->config_context->data[i];
            if (COMP_HTTP_HOST == dc->comp) {
                log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                                "can't use ssl.pemfile with $HTTP[\"host\"], "
                                "openssl version does not support TLS "
                                "extensions");
                return -1;
            }
          #endif
            if (network_openssl_load_pemfile(srv, s, i)) return -1;
        }


        if (!buffer_string_is_empty(s->ssl_ca_dn_file)) {
            s->ssl_ca_file_cert_names =
              SSL_load_client_CA_file(s->ssl_ca_dn_file->ptr);
            if (NULL == s->ssl_ca_file_cert_names) {
                log_error_write(srv, __FILE__, __LINE__, "ssb", "SSL:",
                                ERR_error_string(ERR_get_error(), NULL),
                                s->ssl_ca_dn_file);
            }
        }

        if (NULL == s->ssl_ca_file_cert_names
            && !buffer_string_is_empty(s->ssl_ca_file)) {
            s->ssl_ca_file_cert_names =
              SSL_load_client_CA_file(s->ssl_ca_file->ptr);
            if (NULL == s->ssl_ca_file_cert_names) {
                log_error_write(srv, __FILE__, __LINE__, "ssb", "SSL:",
                                ERR_error_string(ERR_get_error(), NULL),
                                s->ssl_ca_file);
            }
        }

        if (buffer_string_is_empty(s->ssl_pemfile) || !s->ssl_enabled) continue;

        if (NULL == (s->ssl_ctx = SSL_CTX_new(SSLv23_server_method()))) {
            log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                            ERR_error_string(ERR_get_error(), NULL));
            return -1;
        }

        /* completely useless identifier;
         * required for client cert verification to work with sessions */
        if (0 == SSL_CTX_set_session_id_context(
                   s->ssl_ctx,(const unsigned char*)CONST_STR_LEN("lighttpd"))){
            log_error_write(srv, __FILE__, __LINE__, "ss:s", "SSL:",
                            "failed to set session context",
                            ERR_error_string(ERR_get_error(), NULL));
            return -1;
        }

        if (s->ssl_empty_fragments) {
          #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
            ssloptions &= ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS;
          #else
            ssloptions &= ~0x00000800L; /* hardcode constant */
            log_error_write(srv, __FILE__, __LINE__, "ss", "WARNING: SSL:",
                            "'insert empty fragments' not supported by the "
                            "openssl version used to compile lighttpd with");
          #endif
        }

        SSL_CTX_set_options(s->ssl_ctx, ssloptions);
        SSL_CTX_set_info_callback(s->ssl_ctx, ssl_info_callback);

        if (!s->ssl_use_sslv2 && 0 != SSL_OP_NO_SSLv2) {
            /* disable SSLv2 */
            if ((SSL_OP_NO_SSLv2
                 & SSL_CTX_set_options(s->ssl_ctx, SSL_OP_NO_SSLv2))
                != SSL_OP_NO_SSLv2) {
                log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                                ERR_error_string(ERR_get_error(), NULL));
                return -1;
            }
        }

        if (!s->ssl_use_sslv3 && 0 != SSL_OP_NO_SSLv3) {
            /* disable SSLv3 */
            if ((SSL_OP_NO_SSLv3
                 & SSL_CTX_set_options(s->ssl_ctx, SSL_OP_NO_SSLv3))
                != SSL_OP_NO_SSLv3) {
                log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                                ERR_error_string(ERR_get_error(), NULL));
                return -1;
            }
        }

        if (!buffer_string_is_empty(s->ssl_cipher_list)) {
            /* Disable support for low encryption ciphers */
            if (SSL_CTX_set_cipher_list(s->ssl_ctx,s->ssl_cipher_list->ptr)!=1){
                log_error_write(srv, __FILE__, __LINE__, "ss", "SSL:",
                                ERR_error_string(ERR_get_error(), NULL));
                return -1;
            }

            if (s->ssl_honor_cipher_order) {
                SSL_CTX_set_options(s->ssl_ctx,SSL_OP_CIPHER_SERVER_PREFERENCE);
            }
        }

      #ifndef OPENSSL_NO_DH
      {
        DH *dh;
        /* Support for Diffie-Hellman key exchange */
        if (!buffer_string_is_empty(s->ssl_dh_file)) {
            /* DH parameters from file */
            BIO *bio;
            bio = BIO_new_file((char *) s->ssl_dh_file->ptr, "r");
            if (bio == NULL) {
                log_error_write(srv, __FILE__, __LINE__, "ss",
                                "SSL: Unable to open file",
                                s->ssl_dh_file->ptr);
                return -1;
            }
            dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
            BIO_free(bio);
            if (dh == NULL) {
                log_error_write(srv, __FILE__, __LINE__, "ss",
                                "SSL: PEM_read_bio_DHparams failed",
                                s->ssl_dh_file->ptr);
                return -1;
            }
        } else {
            BIGNUM *dh_p, *dh_g;
            /* Default DH parameters from RFC5114 */
            dh = DH_new();
            if (dh == NULL) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "SSL: DH_new () failed");
                return -1;
            }
            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)) {
                DH_free(dh);
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "SSL: BN_bin2bn () failed");
                return -1;
            }
          #if OPENSSL_VERSION_NUMBER < 0x10100000L \
           || defined(LIBRESSL_VERSION_NUMBER)
            dh->p = dh_p;
            dh->g = dh_g;
            dh->length = 160;
          #else
            DH_set0_pqg(dh, dh_p, NULL, dh_g);
            DH_set_length(dh, 160);
          #endif
        }
        SSL_CTX_set_tmp_dh(s->ssl_ctx,dh);
        SSL_CTX_set_options(s->ssl_ctx,SSL_OP_SINGLE_DH_USE);
        DH_free(dh);
      }
      #else
        if (!buffer_string_is_empty(s->ssl_dh_file)) {
            log_error_write(srv, __FILE__, __LINE__, "ss",
                            "SSL: openssl compiled without DH support, "
                            "can't load parameters from", s->ssl_dh_file->ptr);
        }
      #endif

      #if OPENSSL_VERSION_NUMBER >= 0x0090800fL
      #ifndef OPENSSL_NO_ECDH
      {
        int nid = 0;
        /* Support for Elliptic-Curve Diffie-Hellman key exchange */
        if (!buffer_string_is_empty(s->ssl_ec_curve)) {
            /* OpenSSL only supports the "named curves"
             * from RFC 4492, section 5.1.1. */
            nid = OBJ_sn2nid((char *) s->ssl_ec_curve->ptr);
            if (nid == 0) {
                log_error_write(srv, __FILE__, __LINE__, "ss",
                                "SSL: Unknown curve name",
                                s->ssl_ec_curve->ptr);
                return -1;
            }
        } else {
          #if OPENSSL_VERSION_NUMBER < 0x10002000
            /* Default curve */
            nid = OBJ_sn2nid("prime256v1");
          #elif OPENSSL_VERSION_NUMBER < 0x10100000L \
             || defined(LIBRESSL_VERSION_NUMBER)
            if (!SSL_CTX_set_ecdh_auto(s->ssl_ctx, 1)) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "SSL: SSL_CTX_set_ecdh_auto() failed");
            }
          #endif
        }
        if (nid) {
            EC_KEY *ecdh;
            ecdh = EC_KEY_new_by_curve_name(nid);
            if (ecdh == NULL) {
                log_error_write(srv, __FILE__, __LINE__, "ss",
                                "SSL: Unable to create curve",
                                s->ssl_ec_curve->ptr);
                return -1;
            }
            SSL_CTX_set_tmp_ecdh(s->ssl_ctx,ecdh);
            SSL_CTX_set_options(s->ssl_ctx,SSL_OP_SINGLE_ECDH_USE);
            EC_KEY_free(ecdh);
        }
      }
      #endif
      #endif

        /* load all ssl.ca-files specified in the config into each SSL_CTX
         * to be prepared for SNI */
        for (size_t j = 0; j < srv->config_context->used; ++j) {
            plugin_config *s1 = p->config_storage[j];

            if (!buffer_string_is_empty(s1->ssl_ca_dn_file)) {
                if (1 != SSL_CTX_load_verify_locations(
                           s->ssl_ctx, s1->ssl_ca_dn_file->ptr, NULL)) {
                    log_error_write(srv, __FILE__, __LINE__, "ssb", "SSL:",
                                    ERR_error_string(ERR_get_error(), NULL),
                                    s1->ssl_ca_dn_file);
                    return -1;
                }
            }
            if (!buffer_string_is_empty(s1->ssl_ca_file)) {
                if (1 != SSL_CTX_load_verify_locations(
                           s->ssl_ctx, s1->ssl_ca_file->ptr, NULL)) {
                    log_error_write(srv, __FILE__, __LINE__, "ssb", "SSL:",
                                    ERR_error_string(ERR_get_error(), NULL),
                                    s1->ssl_ca_file);
                    return -1;
                }
            }
        }

        if (s->ssl_verifyclient) {
            int mode;
            if (NULL == s->ssl_ca_file_cert_names) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "SSL: You specified ssl.verifyclient.activate "
                                "but no ssl.ca-file or ssl.ca-dn-file");
                return -1;
            }
            SSL_CTX_set_client_CA_list(
              s->ssl_ctx, SSL_dup_CA_list(s->ssl_ca_file_cert_names));
            mode = SSL_VERIFY_PEER;
            if (s->ssl_verifyclient_enforce) {
                mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
            }
            SSL_CTX_set_verify(s->ssl_ctx, mode, verify_callback);