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view src/http/modules/ngx_http_ssl_module.c @ 7629:f47f7d3d1bfa

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Mp4: fixed possible chunk offset overflow. In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming the "mdat" atom, chunk offsets are casted to off_t values which are typically 64-bit signed integers. A specially crafted mp4 file with huge chunk offsets may lead to off_t overflow and result in negative trim boundaries. The consequences of the overflow are: - Incorrect Content-Length header value in the response. - Negative left boundary of the response file buffer holding the trimmed "mdat". This leads to pread()/sendfile() errors followed by closing the client connection. On rare systems where off_t is a 32-bit integer, this scenario is also feasible with the "stco" atom. The fix is to add checks which make sure data chunks referenced by each track are within the mp4 file boundaries. Additionally a few more checks are added to ensure mp4 file consistency and log errors.
author Roman Arutyunyan <arut@nginx.com>
date Wed, 26 Feb 2020 15:10:46 +0300
parents ef7ee19776db
children 8409f9df6219 5d91389e0fd3
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef ngx_int_t (*ngx_ssl_variable_handler_pt)(ngx_connection_t *c,
    ngx_pool_t *pool, ngx_str_t *s);


#define NGX_DEFAULT_CIPHERS     "HIGH:!aNULL:!MD5"
#define NGX_DEFAULT_ECDH_CURVE  "auto"

#define NGX_HTTP_NPN_ADVERTISE  "\x08http/1.1"


#ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
static int ngx_http_ssl_alpn_select(ngx_ssl_conn_t *ssl_conn,
    const unsigned char **out, unsigned char *outlen,
    const unsigned char *in, unsigned int inlen, void *arg);
#endif

#ifdef TLSEXT_TYPE_next_proto_neg
static int ngx_http_ssl_npn_advertised(ngx_ssl_conn_t *ssl_conn,
    const unsigned char **out, unsigned int *outlen, void *arg);
#endif

static ngx_int_t ngx_http_ssl_static_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_ssl_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_ssl_add_variables(ngx_conf_t *cf);
static void *ngx_http_ssl_create_srv_conf(ngx_conf_t *cf);
static char *ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf,
    void *parent, void *child);

static ngx_int_t ngx_http_ssl_compile_certificates(ngx_conf_t *cf,
    ngx_http_ssl_srv_conf_t *conf);

static char *ngx_http_ssl_enable(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ssl_password_file(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_ssl_session_cache(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);

static ngx_int_t ngx_http_ssl_init(ngx_conf_t *cf);


static ngx_conf_bitmask_t  ngx_http_ssl_protocols[] = {
    { ngx_string("SSLv2"), NGX_SSL_SSLv2 },
    { ngx_string("SSLv3"), NGX_SSL_SSLv3 },
    { ngx_string("TLSv1"), NGX_SSL_TLSv1 },
    { ngx_string("TLSv1.1"), NGX_SSL_TLSv1_1 },
    { ngx_string("TLSv1.2"), NGX_SSL_TLSv1_2 },
    { ngx_string("TLSv1.3"), NGX_SSL_TLSv1_3 },
    { ngx_null_string, 0 }
};


static ngx_conf_enum_t  ngx_http_ssl_verify[] = {
    { ngx_string("off"), 0 },
    { ngx_string("on"), 1 },
    { ngx_string("optional"), 2 },
    { ngx_string("optional_no_ca"), 3 },
    { ngx_null_string, 0 }
};


static ngx_conf_deprecated_t  ngx_http_ssl_deprecated = {
    ngx_conf_deprecated, "ssl", "listen ... ssl"
};


static ngx_command_t  ngx_http_ssl_commands[] = {

    { ngx_string("ssl"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_http_ssl_enable,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, enable),
      &ngx_http_ssl_deprecated },

    { ngx_string("ssl_certificate"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, certificates),
      NULL },

    { ngx_string("ssl_certificate_key"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, certificate_keys),
      NULL },

    { ngx_string("ssl_password_file"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_http_ssl_password_file,
      NGX_HTTP_SRV_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ssl_dhparam"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, dhparam),
      NULL },

    { ngx_string("ssl_ecdh_curve"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, ecdh_curve),
      NULL },

    { ngx_string("ssl_protocols"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, protocols),
      &ngx_http_ssl_protocols },

    { ngx_string("ssl_ciphers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, ciphers),
      NULL },

    { ngx_string("ssl_buffer_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, buffer_size),
      NULL },

    { ngx_string("ssl_verify_client"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_enum_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, verify),
      &ngx_http_ssl_verify },

    { ngx_string("ssl_verify_depth"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, verify_depth),
      NULL },

    { ngx_string("ssl_client_certificate"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, client_certificate),
      NULL },

    { ngx_string("ssl_trusted_certificate"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, trusted_certificate),
      NULL },

    { ngx_string("ssl_prefer_server_ciphers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, prefer_server_ciphers),
      NULL },

    { ngx_string("ssl_session_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE12,
      ngx_http_ssl_session_cache,
      NGX_HTTP_SRV_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("ssl_session_tickets"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, session_tickets),
      NULL },

    { ngx_string("ssl_session_ticket_key"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, session_ticket_keys),
      NULL },

    { ngx_string("ssl_session_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_sec_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, session_timeout),
      NULL },

    { ngx_string("ssl_crl"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, crl),
      NULL },

    { ngx_string("ssl_stapling"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, stapling),
      NULL },

    { ngx_string("ssl_stapling_file"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, stapling_file),
      NULL },

    { ngx_string("ssl_stapling_responder"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, stapling_responder),
      NULL },

    { ngx_string("ssl_stapling_verify"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, stapling_verify),
      NULL },

    { ngx_string("ssl_early_data"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_SRV_CONF_OFFSET,
      offsetof(ngx_http_ssl_srv_conf_t, early_data),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_ssl_module_ctx = {
    ngx_http_ssl_add_variables,            /* preconfiguration */
    ngx_http_ssl_init,                     /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    ngx_http_ssl_create_srv_conf,          /* create server configuration */
    ngx_http_ssl_merge_srv_conf,           /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_ssl_module = {
    NGX_MODULE_V1,
    &ngx_http_ssl_module_ctx,              /* module context */
    ngx_http_ssl_commands,                 /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_http_variable_t  ngx_http_ssl_vars[] = {

    { ngx_string("ssl_protocol"), NULL, ngx_http_ssl_static_variable,
      (uintptr_t) ngx_ssl_get_protocol, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_cipher"), NULL, ngx_http_ssl_static_variable,
      (uintptr_t) ngx_ssl_get_cipher_name, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_ciphers"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_ciphers, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_curves"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_curves, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_session_id"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_session_id, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_session_reused"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_session_reused, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_early_data"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_early_data,
      NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("ssl_server_name"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_server_name, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_cert"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_certificate, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_raw_cert"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_raw_certificate,
      NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_escaped_cert"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_escaped_certificate,
      NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_s_dn"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_subject_dn, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_i_dn"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_issuer_dn, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_s_dn_legacy"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_subject_dn_legacy, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_i_dn_legacy"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_issuer_dn_legacy, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_serial"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_serial_number, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_fingerprint"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_fingerprint, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_verify"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_client_verify, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_v_start"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_client_v_start, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_v_end"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_client_v_end, NGX_HTTP_VAR_CHANGEABLE, 0 },

    { ngx_string("ssl_client_v_remain"), NULL, ngx_http_ssl_variable,
      (uintptr_t) ngx_ssl_get_client_v_remain, NGX_HTTP_VAR_CHANGEABLE, 0 },

      ngx_http_null_variable
};


static ngx_str_t ngx_http_ssl_sess_id_ctx = ngx_string("HTTP");


#ifdef TLSEXT_TYPE_application_layer_protocol_negotiation

static int
ngx_http_ssl_alpn_select(ngx_ssl_conn_t *ssl_conn, const unsigned char **out,
    unsigned char *outlen, const unsigned char *in, unsigned int inlen,
    void *arg)
{
    unsigned int            srvlen;
    unsigned char          *srv;
#if (NGX_DEBUG)
    unsigned int            i;
#endif
#if (NGX_HTTP_V2)
    ngx_http_connection_t  *hc;
#endif
#if (NGX_HTTP_V2 || NGX_DEBUG)
    ngx_connection_t       *c;

    c = ngx_ssl_get_connection(ssl_conn);
#endif

#if (NGX_DEBUG)
    for (i = 0; i < inlen; i += in[i] + 1) {
        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                       "SSL ALPN supported by client: %*s",
                       (size_t) in[i], &in[i + 1]);
    }
#endif

#if (NGX_HTTP_V2)
    hc = c->data;

    if (hc->addr_conf->http2) {
        srv =
           (unsigned char *) NGX_HTTP_V2_ALPN_ADVERTISE NGX_HTTP_NPN_ADVERTISE;
        srvlen = sizeof(NGX_HTTP_V2_ALPN_ADVERTISE NGX_HTTP_NPN_ADVERTISE) - 1;

    } else
#endif
    {
        srv = (unsigned char *) NGX_HTTP_NPN_ADVERTISE;
        srvlen = sizeof(NGX_HTTP_NPN_ADVERTISE) - 1;
    }

    if (SSL_select_next_proto((unsigned char **) out, outlen, srv, srvlen,
                              in, inlen)
        != OPENSSL_NPN_NEGOTIATED)
    {
        return SSL_TLSEXT_ERR_NOACK;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "SSL ALPN selected: %*s", (size_t) *outlen, *out);

    return SSL_TLSEXT_ERR_OK;
}

#endif


#ifdef TLSEXT_TYPE_next_proto_neg

static int
ngx_http_ssl_npn_advertised(ngx_ssl_conn_t *ssl_conn,
    const unsigned char **out, unsigned int *outlen, void *arg)
{
#if (NGX_HTTP_V2 || NGX_DEBUG)
    ngx_connection_t  *c;

    c = ngx_ssl_get_connection(ssl_conn);
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "SSL NPN advertised");
#endif

#if (NGX_HTTP_V2)
    {
    ngx_http_connection_t  *hc;

    hc = c->data;

    if (hc->addr_conf->http2) {
        *out =
            (unsigned char *) NGX_HTTP_V2_NPN_ADVERTISE NGX_HTTP_NPN_ADVERTISE;
        *outlen = sizeof(NGX_HTTP_V2_NPN_ADVERTISE NGX_HTTP_NPN_ADVERTISE) - 1;

        return SSL_TLSEXT_ERR_OK;
    }
    }
#endif

    *out = (unsigned char *) NGX_HTTP_NPN_ADVERTISE;
    *outlen = sizeof(NGX_HTTP_NPN_ADVERTISE) - 1;

    return SSL_TLSEXT_ERR_OK;
}

#endif


static ngx_int_t
ngx_http_ssl_static_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_ssl_variable_handler_pt  handler = (ngx_ssl_variable_handler_pt) data;

    size_t     len;
    ngx_str_t  s;

    if (r->connection->ssl) {

        (void) handler(r->connection, NULL, &s);

        v->data = s.data;

        for (len = 0; v->data[len]; len++) { /* void */ }

        v->len = len;
        v->valid = 1;
        v->no_cacheable = 0;
        v->not_found = 0;

        return NGX_OK;
    }

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_ssl_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_ssl_variable_handler_pt  handler = (ngx_ssl_variable_handler_pt) data;

    ngx_str_t  s;

    if (r->connection->ssl) {

        if (handler(r->connection, r->pool, &s) != NGX_OK) {
            return NGX_ERROR;
        }

        v->len = s.len;
        v->data = s.data;

        if (v->len) {
            v->valid = 1;
            v->no_cacheable = 0;
            v->not_found = 0;

            return NGX_OK;
        }
    }

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_ssl_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

    for (v = ngx_http_ssl_vars; v->name.len; v++) {
        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

        var->get_handler = v->get_handler;
        var->data = v->data;
    }

    return NGX_OK;
}


static void *
ngx_http_ssl_create_srv_conf(ngx_conf_t *cf)
{
    ngx_http_ssl_srv_conf_t  *sscf;

    sscf = ngx_pcalloc(cf->pool, sizeof(ngx_http_ssl_srv_conf_t));
    if (sscf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     sscf->protocols = 0;
     *     sscf->certificate_values = NULL;
     *     sscf->dhparam = { 0, NULL };
     *     sscf->ecdh_curve = { 0, NULL };
     *     sscf->client_certificate = { 0, NULL };
     *     sscf->trusted_certificate = { 0, NULL };
     *     sscf->crl = { 0, NULL };
     *     sscf->ciphers = { 0, NULL };
     *     sscf->shm_zone = NULL;
     *     sscf->stapling_file = { 0, NULL };
     *     sscf->stapling_responder = { 0, NULL };
     */

    sscf->enable = NGX_CONF_UNSET;
    sscf->prefer_server_ciphers = NGX_CONF_UNSET;
    sscf->early_data = NGX_CONF_UNSET;
    sscf->buffer_size = NGX_CONF_UNSET_SIZE;
    sscf->verify = NGX_CONF_UNSET_UINT;
    sscf->verify_depth = NGX_CONF_UNSET_UINT;
    sscf->certificates = NGX_CONF_UNSET_PTR;
    sscf->certificate_keys = NGX_CONF_UNSET_PTR;
    sscf->passwords = NGX_CONF_UNSET_PTR;
    sscf->builtin_session_cache = NGX_CONF_UNSET;
    sscf->session_timeout = NGX_CONF_UNSET;
    sscf->session_tickets = NGX_CONF_UNSET;
    sscf->session_ticket_keys = NGX_CONF_UNSET_PTR;
    sscf->stapling = NGX_CONF_UNSET;
    sscf->stapling_verify = NGX_CONF_UNSET;

    return sscf;
}


static char *
ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_ssl_srv_conf_t *prev = parent;
    ngx_http_ssl_srv_conf_t *conf = child;

    ngx_pool_cleanup_t  *cln;

    if (conf->enable == NGX_CONF_UNSET) {
        if (prev->enable == NGX_CONF_UNSET) {
            conf->enable = 0;

        } else {
            conf->enable = prev->enable;
            conf->file = prev->file;
            conf->line = prev->line;
        }
    }

    ngx_conf_merge_value(conf->session_timeout,
                         prev->session_timeout, 300);

    ngx_conf_merge_value(conf->prefer_server_ciphers,
                         prev->prefer_server_ciphers, 0);

    ngx_conf_merge_value(conf->early_data, prev->early_data, 0);

    ngx_conf_merge_bitmask_value(conf->protocols, prev->protocols,
                         (NGX_CONF_BITMASK_SET|NGX_SSL_TLSv1
                          |NGX_SSL_TLSv1_1|NGX_SSL_TLSv1_2));

    ngx_conf_merge_size_value(conf->buffer_size, prev->buffer_size,
                         NGX_SSL_BUFSIZE);

    ngx_conf_merge_uint_value(conf->verify, prev->verify, 0);
    ngx_conf_merge_uint_value(conf->verify_depth, prev->verify_depth, 1);

    ngx_conf_merge_ptr_value(conf->certificates, prev->certificates, NULL);
    ngx_conf_merge_ptr_value(conf->certificate_keys, prev->certificate_keys,
                         NULL);

    ngx_conf_merge_ptr_value(conf->passwords, prev->passwords, NULL);

    ngx_conf_merge_str_value(conf->dhparam, prev->dhparam, "");

    ngx_conf_merge_str_value(conf->client_certificate, prev->client_certificate,
                         "");
    ngx_conf_merge_str_value(conf->trusted_certificate,
                         prev->trusted_certificate, "");
    ngx_conf_merge_str_value(conf->crl, prev->crl, "");

    ngx_conf_merge_str_value(conf->ecdh_curve, prev->ecdh_curve,
                         NGX_DEFAULT_ECDH_CURVE);

    ngx_conf_merge_str_value(conf->ciphers, prev->ciphers, NGX_DEFAULT_CIPHERS);

    ngx_conf_merge_value(conf->stapling, prev->stapling, 0);
    ngx_conf_merge_value(conf->stapling_verify, prev->stapling_verify, 0);
    ngx_conf_merge_str_value(conf->stapling_file, prev->stapling_file, "");
    ngx_conf_merge_str_value(conf->stapling_responder,
                         prev->stapling_responder, "");

    conf->ssl.log = cf->log;

    if (conf->enable) {

        if (conf->certificates == NULL) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate\" is defined for "
                          "the \"ssl\" directive in %s:%ui",
                          conf->file, conf->line);
            return NGX_CONF_ERROR;
        }

        if (conf->certificate_keys == NULL) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate_key\" is defined for "
                          "the \"ssl\" directive in %s:%ui",
                          conf->file, conf->line);
            return NGX_CONF_ERROR;
        }

        if (conf->certificate_keys->nelts < conf->certificates->nelts) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate_key\" is defined "
                          "for certificate \"%V\" and "
                          "the \"ssl\" directive in %s:%ui",
                          ((ngx_str_t *) conf->certificates->elts)
                          + conf->certificates->nelts - 1,
                          conf->file, conf->line);
            return NGX_CONF_ERROR;
        }

    } else {

        if (conf->certificates == NULL) {
            return NGX_CONF_OK;
        }

        if (conf->certificate_keys == NULL
            || conf->certificate_keys->nelts < conf->certificates->nelts)
        {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no \"ssl_certificate_key\" is defined "
                          "for certificate \"%V\"",
                          ((ngx_str_t *) conf->certificates->elts)
                          + conf->certificates->nelts - 1);
            return NGX_CONF_ERROR;
        }
    }

    if (ngx_ssl_create(&conf->ssl, conf->protocols, conf) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    cln = ngx_pool_cleanup_add(cf->pool, 0);
    if (cln == NULL) {
        ngx_ssl_cleanup_ctx(&conf->ssl);
        return NGX_CONF_ERROR;
    }

    cln->handler = ngx_ssl_cleanup_ctx;
    cln->data = &conf->ssl;

#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME

    if (SSL_CTX_set_tlsext_servername_callback(conf->ssl.ctx,
                                               ngx_http_ssl_servername)
        == 0)
    {
        ngx_log_error(NGX_LOG_WARN, cf->log, 0,
            "nginx was built with SNI support, however, now it is linked "
            "dynamically to an OpenSSL library which has no tlsext support, "
            "therefore SNI is not available");
    }

#endif

#ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
    SSL_CTX_set_alpn_select_cb(conf->ssl.ctx, ngx_http_ssl_alpn_select, NULL);
#endif

#ifdef TLSEXT_TYPE_next_proto_neg
    SSL_CTX_set_next_protos_advertised_cb(conf->ssl.ctx,
                                          ngx_http_ssl_npn_advertised, NULL);
#endif

    if (ngx_http_ssl_compile_certificates(cf, conf) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    if (conf->certificate_values) {

#ifdef SSL_R_CERT_CB_ERROR

        /* install callback to lookup certificates */

        SSL_CTX_set_cert_cb(conf->ssl.ctx, ngx_http_ssl_certificate, conf);

#else
        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                      "variables in "
                      "\"ssl_certificate\" and \"ssl_certificate_key\" "
                      "directives are not supported on this platform");
        return NGX_CONF_ERROR;
#endif

    } else {

        /* configure certificates */

        if (ngx_ssl_certificates(cf, &conf->ssl, conf->certificates,
                                 conf->certificate_keys, conf->passwords)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }
    }

    if (ngx_ssl_ciphers(cf, &conf->ssl, &conf->ciphers,
                        conf->prefer_server_ciphers)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    conf->ssl.buffer_size = conf->buffer_size;

    if (conf->verify) {

        if (conf->client_certificate.len == 0 && conf->verify != 3) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no ssl_client_certificate for ssl_verify_client");
            return NGX_CONF_ERROR;
        }

        if (ngx_ssl_client_certificate(cf, &conf->ssl,
                                       &conf->client_certificate,
                                       conf->verify_depth)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }
    }

    if (ngx_ssl_trusted_certificate(cf, &conf->ssl,
                                    &conf->trusted_certificate,
                                    conf->verify_depth)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    if (ngx_ssl_crl(cf, &conf->ssl, &conf->crl) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    if (ngx_ssl_dhparam(cf, &conf->ssl, &conf->dhparam) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    if (ngx_ssl_ecdh_curve(cf, &conf->ssl, &conf->ecdh_curve) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_value(conf->builtin_session_cache,
                         prev->builtin_session_cache, NGX_SSL_NONE_SCACHE);

    if (conf->shm_zone == NULL) {
        conf->shm_zone = prev->shm_zone;
    }

    if (ngx_ssl_session_cache(&conf->ssl, &ngx_http_ssl_sess_id_ctx,
                              conf->certificates, conf->builtin_session_cache,
                              conf->shm_zone, conf->session_timeout)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_value(conf->session_tickets, prev->session_tickets, 1);

#ifdef SSL_OP_NO_TICKET
    if (!conf->session_tickets) {
        SSL_CTX_set_options(conf->ssl.ctx, SSL_OP_NO_TICKET);
    }
#endif

    ngx_conf_merge_ptr_value(conf->session_ticket_keys,
                         prev->session_ticket_keys, NULL);

    if (ngx_ssl_session_ticket_keys(cf, &conf->ssl, conf->session_ticket_keys)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    if (conf->stapling) {

        if (ngx_ssl_stapling(cf, &conf->ssl, &conf->stapling_file,
                             &conf->stapling_responder, conf->stapling_verify)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }

    }

    if (ngx_ssl_early_data(cf, &conf->ssl, conf->early_data) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_ssl_compile_certificates(ngx_conf_t *cf,
    ngx_http_ssl_srv_conf_t *conf)
{
    ngx_str_t                         *cert, *key;
    ngx_uint_t                         i, nelts;
    ngx_http_complex_value_t          *cv;
    ngx_http_compile_complex_value_t   ccv;

    cert = conf->certificates->elts;
    key = conf->certificate_keys->elts;
    nelts = conf->certificates->nelts;

    for (i = 0; i < nelts; i++) {

        if (ngx_http_script_variables_count(&cert[i])) {
            goto found;
        }

        if (ngx_http_script_variables_count(&key[i])) {
            goto found;
        }
    }

    return NGX_OK;

found:

    conf->certificate_values = ngx_array_create(cf->pool, nelts,
                                             sizeof(ngx_http_complex_value_t));
    if (conf->certificate_values == NULL) {
        return NGX_ERROR;
    }

    conf->certificate_key_values = ngx_array_create(cf->pool, nelts,
                                             sizeof(ngx_http_complex_value_t));
    if (conf->certificate_key_values == NULL) {
        return NGX_ERROR;
    }

    for (i = 0; i < nelts; i++) {

        cv = ngx_array_push(conf->certificate_values);
        if (cv == NULL) {
            return NGX_ERROR;
        }

        ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

        ccv.cf = cf;
        ccv.value = &cert[i];
        ccv.complex_value = cv;
        ccv.zero = 1;

        if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
            return NGX_ERROR;
        }

        cv = ngx_array_push(conf->certificate_key_values);
        if (cv == NULL) {
            return NGX_ERROR;
        }

        ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

        ccv.cf = cf;
        ccv.value = &key[i];
        ccv.complex_value = cv;
        ccv.zero = 1;

        if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
            return NGX_ERROR;
        }
    }

    conf->passwords = ngx_ssl_preserve_passwords(cf, conf->passwords);
    if (conf->passwords == NULL) {
        return NGX_ERROR;
    }

    return NGX_OK;
}


static char *
ngx_http_ssl_enable(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_ssl_srv_conf_t *sscf = conf;

    char  *rv;

    rv = ngx_conf_set_flag_slot(cf, cmd, conf);

    if (rv != NGX_CONF_OK) {
        return rv;
    }

    sscf->file = cf->conf_file->file.name.data;
    sscf->line = cf->conf_file->line;

    return NGX_CONF_OK;
}


static char *
ngx_http_ssl_password_file(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_ssl_srv_conf_t *sscf = conf;

    ngx_str_t  *value;

    if (sscf->passwords != NGX_CONF_UNSET_PTR) {
        return "is duplicate";
    }

    value = cf->args->elts;

    sscf->passwords = ngx_ssl_read_password_file(cf, &value[1]);

    if (sscf->passwords == NULL) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_ssl_session_cache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_ssl_srv_conf_t *sscf = conf;

    size_t       len;
    ngx_str_t   *value, name, size;
    ngx_int_t    n;
    ngx_uint_t   i, j;

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; i++) {

        if (ngx_strcmp(value[i].data, "off") == 0) {
            sscf->builtin_session_cache = NGX_SSL_NO_SCACHE;
            continue;
        }

        if (ngx_strcmp(value[i].data, "none") == 0) {
            sscf->builtin_session_cache = NGX_SSL_NONE_SCACHE;
            continue;
        }

        if (ngx_strcmp(value[i].data, "builtin") == 0) {
            sscf->builtin_session_cache = NGX_SSL_DFLT_BUILTIN_SCACHE;
            continue;
        }

        if (value[i].len > sizeof("builtin:") - 1
            && ngx_strncmp(value[i].data, "builtin:", sizeof("builtin:") - 1)
               == 0)
        {
            n = ngx_atoi(value[i].data + sizeof("builtin:") - 1,
                         value[i].len - (sizeof("builtin:") - 1));

            if (n == NGX_ERROR) {
                goto invalid;
            }

            sscf->builtin_session_cache = n;

            continue;
        }

        if (value[i].len > sizeof("shared:") - 1
            && ngx_strncmp(value[i].data, "shared:", sizeof("shared:") - 1)
               == 0)
        {
            len = 0;

            for (j = sizeof("shared:") - 1; j < value[i].len; j++) {
                if (value[i].data[j] == ':') {
                    break;
                }

                len++;
            }

            if (len == 0) {
                goto invalid;
            }

            name.len = len;
            name.data = value[i].data + sizeof("shared:") - 1;

            size.len = value[i].len - j - 1;
            size.data = name.data + len + 1;

            n = ngx_parse_size(&size);

            if (n == NGX_ERROR) {
                goto invalid;
            }

            if (n < (ngx_int_t) (8 * ngx_pagesize)) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "session cache \"%V\" is too small",
                                   &value[i]);

                return NGX_CONF_ERROR;
            }

            sscf->shm_zone = ngx_shared_memory_add(cf, &name, n,
                                                   &ngx_http_ssl_module);
            if (sscf->shm_zone == NULL) {
                return NGX_CONF_ERROR;
            }

            sscf->shm_zone->init = ngx_ssl_session_cache_init;

            continue;
        }

        goto invalid;
    }

    if (sscf->shm_zone && sscf->builtin_session_cache == NGX_CONF_UNSET) {
        sscf->builtin_session_cache = NGX_SSL_NO_BUILTIN_SCACHE;
    }

    return NGX_CONF_OK;

invalid:

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "invalid session cache \"%V\"", &value[i]);

    return NGX_CONF_ERROR;
}


static ngx_int_t
ngx_http_ssl_init(ngx_conf_t *cf)
{
    ngx_uint_t                   a, p, s;
    ngx_http_conf_addr_t        *addr;
    ngx_http_conf_port_t        *port;
    ngx_http_ssl_srv_conf_t     *sscf;
    ngx_http_core_loc_conf_t    *clcf;
    ngx_http_core_srv_conf_t   **cscfp, *cscf;
    ngx_http_core_main_conf_t   *cmcf;

    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
    cscfp = cmcf->servers.elts;

    for (s = 0; s < cmcf->servers.nelts; s++) {

        sscf = cscfp[s]->ctx->srv_conf[ngx_http_ssl_module.ctx_index];

        if (sscf->ssl.ctx == NULL || !sscf->stapling) {
            continue;
        }

        clcf = cscfp[s]->ctx->loc_conf[ngx_http_core_module.ctx_index];

        if (ngx_ssl_stapling_resolver(cf, &sscf->ssl, clcf->resolver,
                                      clcf->resolver_timeout)
            != NGX_OK)
        {
            return NGX_ERROR;
        }
    }

    if (cmcf->ports == NULL) {
        return NGX_OK;
    }

    port = cmcf->ports->elts;
    for (p = 0; p < cmcf->ports->nelts; p++) {

        addr = port[p].addrs.elts;
        for (a = 0; a < port[p].addrs.nelts; a++) {

            if (!addr[a].opt.ssl) {
                continue;
            }

            cscf = addr[a].default_server;
            sscf = cscf->ctx->srv_conf[ngx_http_ssl_module.ctx_index];

            if (sscf->certificates == NULL) {
                ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                              "no \"ssl_certificate\" is defined for "
                              "the \"listen ... ssl\" directive in %s:%ui",
                              cscf->file_name, cscf->line);
                return NGX_ERROR;
            }
        }
    }

    return NGX_OK;
}