view src/http/modules/ngx_http_secure_link_module.c @ 7973:3443c02ca1d1

SSL: $ssl_curve (ticket #2135). The variable contains a negotiated curve used for the handshake key exchange process. Known curves are listed by their names, unknown ones are shown in hex. Note that for resumed sessions in TLSv1.2 and older protocols, $ssl_curve contains the curve used during the initial handshake, while in TLSv1.3 it contains the curve used during the session resumption (see the SSL_get_negotiated_group manual page for details). The variable is only meaningful when using OpenSSL 3.0 and above. With older versions the variable is empty.
author Sergey Kandaurov <pluknet@nginx.com>
date Mon, 01 Nov 2021 18:09:34 +0300
parents bdd4d89370a7
children
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>
#include <ngx_md5.h>


typedef struct {
    ngx_http_complex_value_t  *variable;
    ngx_http_complex_value_t  *md5;
    ngx_str_t                  secret;
} ngx_http_secure_link_conf_t;


typedef struct {
    ngx_str_t                  expires;
} ngx_http_secure_link_ctx_t;


static ngx_int_t ngx_http_secure_link_old_variable(ngx_http_request_t *r,
    ngx_http_secure_link_conf_t *conf, ngx_http_variable_value_t *v,
    uintptr_t data);
static ngx_int_t ngx_http_secure_link_expires_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static void *ngx_http_secure_link_create_conf(ngx_conf_t *cf);
static char *ngx_http_secure_link_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static ngx_int_t ngx_http_secure_link_add_variables(ngx_conf_t *cf);


static ngx_command_t  ngx_http_secure_link_commands[] = {

    { ngx_string("secure_link"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_set_complex_value_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_secure_link_conf_t, variable),
      NULL },

    { ngx_string("secure_link_md5"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_set_complex_value_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_secure_link_conf_t, md5),
      NULL },

    { ngx_string("secure_link_secret"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_secure_link_conf_t, secret),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_secure_link_module_ctx = {
    ngx_http_secure_link_add_variables,    /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_secure_link_create_conf,      /* create location configuration */
    ngx_http_secure_link_merge_conf        /* merge location configuration */
};


ngx_module_t  ngx_http_secure_link_module = {
    NGX_MODULE_V1,
    &ngx_http_secure_link_module_ctx,      /* module context */
    ngx_http_secure_link_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_str_t  ngx_http_secure_link_name = ngx_string("secure_link");
static ngx_str_t  ngx_http_secure_link_expires_name =
    ngx_string("secure_link_expires");


static ngx_int_t
ngx_http_secure_link_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    u_char                       *p, *last;
    ngx_str_t                     val, hash;
    time_t                        expires;
    ngx_md5_t                     md5;
    ngx_http_secure_link_ctx_t   *ctx;
    ngx_http_secure_link_conf_t  *conf;
    u_char                        hash_buf[18], md5_buf[16];

    conf = ngx_http_get_module_loc_conf(r, ngx_http_secure_link_module);

    if (conf->secret.data) {
        return ngx_http_secure_link_old_variable(r, conf, v, data);
    }

    if (conf->variable == NULL || conf->md5 == NULL) {
        goto not_found;
    }

    if (ngx_http_complex_value(r, conf->variable, &val) != NGX_OK) {
        return NGX_ERROR;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "secure link: \"%V\"", &val);

    last = val.data + val.len;

    p = ngx_strlchr(val.data, last, ',');
    expires = 0;

    if (p) {
        val.len = p++ - val.data;

        expires = ngx_atotm(p, last - p);
        if (expires <= 0) {
            goto not_found;
        }

        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_secure_link_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_secure_link_module);

        ctx->expires.len = last - p;
        ctx->expires.data = p;
    }

    if (val.len > 24) {
        goto not_found;
    }

    hash.data = hash_buf;

    if (ngx_decode_base64url(&hash, &val) != NGX_OK) {
        goto not_found;
    }

    if (hash.len != 16) {
        goto not_found;
    }

    if (ngx_http_complex_value(r, conf->md5, &val) != NGX_OK) {
        return NGX_ERROR;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "secure link md5: \"%V\"", &val);

    ngx_md5_init(&md5);
    ngx_md5_update(&md5, val.data, val.len);
    ngx_md5_final(md5_buf, &md5);

    if (ngx_memcmp(hash_buf, md5_buf, 16) != 0) {
        goto not_found;
    }

    v->data = (u_char *) ((expires && expires < ngx_time()) ? "0" : "1");
    v->len = 1;
    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;

    return NGX_OK;

not_found:

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_secure_link_old_variable(ngx_http_request_t *r,
    ngx_http_secure_link_conf_t *conf, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    u_char      *p, *start, *end, *last;
    size_t       len;
    ngx_int_t    n;
    ngx_uint_t   i;
    ngx_md5_t    md5;
    u_char       hash[16];

    p = &r->unparsed_uri.data[1];
    last = r->unparsed_uri.data + r->unparsed_uri.len;

    while (p < last) {
        if (*p++ == '/') {
            start = p;
            goto md5_start;
        }
    }

    goto not_found;

md5_start:

    while (p < last) {
        if (*p++ == '/') {
            end = p - 1;
            goto url_start;
        }
    }

    goto not_found;

url_start:

    len = last - p;

    if (end - start != 32 || len == 0) {
        goto not_found;
    }

    ngx_md5_init(&md5);
    ngx_md5_update(&md5, p, len);
    ngx_md5_update(&md5, conf->secret.data, conf->secret.len);
    ngx_md5_final(hash, &md5);

    for (i = 0; i < 16; i++) {
        n = ngx_hextoi(&start[2 * i], 2);
        if (n == NGX_ERROR || n != hash[i]) {
            goto not_found;
        }
    }

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

    return NGX_OK;

not_found:

    v->not_found = 1;

    return NGX_OK;
}


static ngx_int_t
ngx_http_secure_link_expires_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_http_secure_link_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_secure_link_module);

    if (ctx) {
        v->len = ctx->expires.len;
        v->valid = 1;
        v->no_cacheable = 0;
        v->not_found = 0;
        v->data = ctx->expires.data;

    } else {
        v->not_found = 1;
    }

    return NGX_OK;
}


static void *
ngx_http_secure_link_create_conf(ngx_conf_t *cf)
{
    ngx_http_secure_link_conf_t  *conf;

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

    /*
     * set by ngx_pcalloc():
     *
     *     conf->secret = { 0, NULL };
     */

    conf->variable = NGX_CONF_UNSET_PTR;
    conf->md5 = NGX_CONF_UNSET_PTR;

    return conf;
}


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

    if (conf->secret.data) {
        ngx_conf_init_ptr_value(conf->variable, NULL);
        ngx_conf_init_ptr_value(conf->md5, NULL);

        if (conf->variable || conf->md5) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "\"secure_link_secret\" cannot be mixed with "
                               "\"secure_link\" and \"secure_link_md5\"");
            return NGX_CONF_ERROR;
        }

        return NGX_CONF_OK;
    }

    ngx_conf_merge_ptr_value(conf->variable, prev->variable, NULL);
    ngx_conf_merge_ptr_value(conf->md5, prev->md5, NULL);

    if (conf->variable == NULL && conf->md5 == NULL) {
        conf->secret = prev->secret;
    }

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_secure_link_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var;

    var = ngx_http_add_variable(cf, &ngx_http_secure_link_name, 0);
    if (var == NULL) {
        return NGX_ERROR;
    }

    var->get_handler = ngx_http_secure_link_variable;

    var = ngx_http_add_variable(cf, &ngx_http_secure_link_expires_name, 0);
    if (var == NULL) {
        return NGX_ERROR;
    }

    var->get_handler = ngx_http_secure_link_expires_variable;

    return NGX_OK;
}