view src/http/modules/ngx_http_secure_link_module.c @ 7355:b64adc956643

Rewrite: removed r->err_status special handling (ticket #1634). Trying to look into r->err_status in the "return" directive makes it behave differently than real errors generated in other parts of the code, and is an endless source of various problems. This behaviour was introduced in 726:7b71936d5299 (0.4.4) with the comment "fix: "return" always overrode "error_page" response code". It is not clear if there were any real cases this was expected to fix, but there are several cases which are broken due to this change, some previously fixed (4147:7f64de1cc2c0). In ticket #1634, the problem is that when r->err_status is set to a non-special status code, it is not possible to return a response by simply returning r->err_status. If this is the case, the only option is to return script's e->status instead. An example configuration: location / { error_page 404 =200 /err502; return 404; } location = /err502 { return 502; } After the change, such a configuration will properly return standard 502 error, much like it happens when a 502 error is generated by proxy_pass. This also fixes the following configuration to properly close connection as clearly requested by "return 444": location / { error_page 404 /close; return 404; } location = /close { return 444; } Previously, this required "error_page 404 = /close;" to work as intended.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 21 Sep 2018 15:59:33 +0300
parents c7d4017c8876
children bdd4d89370a7
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->variable = NULL;
     *     conf->md5 = NULL;
     *     conf->secret = { 0, NULL };
     */

    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) {
        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;
    }

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

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

    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;
}