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/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_md5.h>
typedef struct {
ngx_str_t secret;
} ngx_http_secure_link_conf_t;
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_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 = ngx_string("secure_link");
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, *start, *end, *last;
size_t len;
ngx_int_t n;
ngx_uint_t i;
ngx_md5_t md5;
ngx_http_secure_link_conf_t *conf;
u_char hash[16];
conf = ngx_http_get_module_loc_conf(r, ngx_http_secure_link_module);
if (conf->secret.len == 0) {
goto not_found;
}
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 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 }
*/
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;
ngx_conf_merge_str_value(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, NGX_HTTP_VAR_NOHASH);
if (var == NULL) {
return NGX_ERROR;
}
var->get_handler = ngx_http_secure_link_variable;
return NGX_OK;
}
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