Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_referer_module.c @ 4664:356c91151658 stable-1.2
Merge of r4618: rewrite escaping fix (ticket #162).
The following code resulted in incorrect escaping of uri and possible
segfault:
location / {
rewrite ^(.*) $1?c=$1;
return 200 "$uri";
}
If there were arguments in a rewrite's replacement string, and length was
actually calculated (due to duplicate captures as in the example above,
or variables present), the is_args flag was set and incorrectly copied
after length calculation. This resulted in escaping applied to the uri part
of the replacement, resulting in incorrect escaping. Additionally, buffer
was allocated without escaping expected, thus this also resulted in buffer
overrun and possible segfault.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 04 Jun 2012 11:07:19 +0000 |
parents | d620f497c50f |
children | 8f74cf107137 |
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> #define NGX_HTTP_REFERER_NO_URI_PART ((void *) 4) #if !(NGX_PCRE) #define ngx_regex_t void #endif typedef struct { ngx_hash_combined_t hash; #if (NGX_PCRE) ngx_array_t *regex; #endif ngx_flag_t no_referer; ngx_flag_t blocked_referer; ngx_hash_keys_arrays_t *keys; ngx_uint_t referer_hash_max_size; ngx_uint_t referer_hash_bucket_size; } ngx_http_referer_conf_t; static void * ngx_http_referer_create_conf(ngx_conf_t *cf); static char * ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_add_referer(ngx_conf_t *cf, ngx_hash_keys_arrays_t *keys, ngx_str_t *value, ngx_str_t *uri); static char *ngx_http_add_regex_referer(ngx_conf_t *cf, ngx_http_referer_conf_t *rlcf, ngx_str_t *name, ngx_regex_t *regex); static int ngx_libc_cdecl ngx_http_cmp_referer_wildcards(const void *one, const void *two); static ngx_command_t ngx_http_referer_commands[] = { { ngx_string("valid_referers"), NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_valid_referers, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("referer_hash_max_size"), NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_referer_conf_t, referer_hash_max_size), NULL }, { ngx_string("referer_hash_bucket_size"), NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_referer_conf_t, referer_hash_bucket_size), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_referer_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_referer_create_conf, /* create location configuration */ ngx_http_referer_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_referer_module = { NGX_MODULE_V1, &ngx_http_referer_module_ctx, /* module context */ ngx_http_referer_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_int_t ngx_http_referer_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { u_char *p, *ref, *last; size_t len; ngx_str_t *uri; ngx_uint_t i, key; ngx_http_referer_conf_t *rlcf; u_char buf[256]; rlcf = ngx_http_get_module_loc_conf(r, ngx_http_referer_module); if (rlcf->hash.hash.buckets == NULL && rlcf->hash.wc_head == NULL && rlcf->hash.wc_tail == NULL #if (NGX_PCRE) && rlcf->regex == NULL #endif ) { goto valid; } if (r->headers_in.referer == NULL) { if (rlcf->no_referer) { goto valid; } goto invalid; } len = r->headers_in.referer->value.len; ref = r->headers_in.referer->value.data; if (len >= sizeof("http://i.ru") - 1) { last = ref + len; if (ngx_strncasecmp(ref, (u_char *) "http://", 7) == 0) { ref += 7; goto valid_scheme; } else if (ngx_strncasecmp(ref, (u_char *) "https://", 8) == 0) { ref += 8; goto valid_scheme; } } if (rlcf->blocked_referer) { goto valid; } goto invalid; valid_scheme: i = 0; key = 0; for (p = ref; p < last; p++) { if (*p == '/' || *p == ':') { break; } buf[i] = ngx_tolower(*p); key = ngx_hash(key, buf[i++]); if (i == 256) { goto invalid; } } uri = ngx_hash_find_combined(&rlcf->hash, key, buf, p - ref); if (uri) { goto uri; } #if (NGX_PCRE) if (rlcf->regex) { ngx_int_t rc; ngx_str_t referer; referer.len = len - 7; referer.data = ref; rc = ngx_regex_exec_array(rlcf->regex, &referer, r->connection->log); if (rc == NGX_OK) { goto valid; } if (rc == NGX_ERROR) { return rc; } /* NGX_DECLINED */ } #endif invalid: *v = ngx_http_variable_true_value; return NGX_OK; uri: for ( /* void */ ; p < last; p++) { if (*p == '/') { break; } } len = last - p; if (uri == NGX_HTTP_REFERER_NO_URI_PART) { goto valid; } if (len < uri->len || ngx_strncmp(uri->data, p, uri->len) != 0) { goto invalid; } valid: *v = ngx_http_variable_null_value; return NGX_OK; } static void * ngx_http_referer_create_conf(ngx_conf_t *cf) { ngx_http_referer_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_referer_conf_t)); if (conf == NULL) { return NULL; } #if (NGX_PCRE) conf->regex = NGX_CONF_UNSET_PTR; #endif conf->no_referer = NGX_CONF_UNSET; conf->blocked_referer = NGX_CONF_UNSET; conf->referer_hash_max_size = NGX_CONF_UNSET_UINT; conf->referer_hash_bucket_size = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_referer_conf_t *prev = parent; ngx_http_referer_conf_t *conf = child; ngx_hash_init_t hash; if (conf->keys == NULL) { conf->hash = prev->hash; #if (NGX_PCRE) ngx_conf_merge_ptr_value(conf->regex, prev->regex, NULL); #endif ngx_conf_merge_value(conf->no_referer, prev->no_referer, 0); ngx_conf_merge_value(conf->blocked_referer, prev->blocked_referer, 0); ngx_conf_merge_uint_value(conf->referer_hash_max_size, prev->referer_hash_max_size, 2048); ngx_conf_merge_uint_value(conf->referer_hash_bucket_size, prev->referer_hash_bucket_size, 64); return NGX_CONF_OK; } if ((conf->no_referer == 1 || conf->blocked_referer == 1) && conf->keys->keys.nelts == 0 && conf->keys->dns_wc_head.nelts == 0 && conf->keys->dns_wc_tail.nelts == 0) { ngx_log_error(NGX_LOG_EMERG, cf->log, 0, "the \"none\" or \"blocked\" referers are specified " "in the \"valid_referers\" directive " "without any valid referer"); return NGX_CONF_ERROR; } ngx_conf_merge_uint_value(conf->referer_hash_max_size, prev->referer_hash_max_size, 2048); ngx_conf_merge_uint_value(conf->referer_hash_bucket_size, prev->referer_hash_bucket_size, 64); conf->referer_hash_bucket_size = ngx_align(conf->referer_hash_bucket_size, ngx_cacheline_size); hash.key = ngx_hash_key_lc; hash.max_size = conf->referer_hash_max_size; hash.bucket_size = conf->referer_hash_bucket_size; hash.name = "referer_hash"; hash.pool = cf->pool; if (conf->keys->keys.nelts) { hash.hash = &conf->hash.hash; hash.temp_pool = NULL; if (ngx_hash_init(&hash, conf->keys->keys.elts, conf->keys->keys.nelts) != NGX_OK) { return NGX_CONF_ERROR; } } if (conf->keys->dns_wc_head.nelts) { ngx_qsort(conf->keys->dns_wc_head.elts, (size_t) conf->keys->dns_wc_head.nelts, sizeof(ngx_hash_key_t), ngx_http_cmp_referer_wildcards); hash.hash = NULL; hash.temp_pool = cf->temp_pool; if (ngx_hash_wildcard_init(&hash, conf->keys->dns_wc_head.elts, conf->keys->dns_wc_head.nelts) != NGX_OK) { return NGX_CONF_ERROR; } conf->hash.wc_head = (ngx_hash_wildcard_t *) hash.hash; } if (conf->keys->dns_wc_tail.nelts) { ngx_qsort(conf->keys->dns_wc_tail.elts, (size_t) conf->keys->dns_wc_tail.nelts, sizeof(ngx_hash_key_t), ngx_http_cmp_referer_wildcards); hash.hash = NULL; hash.temp_pool = cf->temp_pool; if (ngx_hash_wildcard_init(&hash, conf->keys->dns_wc_tail.elts, conf->keys->dns_wc_tail.nelts) != NGX_OK) { return NGX_CONF_ERROR; } conf->hash.wc_tail = (ngx_hash_wildcard_t *) hash.hash; } #if (NGX_PCRE) ngx_conf_merge_ptr_value(conf->regex, prev->regex, NULL); #endif if (conf->no_referer == NGX_CONF_UNSET) { conf->no_referer = 0; } if (conf->blocked_referer == NGX_CONF_UNSET) { conf->blocked_referer = 0; } conf->keys = NULL; return NGX_CONF_OK; } static char * ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_referer_conf_t *rlcf = conf; u_char *p; ngx_str_t *value, uri, name; ngx_uint_t i, n; ngx_http_variable_t *var; ngx_http_server_name_t *sn; ngx_http_core_srv_conf_t *cscf; ngx_str_set(&name, "invalid_referer"); var = ngx_http_add_variable(cf, &name, NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOHASH); if (var == NULL) { return NGX_CONF_ERROR; } var->get_handler = ngx_http_referer_variable; if (rlcf->keys == NULL) { rlcf->keys = ngx_pcalloc(cf->temp_pool, sizeof(ngx_hash_keys_arrays_t)); if (rlcf->keys == NULL) { return NGX_CONF_ERROR; } rlcf->keys->pool = cf->pool; rlcf->keys->temp_pool = cf->pool; if (ngx_hash_keys_array_init(rlcf->keys, NGX_HASH_SMALL) != NGX_OK) { return NGX_CONF_ERROR; } } value = cf->args->elts; for (i = 1; i < cf->args->nelts; i++) { if (value[i].len == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid referer \"%V\"", &value[i]); return NGX_CONF_ERROR; } if (ngx_strcmp(value[i].data, "none") == 0) { rlcf->no_referer = 1; continue; } if (ngx_strcmp(value[i].data, "blocked") == 0) { rlcf->blocked_referer = 1; continue; } ngx_str_null(&uri); if (ngx_strcmp(value[i].data, "server_names") == 0) { cscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_core_module); sn = cscf->server_names.elts; for (n = 0; n < cscf->server_names.nelts; n++) { #if (NGX_PCRE) if (sn[n].regex) { if (ngx_http_add_regex_referer(cf, rlcf, &sn[n].name, sn[n].regex->regex) != NGX_OK) { return NGX_CONF_ERROR; } continue; } #endif if (ngx_http_add_referer(cf, rlcf->keys, &sn[n].name, &uri) != NGX_OK) { return NGX_CONF_ERROR; } } continue; } if (value[i].data[0] == '~') { if (ngx_http_add_regex_referer(cf, rlcf, &value[i], NULL) != NGX_OK) { return NGX_CONF_ERROR; } continue; } p = (u_char *) ngx_strchr(value[i].data, '/'); if (p) { uri.len = (value[i].data + value[i].len) - p; uri.data = p; value[i].len = p - value[i].data; } if (ngx_http_add_referer(cf, rlcf->keys, &value[i], &uri) != NGX_OK) { return NGX_CONF_ERROR; } } return NGX_CONF_OK; } static char * ngx_http_add_referer(ngx_conf_t *cf, ngx_hash_keys_arrays_t *keys, ngx_str_t *value, ngx_str_t *uri) { ngx_int_t rc; ngx_str_t *u; if (uri->len == 0) { u = NGX_HTTP_REFERER_NO_URI_PART; } else { u = ngx_palloc(cf->pool, sizeof(ngx_str_t)); if (u == NULL) { return NGX_CONF_ERROR; } *u = *uri; } rc = ngx_hash_add_key(keys, value, u, NGX_HASH_WILDCARD_KEY); if (rc == NGX_OK) { return NGX_CONF_OK; } if (rc == NGX_DECLINED) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid hostname or wildcard \"%V\"", value); } if (rc == NGX_BUSY) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "conflicting parameter \"%V\"", value); } return NGX_CONF_ERROR; } static char * ngx_http_add_regex_referer(ngx_conf_t *cf, ngx_http_referer_conf_t *rlcf, ngx_str_t *name, ngx_regex_t *regex) { #if (NGX_PCRE) ngx_regex_elt_t *re; ngx_regex_compile_t rc; u_char errstr[NGX_MAX_CONF_ERRSTR]; if (name->len == 1) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty regex in \"%V\"", name); return NGX_CONF_ERROR; } if (rlcf->regex == NGX_CONF_UNSET_PTR) { rlcf->regex = ngx_array_create(cf->pool, 2, sizeof(ngx_regex_elt_t)); if (rlcf->regex == NULL) { return NGX_CONF_ERROR; } } re = ngx_array_push(rlcf->regex); if (re == NULL) { return NGX_CONF_ERROR; } if (regex) { re->regex = regex; re->name = name->data; return NGX_CONF_OK; } name->len--; name->data++; ngx_memzero(&rc, sizeof(ngx_regex_compile_t)); rc.pattern = *name; rc.pool = cf->pool; rc.options = NGX_REGEX_CASELESS; rc.err.len = NGX_MAX_CONF_ERRSTR; rc.err.data = errstr; if (ngx_regex_compile(&rc) != NGX_OK) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V", &rc.err); return NGX_CONF_ERROR; } re->regex = rc.regex; re->name = name->data; return NGX_CONF_OK; #else ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "the using of the regex \"%V\" requires PCRE library", name); return NGX_CONF_ERROR; #endif } static int ngx_libc_cdecl ngx_http_cmp_referer_wildcards(const void *one, const void *two) { ngx_hash_key_t *first, *second; first = (ngx_hash_key_t *) one; second = (ngx_hash_key_t *) two; return ngx_dns_strcmp(first->key.data, second->key.data); }