Mercurial > hg > nginx
view src/http/modules/ngx_http_map_module.c @ 7054:e02555553d0b
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | ec10ce307dc0 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_uint_t hash_max_size; ngx_uint_t hash_bucket_size; } ngx_http_map_conf_t; typedef struct { ngx_hash_keys_arrays_t keys; ngx_array_t *values_hash; #if (NGX_PCRE) ngx_array_t regexes; #endif ngx_http_variable_value_t *default_value; ngx_conf_t *cf; unsigned hostnames:1; unsigned no_cacheable:1; } ngx_http_map_conf_ctx_t; typedef struct { ngx_http_map_t map; ngx_http_complex_value_t value; ngx_http_variable_value_t *default_value; ngx_uint_t hostnames; /* unsigned hostnames:1 */ } ngx_http_map_ctx_t; static int ngx_libc_cdecl ngx_http_map_cmp_dns_wildcards(const void *one, const void *two); static void *ngx_http_map_create_conf(ngx_conf_t *cf); static char *ngx_http_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf); static ngx_command_t ngx_http_map_commands[] = { { ngx_string("map"), NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2, ngx_http_map_block, NGX_HTTP_MAIN_CONF_OFFSET, 0, NULL }, { ngx_string("map_hash_max_size"), NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_MAIN_CONF_OFFSET, offsetof(ngx_http_map_conf_t, hash_max_size), NULL }, { ngx_string("map_hash_bucket_size"), NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_MAIN_CONF_OFFSET, offsetof(ngx_http_map_conf_t, hash_bucket_size), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_map_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ ngx_http_map_create_conf, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_map_module = { NGX_MODULE_V1, &ngx_http_map_module_ctx, /* module context */ ngx_http_map_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_map_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { ngx_http_map_ctx_t *map = (ngx_http_map_ctx_t *) data; ngx_str_t val, str; ngx_http_complex_value_t *cv; ngx_http_variable_value_t *value; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http map started"); if (ngx_http_complex_value(r, &map->value, &val) != NGX_OK) { return NGX_ERROR; } if (map->hostnames && val.len > 0 && val.data[val.len - 1] == '.') { val.len--; } value = ngx_http_map_find(r, &map->map, &val); if (value == NULL) { value = map->default_value; } if (!value->valid) { cv = (ngx_http_complex_value_t *) value->data; if (ngx_http_complex_value(r, cv, &str) != NGX_OK) { return NGX_ERROR; } v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->len = str.len; v->data = str.data; } else { *v = *value; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http map: \"%V\" \"%v\"", &val, v); return NGX_OK; } static void * ngx_http_map_create_conf(ngx_conf_t *cf) { ngx_http_map_conf_t *mcf; mcf = ngx_palloc(cf->pool, sizeof(ngx_http_map_conf_t)); if (mcf == NULL) { return NULL; } mcf->hash_max_size = NGX_CONF_UNSET_UINT; mcf->hash_bucket_size = NGX_CONF_UNSET_UINT; return mcf; } static char * ngx_http_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_map_conf_t *mcf = conf; char *rv; ngx_str_t *value, name; ngx_conf_t save; ngx_pool_t *pool; ngx_hash_init_t hash; ngx_http_map_ctx_t *map; ngx_http_variable_t *var; ngx_http_map_conf_ctx_t ctx; ngx_http_compile_complex_value_t ccv; if (mcf->hash_max_size == NGX_CONF_UNSET_UINT) { mcf->hash_max_size = 2048; } if (mcf->hash_bucket_size == NGX_CONF_UNSET_UINT) { mcf->hash_bucket_size = ngx_cacheline_size; } else { mcf->hash_bucket_size = ngx_align(mcf->hash_bucket_size, ngx_cacheline_size); } map = ngx_pcalloc(cf->pool, sizeof(ngx_http_map_ctx_t)); if (map == NULL) { return NGX_CONF_ERROR; } value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &map->value; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } name = value[2]; if (name.data[0] != '$') { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid variable name \"%V\"", &name); return NGX_CONF_ERROR; } name.len--; name.data++; var = ngx_http_add_variable(cf, &name, NGX_HTTP_VAR_CHANGEABLE); if (var == NULL) { return NGX_CONF_ERROR; } var->get_handler = ngx_http_map_variable; var->data = (uintptr_t) map; pool = ngx_create_pool(NGX_DEFAULT_POOL_SIZE, cf->log); if (pool == NULL) { return NGX_CONF_ERROR; } ctx.keys.pool = cf->pool; ctx.keys.temp_pool = pool; if (ngx_hash_keys_array_init(&ctx.keys, NGX_HASH_LARGE) != NGX_OK) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } ctx.values_hash = ngx_pcalloc(pool, sizeof(ngx_array_t) * ctx.keys.hsize); if (ctx.values_hash == NULL) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } #if (NGX_PCRE) if (ngx_array_init(&ctx.regexes, cf->pool, 2, sizeof(ngx_http_map_regex_t)) != NGX_OK) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } #endif ctx.default_value = NULL; ctx.cf = &save; ctx.hostnames = 0; ctx.no_cacheable = 0; save = *cf; cf->pool = pool; cf->ctx = &ctx; cf->handler = ngx_http_map; cf->handler_conf = conf; rv = ngx_conf_parse(cf, NULL); *cf = save; if (rv != NGX_CONF_OK) { ngx_destroy_pool(pool); return rv; } if (ctx.no_cacheable) { var->flags |= NGX_HTTP_VAR_NOCACHEABLE; } map->default_value = ctx.default_value ? ctx.default_value: &ngx_http_variable_null_value; map->hostnames = ctx.hostnames; hash.key = ngx_hash_key_lc; hash.max_size = mcf->hash_max_size; hash.bucket_size = mcf->hash_bucket_size; hash.name = "map_hash"; hash.pool = cf->pool; if (ctx.keys.keys.nelts) { hash.hash = &map->map.hash.hash; hash.temp_pool = NULL; if (ngx_hash_init(&hash, ctx.keys.keys.elts, ctx.keys.keys.nelts) != NGX_OK) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } } if (ctx.keys.dns_wc_head.nelts) { ngx_qsort(ctx.keys.dns_wc_head.elts, (size_t) ctx.keys.dns_wc_head.nelts, sizeof(ngx_hash_key_t), ngx_http_map_cmp_dns_wildcards); hash.hash = NULL; hash.temp_pool = pool; if (ngx_hash_wildcard_init(&hash, ctx.keys.dns_wc_head.elts, ctx.keys.dns_wc_head.nelts) != NGX_OK) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } map->map.hash.wc_head = (ngx_hash_wildcard_t *) hash.hash; } if (ctx.keys.dns_wc_tail.nelts) { ngx_qsort(ctx.keys.dns_wc_tail.elts, (size_t) ctx.keys.dns_wc_tail.nelts, sizeof(ngx_hash_key_t), ngx_http_map_cmp_dns_wildcards); hash.hash = NULL; hash.temp_pool = pool; if (ngx_hash_wildcard_init(&hash, ctx.keys.dns_wc_tail.elts, ctx.keys.dns_wc_tail.nelts) != NGX_OK) { ngx_destroy_pool(pool); return NGX_CONF_ERROR; } map->map.hash.wc_tail = (ngx_hash_wildcard_t *) hash.hash; } #if (NGX_PCRE) if (ctx.regexes.nelts) { map->map.regex = ctx.regexes.elts; map->map.nregex = ctx.regexes.nelts; } #endif ngx_destroy_pool(pool); return rv; } static int ngx_libc_cdecl ngx_http_map_cmp_dns_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); } static char * ngx_http_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf) { u_char *data; size_t len; ngx_int_t rv; ngx_str_t *value, v; ngx_uint_t i, key; ngx_http_map_conf_ctx_t *ctx; ngx_http_complex_value_t cv, *cvp; ngx_http_variable_value_t *var, **vp; ngx_http_compile_complex_value_t ccv; ctx = cf->ctx; value = cf->args->elts; if (cf->args->nelts == 1 && ngx_strcmp(value[0].data, "hostnames") == 0) { ctx->hostnames = 1; return NGX_CONF_OK; } if (cf->args->nelts == 1 && ngx_strcmp(value[0].data, "volatile") == 0) { ctx->no_cacheable = 1; return NGX_CONF_OK; } if (cf->args->nelts != 2) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid number of the map parameters"); return NGX_CONF_ERROR; } if (ngx_strcmp(value[0].data, "include") == 0) { return ngx_conf_include(cf, dummy, conf); } key = 0; for (i = 0; i < value[1].len; i++) { key = ngx_hash(key, value[1].data[i]); } key %= ctx->keys.hsize; vp = ctx->values_hash[key].elts; if (vp) { for (i = 0; i < ctx->values_hash[key].nelts; i++) { if (vp[i]->valid) { data = vp[i]->data; len = vp[i]->len; } else { cvp = (ngx_http_complex_value_t *) vp[i]->data; data = cvp->value.data; len = cvp->value.len; } if (value[1].len != len) { continue; } if (ngx_strncmp(value[1].data, data, len) == 0) { var = vp[i]; goto found; } } } else { if (ngx_array_init(&ctx->values_hash[key], cf->pool, 4, sizeof(ngx_http_variable_value_t *)) != NGX_OK) { return NGX_CONF_ERROR; } } var = ngx_palloc(ctx->keys.pool, sizeof(ngx_http_variable_value_t)); if (var == NULL) { return NGX_CONF_ERROR; } v.len = value[1].len; v.data = ngx_pstrdup(ctx->keys.pool, &value[1]); if (v.data == NULL) { return NGX_CONF_ERROR; } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = ctx->cf; ccv.value = &v; ccv.complex_value = &cv; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } if (cv.lengths != NULL) { cvp = ngx_palloc(ctx->keys.pool, sizeof(ngx_http_complex_value_t)); if (cvp == NULL) { return NGX_CONF_ERROR; } *cvp = cv; var->len = 0; var->data = (u_char *) cvp; var->valid = 0; } else { var->len = v.len; var->data = v.data; var->valid = 1; } var->no_cacheable = 0; var->not_found = 0; vp = ngx_array_push(&ctx->values_hash[key]); if (vp == NULL) { return NGX_CONF_ERROR; } *vp = var; found: if (ngx_strcmp(value[0].data, "default") == 0) { if (ctx->default_value) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate default map parameter"); return NGX_CONF_ERROR; } ctx->default_value = var; return NGX_CONF_OK; } #if (NGX_PCRE) if (value[0].len && value[0].data[0] == '~') { ngx_regex_compile_t rc; ngx_http_map_regex_t *regex; u_char errstr[NGX_MAX_CONF_ERRSTR]; regex = ngx_array_push(&ctx->regexes); if (regex == NULL) { return NGX_CONF_ERROR; } value[0].len--; value[0].data++; ngx_memzero(&rc, sizeof(ngx_regex_compile_t)); if (value[0].data[0] == '*') { value[0].len--; value[0].data++; rc.options = NGX_REGEX_CASELESS; } rc.pattern = value[0]; rc.err.len = NGX_MAX_CONF_ERRSTR; rc.err.data = errstr; regex->regex = ngx_http_regex_compile(ctx->cf, &rc); if (regex->regex == NULL) { return NGX_CONF_ERROR; } regex->value = var; return NGX_CONF_OK; } #endif if (value[0].len && value[0].data[0] == '\\') { value[0].len--; value[0].data++; } rv = ngx_hash_add_key(&ctx->keys, &value[0], var, (ctx->hostnames) ? NGX_HASH_WILDCARD_KEY : 0); if (rv == NGX_OK) { return NGX_CONF_OK; } if (rv == NGX_DECLINED) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid hostname or wildcard \"%V\"", &value[0]); } if (rv == NGX_BUSY) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "conflicting parameter \"%V\"", &value[0]); } return NGX_CONF_ERROR; }