Mercurial > hg > nginx
view src/http/modules/ngx_http_upstream_zone_module.c @ 7060:1adc6b0d5eaa stable-1.12
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 | 341e4303d25b |
children | 1eb753aa8e5e |
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/* * Copyright (C) Ruslan Ermilov * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static char *ngx_http_upstream_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_http_upstream_init_zone(ngx_shm_zone_t *shm_zone, void *data); static ngx_http_upstream_rr_peers_t *ngx_http_upstream_zone_copy_peers( ngx_slab_pool_t *shpool, ngx_http_upstream_srv_conf_t *uscf); static ngx_command_t ngx_http_upstream_zone_commands[] = { { ngx_string("zone"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE12, ngx_http_upstream_zone, 0, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_zone_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* 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_upstream_zone_module = { NGX_MODULE_V1, &ngx_http_upstream_zone_module_ctx, /* module context */ ngx_http_upstream_zone_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 char * ngx_http_upstream_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ssize_t size; ngx_str_t *value; ngx_http_upstream_srv_conf_t *uscf; ngx_http_upstream_main_conf_t *umcf; uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module); umcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_upstream_module); value = cf->args->elts; if (!value[1].len) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone name \"%V\"", &value[1]); return NGX_CONF_ERROR; } if (cf->args->nelts == 3) { size = ngx_parse_size(&value[2]); if (size == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone size \"%V\"", &value[2]); return NGX_CONF_ERROR; } if (size < (ssize_t) (8 * ngx_pagesize)) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "zone \"%V\" is too small", &value[1]); return NGX_CONF_ERROR; } } else { size = 0; } uscf->shm_zone = ngx_shared_memory_add(cf, &value[1], size, &ngx_http_upstream_module); if (uscf->shm_zone == NULL) { return NGX_CONF_ERROR; } uscf->shm_zone->init = ngx_http_upstream_init_zone; uscf->shm_zone->data = umcf; uscf->shm_zone->noreuse = 1; return NGX_CONF_OK; } static ngx_int_t ngx_http_upstream_init_zone(ngx_shm_zone_t *shm_zone, void *data) { size_t len; ngx_uint_t i; ngx_slab_pool_t *shpool; ngx_http_upstream_rr_peers_t *peers, **peersp; ngx_http_upstream_srv_conf_t *uscf, **uscfp; ngx_http_upstream_main_conf_t *umcf; shpool = (ngx_slab_pool_t *) shm_zone->shm.addr; umcf = shm_zone->data; uscfp = umcf->upstreams.elts; if (shm_zone->shm.exists) { peers = shpool->data; for (i = 0; i < umcf->upstreams.nelts; i++) { uscf = uscfp[i]; if (uscf->shm_zone != shm_zone) { continue; } uscf->peer.data = peers; peers = peers->zone_next; } return NGX_OK; } len = sizeof(" in upstream zone \"\"") + shm_zone->shm.name.len; shpool->log_ctx = ngx_slab_alloc(shpool, len); if (shpool->log_ctx == NULL) { return NGX_ERROR; } ngx_sprintf(shpool->log_ctx, " in upstream zone \"%V\"%Z", &shm_zone->shm.name); /* copy peers to shared memory */ peersp = (ngx_http_upstream_rr_peers_t **) (void *) &shpool->data; for (i = 0; i < umcf->upstreams.nelts; i++) { uscf = uscfp[i]; if (uscf->shm_zone != shm_zone) { continue; } peers = ngx_http_upstream_zone_copy_peers(shpool, uscf); if (peers == NULL) { return NGX_ERROR; } *peersp = peers; peersp = &peers->zone_next; } return NGX_OK; } static ngx_http_upstream_rr_peers_t * ngx_http_upstream_zone_copy_peers(ngx_slab_pool_t *shpool, ngx_http_upstream_srv_conf_t *uscf) { ngx_http_upstream_rr_peer_t *peer, **peerp; ngx_http_upstream_rr_peers_t *peers, *backup; peers = ngx_slab_alloc(shpool, sizeof(ngx_http_upstream_rr_peers_t)); if (peers == NULL) { return NULL; } ngx_memcpy(peers, uscf->peer.data, sizeof(ngx_http_upstream_rr_peers_t)); peers->shpool = shpool; for (peerp = &peers->peer; *peerp; peerp = &peer->next) { /* pool is unlocked */ peer = ngx_slab_calloc_locked(shpool, sizeof(ngx_http_upstream_rr_peer_t)); if (peer == NULL) { return NULL; } ngx_memcpy(peer, *peerp, sizeof(ngx_http_upstream_rr_peer_t)); *peerp = peer; } if (peers->next == NULL) { goto done; } backup = ngx_slab_alloc(shpool, sizeof(ngx_http_upstream_rr_peers_t)); if (backup == NULL) { return NULL; } ngx_memcpy(backup, peers->next, sizeof(ngx_http_upstream_rr_peers_t)); backup->shpool = shpool; for (peerp = &backup->peer; *peerp; peerp = &peer->next) { /* pool is unlocked */ peer = ngx_slab_calloc_locked(shpool, sizeof(ngx_http_upstream_rr_peer_t)); if (peer == NULL) { return NULL; } ngx_memcpy(peer, *peerp, sizeof(ngx_http_upstream_rr_peer_t)); *peerp = peer; } peers->next = backup; done: uscf->peer.data = peers; return peers; }