Mercurial > hg > nginx
view src/http/modules/ngx_http_upstream_hash_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 | 29bf0dbc0a77 |
children | 6c52b24fcf8e |
line wrap: on
line source
/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { uint32_t hash; ngx_str_t *server; } ngx_http_upstream_chash_point_t; typedef struct { ngx_uint_t number; ngx_http_upstream_chash_point_t point[1]; } ngx_http_upstream_chash_points_t; typedef struct { ngx_http_complex_value_t key; ngx_http_upstream_chash_points_t *points; } ngx_http_upstream_hash_srv_conf_t; typedef struct { /* the round robin data must be first */ ngx_http_upstream_rr_peer_data_t rrp; ngx_http_upstream_hash_srv_conf_t *conf; ngx_str_t key; ngx_uint_t tries; ngx_uint_t rehash; uint32_t hash; ngx_event_get_peer_pt get_rr_peer; } ngx_http_upstream_hash_peer_data_t; static ngx_int_t ngx_http_upstream_init_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data); static ngx_int_t ngx_http_upstream_init_chash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static int ngx_libc_cdecl ngx_http_upstream_chash_cmp_points(const void *one, const void *two); static ngx_uint_t ngx_http_upstream_find_chash_point( ngx_http_upstream_chash_points_t *points, uint32_t hash); static ngx_int_t ngx_http_upstream_init_chash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data); static void *ngx_http_upstream_hash_create_conf(ngx_conf_t *cf); static char *ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_upstream_hash_commands[] = { { ngx_string("hash"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE12, ngx_http_upstream_hash, NGX_HTTP_SRV_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_hash_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_http_upstream_hash_create_conf, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_upstream_hash_module = { NGX_MODULE_V1, &ngx_http_upstream_hash_module_ctx, /* module context */ ngx_http_upstream_hash_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_upstream_init_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_hash_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { ngx_http_upstream_hash_srv_conf_t *hcf; ngx_http_upstream_hash_peer_data_t *hp; hp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_hash_peer_data_t)); if (hp == NULL) { return NGX_ERROR; } r->upstream->peer.data = &hp->rrp; if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) { return NGX_ERROR; } r->upstream->peer.get = ngx_http_upstream_get_hash_peer; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); if (ngx_http_complex_value(r, &hcf->key, &hp->key) != NGX_OK) { return NGX_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "upstream hash key:\"%V\"", &hp->key); hp->conf = hcf; hp->tries = 0; hp->rehash = 0; hp->hash = 0; hp->get_rr_peer = ngx_http_upstream_get_round_robin_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_hash_peer_data_t *hp = data; time_t now; u_char buf[NGX_INT_T_LEN]; size_t size; uint32_t hash; ngx_int_t w; uintptr_t m; ngx_uint_t n, p; ngx_http_upstream_rr_peer_t *peer; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get hash peer, try: %ui", pc->tries); ngx_http_upstream_rr_peers_wlock(hp->rrp.peers); if (hp->tries > 20 || hp->rrp.peers->single) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } now = ngx_time(); pc->cached = 0; pc->connection = NULL; for ( ;; ) { /* * Hash expression is compatible with Cache::Memcached: * ((crc32([REHASH] KEY) >> 16) & 0x7fff) + PREV_HASH * with REHASH omitted at the first iteration. */ ngx_crc32_init(hash); if (hp->rehash > 0) { size = ngx_sprintf(buf, "%ui", hp->rehash) - buf; ngx_crc32_update(&hash, buf, size); } ngx_crc32_update(&hash, hp->key.data, hp->key.len); ngx_crc32_final(hash); hash = (hash >> 16) & 0x7fff; hp->hash += hash; hp->rehash++; w = hp->hash % hp->rrp.peers->total_weight; peer = hp->rrp.peers->peer; p = 0; while (w >= peer->weight) { w -= peer->weight; peer = peer->next; p++; } n = p / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); if (hp->rrp.tried[n] & m) { goto next; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get hash peer, value:%uD, peer:%ui", hp->hash, p); if (peer->down) { goto next; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { goto next; } if (peer->max_conns && peer->conns >= peer->max_conns) { goto next; } break; next: if (++hp->tries > 20) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } } hp->rrp.current = peer; pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; peer->conns++; if (now - peer->checked > peer->fail_timeout) { peer->checked = now; } ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); hp->rrp.tried[n] |= m; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_chash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { u_char *host, *port, c; size_t host_len, port_len, size; uint32_t hash, base_hash; ngx_str_t *server; ngx_uint_t npoints, i, j; ngx_http_upstream_rr_peer_t *peer; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_chash_points_t *points; ngx_http_upstream_hash_srv_conf_t *hcf; union { uint32_t value; u_char byte[4]; } prev_hash; if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_chash_peer; peers = us->peer.data; npoints = peers->total_weight * 160; size = sizeof(ngx_http_upstream_chash_points_t) + sizeof(ngx_http_upstream_chash_point_t) * (npoints - 1); points = ngx_palloc(cf->pool, size); if (points == NULL) { return NGX_ERROR; } points->number = 0; for (peer = peers->peer; peer; peer = peer->next) { server = &peer->server; /* * Hash expression is compatible with Cache::Memcached::Fast: * crc32(HOST \0 PORT PREV_HASH). */ if (server->len >= 5 && ngx_strncasecmp(server->data, (u_char *) "unix:", 5) == 0) { host = server->data + 5; host_len = server->len - 5; port = NULL; port_len = 0; goto done; } for (j = 0; j < server->len; j++) { c = server->data[server->len - j - 1]; if (c == ':') { host = server->data; host_len = server->len - j - 1; port = server->data + server->len - j; port_len = j; goto done; } if (c < '0' || c > '9') { break; } } host = server->data; host_len = server->len; port = NULL; port_len = 0; done: ngx_crc32_init(base_hash); ngx_crc32_update(&base_hash, host, host_len); ngx_crc32_update(&base_hash, (u_char *) "", 1); ngx_crc32_update(&base_hash, port, port_len); prev_hash.value = 0; npoints = peer->weight * 160; for (j = 0; j < npoints; j++) { hash = base_hash; ngx_crc32_update(&hash, prev_hash.byte, 4); ngx_crc32_final(hash); points->point[points->number].hash = hash; points->point[points->number].server = server; points->number++; #if (NGX_HAVE_LITTLE_ENDIAN) prev_hash.value = hash; #else prev_hash.byte[0] = (u_char) (hash & 0xff); prev_hash.byte[1] = (u_char) ((hash >> 8) & 0xff); prev_hash.byte[2] = (u_char) ((hash >> 16) & 0xff); prev_hash.byte[3] = (u_char) ((hash >> 24) & 0xff); #endif } } ngx_qsort(points->point, points->number, sizeof(ngx_http_upstream_chash_point_t), ngx_http_upstream_chash_cmp_points); for (i = 0, j = 1; j < points->number; j++) { if (points->point[i].hash != points->point[j].hash) { points->point[++i] = points->point[j]; } } points->number = i + 1; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); hcf->points = points; return NGX_OK; } static int ngx_libc_cdecl ngx_http_upstream_chash_cmp_points(const void *one, const void *two) { ngx_http_upstream_chash_point_t *first = (ngx_http_upstream_chash_point_t *) one; ngx_http_upstream_chash_point_t *second = (ngx_http_upstream_chash_point_t *) two; if (first->hash < second->hash) { return -1; } else if (first->hash > second->hash) { return 1; } else { return 0; } } static ngx_uint_t ngx_http_upstream_find_chash_point(ngx_http_upstream_chash_points_t *points, uint32_t hash) { ngx_uint_t i, j, k; ngx_http_upstream_chash_point_t *point; /* find first point >= hash */ point = &points->point[0]; i = 0; j = points->number; while (i < j) { k = (i + j) / 2; if (hash > point[k].hash) { i = k + 1; } else if (hash < point[k].hash) { j = k; } else { return k; } } return i; } static ngx_int_t ngx_http_upstream_init_chash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { uint32_t hash; ngx_http_upstream_hash_srv_conf_t *hcf; ngx_http_upstream_hash_peer_data_t *hp; if (ngx_http_upstream_init_hash_peer(r, us) != NGX_OK) { return NGX_ERROR; } r->upstream->peer.get = ngx_http_upstream_get_chash_peer; hp = r->upstream->peer.data; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); hash = ngx_crc32_long(hp->key.data, hp->key.len); ngx_http_upstream_rr_peers_rlock(hp->rrp.peers); hp->hash = ngx_http_upstream_find_chash_point(hcf->points, hash); ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return NGX_OK; } static ngx_int_t ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_hash_peer_data_t *hp = data; time_t now; intptr_t m; ngx_str_t *server; ngx_int_t total; ngx_uint_t i, n, best_i; ngx_http_upstream_rr_peer_t *peer, *best; ngx_http_upstream_chash_point_t *point; ngx_http_upstream_chash_points_t *points; ngx_http_upstream_hash_srv_conf_t *hcf; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get consistent hash peer, try: %ui", pc->tries); ngx_http_upstream_rr_peers_wlock(hp->rrp.peers); pc->cached = 0; pc->connection = NULL; now = ngx_time(); hcf = hp->conf; points = hcf->points; point = &points->point[0]; for ( ;; ) { server = point[hp->hash % points->number].server; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "consistent hash peer:%uD, server:\"%V\"", hp->hash, server); best = NULL; best_i = 0; total = 0; for (peer = hp->rrp.peers->peer, i = 0; peer; peer = peer->next, i++) { n = i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); if (hp->rrp.tried[n] & m) { continue; } if (peer->down) { continue; } if (peer->server.len != server->len || ngx_strncmp(peer->server.data, server->data, server->len) != 0) { continue; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { continue; } if (peer->max_conns && peer->conns >= peer->max_conns) { continue; } peer->current_weight += peer->effective_weight; total += peer->effective_weight; if (peer->effective_weight < peer->weight) { peer->effective_weight++; } if (best == NULL || peer->current_weight > best->current_weight) { best = peer; best_i = i; } } if (best) { best->current_weight -= total; goto found; } hp->hash++; hp->tries++; if (hp->tries >= points->number) { pc->name = hp->rrp.peers->name; ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return NGX_BUSY; } } found: hp->rrp.current = best; pc->sockaddr = best->sockaddr; pc->socklen = best->socklen; pc->name = &best->name; best->conns++; if (now - best->checked > best->fail_timeout) { best->checked = now; } ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); n = best_i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << best_i % (8 * sizeof(uintptr_t)); hp->rrp.tried[n] |= m; return NGX_OK; } static void * ngx_http_upstream_hash_create_conf(ngx_conf_t *cf) { ngx_http_upstream_hash_srv_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_upstream_hash_srv_conf_t)); if (conf == NULL) { return NULL; } conf->points = NULL; return conf; } static char * ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_upstream_hash_srv_conf_t *hcf = conf; ngx_str_t *value; ngx_http_upstream_srv_conf_t *uscf; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &hcf->key; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module); if (uscf->peer.init_upstream) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "load balancing method redefined"); } uscf->flags = NGX_HTTP_UPSTREAM_CREATE |NGX_HTTP_UPSTREAM_WEIGHT |NGX_HTTP_UPSTREAM_MAX_CONNS |NGX_HTTP_UPSTREAM_MAX_FAILS |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT |NGX_HTTP_UPSTREAM_DOWN; if (cf->args->nelts == 2) { uscf->peer.init_upstream = ngx_http_upstream_init_hash; } else if (ngx_strcmp(value[2].data, "consistent") == 0) { uscf->peer.init_upstream = ngx_http_upstream_init_chash; } else { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[2]); return NGX_CONF_ERROR; } return NGX_CONF_OK; }