Mercurial > hg > nginx
view src/http/modules/ngx_http_realip_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 | cecf415643d7 |
children | df1a62c83b1b |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #define NGX_HTTP_REALIP_XREALIP 0 #define NGX_HTTP_REALIP_XFWD 1 #define NGX_HTTP_REALIP_HEADER 2 #define NGX_HTTP_REALIP_PROXY 3 typedef struct { ngx_array_t *from; /* array of ngx_cidr_t */ ngx_uint_t type; ngx_uint_t hash; ngx_str_t header; ngx_flag_t recursive; } ngx_http_realip_loc_conf_t; typedef struct { ngx_connection_t *connection; struct sockaddr *sockaddr; socklen_t socklen; ngx_str_t addr_text; } ngx_http_realip_ctx_t; static ngx_int_t ngx_http_realip_handler(ngx_http_request_t *r); static ngx_int_t ngx_http_realip_set_addr(ngx_http_request_t *r, ngx_addr_t *addr); static void ngx_http_realip_cleanup(void *data); static char *ngx_http_realip_from(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_realip(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static void *ngx_http_realip_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_realip_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_realip_add_variables(ngx_conf_t *cf); static ngx_int_t ngx_http_realip_init(ngx_conf_t *cf); static ngx_http_realip_ctx_t *ngx_http_realip_get_module_ctx( ngx_http_request_t *r); static ngx_int_t ngx_http_realip_remote_addr_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_int_t ngx_http_realip_remote_port_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_command_t ngx_http_realip_commands[] = { { ngx_string("set_real_ip_from"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_realip_from, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("real_ip_header"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_realip, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("real_ip_recursive"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_realip_loc_conf_t, recursive), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_realip_module_ctx = { ngx_http_realip_add_variables, /* preconfiguration */ ngx_http_realip_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_realip_create_loc_conf, /* create location configuration */ ngx_http_realip_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_realip_module = { NGX_MODULE_V1, &ngx_http_realip_module_ctx, /* module context */ ngx_http_realip_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_http_variable_t ngx_http_realip_vars[] = { { ngx_string("realip_remote_addr"), NULL, ngx_http_realip_remote_addr_variable, 0, 0, 0 }, { ngx_string("realip_remote_port"), NULL, ngx_http_realip_remote_port_variable, 0, 0, 0 }, { ngx_null_string, NULL, NULL, 0, 0, 0 } }; static ngx_int_t ngx_http_realip_handler(ngx_http_request_t *r) { u_char *p; size_t len; ngx_str_t *value; ngx_uint_t i, hash; ngx_addr_t addr; ngx_array_t *xfwd; ngx_list_part_t *part; ngx_table_elt_t *header; ngx_connection_t *c; ngx_http_realip_ctx_t *ctx; ngx_http_realip_loc_conf_t *rlcf; rlcf = ngx_http_get_module_loc_conf(r, ngx_http_realip_module); if (rlcf->from == NULL) { return NGX_DECLINED; } ctx = ngx_http_realip_get_module_ctx(r); if (ctx) { return NGX_DECLINED; } switch (rlcf->type) { case NGX_HTTP_REALIP_XREALIP: if (r->headers_in.x_real_ip == NULL) { return NGX_DECLINED; } value = &r->headers_in.x_real_ip->value; xfwd = NULL; break; case NGX_HTTP_REALIP_XFWD: xfwd = &r->headers_in.x_forwarded_for; if (xfwd->elts == NULL) { return NGX_DECLINED; } value = NULL; break; case NGX_HTTP_REALIP_PROXY: value = &r->connection->proxy_protocol_addr; if (value->len == 0) { return NGX_DECLINED; } xfwd = NULL; break; default: /* NGX_HTTP_REALIP_HEADER */ part = &r->headers_in.headers.part; header = part->elts; hash = rlcf->hash; len = rlcf->header.len; p = rlcf->header.data; for (i = 0; /* void */ ; i++) { if (i >= part->nelts) { if (part->next == NULL) { break; } part = part->next; header = part->elts; i = 0; } if (hash == header[i].hash && len == header[i].key.len && ngx_strncmp(p, header[i].lowcase_key, len) == 0) { value = &header[i].value; xfwd = NULL; goto found; } } return NGX_DECLINED; } found: c = r->connection; addr.sockaddr = c->sockaddr; addr.socklen = c->socklen; /* addr.name = c->addr_text; */ if (ngx_http_get_forwarded_addr(r, &addr, xfwd, value, rlcf->from, rlcf->recursive) != NGX_DECLINED) { if (rlcf->type == NGX_HTTP_REALIP_PROXY) { ngx_inet_set_port(addr.sockaddr, c->proxy_protocol_port); } return ngx_http_realip_set_addr(r, &addr); } return NGX_DECLINED; } static ngx_int_t ngx_http_realip_set_addr(ngx_http_request_t *r, ngx_addr_t *addr) { size_t len; u_char *p; u_char text[NGX_SOCKADDR_STRLEN]; ngx_connection_t *c; ngx_pool_cleanup_t *cln; ngx_http_realip_ctx_t *ctx; cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_realip_ctx_t)); if (cln == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ctx = cln->data; c = r->connection; len = ngx_sock_ntop(addr->sockaddr, addr->socklen, text, NGX_SOCKADDR_STRLEN, 0); if (len == 0) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } p = ngx_pnalloc(c->pool, len); if (p == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_memcpy(p, text, len); cln->handler = ngx_http_realip_cleanup; ngx_http_set_ctx(r, ctx, ngx_http_realip_module); ctx->connection = c; ctx->sockaddr = c->sockaddr; ctx->socklen = c->socklen; ctx->addr_text = c->addr_text; c->sockaddr = addr->sockaddr; c->socklen = addr->socklen; c->addr_text.len = len; c->addr_text.data = p; return NGX_DECLINED; } static void ngx_http_realip_cleanup(void *data) { ngx_http_realip_ctx_t *ctx = data; ngx_connection_t *c; c = ctx->connection; c->sockaddr = ctx->sockaddr; c->socklen = ctx->socklen; c->addr_text = ctx->addr_text; } static char * ngx_http_realip_from(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_realip_loc_conf_t *rlcf = conf; ngx_int_t rc; ngx_str_t *value; ngx_cidr_t *cidr; value = cf->args->elts; if (rlcf->from == NULL) { rlcf->from = ngx_array_create(cf->pool, 2, sizeof(ngx_cidr_t)); if (rlcf->from == NULL) { return NGX_CONF_ERROR; } } cidr = ngx_array_push(rlcf->from); if (cidr == NULL) { return NGX_CONF_ERROR; } #if (NGX_HAVE_UNIX_DOMAIN) if (ngx_strcmp(value[1].data, "unix:") == 0) { cidr->family = AF_UNIX; return NGX_CONF_OK; } #endif rc = ngx_ptocidr(&value[1], cidr); if (rc == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[1]); return NGX_CONF_ERROR; } if (rc == NGX_DONE) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "low address bits of %V are meaningless", &value[1]); } return NGX_CONF_OK; } static char * ngx_http_realip(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_realip_loc_conf_t *rlcf = conf; ngx_str_t *value; if (rlcf->type != NGX_CONF_UNSET_UINT) { return "is duplicate"; } value = cf->args->elts; if (ngx_strcmp(value[1].data, "X-Real-IP") == 0) { rlcf->type = NGX_HTTP_REALIP_XREALIP; return NGX_CONF_OK; } if (ngx_strcmp(value[1].data, "X-Forwarded-For") == 0) { rlcf->type = NGX_HTTP_REALIP_XFWD; return NGX_CONF_OK; } if (ngx_strcmp(value[1].data, "proxy_protocol") == 0) { rlcf->type = NGX_HTTP_REALIP_PROXY; return NGX_CONF_OK; } rlcf->type = NGX_HTTP_REALIP_HEADER; rlcf->hash = ngx_hash_strlow(value[1].data, value[1].data, value[1].len); rlcf->header = value[1]; return NGX_CONF_OK; } static void * ngx_http_realip_create_loc_conf(ngx_conf_t *cf) { ngx_http_realip_loc_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_realip_loc_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->from = NULL; * conf->hash = 0; * conf->header = { 0, NULL }; */ conf->type = NGX_CONF_UNSET_UINT; conf->recursive = NGX_CONF_UNSET; return conf; } static char * ngx_http_realip_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_realip_loc_conf_t *prev = parent; ngx_http_realip_loc_conf_t *conf = child; if (conf->from == NULL) { conf->from = prev->from; } ngx_conf_merge_uint_value(conf->type, prev->type, NGX_HTTP_REALIP_XREALIP); ngx_conf_merge_value(conf->recursive, prev->recursive, 0); if (conf->header.len == 0) { conf->hash = prev->hash; conf->header = prev->header; } return NGX_CONF_OK; } static ngx_int_t ngx_http_realip_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var, *v; for (v = ngx_http_realip_vars; v->name.len; v++) { var = ngx_http_add_variable(cf, &v->name, v->flags); if (var == NULL) { return NGX_ERROR; } var->get_handler = v->get_handler; var->data = v->data; } return NGX_OK; } static ngx_int_t ngx_http_realip_init(ngx_conf_t *cf) { ngx_http_handler_pt *h; ngx_http_core_main_conf_t *cmcf; cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_POST_READ_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_realip_handler; h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_realip_handler; return NGX_OK; } static ngx_http_realip_ctx_t * ngx_http_realip_get_module_ctx(ngx_http_request_t *r) { ngx_pool_cleanup_t *cln; ngx_http_realip_ctx_t *ctx; ctx = ngx_http_get_module_ctx(r, ngx_http_realip_module); if (ctx == NULL && (r->internal || r->filter_finalize)) { /* * if module context was reset, the original address * can still be found in the cleanup handler */ for (cln = r->pool->cleanup; cln; cln = cln->next) { if (cln->handler == ngx_http_realip_cleanup) { ctx = cln->data; break; } } } return ctx; } static ngx_int_t ngx_http_realip_remote_addr_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { ngx_str_t *addr_text; ngx_http_realip_ctx_t *ctx; ctx = ngx_http_realip_get_module_ctx(r); addr_text = ctx ? &ctx->addr_text : &r->connection->addr_text; v->len = addr_text->len; v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->data = addr_text->data; return NGX_OK; } static ngx_int_t ngx_http_realip_remote_port_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { ngx_uint_t port; struct sockaddr *sa; ngx_http_realip_ctx_t *ctx; ctx = ngx_http_realip_get_module_ctx(r); sa = ctx ? ctx->sockaddr : r->connection->sockaddr; v->len = 0; v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->data = ngx_pnalloc(r->pool, sizeof("65535") - 1); if (v->data == NULL) { return NGX_ERROR; } port = ngx_inet_get_port(sa); if (port > 0 && port < 65536) { v->len = ngx_sprintf(v->data, "%ui", port) - v->data; } return NGX_OK; }