Mercurial > hg > nginx
view src/http/modules/ngx_http_browser_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 | f84a98a03d0d |
children | 1b82e86dd3e7 |
line wrap: on
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> /* * The module can check browser versions conforming to the following formats: * X, X.X, X.X.X, and X.X.X.X. The maximum values of each format may be * 4000, 4000.99, 4000.99.99, and 4000.99.99.99. */ #define NGX_HTTP_MODERN_BROWSER 0 #define NGX_HTTP_ANCIENT_BROWSER 1 typedef struct { u_char browser[12]; size_t skip; size_t add; u_char name[12]; } ngx_http_modern_browser_mask_t; typedef struct { ngx_uint_t version; size_t skip; size_t add; u_char name[12]; } ngx_http_modern_browser_t; typedef struct { ngx_str_t name; ngx_http_get_variable_pt handler; uintptr_t data; } ngx_http_browser_variable_t; typedef struct { ngx_array_t *modern_browsers; ngx_array_t *ancient_browsers; ngx_http_variable_value_t *modern_browser_value; ngx_http_variable_value_t *ancient_browser_value; unsigned modern_unlisted_browsers:1; unsigned netscape4:1; } ngx_http_browser_conf_t; static ngx_int_t ngx_http_msie_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_int_t ngx_http_browser_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_uint_t ngx_http_browser(ngx_http_request_t *r, ngx_http_browser_conf_t *cf); static ngx_int_t ngx_http_browser_add_variable(ngx_conf_t *cf); static void *ngx_http_browser_create_conf(ngx_conf_t *cf); static char *ngx_http_browser_merge_conf(ngx_conf_t *cf, void *parent, void *child); static int ngx_libc_cdecl ngx_http_modern_browser_sort(const void *one, const void *two); static char *ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static char *ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_browser_commands[] = { { ngx_string("modern_browser"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12, ngx_http_modern_browser, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("ancient_browser"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_ancient_browser, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("modern_browser_value"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_modern_browser_value, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("ancient_browser_value"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_ancient_browser_value, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_browser_module_ctx = { ngx_http_browser_add_variable, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_browser_create_conf, /* create location configuration */ ngx_http_browser_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_browser_module = { NGX_MODULE_V1, &ngx_http_browser_module_ctx, /* module context */ ngx_http_browser_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_modern_browser_mask_t ngx_http_modern_browser_masks[] = { /* Opera must be the first browser to check */ /* * "Opera/7.50 (X11; FreeBSD i386; U) [en]" * "Mozilla/5.0 (X11; FreeBSD i386; U) Opera 7.50 [en]" * "Mozilla/4.0 (compatible; MSIE 6.0; X11; FreeBSD i386) Opera 7.50 [en]" * "Opera/8.0 (Windows NT 5.1; U; ru)" * "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; en) Opera 8.0" * "Opera/9.01 (X11; FreeBSD 6 i386; U; en)" */ { "opera", 0, sizeof("Opera ") - 1, "Opera"}, /* "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)" */ { "msie", sizeof("Mozilla/4.0 (compatible; ") - 1, sizeof("MSIE ") - 1, "MSIE "}, /* * "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020610" * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.5) Gecko/20031006" * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.6) Gecko/20040206 * Firefox/0.8" * "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.7.8) * Gecko/20050511 Firefox/1.0.4" * "Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.0.5) Gecko/20060729 * Firefox/1.5.0.5" */ { "gecko", sizeof("Mozilla/5.0 (") - 1, sizeof("rv:") - 1, "rv:"}, /* * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/125.2 * (KHTML, like Gecko) Safari/125.7" * "Mozilla/5.0 (SymbianOS/9.1; U; en-us) AppleWebKit/413 * (KHTML, like Gecko) Safari/413" * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/418 * (KHTML, like Gecko) Safari/417.9.3" * "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; ru-ru) AppleWebKit/418.8 * (KHTML, like Gecko) Safari/419.3" */ { "safari", sizeof("Mozilla/5.0 (") - 1, sizeof("Safari/") - 1, "Safari/"}, /* * "Mozilla/5.0 (compatible; Konqueror/3.1; Linux)" * "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.2 (like Gecko)" * "Mozilla/5.0 (compatible; Konqueror/3.5; FreeBSD) KHTML/3.5.1 * (like Gecko)" */ { "konqueror", sizeof("Mozilla/5.0 (compatible; ") - 1, sizeof("Konqueror/") - 1, "Konqueror/"}, { "", 0, 0, "" } }; static ngx_http_browser_variable_t ngx_http_browsers[] = { { ngx_string("msie"), ngx_http_msie_variable, 0 }, { ngx_string("modern_browser"), ngx_http_browser_variable, NGX_HTTP_MODERN_BROWSER }, { ngx_string("ancient_browser"), ngx_http_browser_variable, NGX_HTTP_ANCIENT_BROWSER }, { ngx_null_string, NULL, 0 } }; static ngx_int_t ngx_http_browser_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { ngx_uint_t rc; ngx_http_browser_conf_t *cf; cf = ngx_http_get_module_loc_conf(r, ngx_http_browser_module); rc = ngx_http_browser(r, cf); if (data == NGX_HTTP_MODERN_BROWSER && rc == NGX_HTTP_MODERN_BROWSER) { *v = *cf->modern_browser_value; return NGX_OK; } if (data == NGX_HTTP_ANCIENT_BROWSER && rc == NGX_HTTP_ANCIENT_BROWSER) { *v = *cf->ancient_browser_value; return NGX_OK; } *v = ngx_http_variable_null_value; return NGX_OK; } static ngx_uint_t ngx_http_browser(ngx_http_request_t *r, ngx_http_browser_conf_t *cf) { size_t len; u_char *name, *ua, *last, c; ngx_str_t *ancient; ngx_uint_t i, version, ver, scale; ngx_http_modern_browser_t *modern; if (r->headers_in.user_agent == NULL) { if (cf->modern_unlisted_browsers) { return NGX_HTTP_MODERN_BROWSER; } return NGX_HTTP_ANCIENT_BROWSER; } ua = r->headers_in.user_agent->value.data; len = r->headers_in.user_agent->value.len; last = ua + len; if (cf->modern_browsers) { modern = cf->modern_browsers->elts; for (i = 0; i < cf->modern_browsers->nelts; i++) { name = ua + modern[i].skip; if (name >= last) { continue; } name = (u_char *) ngx_strstr(name, modern[i].name); if (name == NULL) { continue; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "browser: \"%s\"", name); name += modern[i].add; if (name >= last) { continue; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "version: \"%ui\" \"%s\"", modern[i].version, name); version = 0; ver = 0; scale = 1000000; while (name < last) { c = *name++; if (c >= '0' && c <= '9') { ver = ver * 10 + (c - '0'); continue; } if (c == '.') { version += ver * scale; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "version: \"%ui\" \"%ui\"", modern[i].version, version); if (version > modern[i].version) { return NGX_HTTP_MODERN_BROWSER; } ver = 0; scale /= 100; continue; } break; } version += ver * scale; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "version: \"%ui\" \"%ui\"", modern[i].version, version); if (version >= modern[i].version) { return NGX_HTTP_MODERN_BROWSER; } return NGX_HTTP_ANCIENT_BROWSER; } if (!cf->modern_unlisted_browsers) { return NGX_HTTP_ANCIENT_BROWSER; } } if (cf->netscape4) { if (len > sizeof("Mozilla/4.72 ") - 1 && ngx_strncmp(ua, "Mozilla/", sizeof("Mozilla/") - 1) == 0 && ua[8] > '0' && ua[8] < '5') { return NGX_HTTP_ANCIENT_BROWSER; } } if (cf->ancient_browsers) { ancient = cf->ancient_browsers->elts; for (i = 0; i < cf->ancient_browsers->nelts; i++) { if (len >= ancient[i].len && ngx_strstr(ua, ancient[i].data) != NULL) { return NGX_HTTP_ANCIENT_BROWSER; } } } if (cf->modern_unlisted_browsers) { return NGX_HTTP_MODERN_BROWSER; } return NGX_HTTP_ANCIENT_BROWSER; } static ngx_int_t ngx_http_msie_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { if (r->headers_in.msie) { *v = ngx_http_variable_true_value; return NGX_OK; } *v = ngx_http_variable_null_value; return NGX_OK; } static ngx_int_t ngx_http_browser_add_variable(ngx_conf_t *cf) { ngx_http_browser_variable_t *var; ngx_http_variable_t *v; for (var = ngx_http_browsers; var->name.len; var++) { v = ngx_http_add_variable(cf, &var->name, NGX_HTTP_VAR_CHANGEABLE); if (v == NULL) { return NGX_ERROR; } v->get_handler = var->handler; v->data = var->data; } return NGX_OK; } static void * ngx_http_browser_create_conf(ngx_conf_t *cf) { ngx_http_browser_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_browser_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->modern_browsers = NULL; * conf->ancient_browsers = NULL; * conf->modern_browser_value = NULL; * conf->ancient_browser_value = NULL; * * conf->modern_unlisted_browsers = 0; * conf->netscape4 = 0; */ return conf; } static char * ngx_http_browser_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_browser_conf_t *prev = parent; ngx_http_browser_conf_t *conf = child; ngx_uint_t i, n; ngx_http_modern_browser_t *browsers, *opera; /* * At the merge the skip field is used to store the browser slot, * it will be used in sorting and then will overwritten * with a real skip value. The zero value means Opera. */ if (conf->modern_browsers == NULL && conf->modern_unlisted_browsers == 0) { conf->modern_browsers = prev->modern_browsers; conf->modern_unlisted_browsers = prev->modern_unlisted_browsers; } else if (conf->modern_browsers != NULL) { browsers = conf->modern_browsers->elts; for (i = 0; i < conf->modern_browsers->nelts; i++) { if (browsers[i].skip == 0) { goto found; } } /* * Opera may contain MSIE string, so if Opera was not enumerated * as modern browsers, then add it and set a unreachable version */ opera = ngx_array_push(conf->modern_browsers); if (opera == NULL) { return NGX_CONF_ERROR; } opera->skip = 0; opera->version = 4001000000U; browsers = conf->modern_browsers->elts; found: ngx_qsort(browsers, (size_t) conf->modern_browsers->nelts, sizeof(ngx_http_modern_browser_t), ngx_http_modern_browser_sort); for (i = 0; i < conf->modern_browsers->nelts; i++) { n = browsers[i].skip; browsers[i].skip = ngx_http_modern_browser_masks[n].skip; browsers[i].add = ngx_http_modern_browser_masks[n].add; (void) ngx_cpystrn(browsers[i].name, ngx_http_modern_browser_masks[n].name, 12); } } if (conf->ancient_browsers == NULL && conf->netscape4 == 0) { conf->ancient_browsers = prev->ancient_browsers; conf->netscape4 = prev->netscape4; } if (conf->modern_browser_value == NULL) { conf->modern_browser_value = prev->modern_browser_value; } if (conf->modern_browser_value == NULL) { conf->modern_browser_value = &ngx_http_variable_true_value; } if (conf->ancient_browser_value == NULL) { conf->ancient_browser_value = prev->ancient_browser_value; } if (conf->ancient_browser_value == NULL) { conf->ancient_browser_value = &ngx_http_variable_true_value; } return NGX_CONF_OK; } static int ngx_libc_cdecl ngx_http_modern_browser_sort(const void *one, const void *two) { ngx_http_modern_browser_t *first = (ngx_http_modern_browser_t *) one; ngx_http_modern_browser_t *second = (ngx_http_modern_browser_t *) two; return (first->skip - second->skip); } static char * ngx_http_modern_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_browser_conf_t *bcf = conf; u_char c; ngx_str_t *value; ngx_uint_t i, n, version, ver, scale; ngx_http_modern_browser_t *browser; ngx_http_modern_browser_mask_t *mask; value = cf->args->elts; if (cf->args->nelts == 2) { if (ngx_strcmp(value[1].data, "unlisted") == 0) { bcf->modern_unlisted_browsers = 1; return NGX_CONF_OK; } return NGX_CONF_ERROR; } if (bcf->modern_browsers == NULL) { bcf->modern_browsers = ngx_array_create(cf->pool, 5, sizeof(ngx_http_modern_browser_t)); if (bcf->modern_browsers == NULL) { return NGX_CONF_ERROR; } } browser = ngx_array_push(bcf->modern_browsers); if (browser == NULL) { return NGX_CONF_ERROR; } mask = ngx_http_modern_browser_masks; for (n = 0; mask[n].browser[0] != '\0'; n++) { if (ngx_strcasecmp(mask[n].browser, value[1].data) == 0) { goto found; } } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unknown browser name \"%V\"", &value[1]); return NGX_CONF_ERROR; found: /* * at this stage the skip field is used to store the browser slot, * it will be used in sorting in merge stage and then will overwritten * with a real value */ browser->skip = n; version = 0; ver = 0; scale = 1000000; for (i = 0; i < value[2].len; i++) { c = value[2].data[i]; if (c >= '0' && c <= '9') { ver = ver * 10 + (c - '0'); continue; } if (c == '.') { version += ver * scale; ver = 0; scale /= 100; continue; } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid browser version \"%V\"", &value[2]); return NGX_CONF_ERROR; } version += ver * scale; browser->version = version; return NGX_CONF_OK; } static char * ngx_http_ancient_browser(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_browser_conf_t *bcf = conf; ngx_str_t *value, *browser; ngx_uint_t i; value = cf->args->elts; for (i = 1; i < cf->args->nelts; i++) { if (ngx_strcmp(value[i].data, "netscape4") == 0) { bcf->netscape4 = 1; continue; } if (bcf->ancient_browsers == NULL) { bcf->ancient_browsers = ngx_array_create(cf->pool, 4, sizeof(ngx_str_t)); if (bcf->ancient_browsers == NULL) { return NGX_CONF_ERROR; } } browser = ngx_array_push(bcf->ancient_browsers); if (browser == NULL) { return NGX_CONF_ERROR; } *browser = value[i]; } return NGX_CONF_OK; } static char * ngx_http_modern_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_browser_conf_t *bcf = conf; ngx_str_t *value; bcf->modern_browser_value = ngx_palloc(cf->pool, sizeof(ngx_http_variable_value_t)); if (bcf->modern_browser_value == NULL) { return NGX_CONF_ERROR; } value = cf->args->elts; bcf->modern_browser_value->len = value[1].len; bcf->modern_browser_value->valid = 1; bcf->modern_browser_value->no_cacheable = 0; bcf->modern_browser_value->not_found = 0; bcf->modern_browser_value->data = value[1].data; return NGX_CONF_OK; } static char * ngx_http_ancient_browser_value(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_browser_conf_t *bcf = conf; ngx_str_t *value; bcf->ancient_browser_value = ngx_palloc(cf->pool, sizeof(ngx_http_variable_value_t)); if (bcf->ancient_browser_value == NULL) { return NGX_CONF_ERROR; } value = cf->args->elts; bcf->ancient_browser_value->len = value[1].len; bcf->ancient_browser_value->valid = 1; bcf->ancient_browser_value->no_cacheable = 0; bcf->ancient_browser_value->not_found = 0; bcf->ancient_browser_value->data = value[1].data; return NGX_CONF_OK; }