Mercurial > hg > nginx
view src/http/modules/ngx_http_browser_module.c @ 7629:f47f7d3d1bfa
Mp4: fixed possible chunk offset overflow.
In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming
the "mdat" atom, chunk offsets are casted to off_t values which are typically
64-bit signed integers. A specially crafted mp4 file with huge chunk offsets
may lead to off_t overflow and result in negative trim boundaries.
The consequences of the overflow are:
- Incorrect Content-Length header value in the response.
- Negative left boundary of the response file buffer holding the trimmed "mdat".
This leads to pread()/sendfile() errors followed by closing the client
connection.
On rare systems where off_t is a 32-bit integer, this scenario is also feasible
with the "stco" atom.
The fix is to add checks which make sure data chunks referenced by each track
are within the mp4 file boundaries. Additionally a few more checks are added to
ensure mp4 file consistency and log errors.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 26 Feb 2020 15:10:46 +0300 |
parents | 2a288909abc6 |
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> /* * 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_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_variables(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_variables, /* 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_variable_t ngx_http_browser_vars[] = { { ngx_string("msie"), NULL, ngx_http_msie_variable, 0, NGX_HTTP_VAR_CHANGEABLE, 0 }, { ngx_string("modern_browser"), NULL, ngx_http_browser_variable, NGX_HTTP_MODERN_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 }, { ngx_string("ancient_browser"), NULL, ngx_http_browser_variable, NGX_HTTP_ANCIENT_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 }, ngx_http_null_variable }; 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_variables(ngx_conf_t *cf) { ngx_http_variable_t *var, *v; for (v = ngx_http_browser_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 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; }