Mercurial > hg > nginx
view src/http/modules/ngx_http_random_index_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 | 061ec464813f |
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> typedef struct { ngx_flag_t enable; } ngx_http_random_index_loc_conf_t; #define NGX_HTTP_RANDOM_INDEX_PREALLOCATE 50 static ngx_int_t ngx_http_random_index_error(ngx_http_request_t *r, ngx_dir_t *dir, ngx_str_t *name); static ngx_int_t ngx_http_random_index_init(ngx_conf_t *cf); static void *ngx_http_random_index_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_random_index_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_command_t ngx_http_random_index_commands[] = { { ngx_string("random_index"), NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_random_index_loc_conf_t, enable), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_random_index_module_ctx = { NULL, /* preconfiguration */ ngx_http_random_index_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_random_index_create_loc_conf, /* create location configuration */ ngx_http_random_index_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_random_index_module = { NGX_MODULE_V1, &ngx_http_random_index_module_ctx, /* module context */ ngx_http_random_index_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_random_index_handler(ngx_http_request_t *r) { u_char *last, *filename; size_t len, allocated, root; ngx_err_t err; ngx_int_t rc; ngx_str_t path, uri, *name; ngx_dir_t dir; ngx_uint_t n, level; ngx_array_t names; ngx_http_random_index_loc_conf_t *rlcf; if (r->uri.data[r->uri.len - 1] != '/') { return NGX_DECLINED; } if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD|NGX_HTTP_POST))) { return NGX_DECLINED; } rlcf = ngx_http_get_module_loc_conf(r, ngx_http_random_index_module); if (!rlcf->enable) { return NGX_DECLINED; } #if (NGX_HAVE_D_TYPE) len = 0; #else len = NGX_HTTP_RANDOM_INDEX_PREALLOCATE; #endif last = ngx_http_map_uri_to_path(r, &path, &root, len); if (last == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } allocated = path.len; path.len = last - path.data - 1; path.data[path.len] = '\0'; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http random index: \"%s\"", path.data); if (ngx_open_dir(&path, &dir) == NGX_ERROR) { err = ngx_errno; if (err == NGX_ENOENT || err == NGX_ENOTDIR || err == NGX_ENAMETOOLONG) { level = NGX_LOG_ERR; rc = NGX_HTTP_NOT_FOUND; } else if (err == NGX_EACCES) { level = NGX_LOG_ERR; rc = NGX_HTTP_FORBIDDEN; } else { level = NGX_LOG_CRIT; rc = NGX_HTTP_INTERNAL_SERVER_ERROR; } ngx_log_error(level, r->connection->log, err, ngx_open_dir_n " \"%s\" failed", path.data); return rc; } if (ngx_array_init(&names, r->pool, 32, sizeof(ngx_str_t)) != NGX_OK) { return ngx_http_random_index_error(r, &dir, &path); } filename = path.data; filename[path.len] = '/'; for ( ;; ) { ngx_set_errno(0); if (ngx_read_dir(&dir) == NGX_ERROR) { err = ngx_errno; if (err != NGX_ENOMOREFILES) { ngx_log_error(NGX_LOG_CRIT, r->connection->log, err, ngx_read_dir_n " \"%V\" failed", &path); return ngx_http_random_index_error(r, &dir, &path); } break; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http random index file: \"%s\"", ngx_de_name(&dir)); if (ngx_de_name(&dir)[0] == '.') { continue; } len = ngx_de_namelen(&dir); if (dir.type == 0 || ngx_de_is_link(&dir)) { /* 1 byte for '/' and 1 byte for terminating '\0' */ if (path.len + 1 + len + 1 > allocated) { allocated = path.len + 1 + len + 1 + NGX_HTTP_RANDOM_INDEX_PREALLOCATE; filename = ngx_pnalloc(r->pool, allocated); if (filename == NULL) { return ngx_http_random_index_error(r, &dir, &path); } last = ngx_cpystrn(filename, path.data, path.len + 1); *last++ = '/'; } ngx_cpystrn(last, ngx_de_name(&dir), len + 1); if (ngx_de_info(filename, &dir) == NGX_FILE_ERROR) { err = ngx_errno; if (err != NGX_ENOENT) { ngx_log_error(NGX_LOG_CRIT, r->connection->log, err, ngx_de_info_n " \"%s\" failed", filename); return ngx_http_random_index_error(r, &dir, &path); } if (ngx_de_link_info(filename, &dir) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno, ngx_de_link_info_n " \"%s\" failed", filename); return ngx_http_random_index_error(r, &dir, &path); } } } if (!ngx_de_is_file(&dir)) { continue; } name = ngx_array_push(&names); if (name == NULL) { return ngx_http_random_index_error(r, &dir, &path); } name->len = len; name->data = ngx_pnalloc(r->pool, len); if (name->data == NULL) { return ngx_http_random_index_error(r, &dir, &path); } ngx_memcpy(name->data, ngx_de_name(&dir), len); } if (ngx_close_dir(&dir) == NGX_ERROR) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno, ngx_close_dir_n " \"%V\" failed", &path); } n = names.nelts; if (n == 0) { return NGX_DECLINED; } name = names.elts; n = (ngx_uint_t) (((uint64_t) ngx_random() * n) / 0x80000000); uri.len = r->uri.len + name[n].len; uri.data = ngx_pnalloc(r->pool, uri.len); if (uri.data == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } last = ngx_copy(uri.data, r->uri.data, r->uri.len); ngx_memcpy(last, name[n].data, name[n].len); return ngx_http_internal_redirect(r, &uri, &r->args); } static ngx_int_t ngx_http_random_index_error(ngx_http_request_t *r, ngx_dir_t *dir, ngx_str_t *name) { if (ngx_close_dir(dir) == NGX_ERROR) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno, ngx_close_dir_n " \"%V\" failed", name); } return NGX_HTTP_INTERNAL_SERVER_ERROR; } static void * ngx_http_random_index_create_loc_conf(ngx_conf_t *cf) { ngx_http_random_index_loc_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_random_index_loc_conf_t)); if (conf == NULL) { return NULL; } conf->enable = NGX_CONF_UNSET; return conf; } static char * ngx_http_random_index_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_random_index_loc_conf_t *prev = parent; ngx_http_random_index_loc_conf_t *conf = child; ngx_conf_merge_value(conf->enable, prev->enable, 0); return NGX_CONF_OK; } static ngx_int_t ngx_http_random_index_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_CONTENT_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_random_index_handler; return NGX_OK; }