Mercurial > hg > nginx
view src/http/modules/ngx_http_gzip_static_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 | a72886067bbb |
children | 99934aade555 |
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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_GZIP_STATIC_OFF 0 #define NGX_HTTP_GZIP_STATIC_ON 1 #define NGX_HTTP_GZIP_STATIC_ALWAYS 2 typedef struct { ngx_uint_t enable; } ngx_http_gzip_static_conf_t; static ngx_int_t ngx_http_gzip_static_handler(ngx_http_request_t *r); static void *ngx_http_gzip_static_create_conf(ngx_conf_t *cf); static char *ngx_http_gzip_static_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_gzip_static_init(ngx_conf_t *cf); static ngx_conf_enum_t ngx_http_gzip_static[] = { { ngx_string("off"), NGX_HTTP_GZIP_STATIC_OFF }, { ngx_string("on"), NGX_HTTP_GZIP_STATIC_ON }, { ngx_string("always"), NGX_HTTP_GZIP_STATIC_ALWAYS }, { ngx_null_string, 0 } }; static ngx_command_t ngx_http_gzip_static_commands[] = { { ngx_string("gzip_static"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_enum_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_gzip_static_conf_t, enable), &ngx_http_gzip_static }, ngx_null_command }; static ngx_http_module_t ngx_http_gzip_static_module_ctx = { NULL, /* preconfiguration */ ngx_http_gzip_static_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_gzip_static_create_conf, /* create location configuration */ ngx_http_gzip_static_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_gzip_static_module = { NGX_MODULE_V1, &ngx_http_gzip_static_module_ctx, /* module context */ ngx_http_gzip_static_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_gzip_static_handler(ngx_http_request_t *r) { u_char *p; size_t root; ngx_str_t path; ngx_int_t rc; ngx_uint_t level; ngx_log_t *log; ngx_buf_t *b; ngx_chain_t out; ngx_table_elt_t *h; ngx_open_file_info_t of; ngx_http_core_loc_conf_t *clcf; ngx_http_gzip_static_conf_t *gzcf; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_DECLINED; } if (r->uri.data[r->uri.len - 1] == '/') { return NGX_DECLINED; } gzcf = ngx_http_get_module_loc_conf(r, ngx_http_gzip_static_module); if (gzcf->enable == NGX_HTTP_GZIP_STATIC_OFF) { return NGX_DECLINED; } if (gzcf->enable == NGX_HTTP_GZIP_STATIC_ON) { rc = ngx_http_gzip_ok(r); } else { /* always */ rc = NGX_OK; } clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); if (!clcf->gzip_vary && rc != NGX_OK) { return NGX_DECLINED; } log = r->connection->log; p = ngx_http_map_uri_to_path(r, &path, &root, sizeof(".gz") - 1); if (p == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } *p++ = '.'; *p++ = 'g'; *p++ = 'z'; *p = '\0'; path.len = p - path.data; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http filename: \"%s\"", path.data); ngx_memzero(&of, sizeof(ngx_open_file_info_t)); of.read_ahead = clcf->read_ahead; of.directio = clcf->directio; of.valid = clcf->open_file_cache_valid; of.min_uses = clcf->open_file_cache_min_uses; of.errors = clcf->open_file_cache_errors; of.events = clcf->open_file_cache_events; if (ngx_http_set_disable_symlinks(r, clcf, &path, &of) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool) != NGX_OK) { switch (of.err) { case 0: return NGX_HTTP_INTERNAL_SERVER_ERROR; case NGX_ENOENT: case NGX_ENOTDIR: case NGX_ENAMETOOLONG: return NGX_DECLINED; case NGX_EACCES: #if (NGX_HAVE_OPENAT) case NGX_EMLINK: case NGX_ELOOP: #endif level = NGX_LOG_ERR; break; default: level = NGX_LOG_CRIT; break; } ngx_log_error(level, log, of.err, "%s \"%s\" failed", of.failed, path.data); return NGX_DECLINED; } if (gzcf->enable == NGX_HTTP_GZIP_STATIC_ON) { r->gzip_vary = 1; if (rc != NGX_OK) { return NGX_DECLINED; } } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http static fd: %d", of.fd); if (of.is_dir) { ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "http dir"); return NGX_DECLINED; } #if !(NGX_WIN32) /* the not regular files are probably Unix specific */ if (!of.is_file) { ngx_log_error(NGX_LOG_CRIT, log, 0, "\"%s\" is not a regular file", path.data); return NGX_HTTP_NOT_FOUND; } #endif r->root_tested = !r->error_page; rc = ngx_http_discard_request_body(r); if (rc != NGX_OK) { return rc; } log->action = "sending response to client"; r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = of.size; r->headers_out.last_modified_time = of.mtime; if (ngx_http_set_etag(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_http_set_content_type(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } h = ngx_list_push(&r->headers_out.headers); if (h == NULL) { return NGX_ERROR; } h->hash = 1; ngx_str_set(&h->key, "Content-Encoding"); ngx_str_set(&h->value, "gzip"); r->headers_out.content_encoding = h; /* we need to allocate all before the header would be sent */ b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t)); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t)); if (b->file == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } b->file_pos = 0; b->file_last = of.size; b->in_file = b->file_last ? 1 : 0; b->last_buf = (r == r->main) ? 1 : 0; b->last_in_chain = 1; b->file->fd = of.fd; b->file->name = path; b->file->log = log; b->file->directio = of.is_directio; out.buf = b; out.next = NULL; return ngx_http_output_filter(r, &out); } static void * ngx_http_gzip_static_create_conf(ngx_conf_t *cf) { ngx_http_gzip_static_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_gzip_static_conf_t)); if (conf == NULL) { return NULL; } conf->enable = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_gzip_static_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_gzip_static_conf_t *prev = parent; ngx_http_gzip_static_conf_t *conf = child; ngx_conf_merge_uint_value(conf->enable, prev->enable, NGX_HTTP_GZIP_STATIC_OFF); return NGX_CONF_OK; } static ngx_int_t ngx_http_gzip_static_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_gzip_static_handler; return NGX_OK; }