Mercurial > hg > nginx
view src/http/modules/ngx_http_empty_gif_module.c @ 6986:0cdee26605f3
Cleaned up r->headers_out.headers allocation error handling.
If initialization of a header failed for some reason after ngx_list_push(),
leaving the header as is can result in uninitialized memory access by
the header filter or the log module. The fix is to clear partially
initialized headers in case of errors.
For the Cache-Control header, the fix is to postpone pushing
r->headers_out.cache_control until its value is completed.
| author | Sergey Kandaurov <pluknet@nginx.com> |
|---|---|
| date | Thu, 20 Apr 2017 18:26:37 +0300 |
| parents | d620f497c50f |
| 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> static char *ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_empty_gif_commands[] = { { ngx_string("empty_gif"), NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS, ngx_http_empty_gif, 0, 0, NULL }, ngx_null_command }; /* the minimal single pixel transparent GIF, 43 bytes */ static u_char ngx_empty_gif[] = { 'G', 'I', 'F', '8', '9', 'a', /* header */ /* logical screen descriptor */ 0x01, 0x00, /* logical screen width */ 0x01, 0x00, /* logical screen height */ 0x80, /* global 1-bit color table */ 0x01, /* background color #1 */ 0x00, /* no aspect ratio */ /* global color table */ 0x00, 0x00, 0x00, /* #0: black */ 0xff, 0xff, 0xff, /* #1: white */ /* graphic control extension */ 0x21, /* extension introducer */ 0xf9, /* graphic control label */ 0x04, /* block size */ 0x01, /* transparent color is given, */ /* no disposal specified, */ /* user input is not expected */ 0x00, 0x00, /* delay time */ 0x01, /* transparent color #1 */ 0x00, /* block terminator */ /* image descriptor */ 0x2c, /* image separator */ 0x00, 0x00, /* image left position */ 0x00, 0x00, /* image top position */ 0x01, 0x00, /* image width */ 0x01, 0x00, /* image height */ 0x00, /* no local color table, no interlaced */ /* table based image data */ 0x02, /* LZW minimum code size, */ /* must be at least 2-bit */ 0x02, /* block size */ 0x4c, 0x01, /* compressed bytes 01_001_100, 0000000_1 */ /* 100: clear code */ /* 001: 1 */ /* 101: end of information code */ 0x00, /* block terminator */ 0x3B /* trailer */ }; static ngx_http_module_t ngx_http_empty_gif_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_empty_gif_module = { NGX_MODULE_V1, &ngx_http_empty_gif_module_ctx, /* module context */ ngx_http_empty_gif_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_str_t ngx_http_gif_type = ngx_string("image/gif"); static ngx_int_t ngx_http_empty_gif_handler(ngx_http_request_t *r) { ngx_http_complex_value_t cv; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } ngx_memzero(&cv, sizeof(ngx_http_complex_value_t)); cv.value.len = sizeof(ngx_empty_gif); cv.value.data = ngx_empty_gif; r->headers_out.last_modified_time = 23349600; return ngx_http_send_response(r, NGX_HTTP_OK, &ngx_http_gif_type, &cv); } static char * ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_empty_gif_handler; return NGX_CONF_OK; }