About the return http status 203

[Maxim Dounin]

Hello!

On Wed, Apr 03, 2013 at 12:09:25PM +0800, Weibin Yao wrote:

> Hi,
> 
> Today In our test box I noticed that nginx sent bad response with 203
> response. You can reproduce the problem with the return directive:
> 
> location / {
>     return 203;
> }
> 
> And the response looks like:
> 
> HTTP/1.1
> Server: nginx/1.3.14
> Date: Wed, 03 Apr 2013 03:54:38 GMT
> Content-Type: application/octet-stream
> Content-Length: 0
> Connection: keep-alive
> 
> This is actually not an illegal HTTP/1.1 response.
> 
> I noticed the related code in the ngx_http_header_filter_module.c:
> 
>  53 static ngx_str_t ngx_http_status_lines[] = {
>  54
>  55     ngx_string("200 OK"),
>  56     ngx_string("201 Created"),
>  57     ngx_string("202 Accepted"),
>  58     ngx_null_string,  /* "203 Non-Authoritative Information" */
>  59     ngx_string("204 No Content"),
>  60     ngx_null_string,  /* "205 Reset Content" */
>  61     ngx_string("206 Partial Content"),
> 
> It seems this behaviour is expected intentionally. It does not follow the
> RFC 2616. If we replace it to be the meaningful status code. Is there any
> problem?

It think this is a bug.  The ngx_http_status_lines[] array doesn't 
contain lines for status codes nginx doesn't generate itself, but 
the code doesn't expect such a hole may be actually hit.  On the 
other hand, for unknown codes outside of the known range it 
correctly returns just a number in a status line.

Quick and dirty patch follows:

--- a/src/http/ngx_http_header_filter_module.c
+++ b/src/http/ngx_http_header_filter_module.c
@@ -270,6 +270,12 @@ ngx_http_header_filter(ngx_http_request_
             len += NGX_INT_T_LEN;
             status_line = NULL;
         }
+
+        if (status_line && status_line->len == 0) {
+            status = r->headers_out.status;
+            len += NGX_INT_T_LEN;
+            status_line = NULL;
+        }
     }
 
     clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);


-- 
Maxim Dounin
http://nginx.org/en/donation.html