[PATCH] uwsgi - prevent protocol overflow

[Maxim Dounin]

Hello!

On Wed, Aug 22, 2018 at 11:57:02PM +0000, Chris Caputo wrote:

> At present, ngx_http_uwsgi_module.c's ngx_http_uwsgi_create_request() has 
> nothing to stop it from dispatching a request exceeding what is possible 
> per the uwsgi protocol:
> 
>   https://uwsgi-docs.readthedocs.io/en/latest/Protocol.html
> 
> The limit is 65,535 (0xffff) and when a request exceeds that size, this 
> function is currently just overflowing, with the uwsgi handler receiving a 
> large buffer with a length that doesn't match it.
> 
> Would someone review and help me get the below code to be accepted?
> 
> Thank you,
> Chris
> 
> --- ngx_http_uwsgi_module.c.original	2018-08-22 23:41:16.309151481 +0000
> +++ ngx_http_uwsgi_module.c	2018-08-22 23:43:39.546795158 +0000
> @@ -960,6 +960,13 @@
>      }
>  #endif
>  
> +    /* enforce uwsgi protocol max len of uint16 */
> +    if (len > 0xffff) {
> +        ngx_log_error (NGX_LOG_ALERT, r->connection->log, 0,
> +                       "uwsgi request is too large for uwsgi protocol: %uz", len);
> +        return NGX_ERROR;
> +    }
> +
>      b = ngx_create_temp_buf(r->pool, len + 4);
>      if (b == NULL) {
>          return NGX_ERROR;

Thanks, I've pushed a slightly simplier patch:

http://hg.nginx.org/nginx/rev/f6e7831a17d4

-- 
Maxim Dounin
http://mdounin.ru/