[PATCH] Limit req: pointer init order issue

[Maxim Dounin]

Hello!

On Mon, May 20, 2013 at 11:55:48PM +0200, Filipe Da Silva wrote:

> Hello,
> 
> It's a tiny issue as only the next test code about 'shm' is broken.
> 
> That's my last patch for the moment.
> 
> Regards.
> Filipe DA SILVA

> # HG changeset patch
> # User F. da Silva<fdasilvayy at gmail.com>
> # Date 1368198460 -7200
> #      Fri May 10 17:07:40 2013 +0200
> # Node ID 44310812509300443b296e4ff0292e0934305a55
> # Parent  8abca47e7ca0537000bbbd307eefdd033a9971e7
> Limit req: pointer init order issue.
> 
> diff -r 8abca47e7ca0 -r 443108125093 src/http/modules/ngx_http_limit_req_module.c
> --- a/src/http/modules/ngx_http_limit_req_module.c	Fri May 10 16:53:45 2013 +0200
> +++ b/src/http/modules/ngx_http_limit_req_module.c	Fri May 10 17:07:40 2013 +0200
> @@ -936,9 +936,7 @@
>          return NGX_CONF_ERROR;
>      }
>  
> -    limits = lrcf->limits.elts;
> -
> -    if (limits == NULL) {
> +    if (lrcf->limits.elts == NULL) {
>          if (ngx_array_init(&lrcf->limits, cf->pool, 1,
>                             sizeof(ngx_http_limit_req_limit_t))
>              != NGX_OK)
> @@ -947,6 +945,8 @@
>          }
>      }
>  
> +    limits = lrcf->limits.elts;
> +
>      for (i = 0; i < lrcf->limits.nelts; i++) {
>          if (shm_zone == limits[i].shm_zone) {
>              return "is duplicate";

There is no problem here: if lrcf->limits.elts == NULL (aka 
limits == NULL), then lrcf->limits.nelts == 0 and the limits 
pointer is never dereferenced.  The patch is not needed.

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