Hello!
On Fri, Sep 13, 2024 at 01:20:34AM -0400, Will Hawkins wrote:
> # HG changeset patch
> # User Will Hawkins <hawki...@obs.cr>
> # Date 1726202944 14400
> # Fri Sep 13 00:49:04 2024 -0400
> # Node ID 5bfd931f3b9641b51344d437207134f094012de5
> # Parent dbf76fdd109fbbba40a7c5299cc277d180f4bbad
> HTTP: Fix infinite loop on NGX_DECLINED in ngx_http_finalize_request
>
> A handler that invokes ngx_http_finalize_request with NGX_DECLINED
> causes an infinite loop because the phase handler index is not
> incremented before restarting the processing of phases.
>
> In (almost) all the other instances where a handler can return
> NGX_DECLINED, the phase handler index is incremented before restarting
> the processing of phases.
>
> This change adds that index increment where it was missing.
>
> diff -r dbf76fdd109f -r 5bfd931f3b96 src/http/ngx_http_request.c
> --- a/src/http/ngx_http_request.c Tue Sep 03 13:11:25 2024 +0300
> +++ b/src/http/ngx_http_request.c Fri Sep 13 00:49:04 2024 -0400
> @@ -2519,6 +2519,7 @@
> if (rc == NGX_DECLINED) {
> r->content_handler = NULL;
> r->write_event_handler = ngx_http_core_run_phases;
> + r->phase_handler++;
> ngx_http_core_run_phases(r);
> return;
> }
>
The ngx_http_finalize_request(NGX_DECLINED) call (or return
NGX_DECLINED) is expected to be used by location content handlers,
as set by r->content_handler (clcf->handler), to switch back to
phase handlers. Note that it clears r->content_handler, so
ngx_http_core_content_phase() will resume normal content phase
processing.
For example, perl module does this when you return NGX_DECLINED
from the perl code.
And incrementing r->phase_handler will certainly screw up things for
this use case.
Could you please clarify why you think that calling
ngx_http_finalize_request(NGX_DECLINED) in other cases might be
needed, and not a bug in the module which does this?
--
Maxim Dounin
http://mdounin.ru/
