nginx-devel Digest, Vol 58, Issue 34

Donatas Abraitis donatas.abraitis at gmail.com
Tue Aug 26 12:09:44 UTC 2014


Hey, Maxim,

after trying to change to NGX_DONE or NGX_HTTP_FORBIDDEN in static
ngx_int_t ngx_http_hostprotect_init(ngx_conf_t *cf), I got this when doing
nginx restart:

nginx: configuration file /opt/nginx/etc/nginx.conf test failed

Thank you.


On Tue, Aug 26, 2014 at 3:00 PM, <nginx-devel-request at nginx.org> wrote:

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> Today's Topics:
>
>    1. [nginx] Sub filter: fixed matching for a single character.
>       (Valentin Bartenev)
>    2. return 403 instead of next phase (Donatas Abraitis)
>    3. Re: header value null termination? (Maxim Dounin)
>    4. Re: return 403 instead of next phase (Maxim Dounin)
>    5. Re: header value null termination? (Steven Hartland)
>    6. Re: [PATCH 0 of 4 v3] Build-system: Cross-compilation support
>       improvement (Samuel Martin)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 25 Aug 2014 12:09:28 +0000
> From: Valentin Bartenev <vbart at nginx.com>
> To: nginx-devel at nginx.org
> Subject: [nginx] Sub filter: fixed matching for a single character.
> Message-ID:
>         <hg.5322be87fc02.1408968568.6026610855610030274 at dev.nginx.com>
> Content-Type: text/plain; charset="us-ascii"
>
> details:   http://hg.nginx.org/nginx/rev/5322be87fc02
> branches:
> changeset: 5810:5322be87fc02
> user:      Valentin Bartenev <vbart at nginx.com>
> date:      Mon Aug 25 16:08:55 2014 +0400
> description:
> Sub filter: fixed matching for a single character.
>
> diffstat:
>
>  src/http/modules/ngx_http_sub_filter_module.c |  8 ++++++++
>  1 files changed, 8 insertions(+), 0 deletions(-)
>
> diffs (18 lines):
>
> diff -r bb26f7ceaaf1 -r 5322be87fc02
> src/http/modules/ngx_http_sub_filter_module.c
> --- a/src/http/modules/ngx_http_sub_filter_module.c     Wed Aug 20
> 13:13:27 2014 +0400
> +++ b/src/http/modules/ngx_http_sub_filter_module.c     Mon Aug 25
> 16:08:55 2014 +0400
> @@ -546,6 +546,14 @@ ngx_http_sub_parse(ngx_http_request_t *r
>
>              for ( ;; ) {
>                  if (ch == match) {
> +
> +                    if (ctx->match.len == 1) {
> +                        ctx->pos = p + 1;
> +                        ctx->copy_end = p;
> +
> +                        return NGX_OK;
> +                    }
> +
>                      copy_end = p;
>                      ctx->looked.data[0] = *p;
>                      looked = 1;
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 25 Aug 2014 17:07:12 +0300
> From: Donatas Abraitis <donatas.abraitis at gmail.com>
> To: nginx-devel at nginx.org
> Subject: return 403 instead of next phase
> Message-ID:
>         <CAPF+HwUmp0iLZKsGs4bDf4jw=
> JY-EweOBKUnjK2DpgFJwdn8dw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hey,
>
> static ngx_int_t ngx_http_hostprotect_init(ngx_conf_t *cf)
> {
>   ngx_http_handler_pt *h;
>   ngx_http_core_main_conf_t *cscf;
>
>   cscf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
>   h = ngx_array_push(&cscf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
>   if(h == NULL)
>     return NGX_ERROR;
>
>   *h = ngx_http_hostprotect_handler;
>
>   return NGX_OK;
> }
>
> static ngx_int_t ngx_http_hostprotect_handler(ngx_http_request_t *r)
> {
>     ...
>     r->headers_out.status = NGX_HTTP_FORBIDDEN;
>     r->headers_out.content_length_n = sizeof(err_msg);
>     ngx_http_send_header(r);
>     return ngx_http_output_filter(r, &out);
> }
>
> Everything looks fine, but backend (in this case Apache) still receives
> requests. Any options to drop the request without allowing it to reach
> backend?
>
> --
> Donatas
> -------------- next part --------------
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>
> ------------------------------
>
> Message: 3
> Date: Mon, 25 Aug 2014 18:32:50 +0400
> From: Maxim Dounin <mdounin at mdounin.ru>
> To: nginx-devel at nginx.org
> Subject: Re: header value null termination?
> Message-ID: <20140825143250.GF1849 at mdounin.ru>
> Content-Type: text/plain; charset=us-ascii
>
> Hello!
>
> On Fri, Aug 22, 2014 at 12:30:22AM +0100, Steven Hartland wrote:
>
> > I'm creating a module in which I needed to set some
> > of the standard headers e.g. Content-Range and Range.
> >
> > Looking through the core source code the standard way
> > to do this seems to be something like this:-
> >
> > r->headers_in.range->value.len =
> >    ngx_sprintf(r->headers_in.range->value.data,
> >        "bytes %O-%O/%O",
> >        range->start, range->end - 1,
> >        r->headers_out.content_length_n)
> >        - r->headers_in.range->value.data;
> >
> > This appears to write a string to value.data which
> > is not \0 terminated hence when interacting with
> > functions such as ngx_http_range_parse unpredictable
> > behaviour follows as it expects the range header to
> > be null terminated.
> >
> > So the question is:-
> >
> > Should header values be null terminated or should
> > functions such as ngx_http_range_parse be updated
> > to deal with non-null terminated strings?
>
> The answer is: no.
>
> In general, strings in nginx are not null terminated, and there is
> no need to null-terminated them.  In some cases though strings are
> guaranteed to be null-terminated - notably, configuration
> directive arguments are always null-terminated, as well as input
> headers.  The ngx_http_range_parse() uses an input header from
> r->headers_in, and it's guaranteed to be null-terminated.
>
> The problem is in the "sample" code you've provided though: it
> tries to modify input headers in r->headers_in.  This is wrong
> thing to do.
>
> --
> Maxim Dounin
> http://nginx.org/
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 25 Aug 2014 20:09:35 +0400
> From: Maxim Dounin <mdounin at mdounin.ru>
> To: nginx-devel at nginx.org
> Subject: Re: return 403 instead of next phase
> Message-ID: <20140825160935.GI1849 at mdounin.ru>
> Content-Type: text/plain; charset=us-ascii
>
> Hello!
>
> On Mon, Aug 25, 2014 at 05:07:12PM +0300, Donatas Abraitis wrote:
>
> > Hey,
> >
> > static ngx_int_t ngx_http_hostprotect_init(ngx_conf_t *cf)
> > {
> >   ngx_http_handler_pt *h;
> >   ngx_http_core_main_conf_t *cscf;
> >
> >   cscf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
> >   h = ngx_array_push(&cscf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
> >   if(h == NULL)
> >     return NGX_ERROR;
> >
> >   *h = ngx_http_hostprotect_handler;
> >
> >   return NGX_OK;
> > }
> >
> > static ngx_int_t ngx_http_hostprotect_handler(ngx_http_request_t *r)
> > {
> >     ...
> >     r->headers_out.status = NGX_HTTP_FORBIDDEN;
> >     r->headers_out.content_length_n = sizeof(err_msg);
> >     ngx_http_send_header(r);
> >     return ngx_http_output_filter(r, &out);
> > }
> >
> > Everything looks fine, but backend (in this case Apache) still receives
> > requests. Any options to drop the request without allowing it to reach
> > backend?
>
> In your code you return NGX_OK from the access phase handler, and
> this means that access checks passed.  This probably not what you
> mean to return.
>
> You have to return NGX_HTTP_FORBIDDEN instead, without sending
> anything back - nginx will send an error page for you (either
> compiled in, or set with error_page directive).
>
> --
> Maxim Dounin
> http://nginx.org/
>
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 25 Aug 2014 19:56:13 +0100
> From: "Steven Hartland" <steven.hartland at multiplay.co.uk>
> To: <nginx-devel at nginx.org>
> Subject: Re: header value null termination?
> Message-ID: <36576796BF8E4676B045066D8BF20D21 at multiplay.co.uk>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>         reply-type=original
>
>
> ----- Original Message -----
> From: "Maxim Dounin" <mdounin at mdounin.ru>
> To: <nginx-devel at nginx.org>
> Sent: Monday, August 25, 2014 3:32 PM
> Subject: Re: header value null termination?
>
>
> > Hello!
> >
> > On Fri, Aug 22, 2014 at 12:30:22AM +0100, Steven Hartland wrote:
> >
> >> I'm creating a module in which I needed to set some
> >> of the standard headers e.g. Content-Range and Range.
> >>
> >> Looking through the core source code the standard way
> >> to do this seems to be something like this:-
> >>
> >> r->headers_in.range->value.len =
> >>    ngx_sprintf(r->headers_in.range->value.data,
> >>        "bytes %O-%O/%O",
> >>        range->start, range->end - 1,
> >>        r->headers_out.content_length_n)
> >>        - r->headers_in.range->value.data;
> >>
> >> This appears to write a string to value.data which
> >> is not \0 terminated hence when interacting with
> >> functions such as ngx_http_range_parse unpredictable
> >> behaviour follows as it expects the range header to
> >> be null terminated.
> >>
> >> So the question is:-
> >>
> >> Should header values be null terminated or should
> >> functions such as ngx_http_range_parse be updated
> >> to deal with non-null terminated strings?
> >
> > The answer is: no.
> >
> > In general, strings in nginx are not null terminated, and there is
> > no need to null-terminated them.  In some cases though strings are
> > guaranteed to be null-terminated - notably, configuration
> > directive arguments are always null-terminated, as well as input
> > headers.  The ngx_http_range_parse() uses an input header from
> > r->headers_in, and it's guaranteed to be null-terminated.
> >
> > The problem is in the "sample" code you've provided though: it
> > tries to modify input headers in r->headers_in.  This is wrong
> > thing to do.
>
> Thanks for the confirming all input headers should be null
> terminated, thats good to hear as thats what I did :)
>
> The task I'm trying to achieve is quite a strange thing to be doing,
> essentially I'm sending different headers to subrequests than the
> original client sent.
>
> I seems the only way to achieve this is to alter sr->headers_in
> as in the sample; unless there's another way to do this?
>
> As part of this project I've got a patch which adds the ability
> to do range requests from 206 responses to
> ngx_http_range_filter_module, is this something that you would
> consider upstreaming?
>
>     Regards
>     Steve
>
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 26 Aug 2014 09:40:57 +0200
> From: Samuel Martin <s.martin49 at gmail.com>
> To: nginx-devel at nginx.org
> Subject: Re: [PATCH 0 of 4 v3] Build-system: Cross-compilation support
>         improvement
> Message-ID:
>         <CAHXCMM+FRHB4oaH3c=
> OKWiSQ-4oFJ+dO7Pqv+scQ4MVqw_2hPw at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Is this a "444 No Response" answer?
>
> On Tue, Aug 12, 2014 at 4:03 PM, Samuel Martin <s.martin49 at gmail.com>
> wrote:
> > ping?
> >
> > On Sat, Aug 2, 2014 at 1:14 AM, Samuel Martin <s.martin49 at gmail.com>
> wrote:
> >> Hi all,
> >>
> >>
> >> Here is the 3rd round of this short series improving nginx build-system
> >> support for cross-compilation.
> >>
> >> This series fixes a couple of issues found in the previous submission.
> >> It still tries to be as less intrusive as possible, and intends to make
> >> easier integration in cross-compilataion frameworks such as Buildroot
> [1].
> >>
> >> These patches include most of the changes needed for porperly supporting
> >> the cross-compilation, except the sys_nerr guessing part [2], which
> cannot
> >> merged in nginx because it is too unix-oriented and based on fragile
> >> assumptions
> >>
> >>
> >> [1] http://buildroot.net/
> >> [2]
> https://github.com/tSed/buildroot/blob/nginx-integration/package/nginx/nginx-0005-auto-unix-make-sys_nerr-guessing-cross-friendly.patch
> >>
> >> Yours,
> >> Samuel
> >
> >
> >
> > --
> > Samuel
>
>
>
> --
> Samuel
>
>
>
> ------------------------------
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel at nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
>
> End of nginx-devel Digest, Vol 58, Issue 34
> *******************************************
>



-- 
Donatas
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