On Sat, Jan 13, 2018 at 09:39:44AM +0100, Anton Lindqvist wrote:
> On Tue, Jan 09, 2018 at 05:38:57PM +0100, Hidvégi Gábor wrote:
> > >Synopsis: httpd reports wrong mimetype when item is in the browser cache
> > >Category: httpd
> > >Environment:
> > System : OpenBSD 6.2
> > Details : OpenBSD 6.2 (GENERIC) #91: Wed Oct 4 00:35:21 MDT
> > 2017
> >
> > [email protected]:/usr/src/sys/arch/armv7/compile/GENERIC
> >
> > Architecture: OpenBSD.armv7
> > Machine : armv7
> > >Description:
> >
> > httpd serves static files (eg. images) with Last-Modified http header. When
> > a browser next time asks whether this file changed (sends If-Modified-Since
> > http header) httpd responds with wrong mimetype, 'text/html' when the
> > resource is in the browser cache (304 Not Modified status code).
> >
> > >How-To-Repeat:
> >
> > This bug is common, not arm only. When for example you open this image:
> > https://man.openbsd.org/openbsd.gif
> >
> > in a browser with developer tools (F12) open, on the network tab you can
> > take a look at the response headers, mimetype is correct (image/gif). After
> > opening press refresh (F5) and look at the response headers again, and you
> > get the incorrect mimetype, 'text/html'.
> >
> > >Fix:
> >
> > check httpd source
>
> Please try out this diff, it makes sure to set the correct MIME-type and
> not respond with a body if the resource has not changed. Sending this to
> tech@ as well.
>
> Index: server_file.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/httpd/server_file.c,v
> retrieving revision 1.65
> diff -u -p -r1.65 server_file.c
> --- server_file.c 2 Feb 2017 22:19:59 -0000 1.65
> +++ server_file.c 12 Jan 2018 19:10:20 -0000
> @@ -230,8 +230,15 @@ server_file_request(struct httpd *env, s
> goto abort;
> }
>
> - if ((ret = server_file_modified_since(clt->clt_descreq, st)) != -1)
> - return (ret);
> + if (server_file_modified_since(clt->clt_descreq, st) == 0) {
> + media = media_find_config(env, srv_conf, path);
> + ret = server_response_http(clt, 304, media, 0,
> + st->st_mtim.tv_sec);
> + if (ret != -1)
> + goto done;
> + else
> + goto fail;
> + }
>
> /* Now open the file, should be readable or we have another problem */
> if ((fd = open(path, O_RDONLY)) == -1)
> @@ -663,10 +670,10 @@ server_file_modified_since(struct http_d
> if (strptime(since->kv_value,
> "%a, %d %h %Y %T %Z", &tm) != NULL &&
> timegm(&tm) >= st->st_mtim.tv_sec)
> - return (304);
> + return (0);
> }
>
> - return (-1);
> + return (1);
> }
>
> int
>
Hey,
I've tested your patch.
When requesting a non-modified CSS file:
#!/bin/sh
host="127.0.0.1"
port="6970"
printf 'GET /style.css HTTP/1.1\r\nHost: %s:%s\r\nIf-Modified-Since:
Sat, 16 Dec 2017 13:07:53 GMT\r\nConnection: close\r\n\r\n' "$host" "$port" | \
nc "$host" "$port"
Full HTTP response:
HTTP/1.1 304 Not Modified
Connection: close
Content-Length: 0
Content-Type: text/css
Date: Sat, 13 Jan 2018 11:54:13 GMT
Last-Modified: Sun, 05 Mar 2017 12:22:05 GMT
Server: OpenBSD httpd
I wonder if httpd should just omit the response header Content-Length and
Content-Type entirely for this statuscode. Some httpd such as Nginx just
omit them aswell.
At the moment responses with redirects (statuscode 301 and 302) also
output a body response. Maybe it is better to handle it in server_http.c
in the function server_abort_http() and not output the body there for some
response status codes? I'm not sure.
--
Kind regards,
Hiltjo
