It's not safe to assume that "Local Redirect Response" is the only
valid use of the Location header.

-- 
Raul

On Sat, Mar 11, 2017 at 5:22 AM,  <[email protected]> wrote:
>>Synopsis:      httpd/slowcgi not RFC compliant w.r.t. Local Redirect Response
>>Category:      user
>>Environment:
>         System      : OpenBSD 6.0 (also under late Feb -current snapshot)
>         Details     : OpenBSD 6.0-stable (GENERIC.MP) #15: Fri Mar 10 
> 11:43:46 AEDT 2017
>                          
> [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
>
>         Architecture: OpenBSD.amd64
>         Machine     : amd64
>>Description:
>
> RFC 3875 The Common Gateway Interface (CGI) Version 1.1
> states:
> ====
> 6.2.2.  Local Redirect Response
>
>    The CGI script can return a URI path and query-string
>    ('local-pathquery') for a local resource in a Location header field.
>    This indicates to the server that it should reprocess the request
>    using the path specified.
>
>       local-redir-response = local-Location NL
>
>    The script MUST NOT return any other header fields or a message-body,
>    and the server MUST generate the response that it would have produced
>    in response to a request containing the URL
>
>       scheme "://" server-name ":" server-port local-pathquery
> ====
>
> httpd/slowcgi fails to comply with this and just returns the Location header
> to the client.
>
>>How-To-Repeat:
>
> # set up a target file
> echo "OK" > /var/www/htdocs/nbg.txt
>
> # create a simple CGI test program
> cat > t.c <<EOC
> #include <stdlib.h>
> #include <stdio.h>
>
> int
> main(__unused int argc, __unused char *argv[])
> {
>         fprintf(stdout, "Location: /nbg.txt\n\n");
>         return 0;
> }
> EOC
>
> # build the CGI program and install as /var/www/cgi-bin/t
> ...
>
> # try retrieving
> : user@host; printf "GET /cgi-bin/t HTTP/1.0\r\nHost: 
> www.example.org\r\n\r\n" \
> :; | nc www.example.org 80
> HTTP/1.0 200 OK
> Connection: close
> Date: Sat, 11 Mar 2017 07:01:23 GMT
> Location: /nbg.txt
> Server: OpenBSD httpd
>
> # "Location: /nbg.txt" is WRONG
>
> # in contrast, trying the equivalent under Apache http (on a Linux host) 
> gives:
> : user@host; printf "GET /cgi-bin/t HTTP/1.0\r\nHost: 
> www.example.org\r\n\r\n" \
> :; | nc www.example.org 80
> HTTP/1.1 200 OK
> Date: Sat, 11 Mar 2017 07:08:23 GMT
> Server: Apache
> Last-Modified: Sat, 11 Mar 2017 06:36:13 GMT
> ETag: "4e36ef-4-54a6eb1c95622"
> Accept-Ranges: bytes
> Content-Length: 3
> Connection: close
> Content-Type: text/plain
>
> OK
>
> # We see the file content, which is the correct behaviour.
>
>>Fix:
>         Not know; presumably patch(es) to httpd will be required.
>
>
> dmesg:
> OpenBSD 6.0-stable (GENERIC.MP) #15: Fri Mar 10 11:43:46 AEDT 2017
>     [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> real mem = 17041805312 (16252MB)
> avail mem = 16520851456 (15755MB)
> mpath0 at root
> scsibus0 at mpath0: 256 targets
> mainbus0 at root
> <deleted as presumed to be irrelevant>
>

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