Topic: mod_ext_filter error

[stparker]

Dear Apache Lounge experts,

I have a custom input filter that I implemented using mod_ext_filter. It has been working well on server version 2.4.35 but is broken on 2.4.41. I am using the same http.conf file and nothing has changed in the server environment. I have not tested on the intervening versions.

I tested further using the "trace" filter example from the Apache Server 2.4.41 documentation with the same result.

Here is the snippet from the http.conf file:

ExtFilterDefine trace-filter mode=input \
cmd="C:/Perl64/bin/perl.exe C:/Apache24/conf/filters/trace_filter.pl"

<Location /trace>
ExtFilterOptions LogStderr
SetInputFilter trace-filter
</Location>

Here is the filter:

#!c:\perl64\bin\perl.exe
#
# Simple trace filter from Apache 2.4 mod_ext_filter documentation.
####################################################################
use strict;

open(SAVED, '>d:/trace.txt')
or die "Can't open trace.txt: $?";

while (<STDIN>) {
print SAVED $_;
print $_;
}

close (SAVED);


It works fine on 2.4.35. But on 2.4.41 the server returns a Bad Request error with the following in the error log:

[ext_filter:error] [pid xxxxx:tid xxxxx] (22)Invalid argument: [client xxx.xxx.xxx.xxx:xxxxx] AH01465: apr_file_pipe_timeout_set(child output)

I am thinking that 2.4.41 must be less forgiving about an issue in my configuration, but I'm stumped how to fix it.

Would anyone have any suggestions?

Thanks,

Steven

[glsmith]

No it looks like you squeezed a bug up to the surface. It looks to be in APR 1.7.0 because I at least see the perl script run and it creates a text file when using a 2.4.41 compiled with APR 1.6.5 like I did when I tried it with 2.4.35.

[dimitry_unified]

I found an Apache bug report for this issue, which was posted 2019-06-08: https://bz.apache.org/bugzilla/show_bug.cgi?id=63491

After some research it turns out that this was because the apr folks didn't merge a fix from trunk (r1809753 into the apr 1.7.x branch.

Pretty quickly, Nick Kew has merged it into 1.7.x in r1882155. So at some point this will hopefully end up in apr 1.7.1, when it is released.

I hope the Apache Lounge maintainers can include this one-liner into a new binary build of Apache 2.4.46, then external filters should start working again.

[Steffen]

What version you need to test.

A guess: VS16 Win64.

Coming days I apply the Patch to separate build, so you can test.

Steffen

[dimitry_unified]

[admin]

Here you go.

Applied :

revision 1882155 by niq, Wed Sep 30 13:54:18 2020 UTC:

[dimitry_unified]

Thank you, external filtering works fine now, with this build!

[Steffen]

New builds with the fix are available now.

Thanks! appreciate it.

Steffen