Crash in sieve_extprogram_create() after dovecot/pigeonhole update

[Oleksandr Natalenko]

Hi all.

My dovecot setup:

pf at vulcan:~ » dovecot --version
2.3.0 (c8b89eb)

on Arch Linux, x86_64 (full config here: [0])

uses sieve plugin to train rspamd system as described in the wiki [1]. It used 
to work fine prior to 2.3.0/0.5.0 update, but now "imap" process crashes when 
I move spam letters from the inbox to the junk folder.

I've recompiled both dovecot and pigeonhole with debug symbols and got this 
stacktrace [2].

As you can see, it fails (with a SIGSEGV) in sieve_extprogram_create(), sieve-
extprograms-common.c:562, which corresponds to this code:

===
562     if ( !smtp_address_isnull(msgdata->envelope.rcpt_params->orcpt.addr) ) 
{
563         program_client_set_env
564             (sprog->program_client, "ORIG_RECIPIENT",
565                 smtp_address_encode(msgdata->envelope.rcpt_params-
>orcpt.addr));
566     }
===

When I dump msgdata structure, I see that rcpt_params is NULL: [3]. Thus, NULL 
pointer dereference occurs.

Here is my report-spam.sieve file: [4]

What I'm doing wrong here? Or is this some bug within pigeonhole? Could you 
please help me with resolving this?

Thanks.

[0] https://gist.github.com/92be2a4abe04149fd4b6971b6b4fa38d
[1] https://wiki2.dovecot.org/HowTo/AntispamWithSieve
[2] https://gist.github.com/8b202ebe9310845b59bcdeed7567026e
[3] https://gist.github.com/a7e30b9e7a6c315d729bdcfe7142f532
[4] https://gist.github.com/fd1aa8943af106408a30155dffe052ab