zlib plugin producing errors on 2.3.0

[Timo Sirainen]

On 5 Jan 2018, at 18.33, Carsten Uppenbrink <info at uppenbrink.net> wrote:
> 
> On 24.12.2017 15:58, Adam Weinberger wrote:
>> Hello,
>> I use the zlib and imap_zlib plugins on FreeBSD. As of 2.3.0, my logs
>> are producing these errors every so often, but AFAICT the messages
>> themselves aren't getting corrupted.
>> Panic: file ostream-zlib.c: line 36 (o_stream_zlib_close): assertion
>> failed: (zstream->ostream.finished ||
>> zstream->ostream.ostream.stream_errno != 0)
>> Fatal: master: service(imap): child 80128 killed with signal 6 (core
>> not dumped - set service imap { drop_priv_before_exec=yes })
>> Panic: file ostream-zlib.c: line 36 (o_stream_zlib_close): assertion
>> failed: (zstream->ostream.finished ||
>> zstream->ostream.ostream.stream_errno != 0)
>> Fatal: master: service(imap): child 80266 killed with signal 6 (core
>> not dumped - set service imap { drop_priv_before_exec=yes })
>> They always come in pairs like that. Following is my doveconf. Let
>> me know what else I can provide here. Thanks!
> 
> I had this errors in my logs, too.
> 
> It happens only to users who using K-9 Mail on Android. They all had a setting enabled called "Use compression on network: Mobile, Wi-Fi, Other" in "Incoming server settings". I didn't looked for other imap clients, because without this setting enabled the errors vanished.
> 
> But it is likely that there are other imap clients who try to compress the transfer.
> No stored mails are corrupted, it is only the connection somehow.

Oh, it's the imap_zlib plugin / IMAP COMPRESS extension that is crashing. Looks like it happens every time when COMPRESS-enabled client disconnects, so it's probably not visible to clients.