[Rspamd-Users] Rspamd Antivirus / F-Prot invalid request string

[Rob Gunther]

I set up a server running Rspamd 1.9.4, using the anti-virus module to
interface with F-PROT Antivirus for Linux v6.2.39.

It works, mostly.

I don't know how often (a few %) but some requests from Rspamd to F-PROT
end up going badly.

I don't see any error being generated on Rspamd side but f-prot will
generate hundreds of line entries like this:

Invalid request string '٭��7�kK��*#0053�#023�\)葛7!LkF��#035�(���~���'
Invalid request string '8?�1�[g�#014[#003�#022�'

I would assume F-PROT is still waiting for a command but Rspamd thinks it
is ready to send the attachment.  When Rspamd starts sending the file for
scanning it results in all the errors on f-prot side.

I have setup Rspamd to only send mime parts.

    scan_mime_parts = true;
    scan_text_mine = false;
    scan_image_mime = false;

Obviously I need to capture a sample message that is causing this, but it
is on a live server with a lot of mail so knowing which message is causing
it is a bit difficult.

Anyone got a debugging suggestion?