could not read from amavisd socket /var/amavis/amavisd.sock: No error: 0

[Fabian Wenk]

Hello

I am running amavisd-new with Sendmail and amavisd-milter on FreeBSD 
12.4, which is installed from FreeBSD Ports. At the end of October I did 
upgrade Perl from 5.34 to 5.36 (including rebuild all depending Ports). 
Today somebody pointed out to me, that sending emails to my server does 
reproducible fail. With digging into this I figured out that this errors 
started a few days after the Perl upgrade.

amavisd-milter then does log this line:
could not read from amavisd socket /var/amavis/amavisd.sock: No error: 0

and the sender gets the following reject message:
451 4.6.0 Content scanner malfunction

With some improvements in configuration in amavisd-new and 
amavisd-milter and testing I have currently a workaround in place with 
the -P option for amavisd-milter.

Initially I did disable amavisd-milter in my Sendmail config and then 
some of the previously rejected emails went through. As now the 
workaround is in place, I figured out that the common thing of this 
emails is the presence of more then one 'DKIM-Signature:' line, e.g. 2 
or even up to 4.

Used versions:
amavisd-milter 1.7.0
amavisd-new 2.12.2

FreeBSD Ports:
https://cgit.freebsd.org/ports/tree/security/amavisd-milter
https://cgit.freebsd.org/ports/tree/security/amavisd-new

Any idea why this now fails with Perl 5.36?


Best regards,
Fabian