Bug#873051: exim4: Exim dumps binary into logfile for DKIM i= field.

[Peter Chubb]

Package: exim4
Version: 4.89-5
Severity: normal

Dear Maintainer,

I'm seeing lines like this in /var/log/exim4/mainlog:

2017-08-23 10:43:51 1dkJlu-0002RD-3Z DKIM: d=reply.shoppingexpress.com.au s=key2 c=relaxed/relaxed a=rsa-sha256 b=1024 i=<BE><8C><99>T<F6><<ED><9D>^F<C1>^L<EE>
^W<CF><F6><F7><B0><CF>x<C7>>4<DD>F^Z<D6> b=1024

When viewed in my MUA, the i= line is more sane:
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; s=key2; d=reply.shoppingexpress.com.au; h=To:Subject:From:MIME-Version:List-Id:List-Unsubscribe:Content-Type:Message-ID:Date; i=promotion at reply.shoppingexpress.com.au; bh=wRB+kyVA7TzcttnzAPNgRyPwu8OYE/zPGMY7ztfyo4s=; b=lGwQjIsqH+OXjC2IKD6+Ok7LtTnm8rU4BrZnQvqoCiybFnGY7SAUfzyddaUfb6rvJEHlBvb/19ur   wrlXjhtS9Vs0OUHYMBvvWtZjO2IRcg2o7C/UItzHETvUcKT/pFFbcSWVN+YppdcG2Y8njYaiw9pA   z1bJrbqzr3O/2DawMQg=

I expect the i= line in the logs to be the same as the i= line in the
DKIM header.

-- Package-specific info:
Exim version 4.89 #2 built 10-Aug-2017 08:17:05
Copyright (c) University of Cambridge, 1995 - 2017
(c) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007 - 2017
Berkeley DB: Berkeley DB 5.3.28: (September  9, 2013)
Support for: crypteq iconv() IPv6 GnuTLS move_frozen_messages DKIM DNSSEC Event OCSP PRDR SOCKS TCP_Fast_Open
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmjz dbmnz dnsdb dsearch nis nis0 passwd
Authenticators: cram_md5 plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore autoreply lmtp pipe smtp
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Configuration file is /var/lib/exim4/config.autogenerated
# /etc/exim4/update-exim4.conf.conf
#
# Edit this file and /etc/mailname by hand and execute update-exim4.conf
# yourself or use 'dpkg-reconfigure exim4-config'
#
# Please note that this is _not_ a dpkg-conffile and that automatic changes
# to this file might happen. The code handling this will honor your local
# changes, so this is usually fine, but will break local schemes that mess
# around with multiple versions of the file.
#
# update-exim4.conf uses this file to determine variable values to replace
# the DEBCONFsomethingDEBCONF strings in the configuration template files.
#
# Most settings found in here do have corresponding questions in the
# Debconf configuration, but not all of them.
#
# This is a Debian specific file

dc_eximconfig_configtype='smarthost'
dc_other_hostnames='wombat.cf:numbat.tk:chubb.wattle.id.au:wombat:wombat.chubb.wattle.id.au:smtp.chubb.wattle.id.au:mail.chubb.wattle.id.au:mail:smtp'
dc_local_interfaces=''
dc_readhost='chubb.wattle.id.au'
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets='192.168.77.0/24 ; 192.168.77.80/24 ; 2001:0388:d000::/48'
dc_smarthost='mx3.chubb.wattle.id.au::587'
#dc_smarthost='mail.optusnet.com.au'
CFILEMODE='644'
dc_use_split_config='true'
dc_hide_mailname='true'
dc_mailname_in_oh='true'
dc_localdelivery='mail_spool'
mailname:wombat.chubb.wattle.id.au
# /etc/default/exim4
EX4DEF_VERSION=''

# 'combined' -	 one daemon running queue and listening on SMTP port
# 'no'       -	 no daemon running the queue
# 'separate' -	 two separate daemons
# 'ppp'      -   only run queue with /etc/ppp/ip-up.d/exim4.
# 'nodaemon' - no daemon is started at all.
# 'queueonly' - only a queue running daemon is started, no SMTP listener.
# setting this to 'no' will also disable queueruns from /etc/ppp/ip-up.d/exim4
QUEUERUNNER='combined'
# how often should we run the queue
QUEUEINTERVAL='30m'
# options common to quez-runner and listening daemon
COMMONOPTIONS=''
# more options for the daemon/process running the queue (applies to the one
# started in /etc/ppp/ip-up.d/exim4, too.
QUEUERUNNEROPTIONS=''
# special flags given to exim directly after the -q. See exim(8)
QFLAGS=''
# Options for the SMTP listener daemon. By default, it is listening on
# port 25 only. To listen on more ports, it is recommended to use
# -oX 25:587:10025 -oP /var/run/exim4/exim.pid
SMTPLISTENEROPTIONS='-oX 25:586:587 -oP /var/run/exim4/exim.pid'

-- System Information:
Debian Release: buster/sid
  APT prefers oldstable
  APT policy: (990, 'oldstable'), (300, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.8.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages exim4 depends on:
ii  debconf             1.5.63
ii  exim4-base          4.89-5
ii  exim4-daemon-light  4.89-5

exim4 recommends no packages.

exim4 suggests no packages.

-- debconf information:
  exim4/drec: