OpenDKIM fails to load when comments are present

[Kaz Wolfe]

Affects: OpenDKIM version 2.10.3

If a comment is present after the `SOCKET=` line in `/etc/default/opendkim` like below, OpenDKIM will fail to launch, citing invalid usage.

    # Command-line options specified here will override the contents of
    # /etc/opendkim.conf. See opendkim(8) for a complete list of options.
    #DAEMON_OPTS=""
    #
    # Uncomment to specify an alternate socket
    # Note that setting this will override any Socket value in opendkim.conf
    #SOCKET="local:/var/run/opendkim/opendkim.sock" # default
    #SOCKET="inet:54321" # listen on all interfaces on port 54321
    #SOCKET="inet:12345@localhost" # listen on loopback on port 12345
    #SOCKET="inet:12345@192.0.2.1" # listen on 192.0.2.1 on port 12345
    SOCKET="inet:12301@localhost" # just a "harmless" little comment

Relevant excerpt from journalctl:

    Jan 14 13:04:43 hostname systemd[1]: Starting DomainKeys Identified Mail (DKIM) Milter...
    -- Subject: Unit opendkim.service has begun start-up
    -- Defined-By: systemd
    -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
    --
    -- Unit opendkim.service has begun starting up.
    Jan 14 13:04:43 hostname opendkim[3173]: opendkim: usage: opendkim -p socketfile [options]
    Jan 14 13:04:43 hostname opendkim[3173]: -A auto-restart
    Jan 14 13:04:43 hostname opendkim[3173]: -b modes select operating modes
    Jan 14 13:04:43 hostname opendkim[3173]: -c canon canonicalization to use when signing
    Jan 14 13:04:43 hostname opendkim[3173]: -d domlist domains to sign
    Jan 14 13:04:43 hostname opendkim[3173]: -D also sign subdomains
    Jan 14 13:04:43 hostname opendkim[3173]: -e name extract configuration value and exit
    Jan 14 13:04:43 hostname opendkim[3173]: -f don't fork-and-exit
    Jan 14 13:04:43 hostname opendkim[3173]: -F time fixed timestamp to use when signing (test mode only)
    Jan 14 13:04:43 hostname opendkim[3173]: -k keyfile location of secret key file
    Jan 14 13:04:43 hostname opendkim[3173]: -l log activity to system log
    Jan 14 13:04:43 hostname opendkim[3173]: -L limit signature limit requirements
    Jan 14 13:04:43 hostname opendkim[3173]: -n check configuration and exit
    Jan 14 13:04:43 hostname opendkim[3173]: -o hdrlist list of headers to omit from signing
    Jan 14 13:04:43 hostname opendkim[3173]: -P pidfile file into which to write process ID
    Jan 14 13:04:43 hostname opendkim[3173]: -q quarantine messages that fail to verify
    Jan 14 13:04:43 hostname opendkim[3173]: -Q query test mode
    Jan 14 13:04:43 hostname opendkim[3173]: -r require basic RFC5322 header compliance
    Jan 14 13:04:43 hostname opendkim[3173]: -s selector selector to use when signing
    Jan 14 13:04:43 hostname opendkim[3173]: -S signalg signature algorithm to use when signing
    Jan 14 13:04:43 hostname opendkim[3173]: -t testfile evaluate RFC5322 message in "testfile"
    Jan 14 13:04:43 hostname opendkim[3173]: -T timeout DNS timeout (seconds)
    Jan 14 13:04:43 hostname opendkim[3173]: -u userid change to specified userid
    Jan 14 13:04:43 hostname opendkim[3173]: -v increase verbosity during testing
    Jan 14 13:04:43 hostname opendkim[3173]: -V print version number and terminate
    Jan 14 13:04:43 hostname opendkim[3173]: -W "why?!" mode (log sign/verify decision logic)
    Jan 14 13:04:43 hostname opendkim[3173]: -x conffile read configuration from conffile
    Jan 14 13:04:43 hostname systemd[1]: opendkim.service: Control process exited, code=exited status=64
    Jan 14 13:04:43 hostname sudo[3162]: pam_unix(sudo:session): session closed for user root
    Jan 14 13:04:43 hostname systemd[1]: Failed to start DomainKeys Identified Mail (DKIM) Milter.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[David Bürgin (glts)]

I’ve checked the code, and unfortunately I’m unable see how the comments
could possibly have any bearing on the behaviour. In any case I am
unable to reproduce this with opendkim version 2.11.0~alpha-11 (Ubuntu
18.04).

[Launchpad Janitor (janitor)]

[Expired for opendkim (Ubuntu) because there has been no activity for 60 days.]