299a2315c1
* Add a migration to delete any existing DKIM key so that existing machines get a fresh 2048-bit key. (Sadly we don't support key rotation so the change is immediate.)
* Because the DNS record for a 2048-bit key is so much longer, the way we read OpenDKIM's DNS record text file had to be modified to combine an arbitrary number of TXT record quoted ("...") strings.
* When writing out the TXT record value, the string must be split into quoted ("...") strings with a maximum length of 255 bytes each, per the DNS spec.
* Added a changelog entry.
81 lines
2.9 KiB
Bash
Executable file
81 lines
2.9 KiB
Bash
Executable file
#!/bin/bash
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# OpenDKIM
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# --------
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#
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# OpenDKIM provides a service that puts a DKIM signature on outbound mail.
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#
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# The DNS configuration for DKIM is done in the management daemon.
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source setup/functions.sh # load our functions
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source /etc/mailinabox.conf # load global vars
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# Install DKIM...
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apt_install opendkim opendkim-tools opendmarc
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# Make sure configuration directories exist.
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mkdir -p /etc/opendkim;
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mkdir -p $STORAGE_ROOT/mail/dkim
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# Used in InternalHosts and ExternalIgnoreList configuration directives.
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# Not quite sure why.
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echo "127.0.0.1" > /etc/opendkim/TrustedHosts
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if grep -q "ExternalIgnoreList" /etc/opendkim.conf; then
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true # already done #NODOC
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else
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# Add various configuration options to the end of `opendkim.conf`.
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cat >> /etc/opendkim.conf << EOF;
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MinimumKeyBits 1024
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ExternalIgnoreList refile:/etc/opendkim/TrustedHosts
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InternalHosts refile:/etc/opendkim/TrustedHosts
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KeyTable refile:/etc/opendkim/KeyTable
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SigningTable refile:/etc/opendkim/SigningTable
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Socket inet:8891@localhost
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RequireSafeKeys false
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EOF
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fi
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# Create a new DKIM key. This creates mail.private and mail.txt
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# in $STORAGE_ROOT/mail/dkim. The former is the private key and
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# the latter is the suggested DNS TXT entry which we'll include
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# in our DNS setup. Note tha the files are named after the
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# 'selector' of the key, which we can change later on to support
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# key rotation.
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#
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# A 1024-bit key is seen as a minimum standard by several providers
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# such as Google. But they and others use a 2048 bit key, so we'll
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# do the same. Keys beyond 2048 bits may exceed DNS record limits.
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if [ ! -f "$STORAGE_ROOT/mail/dkim/mail.private" ]; then
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opendkim-genkey -b 2048 -r -s mail -D $STORAGE_ROOT/mail/dkim
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fi
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# Ensure files are owned by the opendkim user and are private otherwise.
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chown -R opendkim:opendkim $STORAGE_ROOT/mail/dkim
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chmod go-rwx $STORAGE_ROOT/mail/dkim
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tools/editconf.py /etc/opendmarc.conf -s \
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"Syslog=true" \
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"Socket=inet:8893@[127.0.0.1]"
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# Add OpenDKIM and OpenDMARC as milters to postfix, which is how OpenDKIM
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# intercepts outgoing mail to perform the signing (by adding a mail header)
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# and how they both intercept incoming mail to add Authentication-Results
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# headers. The order possibly/probably matters: OpenDMARC relies on the
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# OpenDKIM Authentication-Results header already being present.
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#
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# Be careful. If we add other milters later, this needs to be concatenated
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# on the smtpd_milters line.
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#
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# The OpenDMARC milter is skipped in the SMTP submission listener by
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# configuring smtpd_milters there to only list the OpenDKIM milter
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# (see mail-postfix.sh).
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tools/editconf.py /etc/postfix/main.cf \
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"smtpd_milters=inet:127.0.0.1:8891 inet:127.0.0.1:8893"\
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non_smtpd_milters=\$smtpd_milters \
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milter_default_action=accept
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# Restart services.
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restart_service opendkim
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restart_service opendmarc
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restart_service postfix
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