The panel's signer is the only one. Gone: the opendkim package and its
configuration, the syslog-relay and opendkim programs, /dev/log and
/run/opendkim, the reload by USR1 through supervisord
(internal/supervisor/supervisor.go), internal/syslogrelay, the port of
OpenDKIM's From: parser (internal/milter/mailparse.go and its probe,
harness and test/upstream scripts), OPENDKIM_SOCKET and OPENDKIM_DIR.
Keys: internal/domain/keys.go (Keys, NewKeys, DKIM_DIR=/data/dkim) keeps
the keys and writes a selector table, /data/dkim/selectors ("<name>
<selector>"), which the signer reads in place of the KeyTable - it reads
no database, as the sender check reads none. The table is written before
the signer serves (EnsureServerSigned moved there from the notifier).
Keys and table 0600, directories 0700, the panel's. The entrypoint copies
/data/opendkim/keys once, as the panel user, into /data/dkim.new renamed
when whole, and stops the start if the copy fails; /data/opendkim is left
for a rollback to 2.7.x.
Sender check: one RFC 5322 address as a mail program reads it, held
against the bindings; the 256-byte refusal and the texts naming OpenDKIM
go. Allowed() folded the domain through strings.ToLower, which makes the
Kelvin sign a "k" - the comparison with OpenDKIM's reading had hidden it;
it folds ASCII only now.
Health: two dkim-signer rows (applications, notifications) in Milter
sockets, opendkim out of the liveness set; the card no longer takes any
row with a note for the spam filter. Texts as in the design commit.
KILL stays in deploy/docker-compose.yml: measured on the test server,
root without it cannot signal a process of another uid - supervisord
stopping the panel, Postfix's master its children. The plan's "only use
was the reload" was wrong; the comment now gives the real uses.
e2e: one signature, the panel's, verified by dkimpy; the /data/dkim modes;
the OpenDKIM log and process checks, testNeverSignedForAnother and the
cited opendkim, libopendkim11 and libmilter1.0.1 go.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
internal/milter/sign.go: a milter on two sockets (cmd/panel/signer.go):
sign.sock for 465/587, the key of the domain the SASL login belongs to
(Bindings.DomainOf, the sender_login_maps Postfix reads), and
sign-local.sock for the panel's own sendmail(1) mail, the server's name.
go-msgauth/dkim v0.7.0, relaxed/simple, OpenDKIM's dkim_should_signhdrs[]
(libopendkim/dkim.c:223-246) in message order plus From once more; keys
and selectors from the KeyTable the panel writes, a key path outside the
key directory refused; strict - whatever cannot be signed is deferred.
From the sources: Postfix 3.10.13 milter8.c:2329-2400 hands a folded
header \n-separated, so the signer joins its lines with CRLF; inserts are
1-based in cleanup_ins_header() (cleanup_milter.c:1193), so index 0 is the
top, where OpenDKIM puts its own (opendkim.c:3673). go-milter v0.4.1 calls
no Abort when a connection ends, so a watchdog closes go-msgauth's
streaming signer after an hour and a late end of message is deferred.
Postfix: smtpd_milters = sender check, signer, OpenDKIM, journal;
non_smtpd_milters = the signer's local socket, OpenDKIM - both sign every
message until stage 2. disable_mime_output_conversion=yes (default off,
mail_params.h:3088): an 8-bit message is no longer re-encoded after it is
signed.
Tests: unit tests sign and verify folded, tab-led and space-free headers,
an added From:, a changed body, two messages on a connection, odd bodies,
and five cases deferred. e2e: the sink image has python3-dkim (dkimpy
1.1.8-2) and the stand's DNS; on an application's message and on a
notification the two signatures must agree on h=, bh=, c=, s=, a= and each
must pass dkimverify. On the server: make e2e exit 0 (714 s), go vet + go
test 27 packages ok.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The runtime base is debian:trixie-slim, the build stage golang:1.26-trixie:
Postfix 3.10.13 with upstream's 2026 security fixes up to the August
batch, libmilter 8.18.1, OpenSSL 3.5. Every citation of another program in
code, scripts and documents was re-read against the trixie sources
(dev/upstream; bookworm's kept in dev/upstream-bookworm) and updated;
development.md's cited-package table holds the trixie versions.
What the re-reading changed in behaviour:
- logtail: reject lines with sasl_method/sasl_username/sasl_sender
(smtpd_check.c:1019-1026); cleanup's "removed (canceled)" forgets a
port-25 id (cleanup_api.c:363-364).
- internal/postfix/retry.go reads postconf's stdout only: since 3.9 a
deprecated-parameter warning on stderr made one value too many and the
panel fell back to the compiled-in retry policy.
- logrotate-loop.sh: logrotate 3.22 exits 1 when it ignores a config;
the loop refuses on that output whatever the status.
- postfix-config.sh: cyrus_sasl_config_path set explicitly (bookworm's
07_sasl_config.diff is gone); maillog_file_permissions=0640; mynetworks
explicit; Dockerfile: SYNC_CHROOT= in /etc/default/postfix,
opendkim-tools dropped, openssl named, systemd-standalone-sysusers so
cron does not bring the whole of systemd.
- The selfpost group is 10998, outside the system range 100-999: in
trixie a package took 998 and the build failed (owner's decision:
a conflict-free id, the distribution's own ids untouched). The
entrypoint hands /data back by name when the user or the group differs.
Guide, backup refusal text, help (design commit 68ec8b2), e2e.
- smtpd_hide_client_session=yes on smtps and submission (owner's
decision): Received: names no client, TLS, login or protocol; port 25
keeps the full header. e2e checks both.
- test/upstream/opendkim-probe.sh makes keys with openssl genrsa.
Tests: on the server, make e2e exit 0 (674 s, the image built on trixie),
go vet + go test 27 packages ok. CHANGELOG [Unreleased], guide,
architecture.md, security.md, roadmap.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Comments only, no behaviour changed. Each main.cf/master.cf parameter the
build sets, the wrapper's and the reload hook's reliance on Postfix 3.7.11
(postfix-script, master.5, postconf.5, cleanup_init.c, smtpd_peer.c,
README_FILES), supervisor 4.2.5 (process.py, options.py, events.rst),
logrotate 3.21.0, OpenDKIM's config, Cyrus SASL's sasldb, rspamd 3.11.1
(milter_headers.lua, multimap, the map watcher), Docker Compose, CoreDNS
and certbot now say where that is written. Measurements already there stay
measurements ("date not recorded" where none was); hand-composed fixtures
say so.
Contradictions left for their own commits: C-P31 cleanup's size limit,
C-P42 master outside supervisor's signal, C-V5/V6 startsecs, C-V10,
C-S3/Q3 sasldb written in place, C-Q4/A1 certbot's symlinks, C-R7 rspamd
skips local clients but the signature routine does not, C-P8, C-R4, C-R12,
C-M7, C-E2, C-K8/K9, C-D1.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Initial feature-complete implementation of the v1.0 specification (phases 0-11 of `docs/implementation-plan.md`).
Added:
- Panel (Go, single static binary) with SQLite persistence, one-time
- Domain management with per-domain DKIM (RSA-2048, generated in pure Go) and
- Application (sender identity) management: SASL credentials via `sasldb2`,
- Full Postfix relay config generated from env at container start: SMTPS 465,
- Journal milter (pure Go, `go-milter`) recording every send to `send_log`;
… (6 more in CHANGELOG)
Full detail: CHANGELOG.md (0.1.0).
mixandClaude Opus 5.5