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