5 Commits
Author SHA1 Message Date
mixandClaude Opus 5.5 c2f63d2789 panel-dkim-signing: the queue by name, and findings of the reviews
test / test (push) Canceled after 0s
The first rollout of faa3c11 to the test server crash-looped: without
opendkim the image's package accounts got other numbers (postfix 101 ->
100, postdrop 103 -> 102), the queue under /data kept the old ones, and
postsuper, which "postfix check" runs as the mail owner
(src/postsuper/postsuper.c:1442), could not open it. Rolled back within
five minutes. The entrypoint now hands an existing queue to Postfix's users
by name before postfix-config.sh, and again after it (own_queue).

Technical review (F1-F10):
- F1 high: a backup of an upgraded installation carried /data/opendkim, a
  restore left it root's, and the panel refused every start. The tree is
  left out of archives, and the entrypoint makes it the panel's alone
  (0700/0600; also the security review's F3 - nothing of 2.8 needs the
  group any more; a 2.7.x start re-normalises it).
- F2: List-Unsubscribe-Post is signed (RFC 8058); Sender too (security F1).
- F3: SetServerName keeps the name in lower case - a key written under
  "Mail.Example.com" was never found. Only the DKIM side: the SASL realm
  is compared as written.
- F4: the signer rewrites the selector table at every start
  (WriteSelectors, replacing EnsureServerSigned), and tries again every
  10 s while a rewrite fails.
- F5: e2e signature_over_awkward_headers (folded, tab-led, no space, two
  To:, 8-bit body, List-Unsubscribe-Post) checked by dkimpy;
  TestStartsOnA27Data starts on a 2.7 /data (old key tree, a queue of
  foreign numbers) and checks the copied key signs, the old tree's modes
  and the queue's owners; unit tests for repeated headers and the header
  limit.
- F6: the table's writers are serialised (tableMu).
- F7: the table is read for every message; keys the table no longer names
  are dropped from memory.
- F8: the signature's value brings its own space (SMFIP_HDR_LEADSPC gets
  none from Postfix, cleanup_milter.c:1085).
- F9: a body line over 998 bytes is logged with its domain: Postfix's SMTP
  client breaks it after signing (smtp_proto.c:1266-1274).
- F10: the keys are copied while /data/dkim holds none (not only when it
  is absent), after the old tree is made the panel's (an install from 2.6
  had another uid); the plan's rollback note says what a rollback keeps.

Security review: F2 a header section over 1 MiB is refused (552 5.3.4)
and the kept headers freed once the block is built - fifty connections of
header-only messages could take the panel down; F5 the shown headers a
message has (Subject, Date, To, Cc, Reply-To, Sender) are over-signed,
only when present, since cleanup adds a missing Date: after the milters.
F1 (holding Sender: to the login like From:) changes what is refused and
waits for the owner.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-16 01:44:59 +03:00
mixandClaude Opus 5.5 faa3c11ae7 panel-dkim-signing stage 2: OpenDKIM removed
test / test (push) Canceled after 0s
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>
2026-10-16 01:05:39 +03:00
mixandClaude Opus 5.5 f09b60aaa2 panel-notifications: findings of the technical and security reviews
test / test (push) Canceled after 0s
Neither review (read-only agents, Opus and Fable, over 972a9f8..400aa76) has
a Critical finding. Both found the same serious one, and more:

- The notification about refused mail was built on what a rejected row says
  of itself. Its domain is the one in MAIL FROM, which the client typed and
  Postfix has not yet held against the login when the milter refuses: an
  application over its limit could have had the panel write a message per
  made-up domain, to another tenant's users among others. And the same
  status is written when an application is refused for its client address,
  which is no limit. Refusals are now counted by the domain the login is
  registered under, only for logins that exist and only while a limit is set
  on the login or its domain; one subject per sending domain. They are read
  through a partial index of their own (migration 0005): the query walked
  the whole send log every minute.
- Account and user e-mails were checked with the DMARC report validator,
  which refuses Gmail and the like - the owner's own kind of address. A new
  validate.AccountEmail accepts them and refuses a local part beginning "-".
- "Said" now means sent: what arises while nobody can be told, or while
  Postfix does not take the message, is told at a later check. Its ending
  with nobody left to tell is simply over.
- Two DNS checks must be 45 minutes apart as well as two: the last check
  before a restart and the first after it were minutes apart.
- The notifier's own mail waiting in the queue, and its bounce coming back
  to postmaster@ this server, are not the queue's subject. A listing cut at
  its size limit or with a line too long to read is no listing; postqueue -j
  gets 30 seconds.
- The tables must name the selector the panel shows, not only have the line.
- An a/mx lookup that did not answer inside the SPF check made the record
  "not authorising"; it is "cannot tell" now, for the pages too.
- A ceiling of 60 messages an hour; a pass stops between domains when the
  process is asked to stop; sendmail gets a WaitDelay; days are rounded as a
  person counts; a failed read of the switch shows it on, not off.

Recorded as accepted in security.md, with a roadmap candidate
(from-header-binding): an application can have a message signed as the
server's own name - or, as always, as another registered domain - by writing
it into the From: header, which nothing holds against the login.

Left as found: a recipient whose copy failed while another's went out is not
tried again; a certificate that lives under 14 days is reported at each
renewal.

On the test server, for this tree: go vet clean, go test ./... 23 packages
ok, make e2e ok (326 s).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 17:00:01 +03:00
mixandClaude Opus 5.5 400aa76737 panel-notifications: the start puts the server's name into OpenDKIM's tables
test / test (push) Canceled after 0s
Found on the test server after the rollout of b905f3e: the SigningTable had
the three sending domains and no line for selfpost.mixfed.ru. The tables are
rebuilt when a domain is added or deleted, and nothing had done either since
the upgrade - notifications would have gone out unsigned until something did.
The e2e stand did not show it: it adds a domain right after its start.

The notifier now asks at its start whether the table on disk has the line
and rebuilds the tables once if it does not (domain.Service.EnsureServerSigned).
A failure is logged and costs the signature, not the message.

Checked on Windows: go vet clean; go test ./internal/domain passes apart from
TestWriteLoadPrivateKeyRoundtrip, which fails there on file modes and always
did; the new test holds one rebuild, none the second time, and that a longer
name is not taken for the server's.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 16:27:34 +03:00
mixandClaude Opus 5.5 50fd6b859f panel-notifications: the notifier, its mail and the server's own DKIM key
internal/notify applies the owner's rules. Each subject has a row of state,
so a thing is said once and a restart says nothing again:

- DNS of a sending domain: said after two hourly checks in a row found a
  record wrong, said to be over after two found it right. A lookup that did
  not answer moves nothing; a warning (no DMARC record) is not a subject.
- TLS certificate: at 14 days and at 3, per certificate.
- Queue: a message older than three days, once; once more when none is.
- Level-2 limit: from the rejected rows of the send log, every five minutes;
  at most once a day per domain and application.

Global users are told everything, domain users about their domains; one
message per recipient. With the instance switch off nothing is checked and no
state moves. A message that could not be handed to Postfix is tried again at
the next check.

Mail leaves by sendmail(1) as postmaster@<hostname>, addresses after "--",
no shell. For it to be believed the server's own name is signed like a
sending domain: domain.Service keeps a key for it and a line in OpenDKIM's
tables without a registry row, and non_smtpd_milters now names OpenDKIM. A
sending domain of the same name shares its key with the server.
dnscheck.ServerMail checks the name's DKIM and SPF records;
postfix.QueueMessages reads postqueue -j for arrival times.

The notifier is a sixth role of the panel process. Nothing in the panel
shows or switches it yet.

Checked on Windows: go vet clean; go test passes for notify, store, postfix,
dnscheck, cmd, and domain apart from TestWriteLoadPrivateKeyRoundtrip, which
fails there on file modes and always did. Not yet run in a container: whether
the unprivileged panel may submit is for the e2e step.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 15:56:13 +03:00