Commit Graph
5 Commits
Author SHA1 Message Date
mixandClaude Opus 5.5 b113e72c71 milter, postfix, app, domain: cite the source of what they rely on (assumptions part B)
Comments only, no behaviour changed. go-milter v0.4.1 (session.go: one
session per connection, replaced after a non-continue reply; macros per
stage), Postfix 3.7.11 (milter8.c, smtpd_check.c
reject_auth_sender_login_mismatch(), mail_addr_find.c, showq_compat.c,
mail_conf_time.c, mail_params.h), Cyrus SASL 2.1.28 (saslpasswd.c,
plugins/sasldb.c: deleting a missing login is not an error), OpenDKIM
2.11.0~beta2 (opendkim-db.c, opendkim-genkey), Berkeley DB 5.3 db_dump,
rspamd 3.11.0. Comments that claimed what the source denies are corrected
(sasldb keeps the password as given, not hashed; an embedded newline is
kept, not truncated; rspamd sorts symbols by absolute weight); fixtures say
seen or composed. The sender check's From: parsing gets no citations: it is
replaced by the port of OpenDKIM's dkim_mail_parse next.

Contradictions left for their own commits: B-G5 cleanAddress, B-PS1 first
key wins, B-PQ1 the forced-expire flag, B-PQ10/PQ11 Postfix's time units.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-14 19:36:12 +03:00
mixandClaude Opus 5.5 d398f488e2 inbound-antispam-panel: the filter signs what it judged
test / test (push) Canceled after 0s
Closes what the security review left as an accepted risk: with the
spam filter down - it is attached fail-open - nothing removes verdict
headers a sender wrote himself, and the inbound journal recorded his
verdict as the filter's. The owner asked whether rspamd could add a
header that proves the others are ours (2026-10-12) and agreed to a
signature: a fixed mark could be written by a sender as easily as the
verdict.

  - inbound.FilterKey: a key of 32 random bytes, 64 hex characters, in
    /data/antispam/filter.key, made on the first start with the relay
    on. 0644 like the list files beside it: the filter is another user
    in another container.
  - deploy/antispam/rspamd/milter_headers.conf: a custom routine reads
    the key through the directory the sidecar already mounts and adds
    X-SelfPost-Filter, the HMAC-SHA256 of the message's queue id, hex;
    a header of that name from the sender is removed.
  - internal/milter/inbound.go: the verdict headers are kept as they
    are read, and at end-of-message - when the queue id is known - they
    count only if the signature fits (FilterSignature, hmac.Equal). No
    key, no queue id, no signature or a wrong one: the row is that of
    mail nobody judged (accept, selfpost, no detail).

The signature goes on to the upstream with the mail and is of no use
there: it fits one queue id.

Tried in a throwaway rspamd 3.11 container on the test server before
the Go side was written: the routine loads, signs
(2aa1ca6d... for key 0123...cdef and queue id 4A1B2C3D5E, the value
python's hmac gives and TestFilterSignatureIsWhatTheFilterWrites
pins), removes a sender's header of the same name, and adds nothing
without a queue id.

Tests: signed, unsigned, made-up, another message's, another key's,
the sender's followed by the real one, the next message on the
connection, no queue id; the key made once, read after, replaced when
damaged, left alone by the lists. e2e: filter.key is there, 644, 65
bytes.

docs/security.md: the accepted risk is replaced by a narrower one (the
key is readable on the host); Mail path describes the signature.

Checked on the test server, uncommitted tree: go vet ./... ok,
go test ./... ok (22 packages), make e2e ok.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 08:34:29 +03:00
mixandClaude Opus 5.5 5f86457848 milter: the level-2 limit and the client IP list hold for every message
Security fix, outside the inbound antispam feature. Found by its
technical review (Opus, 2026-10-12), reproduced on the test stand
before the fix: over an application's level-2 limit, two MAIL FROM on
one connection were answered 451 and then accepted.

Cause. Postfix introduces a client to a milter once per connection.
The milter library (go-milter 0.4.1, session.go) replaces the milter's
session after any reply that is not "continue" - a refusal, or the
accept that used to end a message. The new session never saw Connect,
so it had no client address, and both checks passed a message without
one: overLimit returned early ("no client IP to key on") and
authIPAllowed did the same. So every message after the first on a
connection, and every MAIL FROM after a refused one, skipped the
level-2 limit and an application's client IP list. In the code since
1.9.0 for the list and longer for the limit.

Fix.
  - build/postfix-config.sh: milter_mail_macros carries {client_addr},
    so the address comes with every MAIL FROM; MailFrom reads it (both
    spellings of IPv6) in the journal milter and the inbound journal
    milter.
  - overLimit no longer asks for a client address: a ceiling is on a
    domain or an application.
  - authIPAllowed refuses an application that has a client IP list when
    no address is known.
  - Body replies "continue" in both milters, which lets the message
    through as "accept" did and keeps the session.

The inbound journal milter had the same cause with a smaller effect:
rows of a connection's later messages had no client address.

In the same file, the checks of INBOUND_ANTISPAM_MILTER and
INBOUND_JOURNAL_MILTER_SOCKET refuse any character outside their set
first: a glob's "*" matched anything after the first characters.

Tests: a session that never saw Connect is judged by the macro, a
listed and an unlisted address, no address, not an address; the limit
with no client address; the inbound milter answers only "continue".
test/e2e sends two MAIL FROM on one connection over the limit and
wants both refused.

Checked on the test server: e2e red before the fix on exactly that
check, green after; go vet ./... ok, go test ./... ok (22 packages).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 07:51:50 +03:00
mixandClaude Opus 5.5 7192c3861e inbound-antispam-panel: Filter lists, kind column, matches, note on a sheet
Follows the design commit before it (owner's words quoted there).

The lists' tables are Value, Kind, Matched and Remove. The kind tag
opens the entry's sheet: note, day added, how often it decided a
message in the days the log keeps, and the last match.

Matches are read off the journal on each view, nothing is stored
(inbound.Lists.Usage, store.ListSpamListHits). A row counts for an
entry when the list decided the message - a rejected row whose reply is
the deny rule's message, an accepted row whose verdict carries the
allow rule's symbol for that kind - and the entry fits the row's sender
or client address the way rspamd matches it: an address whole, a domain
as the sender's domain, a network containing the client (an
IPv4-mapped address as IPv4). A failure to count shows the lists with
"never" and logs why.

For that the journal milter keeps the lists' own symbols ahead of its
six-symbol cap: rspamd writes symbols heaviest first, so an allow
entry's -100 came last and was cut behind any six others.

The plan gains "Filter list usage": what counting from the journal
implies, and - the owner asked for it in writing - the conditions under
which a counter kept with each entry becomes worth a migration (the
journal cut by its row cap and not by age; a short retention; counts
that must outlive the journal; a slow page). multimap.conf says which
of its texts SelfPost reads back.

Tests: Usage over every kind on both lists and the rows that are
nobody's; the milter's symbol order; the store query; the page and its
sheets; a handler test from journal rows to the numbers on the page.

Seen: the fixture page with a sheet open, headless Edge at 1360 px -
the same as the accepted drawing.

Checked on the test server, uncommitted tree: go vet ./... ok,
go test ./... ok (22 packages), make e2e ok.

Not seen in a real run: a count above zero. It needs an entry added in
the panel, which I cannot sign in to, and then mail that the list
decides; in particular the deny rule's message arriving in mail.log as
the reply of a milter-reject line is what the trial with rspamc showed,
not yet what Postfix logged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 01:08:26 +03:00
mixandClaude Opus 5.5 28ec784ae2 inbound-antispam-panel: inbound journal milter on port 25
Step 3/12 of docs/plans/inbound-antispam-panel.md.

The panel serves a second milter while the inbound relay is on
(internal/milter/inbound.go, socket INBOUND_JOURNAL_MILTER_SOCKET,
default /run/selfpost/inbound-journal.sock). build/postfix-config.sh
puts it last on port 25, after the optional antispam milter, with
default_action=accept; postfix-wrapper.sh waits for its socket. At
end-of-message it writes one inbound_spam_log row per recipient at an
inbound domain - other port-25 recipients (DMARC report addresses) get
none - and always accepts. With a filter attached it reads the verdict
from X-Rspamd-Action and X-Spamd-Result (action, score, up to six
weighted symbols, only what the patterns recognise, 255 bytes); without
one those headers are the sender's and are not read. The plan named
X-Rspamd-Score, which rspamd does not have.

The antispam compose fragment mounts rspamd/milter_headers.conf into
the sidecar so that it adds the two headers (checked in rspamd 3.11:
both routines exist and remove a sender's own headers of those names).

Store: InsertInboundSpam, IsInboundDomain.

Checked on the test server, uncommitted tree: go vet ./... ok,
go test ./... ok (22 packages), make e2e ok - the relayed message of
inbound_relay_delivers_and_refuses has its journal row (accept by
selfpost) and the DMARC report sent through the same listener has none.

Not yet seen in a real run: a verdict written by rspamd reaching this
milter. The e2e stand has no filter, and the test server's only inbound
domain has no upstream, so it accepts no mail.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-11 22:18:14 +03:00