audit 2c: findings of the two reviews

Technical review (Opus, 11 findings, 2 medium) and security review (Fable,
no high or medium) of 3c86280..HEAD. Both confirm the port gives
dkim_mail_parse()'s result on every input it parses, and that no line the
check passes is signed with another domain's key.

- F1 (medium): OpenDKIM's parser takes lines no mail program reads as one
  address - "ceo@bank.com:me@mine.com", "Name <ceo@bank.com:me@mine.com>",
  "<b@evil.com, a@mine.com>", "ceo@bank.com <me@mine.com>",
  "ceo@bank.com@mine.com" - and signs for the last while a lenient reader
  shows the first. The line must now also be one address in RFC 5322's
  grammar (net/mail, display names in any charset passed through), at the
  domain OpenDKIM signs for. A quoted display name may still hold anything.
- F2 (medium): the bindings were asked about OpenDKIM's form of the
  address, quotes and all, so "x"@mine.com passed for an application
  holding @mine.com while x@mine.com belonged to another. They are now
  asked about the reader's address, its local part unquoted, as Postfix
  holds the envelope's.
- F3 / security (low): Bindings.Allowed and DomainOf fold case in ASCII
  only: Postfix folds as Unicode (casefold.c, ICU), but every key and
  login the panel writes is ASCII, and the Unicode fold let the Kelvin sign
  pass for "k" (net/mail then refuses such a line on the domain test).
- F4 (low): a TERM between "postfix start-fg &" and "child=$!" is no longer
  lost: the wrapper stops Postfix as soon as the pid is known.
- F5 (low): for startsecs after a start any failed reload passed as "not
  running". postfix-reload is now build/postfix-reload.sh: exit 75 when
  master -t says no master runs, else exec postfix reload; RunOnce returns
  EndError with the status, and only 75 is taken as done. supervisor.State
  goes.
- F6 (low): crashexit spares postfix-reload too - a reload that could not
  be spawned is reported to whoever asked, not a reason to stop the
  container.
- F7 (low): a certs/ that is itself a link is resolved before the walk
  (filepath.WalkDir does not follow its root).
- F8 (low): at shutdown the tailer reads what is left of the rotated
  file before saving its place. Not changed: a refusal line still waiting
  on the old file at shutdown is not kept - the panel writes refused rows
  itself, only a kill loses one, and that window is the minute's grace.
- F9 (low): pct read as text - empty or unreadable is 100, the rest held
  to 0..100.
- F10 (low): the directory is synced after sasldb2's rename.
- F11 (low): POSTFIX_STARTSECS by expr, so "010" or "08" in
  MILTER_WAIT_TIMEOUT are decimal, not octal or an error.
- Security (low): pagehide also empties defaultValue - the input's value
  attribute and the textarea's text - not only .value. A sasldb2.new left
  by a killed panel is removed at start (entrypoint) and never archived.
  security.md says that links under certs/ are followed and by whom they
  can be placed.

Tests: sender check cases for F1 (four lines), F2 (a bound address
quoted, for its owner and for another), F3; EndError's state and status;
pct cases. architecture.md and CHANGELOG describe the reader rule. Stand
(2026-10-15, make e2e, exit 0); go vet and go test ./... pass on the
server (24 packages).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/milter/sender_test.go

@@ -20,6 +20,8 @@ import (
 // example.org, and two applications share shop.example.org.
 const senderMaps = `@news.example.net news
 @shop.example.org shop,shop2
+desk@shop.example.org shop2
+@kiosk.example.net kiosk
 invoices@example.org billing
 billing@example.org billing
 `
@@ -102,9 +104,24 @@ func TestSenderCheck(t *testing.T) {
 		{"a stranger's address in the display name", "shop", [][2]string{from(`"someone@gmail.example" <a@shop.example.org>`)}, true, ""},
 		{"another sender in an encoded display name", "shop", [][2]string{from("=?utf-8?q?director=40example=2Eorg?= <a@shop.example.org>")}, true, ""},
 		{"a stranger's address in a comment", "shop", [][2]string{from("a@shop.example.org (someone@gmail.example)")}, true, ""},
-		{"an unquoted address as the display name", "shop", [][2]string{from("director@example.org <a@shop.example.org>")}, true, ""},
+		{"an unquoted address as the display name", "shop", [][2]string{from("director@example.org <a@shop.example.org>")}, false, "as a mail program reads it"},
 		{"another domain inside a quoted local part", "shop", [][2]string{from(`"director@example.org"@shop.example.org`)}, true, ""},
-		{"no local part: OpenDKIM takes the domain for it", "shop", [][2]string{from("@shop.example.org")}, true, ""},
+		{"no local part: OpenDKIM takes the domain for it", "shop", [][2]string{from("@shop.example.org")}, false, "as a mail program reads it"},
+		// Lines OpenDKIM signs for the application's domain while a lenient
+		// mail program shows another address first (review of stage 2c, F1).
+		{"another address before a colon", "shop", [][2]string{from("ceo@bank.example:me@shop.example.org")}, false, "as a mail program reads it"},
+		{"a route-like colon inside the brackets", "shop", [][2]string{from("Name <ceo@bank.example:me@shop.example.org>")}, false, "as a mail program reads it"},
+		{"a list inside the brackets", "shop", [][2]string{from("<b@evil.example, a@shop.example.org>")}, false, "as a mail program reads it"},
+		{"an address with two @", "shop", [][2]string{from("ceo@bank.example@shop.example.org")}, false, "as a mail program reads it"},
+		// An address bound to another application, its local part quoted
+		// (F2): a reader and Postfix take "desk" for desk.
+		{"another application's address, quoted", "shop", [][2]string{from(`"desk"@shop.example.org`)}, false, "not an address this application sends as"},
+		{"its own bound address, quoted", "shop2", [][2]string{from(`"desk"@shop.example.org`)}, true, ""},
+		// A look-alike of the domain in a character a Unicode fold maps
+		// to ASCII (F3): OpenDKIM would not sign it, and it is not the
+		// application's.
+		{"the Kelvin sign for k in the domain", "kiosk", [][2]string{from("a@\u212Aiosk.example.net")}, false, "a mail program would show another address"},
+		{"the same domain in ASCII", "kiosk", [][2]string{from("a@kiosk.example.net")}, true, ""},
 
 		{"another registered domain", "shop", [][2]string{from("director@example.org")}, false, "not an address this application sends as"},
 		{"the server's own name", "shop", [][2]string{from("postmaster@mail.example.org")}, false, "not an address this application sends as"},