Files
selfpost/test/e2e/sender_check_test.go
T
mixandClaude Opus 5.5 89fd0a6116
test / test (push) Canceled after 0s
from-header-binding: findings of the technical and security reviews
Both reviews were of c171fb5, read-only, given the code and questions.

Found by both, and the one that would have refused ordinary mail from the
first day: a folded From: line - what a mail library makes of a long display
name - did not parse and was refused with 550. The line is unfolded before it
is read. e2e sends one through Postfix now.

Technical (Opus)
- A display name in a charset Go does not convert (windows-1251, koi8-r) was
  refused: such a name is passed through unread, only the address is judged.
- The statistics ran between binding the socket and serving it, with a
  supervisorctl that has no timeout: they are kept beside the check now and
  nothing of them is waited for. A supervisorctl that fails is logged.
- The count of deferred mail followed smtpd's reject lines and so missed a
  check that stops answering in the middle of a message, where cleanup
  writes them: it is taken at Postfix's warning, the line that names the
  socket. The test line for that case had been invented with the wrong
  process; it is marked as composed from Postfix's source.
- A card whose figures could not be read showed zeros and "ok": dashes and
  "unknown".
- entrypoint removes the sockets a killed container left, which satisfied
  the wrapper's wait before the check was listening.
- Outside quoted strings the line may hold one "@" only - a rule that needs
  no knowledge of OpenDKIM's parser.
- Comments that still spoke of two sockets, or of a session replaced after a
  refusal; the limits of the cards layout on a phone, said where it is defined.

Security (Fable; no Critical or High)
- Another sender's name in an encoded display name passed the second look:
  the decoded name is looked at as well.
- A client could arm the deferred counter by sending the socket's name where
  Postfix quotes it in a warning: the two warnings are matched from their
  first word.
- A refused message wrote a row per recipient: one row, naming the first
  recipient and how many more.
- Docs: the check's lookup is stricter than Postfix's for address extensions
  and the case of logins, rather than "cannot disagree"; what a display name
  looks like to a person is not promised; the timeouts and the 454 at AUTH
  stated as they are; "messages" are connections turned away.

Left as found, in the plan: downtime that crosses midnight is booked on the
day of the restart; a message with the null envelope sender leaves a row
without a domain; a log read again after an unclean stop counts again.

Test server, this tree: go vet ok, go test 23 packages ok, make e2e ok (330 s).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 20:06:02 +03:00

186 lines
7.5 KiB
Go

package e2e
import (
"fmt"
"regexp"
"strconv"
"strings"
"testing"
"time"
)
// otherDomain is a second sending domain of the stand: registered, with a DKIM
// key of its own, and no application of the first domain has any right to it.
const otherDomain = "other.e2e.test"
// testSenderCheck is from-header-binding's "done when": an application is
// refused for another tenant's From:, for the hostname's and for an address
// off its list, and accepted for its own. The envelope sender is the
// application's own every time - Postfix would refuse anything else before
// the header was looked at.
func testSenderCheck(t *testing.T, sc *scenario) {
if _, err := sc.panel.addDomain(otherDomain); err != nil {
t.Fatalf("add the second domain: %v", err)
}
listLogin, listPassword, err := sc.panel.addApplication(sc.domainID, "app-list", "list", "billing@"+senderDomain)
if err != nil {
t.Fatalf("add the application with a list: %v", err)
}
type who struct{ login, password, envelope string }
wildcard := who{sc.appLogin, sc.appPassword, "alerts@" + senderDomain}
list := who{listLogin, listPassword, "billing@" + senderDomain}
for _, c := range []struct {
name string
as who
header string
pass bool
}{
{"own address", wildcard, "alerts@" + senderDomain, true},
{"another address of the domain, with a name", wildcard, `"The Shop" <orders@` + senderDomain + `>`, true},
{"the listed address", list, "billing@" + senderDomain, true},
// What a mail library does with a long display name: the line is
// folded, and Postfix hands the milter both of its lines.
{"a long name, folded onto a second line", wildcard, "\"The Shop, its orders and its returns desk\"\r\n <orders@" + senderDomain + ">", true},
{"another registered domain", wildcard, "director@" + otherDomain, false},
{"the server's own name", wildcard, "postmaster@" + selfpostHostname, false},
{"a domain the server knows nothing of", wildcard, "someone@elsewhere.e2e.test", false},
{"an address off the list", list, "director@" + senderDomain, false},
{"another sender in the display name", wildcard, `"director@` + otherDomain + `" <alerts@` + senderDomain + `>`, false},
} {
token := uniqueToken("from")
res := attemptSend(sendAttempt{
authLogin: c.as.login, authPassword: c.as.password,
from: c.as.envelope, headerFrom: c.header, to: recipient,
subject: "e2e " + token, body: "sender check: " + c.name,
})
if c.pass {
if !res.ok() {
t.Errorf("%s: From: %s was refused: %v", c.name, c.header, res.firstErr())
continue
}
if _, err := findSinkMessage(h.stageDir, token, 30*time.Second); err != nil {
t.Errorf("%s: accepted, and never reached the sink: %v", c.name, err)
}
continue
}
if res.ok() {
t.Errorf("%s: From: %s was accepted", c.name, c.header)
continue
}
// The verdict comes at the end of the headers, which is the end of
// DATA for the client; it is permanent and says what is wrong.
if e := fmt.Sprint(res.dataErr); res.dataErr == nil || !strings.HasPrefix(e, "550 ") || !strings.Contains(e, "5.7.1 From:") {
t.Errorf("%s: want 550 5.7.1 naming the From: line at the end of DATA, got %v", c.name, res.firstErr())
}
if _, err := findSinkMessage(h.stageDir, token, 2*time.Second); err == nil {
t.Errorf("%s: the refused message reached the sink", c.name)
}
}
// A refusal is a row of the Outbound log whose tag says why.
if err := waitFor("the refusals to appear in the Outbound log", 15*time.Second, 500*time.Millisecond, func() (bool, error) {
rows, err := sc.panel.sendLogRows(senderDomain, "")
if err != nil {
return false, err
}
if n := strings.Count(rows, `">wrong From</span>`); n < 5 {
return false, fmt.Errorf("%d rows tagged wrong From, want 5", n)
}
return true, nil
}); err != nil {
t.Error(err)
}
}
// testPanelDownDefersMail: the sender check is the panel's and Postfix
// attaches it strictly, so with the panel stopped mail is deferred - a
// temporary error, nothing accepted unchecked - and the container stays up
// (crashexit fires on PROCESS_STATE_FATAL only; a supervisor stop is STOPPED).
// Once the panel is back it has counted both what that cost: the time it did
// not answer under a running Postfix, and the message that was deferred.
//
// Until 2.4.0 this step proved the opposite, that mail passes with the panel
// down: the journal milter still fails open, but it shares the process with
// the check, and the check does not.
func testPanelDownDefersMail(t *testing.T, sc *scenario) {
supervisorctl := func(verb string) error {
_, err := h.execIn("selfpost", "supervisorctl", "-c", "/etc/supervisor/supervisord.conf", verb, "panel")
return err
}
if err := supervisorctl("stop"); err != nil {
t.Fatalf("stop panel: %v", err)
}
t.Cleanup(func() { _ = supervisorctl("start") })
res := attemptSend(sendAttempt{
authLogin: sc.appLogin, authPassword: sc.appPassword,
from: "alerts@" + senderDomain, to: recipient,
subject: "e2e " + uniqueToken("paneldown"), body: "must be deferred",
})
if res.ok() {
t.Fatal("mail was accepted with the panel down: the sender check did not hold it")
}
// Temporary, and before any message is offered: Postfix answers 451 from
// the connection on, and "454 4.3.0 Try again later" at AUTH, which is
// where a client that authenticates gives up.
if err := res.firstErr(); err == nil || !strings.HasPrefix(fmt.Sprint(err), "4") {
t.Fatalf("want a temporary 4xx with the panel down, got %v", res.firstErr())
}
if err := checkContainerAlive(h); err != nil {
t.Fatalf("container did not survive the panel stopping: %v", err)
}
// What Postfix wrote about it is what the panel counts from; shown so that
// a change of Postfix's wording is seen here and not guessed at.
if out, err := h.execIn("selfpost", "sh", "-c", "grep -i 'milter' /data/log/mail.log | tail -n 6"); err == nil {
t.Logf("mail.log on the deferred message:\n%s", out)
}
time.Sleep(2 * time.Second) // downtime worth a whole second or two
if err := supervisorctl("start"); err != nil {
t.Fatalf("restart panel: %v", err)
}
if err := waitFor("panel HTTP to answer again", 15*time.Second, 300*time.Millisecond, func() (bool, error) {
_, err := sc.panel.status()
return err == nil, err
}); err != nil {
t.Fatal(err)
}
// Mail flows again.
token := uniqueToken("panelback")
res = attemptSend(sendAttempt{
authLogin: sc.appLogin, authPassword: sc.appPassword,
from: "alerts@" + senderDomain, to: recipient,
subject: "e2e " + token, body: "must be accepted again",
})
if !res.ok() {
t.Fatalf("mail is still refused with the panel back: %v", res.firstErr())
}
// Server > Health, "Sender check", today: some downtime, one message.
today := regexp.MustCompile(`<tr><td>Today</td><td>([^<]*)</td><td>(\d+)</td></tr>`)
if err := waitFor("Health to show the downtime and the deferred message", 20*time.Second, 500*time.Millisecond, func() (bool, error) {
_, body, err := sc.panel.get("/server/health")
if err != nil {
return false, err
}
m := today.FindStringSubmatch(body)
if m == nil {
return false, fmt.Errorf("no Sender check row for today on Health")
}
deferred, _ := strconv.Atoi(m[2])
if m[1] == "0 s" || deferred < 1 {
return false, fmt.Errorf("today: panel not answering %q, messages deferred %d", m[1], deferred)
}
if !strings.Contains(body, `<h2>Sender check</h2><div class="sp-end"><span class="tag is-warning is-light">warn</span>`) {
return false, fmt.Errorf("the card does not warn about mail deferred a moment ago")
}
return true, nil
}); err != nil {
t.Fatal(err)
}
}