e2e: the run ends on port 25, with a report, junk and inbound mail

Until now the suite only read back the configuration generated for the
two optional port-25 features. DMARC ingest shipped in 1.7.0 with a
delivery service Postfix could not start, and nothing sent a report
through it until a real one arrived on the test server on 2026-10-11.

The last steps recreate the container with INBOUND_RELAY_ENABLE and
DMARC_REPORTS_ENABLE on, over the same /data, and talk to port 25 as a
stranger's mail server:

- the container log has no postconf warning, the session survives;
- a domain takes the SelfPost-hosted report address; a gzip report
  mailed to it appears under Outbound > DMARC reports; an address nobody
  chose is refused at RCPT;
- a report on another domain and a message with no report are accepted,
  dropped with "dropped: ..." on their delivery lines, counted as two
  parse failures, absent from the queue and from the reports;
- an inbound domain with the sink as upstream and one listed recipient:
  mail for it reaches the sink, another recipient and another domain are
  refused at RCPT.

The stage directory now holds docker-compose.yml and .env, as an
operator's project directory does (a full backup needs them; the
restore scenario that uses it is not in this commit - the panel's full
backup turned out not to work, see the next one).

make e2e on the test server: ok.

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

CHANGELOG.md

@@ -14,8 +14,41 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   time. It is now accepted and discarded - no retry, and no bounce, since the
   envelope sender of such a message is whatever its author wrote. It counts
   as one parse failure and the reason is in the mail log, on the message's
-  own delivery line (Server › System log, `dropped: …`). Only a failure of the database is still
-  retried.
+  own delivery line (Server › System log, `dropped: …`). Only a failure of
+  the database is still retried.
+- DMARC reports are kept 500 **for each domain** (and 90 days), not 500 for
+  the whole server - see Security.
+
+### Security
+
+Review of the DMARC report path (Fable, 2026-10-11), which started to run for
+the first time in 2.0.0. Nothing Critical or High.
+
+- **A report is bounded before it is stored.** The XML comes from anyone who
+  knows a report address, and its 8 MiB limit left room for some 160 000
+  records or a single name of megabytes - rows in the database and cells of
+  the report page. A report holds at most 5 000 records (a larger one is
+  dropped), every text field is cut to 255 bytes, and a record's count is
+  capped so the sums cannot wrap.
+- **One domain's reports cannot push out another's.** The cap of 500 was for
+  the whole server, so a stranger filing reports under one domain's address
+  could evict every other domain's history. It is counted per domain now.
+- The delivery command runs one at a time, not up to a hundred in parallel.
+- The reason written to the mail log for a dropped message is cut to 200
+  bytes and anything outside printable ASCII is replaced: parts of it are the
+  sender's own bytes (a header line, a file name inside an archive).
+- `SELFPOST_DATA_DIR` / `SELFPOST_DB_PATH` with whitespace or `$` are refused
+  at start when DMARC ingest is on, instead of handing the delivery command
+  another path and so an empty database of its own.
+
+### Added
+
+- e2e: the run now ends on port 25 with both optional features on. A DMARC
+  report is mailed to a domain's hosted address and has to appear under
+  Outbound › DMARC reports; a report on another domain and a message with no
+  report are accepted and dropped; mail for an inbound domain reaches its
+  upstream and other recipients are refused. Until now the suite only read
+  back the generated configuration of these features.
 
 ## [2.0.0] - 2026-10-11
 

test/e2e/main_test.go

@@ -70,6 +70,12 @@ const (
 	recipient    = "rcpt@sink.e2e.test"
 )
 
+// The one administrator of the run.
+const (
+	adminUser     = "e2eadmin"
+	adminPassword = "correct-horse-battery-staple"
+)
+
 // scenario carries state forward between the ordered subtests of TestE2E:
 // each later step needs something an earlier one produced (the domain id, the
 // DKIM record, the application credentials, an observed client IP).
@@ -131,10 +137,10 @@ func TestE2E(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if err := p.setup(token, "e2eadmin", "correct-horse-battery-staple"); err != nil {
+		if err := p.setup(token, adminUser, adminPassword); err != nil {
 			t.Fatalf("setup: %v", err)
 		}
-		if err := p.login("e2eadmin", "correct-horse-battery-staple"); err != nil {
+		if err := p.login(adminUser, adminPassword); err != nil {
 			t.Fatalf("login: %v", err)
 		}
 		sc.panel = p
@@ -268,6 +274,20 @@ func TestE2E(t *testing.T) {
 	run("negative_level1_ratelimit", func(t *testing.T) {
 		testLevel1RateLimit(t, sc)
 	})
+
+	// From here on the stand accepts mail on port 25.
+	run("enable_port25_features", func(t *testing.T) {
+		testEnablePort25Features(t, sc)
+	})
+	run("dmarc_report_reaches_the_panel", func(t *testing.T) {
+		testDMARCReportReachesThePanel(t, sc)
+	})
+	run("dmarc_junk_is_dropped", func(t *testing.T) {
+		testDMARCJunkIsDropped(t, sc)
+	})
+	run("inbound_relay_delivers_and_refuses", func(t *testing.T) {
+		testInboundRelay(t, sc)
+	})
 }
 
 // trimZoneSuffix strips the "e2e.test" suffix a fully-qualified DKIM record

test/e2e/port25_client.go

@@ -0,0 +1,81 @@
+package e2e
+
+import (
+	"fmt"
+	"net"
+	"net/smtp"
+	"time"
+)
+
+// port25Addr is where compose.override.yml publishes port 25: no TLS required,
+// no AUTH offered - a stranger's mail server talking to this one.
+const port25Addr = "127.0.0.1:20025"
+
+// deliverPort25 is one transaction on port 25 the way another mail server makes
+// it: HELO, MAIL, RCPT, DATA with message as it stands. The result says at
+// which stage it was refused, like attemptSend's.
+func deliverPort25(from, to, message string) sendResult {
+	var res sendResult
+	conn, err := net.DialTimeout("tcp", port25Addr, 10*time.Second)
+	if err != nil {
+		res.dialErr = fmt.Errorf("dial %s: %w", port25Addr, err)
+		return res
+	}
+	c, err := smtp.NewClient(conn, selfpostHostname)
+	if err != nil {
+		res.dialErr = fmt.Errorf("smtp handshake: %w", err)
+		_ = conn.Close()
+		return res
+	}
+	defer c.Close()
+	if err := c.Hello("mx.stranger.e2e.test"); err != nil {
+		res.dialErr = err
+		return res
+	}
+	if err := c.Mail(from); err != nil {
+		res.mailErr = err
+		_ = c.Quit()
+		return res
+	}
+	if err := c.Rcpt(to); err != nil {
+		res.rcptErr = err
+		_ = c.Quit()
+		return res
+	}
+	w, err := c.Data()
+	if err != nil {
+		res.dataErr = err
+		_ = c.Quit()
+		return res
+	}
+	if _, err := w.Write([]byte(message)); err != nil {
+		res.dataErr = err
+	} else if err := w.Close(); err != nil {
+		res.dataErr = err
+	}
+	_ = c.Quit()
+	return res
+}
+
+// waitForPort25Ready polls port 25 until Postfix greets on it. A bare connect
+// is not enough: Docker's proxy accepts on the published port whether or not
+// anything listens behind it.
+func waitForPort25Ready(timeout time.Duration) error {
+	return waitFor("port 25 to greet", timeout, 500*time.Millisecond, func() (bool, error) {
+		conn, err := net.DialTimeout("tcp", port25Addr, 2*time.Second)
+		if err != nil {
+			return false, err
+		}
+		defer conn.Close()
+		_ = conn.SetReadDeadline(time.Now().Add(3 * time.Second))
+		buf := make([]byte, 4)
+		n, err := conn.Read(buf)
+		if err != nil {
+			return false, err
+		}
+		if string(buf[:n]) != "220 " {
+			return false, fmt.Errorf("greeting starts with %q", buf[:n])
+		}
+		return true, nil
+	})
+}

test/e2e/port25_features_test.go

@@ -0,0 +1,274 @@
+package e2e
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/base64"
+	"fmt"
+	"net/url"
+	"regexp"
+	"strings"
+	"testing"
+	"time"
+)
+
+// The stand starts with both port-25 features off, as a new installation does.
+// The last part of the run switches them on and uses them from outside, the
+// way a stranger's mail server would: until 2.0.1 the suite only read back the
+// generated configuration, and DMARC ingest shipped in 1.7.0 with a delivery
+// service Postfix could not start - nothing ever sent a report through it.
+
+// testEnablePort25Features recreates the container with the inbound relay and
+// DMARC ingest on, over the same /data.
+func testEnablePort25Features(t *testing.T, sc *scenario) {
+	h.env = append(h.env, "INBOUND_RELAY_ENABLE=true", "DMARC_REPORTS_ENABLE=true")
+	if err := h.recreateSelfpost(); err != nil {
+		t.Fatalf("recreate selfpost with the port-25 features on: %v", err)
+	}
+	if err := waitForPanelReady(); err != nil {
+		t.Fatalf("panel after enabling the port-25 features: %v\n%s", err, h.logs("selfpost"))
+	}
+	if err := waitForSMTPSReady(60 * time.Second); err != nil {
+		t.Fatal(err)
+	}
+	if err := waitForPort25Ready(60 * time.Second); err != nil {
+		t.Fatalf("%v\n%s", err, h.logs("selfpost"))
+	}
+	if err := checkSupervisorProcesses(h); err != nil {
+		t.Fatal(err)
+	}
+	// Nothing in the container's own output may complain about the generated
+	// configuration: the broken delivery service of 1.7.0-1.9.5 was announced
+	// there at every start ("unmatched service_name/type") and went unread.
+	logs := h.logs("selfpost")
+	for _, bad := range []string{"unmatched service_name", "postconf: warning", "postconf: fatal"} {
+		if strings.Contains(logs, bad) {
+			t.Fatalf("the container log has %q with the port-25 features on:\n%s", bad, logs)
+		}
+	}
+	resp, err := sc.panel.status()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.Request.URL.Path != "/overview" {
+		t.Fatalf("the session did not survive the recreate: landed on %s", resp.Request.URL.Path)
+	}
+}
+
+const reportReporter = "reporter.e2e.test"
+
+// aggregateXML is a DMARC aggregate report on domain, as a receiver sends it.
+func aggregateXML(domain, reportID string) string {
+	return `<?xml version="1.0"?>
+<feedback>
+  <report_metadata>
+    <org_name>` + reportReporter + `</org_name>
+    <email>noreply@` + reportReporter + `</email>
+    <report_id>` + reportID + `</report_id>
+    <date_range><begin>1723593600</begin><end>1723680000</end></date_range>
+  </report_metadata>
+  <policy_published>
+    <domain>` + domain + `</domain>
+    <p>none</p><sp>none</sp><pct>100</pct>
+    <adkim>r</adkim><aspf>r</aspf>
+  </policy_published>
+  <record>
+    <row>
+      <source_ip>203.0.113.10</source_ip>
+      <count>7</count>
+      <policy_evaluated>
+        <disposition>none</disposition>
+        <dkim>pass</dkim><spf>pass</spf>
+      </policy_evaluated>
+    </row>
+    <identifiers><header_from>` + domain + `</header_from></identifiers>
+  </record>
+</feedback>
+`
+}
+
+// reportMessage is the mail a receiver sends a report in: one gzip attachment,
+// base64 in 76-column lines.
+func reportMessage(t *testing.T, to, xml string) string {
+	t.Helper()
+	var gz bytes.Buffer
+	zw := gzip.NewWriter(&gz)
+	if _, err := zw.Write([]byte(xml)); err != nil {
+		t.Fatal(err)
+	}
+	if err := zw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	encoded := base64.StdEncoding.EncodeToString(gz.Bytes())
+	var b strings.Builder
+	fmt.Fprintf(&b, "From: noreply@%s\r\nTo: %s\r\nSubject: Report domain: %s\r\nDate: %s\r\nMIME-Version: 1.0\r\n",
+		reportReporter, to, senderDomain, time.Now().UTC().Format(time.RFC1123Z))
+	b.WriteString("Content-Type: application/gzip; name=\"report.xml.gz\"\r\nContent-Transfer-Encoding: base64\r\n\r\n")
+	for len(encoded) > 76 {
+		b.WriteString(encoded[:76] + "\r\n")
+		encoded = encoded[76:]
+	}
+	b.WriteString(encoded + "\r\n")
+	return b.String()
+}
+
+// testDMARCReportReachesThePanel gives the sending domain a SelfPost-hosted
+// report address and mails a report to it on port 25. It has to show up under
+// Outbound > DMARC reports.
+func testDMARCReportReachesThePanel(t *testing.T, sc *scenario) {
+	address := "dmarc-reports+" + senderDomain + "@" + selfpostHostname
+	resp, body, err := sc.panel.postForm("/outbound/domains/"+sc.domainID+"/settings/reports", url.Values{"dmarc_rua_mode": {"hosted"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.StatusCode != 200 || resp.Request.URL.Path != "/outbound/domains/"+sc.domainID {
+		t.Fatalf("choosing the hosted report address: status %d, landed on %s:\n%.800s", resp.StatusCode, resp.Request.URL.Path, body)
+	}
+
+	// An address nobody chose is refused before DATA, hosted form or not.
+	res := deliverPort25("noreply@"+reportReporter, "dmarc-reports+nobody.e2e.test@"+selfpostHostname, "Subject: x\r\n\r\nx\r\n")
+	if res.rcptErr == nil {
+		t.Fatalf("port 25 accepted a report address no domain uses (first error: %v)", res.firstErr())
+	}
+
+	res = deliverPort25("noreply@"+reportReporter, address, reportMessage(t, address, aggregateXML(senderDomain, "e2e-report-1")))
+	if !res.ok() {
+		t.Fatalf("port 25 did not accept a report at %s: %v", address, res.firstErr())
+	}
+	if err := waitFor("the report to appear under Outbound > DMARC reports", 30*time.Second, 500*time.Millisecond, func() (bool, error) {
+		resp, body, err := sc.panel.get("/outbound/dmarc")
+		if err != nil {
+			return false, err
+		}
+		if resp.StatusCode != 200 {
+			return false, fmt.Errorf("GET /outbound/dmarc = %d", resp.StatusCode)
+		}
+		if strings.Contains(body, reportReporter) {
+			return true, nil
+		}
+		return false, fmt.Errorf("no report from %s on the page yet; mail log:\n%s", reportReporter, mailLogTail(h, "dmarc-ingest"))
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// testDMARCJunkIsDropped mails two things that are not reports this relay
+// keeps to the same address: a report on somebody else's domain, and a message
+// with no report in it. Each is accepted, dropped at once with the reason in
+// the mail log, and counted; neither stays in the queue to be tried again and
+// neither becomes a report.
+func testDMARCJunkIsDropped(t *testing.T, sc *scenario) {
+	address := "dmarc-reports+" + senderDomain + "@" + selfpostHostname
+	junk := map[string]string{
+		"a report on another domain": reportMessage(t, address, aggregateXML("stranger.e2e.test", "e2e-report-2")),
+		"a message with no report":   "From: someone@stranger.e2e.test\r\nTo: " + address + "\r\nSubject: hello\r\n\r\nnot a report\r\n",
+	}
+	for what, msg := range junk {
+		if res := deliverPort25("someone@stranger.e2e.test", address, msg); !res.ok() {
+			t.Fatalf("%s was refused on port 25 instead of being accepted and dropped: %v", what, res.firstErr())
+		}
+	}
+
+	dropped := regexp.MustCompile(`status=sent \(delivered via dmarc-ingest service \(dropped: [^)]`)
+	if err := waitFor("both messages to be dropped", 30*time.Second, 500*time.Millisecond, func() (bool, error) {
+		log := mailLogTail(h, "dmarc-ingest")
+		if n := len(dropped.FindAllString(log, -1)); n != len(junk) {
+			return false, fmt.Errorf("%d of %d dropped so far; mail log:\n%s", n, len(junk), log)
+		}
+		return true, nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	queue, err := h.execIn("selfpost", "postqueue", "-p")
+	if err != nil {
+		t.Fatalf("postqueue -p: %v\n%s", err, queue)
+	}
+	if !strings.Contains(queue, "Mail queue is empty") {
+		t.Fatalf("a dropped message is still in the queue:\n%s", queue)
+	}
+
+	_, body, err := sc.panel.get("/outbound/dmarc")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(body, "2 parse failures") {
+		t.Fatalf("the DMARC page does not count the two dropped messages as parse failures:\n%s", body)
+	}
+	if strings.Contains(body, "stranger.e2e.test") {
+		t.Fatal("the report on another domain was stored")
+	}
+}
+
+// mailLogTail returns the lines of the end of the mail log that contain filter.
+func mailLogTail(s *stack, filter string) string {
+	out, err := s.execIn("selfpost", "tail", "-n", "400", "/data/log/mail.log")
+	if err != nil {
+		return "(mail log unreadable: " + err.Error() + ")"
+	}
+	var b strings.Builder
+	for _, line := range strings.Split(out, "\n") {
+		if strings.Contains(line, filter) {
+			b.WriteString(line + "\n")
+		}
+	}
+	return b.String()
+}
+
+const (
+	inboundDomain    = "in.e2e.test"
+	inboundRecipient = "user@" + inboundDomain
+)
+
+// testInboundRelay sets up an inbound domain with the sink as its upstream and
+// one listed recipient, then talks to port 25 as a stranger: mail for the
+// listed recipient reaches the upstream, mail for anyone else at the domain
+// and for a domain that is not configured is refused before DATA.
+func testInboundRelay(t *testing.T, sc *scenario) {
+	resp, body, err := sc.panel.postForm("/inbound/domains", url.Values{"name": {inboundDomain}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	m := regexp.MustCompile(`^/inbound/domains/(\d+)$`).FindStringSubmatch(resp.Request.URL.Path)
+	if m == nil {
+		t.Fatalf("add inbound domain: landed on %s:\n%.800s", resp.Request.URL.Path, body)
+	}
+	base := "/inbound/domains/" + m[1]
+
+	// The sink by address: an upstream named by an IP is delivered to as it
+	// stands, with no MX lookup in between.
+	resp, body, err = sc.panel.postForm(base+"/upstream", url.Values{"host": {"10.77.0.11"}, "port": {"25"}, "tls_mode": {"none"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.StatusCode != 200 || resp.Request.URL.Path != base {
+		t.Fatalf("set the upstream: status %d, landed on %s:\n%.800s", resp.StatusCode, resp.Request.URL.Path, body)
+	}
+	resp, body, err = sc.panel.postForm(base+"/recipients", url.Values{"recipient_mode": {"list"}, "addresses": {inboundRecipient}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.StatusCode != 200 || resp.Request.URL.Path != base {
+		t.Fatalf("set the recipients: status %d, landed on %s:\n%.800s", resp.StatusCode, resp.Request.URL.Path, body)
+	}
+
+	message := func(to, token string) string {
+		return fmt.Sprintf("From: someone@stranger.e2e.test\r\nTo: %s\r\nSubject: e2e %s\r\nDate: %s\r\n\r\nmail for the inbound domain\r\n",
+			to, token, time.Now().UTC().Format(time.RFC1123Z))
+	}
+
+	token := uniqueToken("inbound")
+	if res := deliverPort25("someone@stranger.e2e.test", inboundRecipient, message(inboundRecipient, token)); !res.ok() {
+		t.Fatalf("port 25 did not accept mail for %s: %v", inboundRecipient, res.firstErr())
+	}
+	if _, err := findSinkMessage(h.stageDir, token, 30*time.Second); err != nil {
+		t.Fatalf("mail for the inbound domain never reached its upstream: %v\n%s", err, mailLogTail(h, "postfix/"))
+	}
+
+	for _, to := range []string{"nobody@" + inboundDomain, "someone@elsewhere.e2e.test"} {
+		res := deliverPort25("someone@stranger.e2e.test", to, message(to, uniqueToken("refused")))
+		if res.rcptErr == nil {
+			t.Fatalf("port 25 accepted the recipient %s (first error: %v)", to, res.firstErr())
+		}
+	}
+}

test/e2e/stack.go

@@ -24,6 +24,10 @@ type stack struct {
 	baseComposeFile string
 	overrideFile    string
 	stageDir        string
+	// env is added to compose's own environment. The shipped compose file takes
+	// the optional features from there (${INBOUND_RELAY_ENABLE:-false} and the
+	// like), so this is how a later part of the run switches them on.
+	env []string
 }
 
 func newStack() (*stack, error) {
@@ -64,6 +68,7 @@ func (s *stack) compose(args ...string) ([]byte, error) {
 	// looked at (that mapping only reaches the container, not compose's own
 	// variable interpolation), so it has to be set here too.
 	cmd.Env = append(os.Environ(), "SELFPOST_HOSTNAME="+selfpostHostname)
+	cmd.Env = append(cmd.Env, s.env...)
 	var out bytes.Buffer
 	cmd.Stdout = &out
 	cmd.Stderr = &out
@@ -102,6 +107,14 @@ func (s *stack) restartSelfpost() error {
 	return err
 }
 
+// recreateSelfpost replaces the selfpost container with one started from the
+// same /data and the environment as it is now (see env), leaving the DNS and
+// sink sidecars and their state alone.
+func (s *stack) recreateSelfpost() error {
+	_, err := s.compose("up", "-d", "--force-recreate", "--no-deps", "selfpost")
+	return err
+}
+
 func (s *stack) down() {
 	_, _ = s.compose("down", "-v", "--remove-orphans")
 }

test/e2e/stage.go

@@ -39,6 +39,9 @@ func prepareStage(s *stack) error {
 	); err != nil {
 		return err
 	}
+	if err := writeDeployFiles(s); err != nil {
+		return err
+	}
 	corefile, err := os.ReadFile(filepath.Join("dns", "Corefile"))
 	if err != nil {
 		return fmt.Errorf("read Corefile: %w", err)
@@ -49,6 +52,22 @@ func prepareStage(s *stack) error {
 	return writeZone(s.stageDir, nil)
 }
 
+// writeDeployFiles puts docker-compose.yml and .env into the stage directory.
+// The stage directory is what the container sees as /selfpost-deploy, the
+// operator's project directory, and a full backup refuses to run unless both
+// files are there to be archived. compose reads neither: the stand names its
+// files with -f, and the .env repeats what compose is given anyway.
+func writeDeployFiles(s *stack) error {
+	compose, err := os.ReadFile(s.baseComposeFile)
+	if err != nil {
+		return fmt.Errorf("read the shipped compose file: %w", err)
+	}
+	if err := os.WriteFile(filepath.Join(s.stageDir, "docker-compose.yml"), compose, 0o644); err != nil {
+		return err
+	}
+	return os.WriteFile(filepath.Join(s.stageDir, ".env"), []byte("SELFPOST_HOSTNAME="+selfpostHostname+"\n"), 0o644)
+}
+
 // removeAllBestEffort deletes path; if a previous run left container-UID files
 // on the bind mount, a root alpine one-shot removes them first.
 func removeAllBestEffort(path string) error {