release: 1.9.2: Review pass: port-25 milters, DMARC validation, rate-limit fix

Review pass over `1.4.0`…`1.9.1`: port 25 no longer shares the submission milter chain, DMARC reports are validated before they are stored, and the auto rate limit is correct for a non-default level-1 window. Schema migration `0010` (index only). Upgrading is a tag bump.
Added:
  - SQLite migration `0010_send_log_app_login_index.sql` —
  - DMARC aggregate reports are accepted as **zip** as well as gzip or plain XML
  - e2e: `checkPort25ConfigCombinations` regenerates the Postfix configuration
Changed:
  - README hero line and a **Positioning** block in `docs/product.md` record the
Fixed:
  - The setup account's password is hashed at bcrypt cost `12` like every other
  - Login/setup rate limiter: protecting blocked buckets from eviction is now
  - `postqueue -p` output is bounded to 4 MiB (the timeout alone left the size of
  - [schema-migrations.md](docs/schema-migrations.md): the schema section was
  - postqueue reader is now time-bounded: `postqueue -p` runs under a 5-second
  … (11 more in CHANGELOG)
Changed:
  - [roadmap.md](docs/roadmap.md) now carries everything the 2026-08-19 code
  - Extracted `internal/configsafe` — the empty-value and forbidden-character
  - Build, deploy and migration comments no longer cite the archived
  - Dropped the `parseDomainRateLimitForm` / `parseAppRateLimitForm` pass-through
  - Extracted shared helpers: `internal/atomicfile` (atomic temp-write+rename) and
  … (7 more in CHANGELOG)
Removed:
  - Unused legacy asset `docs/assets/icon.png` (superseded by the four brand SVGs
  - Plan documents for already-shipped features: `domain-stats-auto-ratelimit`,

Full detail: CHANGELOG.md (1.9.2).

internal/postfix/dmarc_test.go

@@ -33,3 +33,21 @@ func TestRenderDMARCMapsEmpty(t *testing.T) {
 		t.Fatalf("expected empty maps")
 	}
 }
+
+func TestRenderDMARCMapsRejectsInjectionTokens(t *testing.T) {
+	_, _, _, err := renderDMARCMaps(DMARCMapsConfig{
+		Recipients: []string{"dmarc@example.com\nattacker@example.com"},
+		Domains:    []string{"example.com"},
+	})
+	if err == nil {
+		t.Fatal("expected recipient token validation error")
+	}
+
+	_, _, _, err = renderDMARCMaps(DMARCMapsConfig{
+		Recipients: []string{"dmarc@example.com"},
+		Domains:    []string{"example.com attacker"},
+	})
+	if err == nil {
+		t.Fatal("expected domain token validation error")
+	}
+}

internal/postfix/inbound.go

@@ -2,11 +2,12 @@ package postfix
 
 import (
 	"fmt"
-	"net"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
+
+	"github.com/mixeme/selfpost/internal/configsafe"
 )
 
 // InboundRoute is one inbound domain's Postfix map material: the relay
@@ -83,12 +84,10 @@ func renderInboundMaps(routes []InboundRoute) (relay, transport, recipients, tls
 	return []byte(relayB.String()), []byte(transportB.String()), []byte(recipB.String()), []byte(tlsB.String()), nil
 }
 
-// inboundNexthop is the Postfix next-hop [host]:port form that disables MX
-// lookup for the explicit upstream.
+// inboundNexthop is the Postfix next-hop [host]:port form. The brackets are
+// what disable the MX lookup, so the operator's explicit upstream is used as
+// given; they also delimit a bare IPv6 address.
 func inboundNexthop(host string, port int) string {
-	if ip := net.ParseIP(host); ip != nil && ip.To4() == nil {
-		return "[" + host + "]:" + strconv.Itoa(port)
-	}
 	return "[" + host + "]:" + strconv.Itoa(port)
 }
 
@@ -118,13 +117,15 @@ func assertInboundRouteSafe(r InboundRoute) error {
 	return nil
 }
 
+// texthashForbidden is what may never appear in a texthash line: whitespace and
+// the newline that would end it, the comma that separates values, and the
+// backslash.
+const texthashForbidden = " \t\r\n,\\"
+
 // assertMapToken rejects values that could break out of a texthash line.
 func assertMapToken(v, what string) error {
-	if v == "" {
-		return fmt.Errorf("postfix: empty %s", what)
-	}
-	if strings.ContainsAny(v, " \t\r\n,\\") {
-		return fmt.Errorf("postfix: unsafe character in %s %q", what, v)
+	if err := configsafe.Token(what, v, texthashForbidden); err != nil {
+		return fmt.Errorf("postfix: %w", err)
 	}
 	return nil
 }

internal/postfix/postfix.go

@@ -7,10 +7,12 @@ package postfix
 
 import (
 	"fmt"
-	"os/exec"
 	"path/filepath"
 	"sort"
 	"strings"
+
+	"github.com/mixeme/selfpost/internal/configsafe"
+	"github.com/mixeme/selfpost/internal/supervisor"
 )
 
 // Postfix manages the on-disk Postfix state the panel is responsible for. After
@@ -122,6 +124,15 @@ func appendUnique(list []string, v string) []string {
 	return append(list, v)
 }
 
+// What may never reach a sender-map line: whitespace and the newline that would
+// end it, the comma that separates values, the colon a lookup key cannot carry,
+// and the backslash. A login additionally may not carry "@" — that would make it
+// look like an address.
+const (
+	senderMapAddressForbidden = " \t\r\n,:\\"
+	senderMapLoginForbidden   = " \t\r\n,:@\\"
+)
+
 // assertMapSafe rejects any address/login value that could break out of a single
 // map line or inject a directive. Addresses are validated to a strict whitelist
 // (letters, digits, '@', '.', '-', '_', '+') and logins to an even stricter one
@@ -129,14 +140,11 @@ func appendUnique(list []string, v string) []string {
 // letting whitespace, a newline or a comma (the value separator) through into
 // the file (security.md).
 func assertMapSafe(address, login string) error {
-	if address == "" || login == "" {
-		return fmt.Errorf("postfix: empty address or login")
+	if err := configsafe.Token("address", address, senderMapAddressForbidden); err != nil {
+		return fmt.Errorf("postfix: %w", err)
 	}
-	if strings.ContainsAny(address, " \t\r\n,:\\") {
-		return fmt.Errorf("postfix: unsafe character in address %q", address)
-	}
-	if strings.ContainsAny(login, " \t\r\n,:@\\") {
-		return fmt.Errorf("postfix: unsafe character in login %q", login)
+	if err := configsafe.Token("login", login, senderMapLoginForbidden); err != nil {
+		return fmt.Errorf("postfix: %w", err)
 	}
 	return nil
 }
@@ -154,17 +162,5 @@ func assertMapSafe(address, login string) error {
 // Arguments are fixed literals — no user input is interpolated into the command,
 // and it never goes through a shell (security.md).
 func reloadViaSupervisor() error {
-	cmd := exec.Command("supervisorctl",
-		"-c", "/etc/supervisor/supervisord.conf",
-		"start", "postfix-reload")
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		// A reload already in flight is not a failure: that pending run reloads
-		// Postfix after our file is in place (the file is written before this).
-		if strings.Contains(string(out), "already started") {
-			return nil
-		}
-		return fmt.Errorf("reload postfix via supervisor: %w: %s", err, strings.TrimSpace(string(out)))
-	}
-	return nil
+	return supervisor.Start("postfix-reload")
 }

internal/postfix/queue.go

@@ -1,12 +1,46 @@
 package postfix
 
 import (
+	"bytes"
+	"context"
 	"fmt"
 	"os/exec"
 	"regexp"
 	"strings"
+	"time"
 )
 
+const postqueueTimeout = 5 * time.Second
+
+// maxQueueOutput bounds how much of `postqueue -p` the panel keeps. A deferred
+// queue with a very large backlog prints one paragraph per message, and the
+// whole listing is held in memory and then rendered into a page — so the read
+// is capped and the remainder reported as truncated rather than being allowed
+// to size the panel's memory by the size of the queue.
+const maxQueueOutput = 4 << 20
+
+// limitWriter keeps the first remaining bytes written to it and drops the rest,
+// recording that it did. Writes always report full consumption so postqueue is
+// never killed by a short write; the extra output is simply discarded.
+type limitWriter struct {
+	buf       bytes.Buffer
+	remaining int
+	truncated bool
+}
+
+func (l *limitWriter) Write(p []byte) (int, error) {
+	keep := len(p)
+	if keep > l.remaining {
+		keep = l.remaining
+		l.truncated = true
+	}
+	if keep > 0 {
+		l.buf.Write(p[:keep])
+		l.remaining -= keep
+	}
+	return len(p), nil
+}
+
 // Queue returns Postfix's own human-readable mail-queue listing
 // (architecture.md § Panel HTTP surface): active, deferred and held messages,
 // exactly as an administrator would see via the CLI. The command takes a
@@ -14,12 +48,24 @@ import (
 // (security.md). The panel is responsible for escaping the output before
 // display (security.md); this function returns it as-is.
 func Queue() (string, error) {
-	cmd := exec.Command("postqueue", "-p")
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		return "", fmt.Errorf("postqueue -p: %w: %s", err, strings.TrimSpace(string(out)))
+	ctx, cancel := context.WithTimeout(context.Background(), postqueueTimeout)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, "postqueue", "-p")
+	out := &limitWriter{remaining: maxQueueOutput}
+	cmd.Stdout = out
+	cmd.Stderr = out
+	err := cmd.Run()
+	if ctx.Err() == context.DeadlineExceeded {
+		return "", fmt.Errorf("postqueue -p timed out after %s", postqueueTimeout)
 	}
-	return string(out), nil
+	if err != nil {
+		return "", fmt.Errorf("postqueue -p: %w: %s", err, strings.TrimSpace(out.buf.String()))
+	}
+	text := out.buf.String()
+	if out.truncated {
+		text += fmt.Sprintf("\n[listing truncated at %d bytes]\n", maxQueueOutput)
+	}
+	return text, nil
 }
 
 // QueueIDs returns the set of queue ids Postfix is still holding — everything

internal/postfix/queue_test.go

@@ -41,3 +41,34 @@ func TestParseQueueIDsOnAnEmptyQueue(t *testing.T) {
 		t.Errorf("got %v, want no ids", ids)
 	}
 }
+
+// The queue listing is held in memory and rendered into a page, so a very large
+// queue must not size the panel's allocation: the writer keeps the cap and
+// reports the rest as dropped, while still accepting every write so postqueue
+// itself is never cut short.
+func TestLimitWriterCapsOutput(t *testing.T) {
+	w := &limitWriter{remaining: 8}
+	n, err := w.Write([]byte("12345"))
+	if n != 5 || err != nil {
+		t.Fatalf("first write = %d, %v", n, err)
+	}
+	if w.truncated {
+		t.Fatal("truncated before the cap was reached")
+	}
+	n, err = w.Write([]byte("67890"))
+	if n != 5 || err != nil {
+		t.Fatalf("second write = %d, %v", n, err)
+	}
+	if !w.truncated {
+		t.Fatal("write past the cap was not recorded as truncated")
+	}
+	if got := w.buf.String(); got != "12345678" {
+		t.Fatalf("kept %q, want the first 8 bytes", got)
+	}
+	if n, err := w.Write([]byte("more")); n != 4 || err != nil {
+		t.Fatalf("write after the cap = %d, %v (must still accept)", n, err)
+	}
+	if got := w.buf.String(); got != "12345678" {
+		t.Fatalf("buffer grew past the cap: %q", got)
+	}
+}

internal/postfix/write.go

@@ -1,47 +1,14 @@
 package postfix
 
 import (
-	"fmt"
 	"os"
-	"path/filepath"
+
+	"github.com/mixeme/selfpost/internal/atomicfile"
 )
 
 // writeFileAtomic writes data to path via a temp file in the same directory
 // followed by a rename, so a concurrent Postfix reload only ever sees the
-// complete old or new map, never a partial write (security.md). It mirrors the
-// same primitive used for the OpenDKIM tables.
+// complete old or new map, never a partial write (security.md).
 func writeFileAtomic(path string, data []byte, perm os.FileMode) error {
-	dir := filepath.Dir(path)
-	tmp, err := os.CreateTemp(dir, ".tmp-*")
-	if err != nil {
-		return fmt.Errorf("create temp in %s: %w", dir, err)
-	}
-	tmpName := tmp.Name()
-	cleanup := true
-	defer func() {
-		if cleanup {
-			_ = os.Remove(tmpName)
-		}
-	}()
-
-	if _, err := tmp.Write(data); err != nil {
-		tmp.Close()
-		return fmt.Errorf("write temp %s: %w", tmpName, err)
-	}
-	if err := tmp.Chmod(perm); err != nil {
-		tmp.Close()
-		return fmt.Errorf("chmod temp %s: %w", tmpName, err)
-	}
-	if err := tmp.Sync(); err != nil {
-		tmp.Close()
-		return fmt.Errorf("sync temp %s: %w", tmpName, err)
-	}
-	if err := tmp.Close(); err != nil {
-		return fmt.Errorf("close temp %s: %w", tmpName, err)
-	}
-	if err := os.Rename(tmpName, path); err != nil {
-		return fmt.Errorf("rename %s -> %s: %w", tmpName, path, err)
-	}
-	cleanup = false
-	return nil
+	return atomicfile.Write(path, data, perm)
 }