Files
selfpost/test/e2e/process_check.go
T
mixandClaude Opus 5.5 8820294472 postfix: ETRN refused and not offered (audit S6)
Security audit 2026-10-17, finding S6 (low), stage 0 - proven from
outside: `ETRN <an inbound domain>` on port 25 answered "250 Queuing
started". smtpd_etrn_restrictions was empty (Postfix allows every client)
and fast_flush_domains = $relay_domains, so a stranger could flush the
deferred queue toward an inbound domain's upstream at will. Now
smtpd_etrn_restrictions=reject (etrn_cmd -> smtpd_check_etrn -> reject_code
554, Postfix 3.10.13 src/smtpd/smtpd.c) and smtpd_discard_ehlo_keywords=etrn.

e2e: testInboundRelay sends EHLO + ETRN for the inbound domain on port 25
and expects 554 and no ETRN in the EHLO reply (etrnPort25);
checkPostfixHardening reads both settings back. To be run on the server.

Docs: architecture.md § Postfix; CHANGELOG; plan.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-17 21:36:55 +03:00

164 lines
6.4 KiB
Go

package e2e
import (
"fmt"
"os"
"path/filepath"
"regexp"
"strings"
"time"
)
// wantRunning are the supervisord programs that must be RUNNING once the
// container is up (build/supervisord.conf). postfix-reload is deliberately
// excluded: autostart=false, so it rests STOPPED until its first run and
// EXITED after it (supervisor 4.2.5, supervisor/process.py,
// Subprocess.finish(); assumptions C-V10).
var wantRunning = []string{"panel", "postfix", "cert-reload", "logrotate"}
// checkSupervisorProcesses shells into the container directly (not through the
// panel's /overview page) so it works before an administrator account even
// exists — this is the first thing the harness checks after `docker compose
// up` (plan C.4). Programs take a moment to leave STARTING right after the
// container starts - postfix its startsecs, MILTER_WAIT_TIMEOUT plus ten
// seconds, 20 on this stand - so this polls rather than checking once.
func checkSupervisorProcesses(s *stack) error {
var lastErr error
err := waitFor("all supervised programs to reach their steady state", 60*time.Second, 500*time.Millisecond, func() (bool, error) {
out, execErr := s.execIn("selfpost", "supervisorctl", "-c", "/etc/supervisor/supervisord.conf", "status")
// supervisorctl exits non-zero when any program is not RUNNING, which
// is expected for postfix-reload — parse the output regardless of exit
// status.
states := parseSupervisorStatus(out)
if len(states) == 0 {
lastErr = fmt.Errorf("supervisorctl status produced nothing to parse: %v\n%s", execErr, out)
return false, lastErr
}
for _, name := range wantRunning {
state, ok := states[name]
if !ok {
lastErr = fmt.Errorf("program %q not reported by supervisorctl:\n%s", name, out)
return false, lastErr
}
if state != "RUNNING" {
lastErr = fmt.Errorf("program %q is %s, want RUNNING:\n%s", name, state, out)
return false, lastErr
}
}
if state, ok := states["postfix-reload"]; ok && state != "STOPPED" && state != "EXITED" {
lastErr = fmt.Errorf("program postfix-reload is %s, want STOPPED or EXITED (autostart=false):\n%s", state, out)
return false, lastErr
}
return true, nil
})
if err != nil {
return fmt.Errorf("%w\n==== selfpost logs ====\n%s", err, s.logs("selfpost"))
}
return nil
}
func parseSupervisorStatus(out string) map[string]string {
states := make(map[string]string)
for _, line := range strings.Split(out, "\n") {
fields := strings.Fields(line)
if len(fields) < 2 {
continue
}
states[fields[0]] = fields[1]
}
return states
}
// checkInboundRelayOff asserts the default image does not accept mail on
// port 25: smtp/inet is absent from master.cf (Debian's stock listener is
// removed when INBOUND_RELAY_ENABLE is not true). For an absent service
// postconf -M prints nothing on stdout and "warning: unmatched request" on
// stderr (Postfix 3.10.13, src/postconf/postconf_master.c,
// pcf_show_master_entries()).
func checkInboundRelayOff(s *stack) error {
out, err := s.execIn("selfpost", "postconf", "-M", "smtp/inet")
combined := out
if err != nil {
combined += err.Error()
}
if strings.Contains(combined, "smtpd") && !strings.Contains(combined, "warning:") && !strings.Contains(combined, "fatal:") {
return fmt.Errorf("inbound smtp/inet is present while INBOUND_RELAY_ENABLE is off:\n%s", out)
}
return nil
}
// checkCitedPackageVersions compares the Debian packages the image runs with
// the versions their sources were read at (docs/development.md, the table
// between the cited-package-versions markers). The image installs unpinned
// from a moving trixie, so a point release changes them on a rebuild
// without anyone reading what changed (assumptions C-D1).
func checkCitedPackageVersions(s *stack) error {
doc, err := os.ReadFile(filepath.Join(s.repoRoot, "docs", "development.md"))
if err != nil {
return err
}
text := string(doc)
start := strings.Index(text, "<!-- cited-package-versions -->")
end := strings.Index(text, "<!-- /cited-package-versions -->")
if start < 0 || end < start {
return fmt.Errorf("docs/development.md has no cited-package-versions table")
}
row := regexp.MustCompile("(?m)^[|] `([^`]+)` [|] `([^`]+)` [|]$")
want := map[string]string{}
var names []string
for _, m := range row.FindAllStringSubmatch(text[start:end], -1) {
want[m[1]] = m[2]
names = append(names, m[1])
}
if len(names) == 0 {
return fmt.Errorf("the cited-package-versions table lists no package")
}
out, err := s.execIn("selfpost", append([]string{"dpkg-query", "-W", "-f", "${Package} ${Version}\n"}, names...)...)
if err != nil {
return fmt.Errorf("dpkg-query: %v\n%s", err, out)
}
var diffs []string
for _, line := range strings.Split(strings.TrimSpace(out), "\n") {
f := strings.Fields(line)
if len(f) == 2 && want[f[0]] != f[1] {
diffs = append(diffs, fmt.Sprintf("%s: the image has %s, the citations were read at %s", f[0], f[1], want[f[0]]))
}
}
if len(diffs) > 0 {
return fmt.Errorf("packages changed under the citations - re-read them (docs/development.md):\n%s", strings.Join(diffs, "\n"))
}
return nil
}
// checkDKIMTree: the keys and the selector table are the panel's alone,
// directories 0700 and files 0600 (build/entrypoint.sh; internal/domain,
// Keys) - no other program reads them since OpenDKIM left - and the table
// is there, written before the signer serves (cmd/panel/signer.go).
func checkDKIMTree(s *stack) error {
out, err := s.execIn("selfpost", "sh", "-c",
`test -f /data/dkim/selectors && find /data/dkim ! \( -user panel -group panel \( -type d -perm 0700 -o -type f -perm 0600 \) \)`)
if err != nil {
return fmt.Errorf("the DKIM tree: %v\n%s", err, out)
}
if strings.TrimSpace(out) != "" {
return fmt.Errorf("not the panel's alone under /data/dkim:\n%s", out)
}
return nil
}
// checkPostfixHardening reads back what postfix-config.sh sets against
// downgrade and enumeration (audit 2026-10-12, L31).
func checkPostfixHardening(s *stack) error {
out, err := s.execIn("selfpost", "postconf", "-h", "smtpd_tls_protocols", "smtpd_tls_mandatory_protocols", "disable_vrfy_command", "smtpd_banner",
"smtpd_etrn_restrictions", "smtpd_discard_ehlo_keywords")
if err != nil {
return fmt.Errorf("postconf: %v\n%s", err, out)
}
got := strings.Split(strings.TrimSpace(out), "\n")
want := []string{">=TLSv1.2", ">=TLSv1.2", "yes", "$myhostname ESMTP", "reject", "etrn"}
if strings.Join(got, "|") != strings.Join(want, "|") {
return fmt.Errorf("postconf -h of the hardened settings = %q, want %q", got, want)
}
return nil
}