feat(tls): o painel diz o digest que o registo TLSA tem de carregar

Uma associacao DANE e o SHA-256 sobre o SubjectPublicKeyInfo do certificado
que esta a ser servido. Se o que esta no DNS e o que o servidor apresenta se
afastarem, qualquer remetente que valide DANE recusa o correio -- e nada no
painel dizia porque.

Passa a mostrar o numero, para poder ser comparado com o registo publicado.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

services/protocols/internal/infrastructure/tls/provider_status.go

@@ -2,8 +2,10 @@ package tlsprovider
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"crypto/tls"
 	"crypto/x509"
+	"encoding/hex"
 	"time"
 
 	"lambdamail/protocols/internal/application/port"
@@ -94,3 +96,18 @@ func (s *ProviderStatus) CertificateSummary(host string) (string, bool, bool) {
 		leaf.CheckSignature(leaf.SignatureAlgorithm, leaf.RawTBSCertificate, leaf.Signature) == nil
 	return issuer, selfSigned, true
 }
+
+// CertificateSpkiDigest is the SHA-256 over the certificate's
+// SubjectPublicKeyInfo: the number a TLSA "3 1 1" record has to carry.
+//
+// Published so an operator can compare what is in DNS against what the server
+// is actually serving. When those two disagree, every DANE-validating sender
+// refuses the mail, and nothing else on the panel would show why.
+func (s *ProviderStatus) CertificateSpkiDigest(host string) (string, bool) {
+	leaf := s.leafFor(host)
+	if leaf == nil {
+		return "", false
+	}
+	sum := sha256.Sum256(leaf.RawSubjectPublicKeyInfo)
+	return hex.EncodeToString(sum[:]), true
+}

services/protocols/internal/infrastructure/tls/provider_status_test.go

@@ -1,6 +1,9 @@
 package tlsprovider
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
 	"testing"
 	"time"
 )
@@ -47,3 +50,37 @@ func TestProviderStatus_ReportsAnEphemeralSelfSignedCertificate(t *testing.T) {
 		t.Error("no issuer reported")
 	}
 }
+
+// The DANE association an operator publishes has to be the hash of the key the
+// server is actually serving. If the two ever drift, mail from a validating
+// sender is refused outright - so the panel states the digest of the live
+// certificate, which is the number to compare against the TLSA record.
+func TestProviderStatus_ReportsTheSpkiDigestOfTheServedCertificate(t *testing.T) {
+	provider, err := NewEphemeralSelfSignedCertProvider()
+	if err != nil {
+		t.Fatalf("build provider: %v", err)
+	}
+	status := NewProviderStatus(provider)
+
+	digest, ok := status.CertificateSpkiDigest("mail.example.test")
+	if !ok {
+		t.Fatal("no digest reported")
+	}
+	// TLSA 3 1 1 is a SHA-256 over the SubjectPublicKeyInfo: 64 hex characters.
+	if len(digest) != 64 {
+		t.Errorf("digest %q is %d characters, want 64", digest, len(digest))
+	}
+	for _, c := range digest {
+		if !strings.ContainsRune("0123456789abcdef", c) {
+			t.Fatalf("digest %q is not lowercase hex", digest)
+		}
+	}
+
+	// It must be the SPKI hash, not a hash of the whole certificate: those are
+	// different numbers and publishing the wrong one breaks delivery.
+	leaf := status.leafFor("mail.example.test")
+	want := sha256.Sum256(leaf.RawSubjectPublicKeyInfo)
+	if digest != hex.EncodeToString(want[:]) {
+		t.Errorf("digest is not the SHA-256 of the SubjectPublicKeyInfo")
+	}
+}

services/protocols/internal/presentation/http/admin_tls_api.go

@@ -23,6 +23,12 @@ type TlsCertificateInspector interface {
 	CertificateSummary(host string) (issuer string, selfSigned bool, ok bool)
 }
 
+// TlsDaneInspector reports the digest a TLSA "3 1 1" record must carry for the
+// certificate currently being served.
+type TlsDaneInspector interface {
+	CertificateSpkiDigest(host string) (string, bool)
+}
+
 type adminTlsAPI struct {
 	source     TlsStatusSource
 	mailHost   string
@@ -99,6 +105,15 @@ func (a *adminTlsAPI) handleStatus(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	// The number a DANE association has to match. Published so an operator can
+	// compare it against the TLSA record in DNS: if the two drift apart, every
+	// validating sender refuses the mail and nothing else here would say why.
+	if dane, ok := a.source.(TlsDaneInspector); ok {
+		if digest, found := dane.CertificateSpkiDigest(a.mailHost); found {
+			status["tlsa_digest"] = digest
+		}
+	}
+
 	if !status["has_certificate"].(bool) {
 		status["state"] = "NO_CERTIFICATE"
 	}

services/webmail/messages/en.json

@@ -112,7 +112,8 @@
     "passwordReset": "Password changed. This user's sessions were signed out.",
     "passwordResetWarning": "Signs out every session this user holds, including one open right now.",
     "removeTotp": "Remove second factor",
-    "totpRemoved": "Second factor removed, with its recovery codes."
+    "totpRemoved": "Second factor removed, with its recovery codes.",
+    "tlsaDigest": "Digest for the TLSA record (DANE 3 1 1)"
   },
   "auth": {
     "adminLoginTitle": "Admin console",

services/webmail/messages/es.json

@@ -112,7 +112,8 @@
     "passwordReset": "Contrasena cambiada. Las sesiones de este usuario se cerraron.",
     "passwordResetWarning": "Cierra todas las sesiones de este usuario, incluida una abierta ahora.",
     "removeTotp": "Quitar segundo factor",
-    "totpRemoved": "Segundo factor eliminado, con sus codigos de recuperacion."
+    "totpRemoved": "Segundo factor eliminado, con sus codigos de recuperacion.",
+    "tlsaDigest": "Digest para el registro TLSA (DANE 3 1 1)"
   },
   "auth": {
     "adminLoginTitle": "Consola de administración",

services/webmail/messages/pt-BR.json

@@ -112,7 +112,8 @@
     "passwordReset": "Palavra-passe alterada. As sessoes deste utilizador foram terminadas.",
     "passwordResetWarning": "Termina todas as sessoes deste utilizador, incluindo a que esteja aberta agora.",
     "removeTotp": "Remover segundo factor",
-    "totpRemoved": "Segundo factor removido, com os codigos de recuperacao."
+    "totpRemoved": "Segundo factor removido, com os codigos de recuperacao.",
+    "tlsaDigest": "Digest para o registo TLSA (DANE 3 1 1)"
   },
   "auth": {
     "adminLoginTitle": "Console de administração",

services/webmail/src/app/(admin)/admin/security/page.tsx

@@ -306,6 +306,17 @@ export default function AdminSecurityPage() {
                 </div>
               </div>
 
+              {/* The number a TLSA "3 1 1" record has to carry. If DNS and this
+                  disagree, every DANE-validating sender refuses the mail. */}
+              {tlsStatus.tlsa_digest ? (
+                <div className="flex flex-col gap-1 rounded-xl bg-dark-card p-3.5 shadow-edge md:col-span-3">
+                  <div className="text-xs text-slate-400">{t("admin.tlsaDigest")}</div>
+                  <div className="break-all font-mono text-[12px] text-slate-200">
+                    {String(tlsStatus.tlsa_digest)}
+                  </div>
+                </div>
+              ) : null}
+
               <div className="flex flex-col gap-1 rounded-xl bg-dark-card p-3.5 shadow-edge">
                 <div className="text-xs text-slate-400">{t("admin.mailHost")}</div>
                 <div className="break-all text-[15px] font-medium text-slate-100">