fix: android root CA error

Author: jbpin

acme/challenge.go

@@ -1481,7 +1481,8 @@ Eczm34A5FNijV3s0/f0UPl7zbJcTx6xwqMIRq6NCMEAwDwYDVR0TAQH/BAUwAwEB
 /zAOBgNVHQ8BAf8EBAMCAQYwHQYDVR0OBBYEFFIyuyz7RkOb3NaBqQ5lZuA0QepA
 MAoGCCqGSM49BAMDA2gAMGUCMETfjPO/HwqReR2CS7p0ZWoD/LHs6hDi422opifH
 EUaYLxwGlT9SLdjkVpz0UUOR5wIxAIoGyxGKRHVTpqpGRFiJtQEOOTp/+s1GcxeY
-uR2zh/80lQyu9vAFCj6E4AXc+osmRg==`
+uR2zh/80lQyu9vAFCj6E4AXc+osmRg==
+-----END CERTIFICATE-----`
 
 // OID for the Android attestation extension
 // https://source.android.com/docs/security/features/keystore/attestation#id-attestation
@@ -1587,9 +1588,12 @@ func doAndroidKeyAttestionFormat(_ context.Context, prov Provisioner, ch *Challe
 		switch root.PublicKey.(type) {
 		case *rsa.PublicKey:
 			rsaRoot, err := pemutil.ParseCertificate([]byte(AndroidRootCARSA))
+			if err != nil {
+				return nil, WrapErrorISE(err, "error parsing root CA RSA")
+			}
 			oldRsaRoot, err := pemutil.ParseCertificate([]byte(OldAndroidRootCARSA))
 			if err != nil {
-				return nil, WrapErrorISE(err, "error parsing root ca")
+				return nil, WrapErrorISE(err, "error parsing old root CA RSA")
 			}
 			// 1. verify public key
 			if !root.PublicKey.(*rsa.PublicKey).Equal(rsaRoot.PublicKey) {
@@ -1602,7 +1606,7 @@ func doAndroidKeyAttestionFormat(_ context.Context, prov Provisioner, ch *Challe
 			if err != nil {
 				return nil, WrapErrorISE(err, "error parsing root ca")
 			}
-			if !root.PublicKey.(*rsa.PublicKey).Equal(ecdsaRoot.PublicKey) {
+			if !root.PublicKey.(*ecdsa.PublicKey).Equal(ecdsaRoot.PublicKey) {
 				return nil, NewDetailedError(ErrorBadAttestationStatementType, "root certificate not signed by Google")
 			}
 			attestationRoots.AddCert(ecdsaRoot)
@@ -1701,7 +1705,7 @@ func doAndroidKeyAttestionFormat(_ context.Context, prov Provisioner, ch *Challe
 
 	// validate challenge
 	if subtle.ConstantTimeCompare([]byte(keyAuth), data.Attestation.AttestationChallenge) != 1 {
-		return nil, NewDetailedError(ErrorBadAttestationStatementType, fmt.Sprintf("challenge mismatch; expected %q, got %q", keyAuth, string(data.Attestation.AttestationChallenge)))
+		return nil, NewDetailedError(ErrorBadAttestationStatementType, "challenge mismatch; expected %q, got %q", keyAuth, string(data.Attestation.AttestationChallenge))
 	}
 
 	return data, nil

acme/challenge_test.go

@@ -5097,6 +5097,74 @@ func Test_deviceAttest01Validate(t *testing.T) {
 	}
 }
 
+func Test_doAndroidKeyAttestionFormat_noAttestationRoots(t *testing.T) {
+	// This test exercises the fallback path when no attestation roots
+	// are configured (the !attOk branch), verifying that:
+	// 1. The ECDSA root parsing and type assertion works correctly
+	// 2. Non-Google roots are properly rejected
+	ca, err := minica.New()
+	require.NoError(t, err)
+
+	signer, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	jwk, keyAuth := mustAccountAndKeyAuthorization(t, "token")
+	keyAuthSum := sha256.Sum256([]byte(keyAuth))
+	sig, err := signer.Sign(rand.Reader, keyAuthSum[:], crypto.SHA256)
+	require.NoError(t, err)
+
+	atts := attestation.KeyDescription{
+		AttestationVersion:       300,
+		AttestationSecurityLevel: 1,
+		AttestationChallenge:     sig,
+		TeeEnforced: attestation.AuthorizationList{
+			AttestationIdSerial: []byte("serial-number"),
+		},
+	}
+	attestByte, err := attestation.CreateKeyDescription(&atts)
+	require.NoError(t, err)
+
+	leaf, err := ca.Sign(&x509.Certificate{
+		Subject:   pkix.Name{CommonName: "attestation cert"},
+		PublicKey: signer.Public(),
+		ExtraExtensions: []pkix.Extension{
+			{Id: oidAndroidAttestation, Value: attestByte},
+		},
+	})
+	require.NoError(t, err)
+
+	att := &attestationObject{
+		Format: "android-key",
+		AttStatement: map[string]any{
+			"x5c": []any{leaf.Raw, ca.Intermediate.Raw, ca.Root.Raw},
+		},
+	}
+
+	// Create provisioner without attestation roots
+	prov := &provisioner.ACME{
+		Type:       "ACME",
+		Name:       "acme",
+		Challenges: []provisioner.ACMEChallenge{provisioner.DEVICE_ATTEST_01},
+	}
+	require.NoError(t, prov.Init(provisioner.Config{
+		Claims: config.GlobalProvisionerClaims,
+	}))
+
+	ch := &Challenge{
+		ID:    "chID",
+		Token: "nonce",
+		Type:  "device-attest-01",
+		Value: "serial-number",
+	}
+
+	_, err = doAndroidKeyAttestionFormat(context.Background(), prov, ch, jwk, att)
+	require.Error(t, err)
+
+	var acmeErr *Error
+	require.ErrorAs(t, err, &acmeErr)
+	assert.Contains(t, acmeErr.Error(), "root certificate not signed by Google")
+}
+
 var (
 	oidTPMManufacturer = asn1.ObjectIdentifier{2, 23, 133, 2, 1}
 	oidTPMModel        = asn1.ObjectIdentifier{2, 23, 133, 2, 2}