fix(endpoint): domains handling with idna (#5685)

* fix(idna): fix handling of domains

Signed-off-by: ivan katliarchuk <ivan.katliarchuk@gmail.com>

* fix(idna): fix handling of domains

Signed-off-by: ivan katliarchuk <ivan.katliarchuk@gmail.com>

* fix(idna): fix handling of domains

Signed-off-by: ivan katliarchuk <ivan.katliarchuk@gmail.com>

---------

Signed-off-by: ivan katliarchuk <ivan.katliarchuk@gmail.com>

endpoint/domain_filter.go

@@ -25,7 +25,8 @@ import (
 	"strings"
 
 	log "github.com/sirupsen/logrus"
-	"golang.org/x/net/idna"
+
+	"sigs.k8s.io/external-dns/internal/idna"
 )
 
 type MatchAllDomainFilters []DomainFilterInterface
@@ -247,9 +248,9 @@ func (df *DomainFilter) MatchParent(domain string) bool {
 }
 
 // normalizeDomain converts a domain to a canonical form, so that we can filter on it
-// it: trim "." suffix, get Unicode version of domain complient with Section 5 of RFC 5891
+// it: trim "." suffix, get Unicode version of domain compliant with Section 5 of RFC 5891
 func normalizeDomain(domain string) string {
-	s, err := idna.Lookup.ToUnicode(strings.TrimSuffix(domain, "."))
+	s, err := idna.Profile.ToUnicode(strings.TrimSuffix(domain, "."))
 	if err != nil {
 		log.Warnf(`Got error while parsing domain %s: %v`, domain, err)
 	}

internal/idna/idna.go

@@ -0,0 +1,29 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package idna
+
+import (
+	"golang.org/x/net/idna"
+)
+
+var (
+	Profile = idna.New(
+		idna.MapForLookup(),
+		idna.Transitional(true),
+		idna.StrictDomainName(false),
+	)
+)

internal/idna/idna_test.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package idna
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestProfileWithDefault(t *testing.T) {
+	tets := []struct {
+		input    string
+		expected string
+	}{
+		{
+			input:    "*.GÖPHER.com",
+			expected: "*.göpher.com",
+		},
+		{
+			input:    "*._abrakadabra.com",
+			expected: "*._abrakadabra.com",
+		},
+		{
+			input:    "_abrakadabra.com",
+			expected: "_abrakadabra.com",
+		},
+		{
+			input:    "*.foo.kube.example.com",
+			expected: "*.foo.kube.example.com",
+		},
+		{
+			input:    "xn--bcher-kva.example.com",
+			expected: "bücher.example.com",
+		},
+	}
+	for _, tt := range tets {
+		t.Run(strings.ToLower(tt.input), func(t *testing.T) {
+			result, err := Profile.ToUnicode(tt.input)
+			assert.NoError(t, err)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}

plan/plan.go

@@ -23,9 +23,9 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	log "github.com/sirupsen/logrus"
-	"golang.org/x/net/idna"
 
 	"sigs.k8s.io/external-dns/endpoint"
+	"sigs.k8s.io/external-dns/internal/idna"
 )
 
 // PropertyComparator is used in Plan for comparing the previous and current custom annotations.
@@ -340,16 +340,10 @@ func filterRecordsForPlan(records []*endpoint.Endpoint, domainFilter endpoint.Ma
 	return filtered
 }
 
-var idnaProfile = idna.New(
-	idna.MapForLookup(),
-	idna.Transitional(true),
-	idna.StrictDomainName(false),
-)
-
 // normalizeDNSName converts a DNS name to a canonical form, so that we can use string equality
 // it: removes space, get ASCII version of dnsName complient with Section 5 of RFC 5891, ensures there is a trailing dot
 func normalizeDNSName(dnsName string) string {
-	s, err := idnaProfile.ToASCII(strings.TrimSpace(dnsName))
+	s, err := idna.Profile.ToASCII(strings.TrimSpace(dnsName))
 	if err != nil {
 		log.Warnf(`Got error while parsing DNSName %s: %v`, dnsName, err)
 	}

provider/zonefinder_test.go

@@ -32,14 +32,16 @@ func TestZoneIDName(t *testing.T) {
 	z.Add("654321", "foo.qux.baz")
 	z.Add("987654", "エイミー.みんな")
 	z.Add("123123", "_metadata.example.com")
+	z.Add("1231231", "_foo._metadata.example.com")
 	z.Add("456456", "_metadata.エイミー.みんな")
 
 	assert.Equal(t, ZoneIDName{
-		"123456": "qux.baz",
-		"654321": "foo.qux.baz",
-		"987654": "エイミー.みんな",
-		"123123": "_metadata.example.com",
-		"456456": "_metadata.エイミー.みんな",
+		"123456":  "qux.baz",
+		"654321":  "foo.qux.baz",
+		"987654":  "エイミー.みんな",
+		"123123":  "_metadata.example.com",
+		"1231231": "_foo._metadata.example.com",
+		"456456":  "_metadata.エイミー.みんな",
 	}, z)
 
 	// simple entry in a domain
@@ -77,6 +79,10 @@ func TestZoneIDName(t *testing.T) {
 	assert.Equal(t, "エイミー.みんな", zoneName)
 	assert.Equal(t, "987654", zoneID)
 
+	zoneID, zoneName = z.FindZone("_foo._metadata.example.com")
+	assert.Equal(t, "_foo._metadata.example.com", zoneName)
+	assert.Equal(t, "1231231", zoneID)
+
 	hook := testutils.LogsUnderTestWithLogLevel(log.WarnLevel, t)
 	_, _ = z.FindZone("???")