Merge pull request #467 from rtpt-erikgeiser/fix_label

Add Support for Labels Containing Partial Domain Names (RFC 4704 Section 4.2)

2 files changed, 20 insertions, 0 deletions

diff --git a/rfc1035label/label.go b/rfc1035label/label.go
index 5a67d7c..042c17b 100644
--- a/rfc1035label/label.go
+++ b/rfc1035label/label.go
@@ -100,6 +100,12 @@ func labelsFromBytes(buf []byte) ([]string, error) {
 
 	for {
 		if pos >= len(buf) {
+			// interpret label without trailing zero-length byte as a partial
+			// domain name field as per RFC 4704 Section 4.2
+			if label != "" {
+				labels = append(labels, label)
+			}
+
 			break
 		}
 		length := int(buf[pos])
diff --git a/rfc1035label/label_test.go b/rfc1035label/label_test.go
index 6098e44..865b41a 100644
--- a/rfc1035label/label_test.go
+++ b/rfc1035label/label_test.go
@@ -28,6 +28,20 @@ func TestLabelsFromBytesZeroLength(t *testing.T) {
 	require.Equal(t, []byte{}, labels.ToBytes())
 }
 
+func TestLabelsFromBytesPartialDomainName(t *testing.T) {
+	// Partial domain name without trailing zero-length byte as per RFC 4704
+	// Section 4.2
+	expected := []byte{
+		0x8, 'h', 'o', 's', 't', 'n', 'a', 'm', 'e',
+	}
+	labels, err := FromBytes(expected)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(labels.Labels))
+	require.Equal(t, len(expected), labels.Length())
+	require.Equal(t, expected, labels.ToBytes())
+	require.Equal(t, "hostname", labels.Labels[0])
+}
+
 func TestLabelsFromBytesInvalidLength(t *testing.T) {
 	_, err := FromBytes([]byte{0x5, 0xaa, 0xbb}) // short length
 	require.Error(t, err)