route53: Don't escape '*' as leftmost label of a domain name.

internal/service/route53/clean.go

@@ -40,6 +40,19 @@ func normalizeDomainNameToAPI(input string) string {
 			output.WriteRune(unicode.ToLower(ch))
 		case ch >= '0' && ch <= '9' || ch >= 'a' && ch <= 'z' || ch == '-' || ch == '.' || ch == '_':
 			output.WriteRune(ch)
+		case ch == '*':
+			// * as leftmost label is retained.
+			const (
+				lenDelimiter = 1
+			)
+			if output.Len() == 0 {
+				if bytes, err := br.Peek(lenDelimiter); err == nil && bytes[0] == '.' {
+					output.WriteRune(ch)
+					continue
+				}
+			}
+			// Three-digit octal code.
+			output.WriteString(fmt.Sprintf("\\%03o", ch))
 		case ch == '\\':
 			const (
 				lenOctalCode = 3
@@ -52,7 +65,8 @@ func normalizeDomainNameToAPI(input string) string {
 				_, _ = br.Discard(lenOctalCode)
 				continue
 			}
-			fallthrough
+			// Three-digit octal code.
+			output.WriteString(fmt.Sprintf("\\%03o", ch))
 		default:
 			// Three-digit octal code.
 			output.WriteString(fmt.Sprintf("\\%03o", ch))

internal/service/route53/clean_test.go

@@ -30,7 +30,10 @@ func TestNormalizeNameIntoAPIRepresentation(t *testing.T) {
 		{"AbC.example.com", "abc.example.com"},
 
 		// convert into escape code
-		{"*.example.com", "\\052.example.com"},
+		{"*.example.com", "*.example.com"}, // * as leftmost label is retained
+		{"*bc.example.com", "\\052bc.example.com"},
+		{"a*c.example.com", "a\\052c.example.com"},
+		{"ab*.example.com", "ab\\052.example.com"},
 		{"!.example.com", "\\041.example.com"},
 		{"a/b.example.com", "a\\057b.example.com"},
 		{"/.example.com", "\\057.example.com"},