decode punycode public suffixes in PublicSuffixMatcher.verify

httpclient5/src/main/java/org/apache/hc/client5/http/psl/PublicSuffixMatcher.java

@@ -249,7 +249,15 @@ public boolean verify(final String domain) {
          if (domain == null) {
              return false;
          }
-         return verifyInternal(domain.startsWith(".") ? domain.substring(1) : domain);
+         // Normalise here so that verifyInternal can assume its input is already lowercase and in
+         // Unicode form. The rules are held that way, so an ACE-encoded (xn--) or mixed-case public
+         // suffix has to be decoded first, mirroring getDomainRoot; otherwise it fails to match a
+         // rule and is mistaken for a registrable domain.
+         String normalized = DnsUtils.normalize(domain.startsWith(".") ? domain.substring(1) : domain);
+         if (normalized.contains("xn-")) {
+             normalized = IDN.toUnicode(normalized);
+         }
+         return verifyInternal(normalized);
      }
 
     @Internal

httpclient5/src/test/java/org/apache/hc/client5/http/psl/TestPublicSuffixMatcher.java

@@ -191,6 +191,18 @@ void testMatchUnicode() {
         Assertions.assertTrue(matcher.matches(".xn--h-2fa.no"));
     }
 
+    @Test
+    void testVerifyUnicode() {
+        // A public suffix must be rejected by verify() whether it is given in Unicode or in its
+        // ACE (xn--) form; matches() already recognises both, so verify() must agree.
+        Assertions.assertTrue(matcher.matches(".xn--h-2fa.no"));
+        Assertions.assertFalse(matcher.verify("hå.no")); // å is <aring>
+        Assertions.assertFalse(matcher.verify("xn--h-2fa.no"));
+        // A genuine registrable domain under the IDN suffix is still allowed, in either form.
+        Assertions.assertTrue(matcher.verify("foo.hå.no"));
+        Assertions.assertTrue(matcher.verify("foo.xn--h-2fa.no"));
+    }
+
     private void checkPublicSuffix(final String input, final String expected) {
         Assertions.assertEquals(expected, pslMatcher.getDomainRoot(input));
     }