Merge pull request #689 from tls-attacker/fix-namedgroups-tostring-null

Fix toString() method that could return null in NamedGroupsGuidelineCheckResult

Author: ic0ns

TLS-Server-Scanner/src/main/java/de/rub/nds/tlsscanner/serverscanner/guideline/results/NamedGroupsGuidelineCheckResult.java

@@ -69,7 +69,7 @@ public String toString() {
         if (groupCount != null) {
             return "Server only supports " + groupCount + " groups.";
         }
-        return null;
+        return "No specific named groups information available.";
     }
 
     public Set<NamedGroup> getNotRecommendedGroups() {

TLS-Server-Scanner/src/test/java/de/rub/nds/tlsscanner/serverscanner/guideline/results/NamedGroupsGuidelineCheckResultTest.java

@@ -0,0 +1,65 @@
+/*
+ * TLS-Scanner - A TLS configuration and analysis tool based on TLS-Attacker
+ *
+ * Copyright 2017-2023 Ruhr University Bochum, Paderborn University, Technology Innovation Institute, and Hackmanit GmbH
+ *
+ * Licensed under Apache License, Version 2.0
+ * http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+package de.rub.nds.tlsscanner.serverscanner.guideline.results;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import de.rub.nds.scanner.core.guideline.GuidelineAdherence;
+import de.rub.nds.tlsattacker.core.constants.NamedGroup;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class NamedGroupsGuidelineCheckResultTest {
+
+    @Test
+    void testToStringNeverReturnsNull() {
+        // Test with CHECK_FAILED adherence
+        NamedGroupsGuidelineCheckResult result1 =
+                new NamedGroupsGuidelineCheckResult("test1", GuidelineAdherence.CHECK_FAILED);
+        assertNotNull(result1.toString());
+        assertTrue(result1.toString().contains("Missing information"));
+
+        // Test with ADHERED adherence
+        NamedGroupsGuidelineCheckResult result2 =
+                new NamedGroupsGuidelineCheckResult("test2", GuidelineAdherence.ADHERED);
+        assertNotNull(result2.toString());
+        assertTrue(result2.toString().contains("Server passed"));
+
+        // Test with not recommended groups
+        Set<NamedGroup> notRecommended = new HashSet<>();
+        notRecommended.add(NamedGroup.SECP224R1);
+        NamedGroupsGuidelineCheckResult result3 =
+                new NamedGroupsGuidelineCheckResult(
+                        "test3", GuidelineAdherence.VIOLATED, notRecommended);
+        assertNotNull(result3.toString());
+        assertTrue(result3.toString().contains("not recommended"));
+
+        // Test with missing required groups
+        NamedGroupsGuidelineCheckResult result4 =
+                new NamedGroupsGuidelineCheckResult(
+                        "test4", GuidelineAdherence.VIOLATED, Arrays.asList(NamedGroup.SECP256R1));
+        assertNotNull(result4.toString());
+        assertTrue(result4.toString().contains("missing one of required"));
+
+        // Test with group count
+        NamedGroupsGuidelineCheckResult result5 =
+                new NamedGroupsGuidelineCheckResult("test5", GuidelineAdherence.VIOLATED, 3);
+        assertNotNull(result5.toString());
+        assertTrue(result5.toString().contains("only supports 3 groups"));
+
+        // Test default case - this is the case that was returning null
+        NamedGroupsGuidelineCheckResult result6 =
+                new NamedGroupsGuidelineCheckResult("test6", GuidelineAdherence.VIOLATED);
+        assertNotNull(result6.toString());
+        assertTrue(result6.toString().contains("No specific named groups information"));
+    }
+}