Fix buffer overflow in password generator.

When the requested length is less than number of characters in a rule a buffer overflow occurs. See #126.
vt-middleware · Jul 20, 2021 · d8a799c · d8a799c
1 parent e15e869
commit d8a799c
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/src/main/java/org/passay/PasswordGenerator.java b/src/main/java/org/passay/PasswordGenerator.java
@@ -74,7 +74,10 @@ public String generatePassword(final int length, final List<CharacterRule> rules
     final CharBuffer buffer = CharBuffer.allocate(length);
     if (rules != null) {
       for (CharacterRule rule : rules) {
-        fillRandomCharacters(rule.getValidCharacters(), rule.getNumberOfCharacters(), buffer);
+        fillRandomCharacters(
+          rule.getValidCharacters(),
+          length <= rule.getNumberOfCharacters() ? length : rule.getNumberOfCharacters(),
+          buffer);
         allChars.append(rule.getValidCharacters());
       }
     }

diff --git a/src/test/java/org/passay/PasswordGeneratorTest.java b/src/test/java/org/passay/PasswordGeneratorTest.java
@@ -89,4 +89,15 @@ public void testGenerator(final String pass)
     AssertJUnit.assertFalse(failCharRule.validate(new PasswordData(pass)).isValid());
     AssertJUnit.assertTrue(verifyCharRule.validate(new PasswordData(pass)).isValid());
   }
+
+
+  /**
+   */
+  @Test(groups = "passgentest")
+  public void testBufferOverflow()
+  {
+    new PasswordGenerator().generatePassword(5, new CharacterRule(EnglishCharacterData.LowerCase, 10));
+    new PasswordGenerator().generatePassword(10, new CharacterRule(EnglishCharacterData.LowerCase, 5));
+    new PasswordGenerator().generatePassword(10, new CharacterRule(EnglishCharacterData.LowerCase, 10));
+  }
 }