Some fixes for certificate validation for anon PKINIT
diff --git a/kerby-kerb/kerb-client/src/main/java/org/apache/kerby/kerberos/kerb/client/preauth/pkinit/PkinitPreauth.java b/kerby-kerb/kerb-client/src/main/java/org/apache/kerby/kerberos/kerb/client/preauth/pkinit/PkinitPreauth.java
index b47a46f..df4af89 100644
--- a/kerby-kerb/kerb-client/src/main/java/org/apache/kerby/kerberos/kerb/client/preauth/pkinit/PkinitPreauth.java
+++ b/kerby-kerb/kerb-client/src/main/java/org/apache/kerby/kerberos/kerb/client/preauth/pkinit/PkinitPreauth.java
@@ -372,8 +372,6 @@
                 throw new KrbException("Failed to load PKINIT anchor");
             }
             
-            Certificate archorCertificate = PkinitCrypto.changeToCertificate(x509Certificate);
-
             CertificateSet certificateSet = signedData.getCertificates();
             List<Certificate> certificates = new ArrayList<>();
             if (certificateSet != null) {
@@ -383,7 +381,7 @@
                 }
             }
             try {
-                PkinitCrypto.validateChain(certificates, archorCertificate);
+                PkinitCrypto.validateChain(certificates, x509Certificate);
             } catch (Exception e) {
                 throw new KrbException(KrbErrorCode.KDC_ERR_INVALID_CERTIFICATE, e);
             }
diff --git a/kerby-kerb/kerb-common/src/main/java/org/apache/kerby/kerberos/kerb/preauth/pkinit/PkinitCrypto.java b/kerby-kerb/kerb-common/src/main/java/org/apache/kerby/kerberos/kerb/preauth/pkinit/PkinitCrypto.java
index cc09a37..63e3e44 100644
--- a/kerby-kerb/kerb-common/src/main/java/org/apache/kerby/kerberos/kerb/preauth/pkinit/PkinitCrypto.java
+++ b/kerby-kerb/kerb-common/src/main/java/org/apache/kerby/kerberos/kerb/preauth/pkinit/PkinitCrypto.java
@@ -18,6 +18,33 @@
  */
 package org.apache.kerby.kerberos.kerb.preauth.pkinit;
 
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+import java.security.cert.CertPath;
+import java.security.cert.CertPathValidator;
+import java.security.cert.CertPathValidatorException;
+import java.security.cert.CertificateEncodingException;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateExpiredException;
+import java.security.cert.CertificateFactory;
+import java.security.cert.CertificateNotYetValidException;
+import java.security.cert.PKIXParameters;
+import java.security.cert.TrustAnchor;
+import java.security.cert.X509Certificate;
+import java.security.spec.InvalidKeySpecException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import javax.crypto.interfaces.DHPublicKey;
+import javax.crypto.spec.DHParameterSpec;
+import javax.crypto.spec.DHPublicKeySpec;
+
 import org.apache.kerby.asn1.type.Asn1ObjectIdentifier;
 import org.apache.kerby.cms.type.CertificateSet;
 import org.apache.kerby.cms.type.DigestAlgorithmIdentifiers;
@@ -36,25 +63,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.crypto.interfaces.DHPublicKey;
-import javax.crypto.spec.DHParameterSpec;
-import javax.crypto.spec.DHPublicKeySpec;
-import java.io.IOException;
-import java.math.BigInteger;
-import java.security.InvalidAlgorithmParameterException;
-import java.security.KeyFactory;
-import java.security.NoSuchAlgorithmException;
-import java.security.NoSuchProviderException;
-import java.security.cert.CertPathValidatorException;
-import java.security.cert.CertificateEncodingException;
-import java.security.cert.CertificateException;
-import java.security.cert.CertificateExpiredException;
-import java.security.cert.CertificateNotYetValidException;
-import java.security.cert.X509Certificate;
-import java.security.spec.InvalidKeySpecException;
-import java.util.ArrayList;
-import java.util.List;
-
 /**
   * Ref. pkinit_crypto_openssl.c in MIT krb5 project.
   */
@@ -329,16 +337,25 @@
      * @throws NoSuchAlgorithmException e
      * @throws InvalidAlgorithmParameterException e
      * @throws CertPathValidatorException e
+     * @throws IOException 
      */
-    public static void validateChain(List<Certificate> certificateList, Certificate anchor)
+    public static void validateChain(List<Certificate> certificateList, X509Certificate anchor)
             throws CertificateException, NoSuchAlgorithmException, NoSuchProviderException,
-            InvalidAlgorithmParameterException, CertPathValidatorException {
+            InvalidAlgorithmParameterException, CertPathValidatorException, IOException {
 
-        //TODO
-        /*
         CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
-        CertPath certPath = certificateFactory.generatertPath(certificateList);
-
+        
+        // Convert into a list of X509Certificates
+        List<X509Certificate> certsList = new ArrayList<>(certificateList.size());
+        for (Certificate cert : certificateList) {
+            X509Certificate parsedCert = 
+                (X509Certificate) certificateFactory.generateCertificate(
+                    new ByteArrayInputStream(cert.encode()));
+            certsList.add(parsedCert);
+        }
+        
+        CertPath certPath = certificateFactory.generateCertPath(certsList);
+        
         CertPathValidator cpv = CertPathValidator.getInstance("PKIX");
 
         TrustAnchor trustAnchor = new TrustAnchor(anchor, null);
@@ -347,7 +364,6 @@
         parameters.setRevocationEnabled(false);
 
         cpv.validate(certPath, parameters);
-        */
     }
 
     /**