1 files changed, 126 insertions, 0 deletions
diff --git a/prov/src/main/java/org/spongycastle/jce/PKCS12Util.java b/prov/src/main/java/org/spongycastle/jce/PKCS12Util.java
new file mode 100644
index 00000000..1cf7823a
--- /dev/null
+++ b/prov/src/main/java/org/spongycastle/jce/PKCS12Util.java
@@ -0,0 +1,126 @@
+package org.spongycastle.jce;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import javax.crypto.Mac;
+import javax.crypto.SecretKey;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.PBEParameterSpec;
+
+import org.spongycastle.asn1.ASN1InputStream;
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.asn1.ASN1OctetString;
+import org.spongycastle.asn1.ASN1Primitive;
+import org.spongycastle.asn1.DERNull;
+import org.spongycastle.asn1.DEROctetString;
+import org.spongycastle.asn1.DEROutputStream;
+import org.spongycastle.asn1.pkcs.ContentInfo;
+import org.spongycastle.asn1.pkcs.MacData;
+import org.spongycastle.asn1.pkcs.Pfx;
+import org.spongycastle.asn1.x509.AlgorithmIdentifier;
+import org.spongycastle.asn1.x509.DigestInfo;
+
+/**
+ * Utility class for reencoding PKCS#12 files to definite length.
+ */
+public class PKCS12Util
+{
+    /**
+     * Just re-encode the outer layer of the PKCS#12 file to definite length encoding.
+     *
+     * @param berPKCS12File - original PKCS#12 file
+     * @return a byte array representing the DER encoding of the PFX structure
+     * @throws IOException
+     */
+    public static byte[] convertToDefiniteLength(byte[] berPKCS12File)
+        throws IOException
+    {
+        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
+        DEROutputStream dOut = new DEROutputStream(bOut);
+
+        Pfx pfx = Pfx.getInstance(berPKCS12File);
+
+        bOut.reset();
+
+        dOut.writeObject(pfx);
+
+        return bOut.toByteArray();
+    }
+
+    /**
+     * Re-encode the PKCS#12 structure to definite length encoding at the inner layer
+     * as well, recomputing the MAC accordingly.
+     *
+     * @param berPKCS12File - original PKCS12 file.
+     * @param provider - provider to use for MAC calculation.
+     * @return a byte array representing the DER encoding of the PFX structure.
+     * @throws IOException on parsing, encoding errors.
+     */
+    public static byte[] convertToDefiniteLength(byte[] berPKCS12File, char[] passwd, String provider)
+        throws IOException
+    {
+        Pfx pfx = Pfx.getInstance(berPKCS12File);
+
+        ContentInfo info = pfx.getAuthSafe();
+
+        ASN1OctetString content = ASN1OctetString.getInstance(info.getContent());
+
+        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
+        DEROutputStream dOut = new DEROutputStream(bOut);
+
+        ASN1InputStream contentIn = new ASN1InputStream(content.getOctets());
+        ASN1Primitive obj = contentIn.readObject();
+
+        dOut.writeObject(obj);
+
+        info = new ContentInfo(info.getContentType(), new DEROctetString(bOut.toByteArray()));
+
+        MacData mData = pfx.getMacData();
+        try
+        {
+            int itCount = mData.getIterationCount().intValue();
+            byte[] data = ASN1OctetString.getInstance(info.getContent()).getOctets();
+            byte[] res = calculatePbeMac(mData.getMac().getAlgorithmId().getObjectId(), mData.getSalt(), itCount, passwd, data, provider);
+
+            AlgorithmIdentifier algId = new AlgorithmIdentifier(mData.getMac().getAlgorithmId().getObjectId(), DERNull.INSTANCE);
+            DigestInfo dInfo = new DigestInfo(algId, res);
+
+            mData = new MacData(dInfo, mData.getSalt(), itCount);
+        }
+        catch (Exception e)
+        {
+            throw new IOException("error constructing MAC: " + e.toString());
+        }
+        
+        pfx = new Pfx(info, mData);
+
+        bOut.reset();
+        
+        dOut.writeObject(pfx);
+        
+        return bOut.toByteArray();
+    }
+
+    private static byte[] calculatePbeMac(
+        ASN1ObjectIdentifier oid,
+        byte[]              salt,
+        int                 itCount,
+        char[]              password,
+        byte[]              data,
+        String              provider)
+        throws Exception
+    {
+        SecretKeyFactory keyFact = SecretKeyFactory.getInstance(oid.getId(), provider);
+        PBEParameterSpec defParams = new PBEParameterSpec(salt, itCount);
+        PBEKeySpec pbeSpec = new PBEKeySpec(password);
+        SecretKey key = keyFact.generateSecret(pbeSpec);
+
+        Mac mac = Mac.getInstance(oid.getId(), provider);
+        mac.init(key, defParams);
+        mac.update(data);
+
+        return mac.doFinal();
+    }
+}