JCE: Zero copy of buffers before returning

Author: rlm2002

src/main/java/com/wolfssl/provider/jce/WolfCryptKeyAgreement.java

@@ -332,8 +332,11 @@ protected int engineGenerateSecret(byte[] sharedSecret, int offset)
                 this.ecPublic = new Ecc();
                 this.ecPrivate.releaseNativeStruct();
                 this.ecPrivate = new Ecc();
-                this.ecPrivate.importPrivateOnCurve(priv, null, this.curveName);
-                zeroArray(priv);
+                try {
+                    this.ecPrivate.importPrivateOnCurve(priv, null, this.curveName);
+                } finally {
+                    zeroArray(priv);
+                }
 
                 this.state = EngineState.WC_PRIVKEY_DONE;
 
@@ -489,8 +492,11 @@ private void wcInitDHParams(Key key, AlgorithmParameterSpec params)
                 "Unable to get DH private key from Key object");
         }
 
-        this.dh.setPrivateKey(dhPriv);
-        zeroArray(dhPriv);
+        try {
+            this.dh.setPrivateKey(dhPriv);
+        } finally {
+            zeroArray(dhPriv);
+        }
 
         return;
     }
@@ -531,6 +537,7 @@ private void wcInitECDHParams(Key key, AlgorithmParameterSpec params)
         BigInteger privateValue = null;
         BigInteger order = null;
         ECParameterSpec ecParams = null;
+        byte[] privKeyBytes;
 
         if (!(key instanceof ECPrivateKey)) {
             throw new InvalidKeyException(
@@ -568,8 +575,15 @@ private void wcInitECDHParams(Key key, AlgorithmParameterSpec params)
             throw new InvalidAlgorithmParameterException(
                 "ECC curve is null, please check algorithm parameters");
         }
-        this.ecPrivate.importPrivateOnCurve(ecKey.getS().toByteArray(),
+
+        privKeyBytes = ecKey.getS().toByteArray();
+
+        try {
+            this.ecPrivate.importPrivateOnCurve(privKeyBytes,
                 null, this.curveName);
+        } finally {
+            zeroArray(privKeyBytes);
+        }
     }
 
     /**

src/main/java/com/wolfssl/provider/jce/WolfCryptRSAPrivateCrtKey.java

@@ -240,6 +240,7 @@ private byte[] removeLeadingZero(byte[] data) {
         if ((data != null) && (data.length > 1) && (data[0] == 0)) {
             byte[] result = new byte[data.length - 1];
             System.arraycopy(data, 1, result, 0, data.length - 1);
+            Arrays.fill(data, (byte)0);
             return result;
         }
         return data;

src/main/java/com/wolfssl/provider/jce/WolfCryptRSAPrivateKey.java

@@ -160,7 +160,9 @@ private byte[] convertBigIntegerToUnsignedBytes(BigInteger value) {
 
         /* Remove leading zero byte if present (sign byte) */
         if ((bytes.length > 0) && (bytes[0] == 0)) {
-            return Arrays.copyOfRange(bytes, 1, bytes.length);
+            byte[] cpyBytes = Arrays.copyOfRange(bytes, 1, bytes.length);
+            Arrays.fill(bytes, (byte)0);
+            return cpyBytes;
         }
         return bytes;
     }

src/main/java/com/wolfssl/wolfcrypt/Ecc.java

@@ -24,6 +24,7 @@
 import java.math.BigInteger;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.spec.EllipticCurve;
+import java.util.Arrays;
 import java.security.spec.ECParameterSpec;
 import java.security.spec.ECFieldFp;
 
@@ -673,6 +674,7 @@ public static byte[] bigIntToFixedSizeByteArray(BigInteger value,
         if ((bytes.length == fieldSizeBytes + 1) && (bytes[0] == 0)) {
             byte[] result = new byte[fieldSizeBytes];
             System.arraycopy(bytes, 1, result, 0, fieldSizeBytes);
+            Arrays.fill(bytes, (byte)0);
             return result;
         }
 
@@ -681,6 +683,7 @@ public static byte[] bigIntToFixedSizeByteArray(BigInteger value,
             byte[] result = new byte[fieldSizeBytes];
             System.arraycopy(bytes, 0, result, fieldSizeBytes - bytes.length,
                 bytes.length);
+            Arrays.fill(bytes, (byte)0);
             return result;
         }