Refactor key encryption methods and add unit tests

app/src/androidTest/java/com/kunzisoft/keepass/tests/crypto/AESKeyTest.kt

@@ -29,8 +29,8 @@ import junit.framework.TestCase
 import com.kunzisoft.keepass.crypto.finalkey.AndroidAESKeyTransformer
 import com.kunzisoft.keepass.crypto.finalkey.NativeAESKeyTransformer
 
-class FinalKeyTest : TestCase() {
+class AESKeyTest : TestCase() {
-    private var mRand: Random? = null
+    private lateinit var mRand: Random
 
     @Throws(Exception::class)
     override fun setUp() {
@@ -40,29 +40,28 @@ class FinalKeyTest : TestCase() {
     }
 
     @Throws(IOException::class)
-    fun testNativeAndroid() {
+    fun testAES() {
         // Test both an old and an even number to test my flip variable
-        testNativeFinalKey(5)
+        testAESFinalKey(5)
-        testNativeFinalKey(6)
+        testAESFinalKey(6)
     }
 
     @Throws(IOException::class)
-    private fun testNativeFinalKey(rounds: Int) {
+    private fun testAESFinalKey(rounds: Long) {
         val seed = ByteArray(32)
         val key = ByteArray(32)
-        val nativeKey: ByteArray
+        val nativeKey: ByteArray?
-        val androidKey: ByteArray
+        val androidKey: ByteArray?
 
-        mRand!!.nextBytes(seed)
+        mRand.nextBytes(seed)
-        mRand!!.nextBytes(key)
+        mRand.nextBytes(key)
 
-        val aKey = AndroidAESKeyTransformer()
+        val androidAESKey = AndroidAESKeyTransformer()
-        androidKey = aKey.transformMasterKey(seed, key, rounds.toLong())
+        androidKey = androidAESKey.transformMasterKey(seed, key, rounds)
 
-        val nKey = NativeAESKeyTransformer()
+        val nativeAESKey = NativeAESKeyTransformer()
-        nativeKey = nKey.transformMasterKey(seed, key, rounds.toLong())
+        nativeKey = nativeAESKey.transformMasterKey(seed, key, rounds)
 
         assertArrayEquals("Does not match", androidKey, nativeKey)
-
     }
 }

app/src/androidTest/java/com/kunzisoft/keepass/tests/crypto/AESTest.kt

@@ -80,6 +80,4 @@ class AESTest : TestCase() {
 
         assertArrayEquals("Arrays differ on size: $dataSize", outAndroid, outNative)
     }
-
-
 }

app/src/androidTest/java/com/kunzisoft/keepass/tests/stream/HashedBlockTest.kt

@@ -33,7 +33,7 @@ import junit.framework.TestCase
 import com.kunzisoft.keepass.stream.HashedBlockInputStream
 import com.kunzisoft.keepass.stream.HashedBlockOutputStream
 
-class HashedBlock : TestCase() {
+class HashedBlockTest : TestCase() {
 
     @Throws(IOException::class)
     fun testBlockAligned() {

app/src/androidTest/java/com/kunzisoft/keepass/tests/utils/UnsignedIntTest.kt

@@ -0,0 +1,28 @@
+package com.kunzisoft.keepass.tests.utils
+
+import com.kunzisoft.keepass.utils.UnsignedInt
+import junit.framework.TestCase
+
+class UnsignedIntTest: TestCase() {
+
+    fun testUInt() {
+        val standardInt = UnsignedInt(15).toInt()
+        assertEquals(15, standardInt)
+        val unsignedInt = UnsignedInt(-1).toLong()
+        assertEquals(4294967295L, unsignedInt)
+    }
+
+    fun testMaxValue() {
+        val maxValue = UnsignedInt.MAX_VALUE.toLong()
+        assertEquals(4294967295L, maxValue)
+        val longValue = UnsignedInt.fromLong(4294967295L).toLong()
+        assertEquals(longValue, maxValue)
+    }
+
+    fun testLong() {
+        val longValue = UnsignedInt.fromLong(50L).toInt()
+        assertEquals(50, longValue)
+        val uIntLongValue = UnsignedInt.fromLong(4294967290).toLong()
+        assertEquals(4294967290, uIntLongValue)
+    }
+}

app/src/androidTest/java/com/kunzisoft/keepass/tests/utils/ValuesTest.kt

@@ -17,7 +17,7 @@
  *  along with KeePassDX.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package com.kunzisoft.keepass.tests
+package com.kunzisoft.keepass.tests.utils
 
 import com.kunzisoft.keepass.database.element.DateInstant
 import com.kunzisoft.keepass.stream.*
@@ -28,7 +28,7 @@ import org.junit.Assert.assertArrayEquals
 import java.io.ByteArrayOutputStream
 import java.util.*
 
-class StringDatabaseKDBUtilsTest : TestCase() {
+class ValuesTest : TestCase() {
 
     fun testReadWriteLongZero() {
         testReadWriteLong(0.toByte())
@@ -82,7 +82,6 @@ class StringDatabaseKDBUtilsTest : TestCase() {
         val dest = uIntTo4Bytes(one)
 
         assertArrayEquals(orig, dest)
-
     }
 
     private fun setArray(buf: ByteArray, value: Byte, size: Int) {
@@ -186,7 +185,7 @@ class StringDatabaseKDBUtilsTest : TestCase() {
 
         val bos = ByteArrayOutputStream()
         val leos = LittleEndianDataOutputStream(bos)
-        leos.writeLong(UnsignedLong.ULONG_MAX_VALUE)
+        leos.writeLong(UnsignedLong.MAX_VALUE)
         leos.close()
 
         val uLongMax = bos.toByteArray()

app/src/main/java/com/kunzisoft/keepass/crypto/NativeLib.kt

@@ -30,7 +30,7 @@ object NativeLib {
     fun init(): Boolean {
         if (!isLoaded) {
             try {
-                System.loadLibrary("final-key") // TODO Rename
+                System.loadLibrary("final-key")
                 System.loadLibrary("argon2")
             } catch (e: UnsatisfiedLinkError) {
                 return false

app/src/main/java/com/kunzisoft/keepass/crypto/finalkey/AESKeyTransformerFactory.kt

@@ -17,21 +17,20 @@
  *  along with KeePassDX.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package com.kunzisoft.keepass.crypto.finalkey;
+package com.kunzisoft.keepass.crypto.finalkey
 
-import com.kunzisoft.keepass.crypto.CipherFactory;
+import com.kunzisoft.keepass.crypto.CipherFactory.deviceBlacklisted
 
-public class AESFactory {
+object AESKeyTransformerFactory : KeyTransformer() {
-
+    override fun transformMasterKey(seed: ByteArray?, key: ByteArray?, rounds: Long): ByteArray? {
-    // TODO Encaspulate
-    public static KeyTransformer createFinalKey() {
         // Prefer the native final key implementation
-        if ( !CipherFactory.INSTANCE.deviceBlacklisted()
+        val keyTransformer = if (!deviceBlacklisted()
                 && NativeAESKeyTransformer.available()) {
-            return new NativeAESKeyTransformer();
+            NativeAESKeyTransformer()
         } else {
             // Fall back on the android crypto implementation
-            return new AndroidAESKeyTransformer();
+            AndroidAESKeyTransformer()
-        }
+        }
+        return keyTransformer.transformMasterKey(seed, key, rounds)
     }
 }

app/src/main/java/com/kunzisoft/keepass/crypto/finalkey/KeyTransformer.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Brian Pellin, Jeremy Jamet / Kunzisoft.
+ * Copyright 2020 Jeremy Jamet / Kunzisoft.
  *
  * This file is part of KeePassDX.
  *
@@ -17,10 +17,11 @@
  *  along with KeePassDX.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package com.kunzisoft.keepass.crypto.finalkey;
+package com.kunzisoft.keepass.crypto.finalkey
 
-import java.io.IOException;
+import java.io.IOException
 
-public abstract class KeyTransformer {
+abstract class KeyTransformer {
-    public abstract byte[] transformMasterKey(byte[] seed, byte[] key, long rounds) throws IOException;
+    @Throws(IOException::class)
+    abstract fun transformMasterKey(seed: ByteArray?, key: ByteArray?, rounds: Long): ByteArray?
 }

app/src/main/java/com/kunzisoft/keepass/crypto/keyDerivation/AesKdf.kt

@@ -22,7 +22,7 @@ package com.kunzisoft.keepass.crypto.keyDerivation
 import android.content.res.Resources
 import com.kunzisoft.keepass.R
 import com.kunzisoft.keepass.crypto.CryptoUtil
-import com.kunzisoft.keepass.crypto.finalkey.AESFactory
+import com.kunzisoft.keepass.crypto.finalkey.AESKeyTransformerFactory
 import com.kunzisoft.keepass.stream.bytes16ToUuid
 import com.kunzisoft.keepass.utils.UnsignedInt
 import java.io.IOException
@@ -63,7 +63,7 @@ class AesKdf internal constructor() : KdfEngine() {
             seed = CryptoUtil.hashSha256(seed)
         }
 
-        return AESFactory.createFinalKey().transformMasterKey(seed, currentMasterKey, rounds)
+        return AESKeyTransformerFactory.transformMasterKey(seed, currentMasterKey, rounds) ?: ByteArray(0)
     }
 
     override fun randomize(p: KdfParameters) {

app/src/main/java/com/kunzisoft/keepass/database/element/database/DatabaseKDB.kt

@@ -19,7 +19,7 @@
 
 package com.kunzisoft.keepass.database.element.database
 
-import com.kunzisoft.keepass.crypto.finalkey.AESFactory
+import com.kunzisoft.keepass.crypto.finalkey.AESKeyTransformerFactory
 import com.kunzisoft.keepass.crypto.keyDerivation.KdfEngine
 import com.kunzisoft.keepass.crypto.keyDerivation.KdfFactory
 import com.kunzisoft.keepass.database.element.entry.EntryKDB
@@ -149,7 +149,7 @@ class DatabaseKDB : DatabaseVersioned<Int, UUID, GroupKDB, EntryKDB>() {
 
         // Encrypt the master key a few times to make brute-force key-search harder
         dos.write(masterSeed)
-        dos.write(AESFactory.createFinalKey().transformMasterKey(masterSeed2, masterKey, numRounds))
+        dos.write(AESKeyTransformerFactory.transformMasterKey(masterSeed2, masterKey, numRounds) ?: ByteArray(0))
 
         finalKey = messageDigest.digest()
     }

app/src/main/java/com/kunzisoft/keepass/database/file/DatabaseHeaderKDBX.kt

@@ -324,7 +324,7 @@ class DatabaseHeaderKDBX(private val databaseV4: DatabaseKDBX) : DatabaseHeader(
 
         @Throws(IOException::class)
         fun computeHeaderHmac(header: ByteArray, key: ByteArray): ByteArray {
-            val blockKey = HmacBlockStream.getHmacKey64(key, UnsignedLong.ULONG_MAX_VALUE)
+            val blockKey = HmacBlockStream.getHmacKey64(key, UnsignedLong.MAX_VALUE)
 
             val hmac: Mac
             try {

app/src/main/java/com/kunzisoft/keepass/database/file/output/DatabaseHeaderOutputKDBX.kt

@@ -66,7 +66,7 @@ constructor(private val databaseKDBX: DatabaseKDBX,
         val hmac: Mac
         try {
             hmac = Mac.getInstance("HmacSHA256")
-            val signingKey = SecretKeySpec(HmacBlockStream.getHmacKey64(hmacKey, UnsignedLong.ULONG_MAX_VALUE), "HmacSHA256")
+            val signingKey = SecretKeySpec(HmacBlockStream.getHmacKey64(hmacKey, UnsignedLong.MAX_VALUE), "HmacSHA256")
             hmac.init(signingKey)
         } catch (e: NoSuchAlgorithmException) {
             throw DatabaseOutputException(e)

app/src/main/java/com/kunzisoft/keepass/utils/UnsignedInt.kt

@@ -65,7 +65,7 @@ class UnsignedInt(private var unsignedValue: Int) {
 
     companion object {
         private const val INT_TO_LONG_MASK: Long = 0xffffffffL
-        private const val UINT_MAX_VALUE: Long = 4294967296L // 2^32
+        private const val UINT_MAX_VALUE: Long = 4294967295L // 2^32
 
         val MAX_VALUE = UnsignedInt(UINT_MAX_VALUE.toInt())
 

app/src/main/java/com/kunzisoft/keepass/utils/UnsignedLong.kt

@@ -44,6 +44,6 @@ class UnsignedLong(private var unsignedValue: Long) {
     }
 
     companion object {
-        const val ULONG_MAX_VALUE: Long = -1
+        const val MAX_VALUE: Long = -1
     }
 }