Merge "SyntheticPasswordCrypto: clean up AES-GCM constants" (96e29c75) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java

+13 −13

Original line number	Diff line number	Diff line
		@@ -50,9 +50,9 @@ import javax.crypto.spec.SecretKeySpec;

		public class SyntheticPasswordCrypto {
		private static final String TAG = "SyntheticPasswordCrypto";
		private static final int PROFILE_KEY_IV_SIZE = 12;
		private static final int DEFAULT_TAG_LENGTH_BITS = 128;
		private static final int AES_KEY_LENGTH = 32; // 256-bit AES key
		private static final int AES_GCM_KEY_SIZE = 32; // AES-256-GCM
		private static final int AES_GCM_IV_SIZE = 12;
		private static final int AES_GCM_TAG_SIZE = 16;
		private static final byte[] PROTECTOR_SECRET_PERSONALIZATION = "application-id".getBytes();
		// Time between the user credential is verified with GK and the decryption of synthetic password
		// under the auth-bound key. This should always happen one after the other, but give it 15
		@@ -65,11 +65,11 @@ public class SyntheticPasswordCrypto {
		if (blob == null) {
		return null;
		}
		byte[] iv = Arrays.copyOfRange(blob, 0, PROFILE_KEY_IV_SIZE);
		byte[] ciphertext = Arrays.copyOfRange(blob, PROFILE_KEY_IV_SIZE, blob.length);
		byte[] iv = Arrays.copyOfRange(blob, 0, AES_GCM_IV_SIZE);
		byte[] ciphertext = Arrays.copyOfRange(blob, AES_GCM_IV_SIZE, blob.length);
		Cipher cipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/"
		+ KeyProperties.BLOCK_MODE_GCM + "/" + KeyProperties.ENCRYPTION_PADDING_NONE);
		cipher.init(Cipher.DECRYPT_MODE, key, new GCMParameterSpec(DEFAULT_TAG_LENGTH_BITS, iv));
		cipher.init(Cipher.DECRYPT_MODE, key, new GCMParameterSpec(AES_GCM_TAG_SIZE * 8, iv));
		return cipher.doFinal(ciphertext);
		}

		@@ -86,13 +86,13 @@ public class SyntheticPasswordCrypto {
		cipher.init(Cipher.ENCRYPT_MODE, key);
		byte[] ciphertext = cipher.doFinal(blob);
		byte[] iv = cipher.getIV();
		if (iv.length != PROFILE_KEY_IV_SIZE) {
		throw new IllegalArgumentException("Invalid iv length: " + iv.length);
		if (iv.length != AES_GCM_IV_SIZE) {
		throw new IllegalArgumentException("Invalid iv length: " + iv.length + " bytes");
		}
		final GCMParameterSpec spec = cipher.getParameters().getParameterSpec(
		GCMParameterSpec.class);
		if (spec.getTLen() != DEFAULT_TAG_LENGTH_BITS) {
		throw new IllegalArgumentException("Invalid tag length: " + spec.getTLen());
		if (spec.getTLen() != AES_GCM_TAG_SIZE * 8) {
		throw new IllegalArgumentException("Invalid tag length: " + spec.getTLen() + " bits");
		}
		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		outputStream.write(iv);
		@@ -102,7 +102,7 @@ public class SyntheticPasswordCrypto {

		public static byte[] encrypt(byte[] keyBytes, byte[] personalization, byte[] message) {
		byte[] keyHash = personalizedHash(personalization, keyBytes);
		SecretKeySpec key = new SecretKeySpec(Arrays.copyOf(keyHash, AES_KEY_LENGTH),
		SecretKeySpec key = new SecretKeySpec(Arrays.copyOf(keyHash, AES_GCM_KEY_SIZE),
		KeyProperties.KEY_ALGORITHM_AES);
		try {
		return encrypt(key, message);
		@@ -116,7 +116,7 @@ public class SyntheticPasswordCrypto {

		public static byte[] decrypt(byte[] keyBytes, byte[] personalization, byte[] ciphertext) {
		byte[] keyHash = personalizedHash(personalization, keyBytes);
		SecretKeySpec key = new SecretKeySpec(Arrays.copyOf(keyHash, AES_KEY_LENGTH),
		SecretKeySpec key = new SecretKeySpec(Arrays.copyOf(keyHash, AES_GCM_KEY_SIZE),
		KeyProperties.KEY_ALGORITHM_AES);
		try {
		return decrypt(key, ciphertext);
		@@ -199,7 +199,7 @@ public class SyntheticPasswordCrypto {
		long sid) {
		try {
		KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES);
		keyGenerator.init(AES_KEY_LENGTH * 8, new SecureRandom());
		keyGenerator.init(AES_GCM_KEY_SIZE * 8, new SecureRandom());
		SecretKey keyStoreKey = keyGenerator.generateKey();
		final KeyStore keyStore = getKeyStore();
		KeyProtection.Builder builder = new KeyProtection.Builder(KeyProperties.PURPOSE_DECRYPT)