Merge "Store output of SP800Derive in non-movable byte array" into main (edbc28db) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/locksettings/SP800Derive.java

+22 −3

Original line number	Diff line number	Diff line
		@@ -16,11 +16,14 @@

		package com.android.server.locksettings;

		import com.android.internal.util.ArrayUtils;

		import java.nio.ByteBuffer;
		import java.security.InvalidKeyException;
		import java.security.NoSuchAlgorithmException;

		import javax.crypto.Mac;
		import javax.crypto.ShortBufferException;
		import javax.crypto.spec.SecretKeySpec;

		/**
		@@ -34,6 +37,8 @@ import javax.crypto.spec.SecretKeySpec;
		* L suffix: 32 bits
		*/
		class SP800Derive {
		private static final int OUTPUT_LENGTH = 32; // length of output in bytes

		private final byte[] mKeyBytes;

		SP800Derive(byte[] keyBytes) {
		@@ -44,6 +49,9 @@ class SP800Derive {
		try {
		final Mac m = Mac.getInstance("HmacSHA256");
		m.init(new SecretKeySpec(mKeyBytes, m.getAlgorithm()));
		if (m.getMacLength() != OUTPUT_LENGTH) {
		throw new IllegalStateException("Wrong output length");
		}
		return m;
		} catch (InvalidKeyException \| NoSuchAlgorithmException e) {
		throw new RuntimeException(e);
		@@ -61,7 +69,7 @@ class SP800Derive {
		final Mac m = getMac();
		update32(m, 1); // Hardwired counter value
		m.update(fixedInput);
		return m.doFinal();
		return doFinal(m);
		}

		/**
		@@ -76,7 +84,18 @@ class SP800Derive {
		m.update((byte) 0);
		m.update(context);
		update32(m, context.length * 8); // Disambiguate context
		update32(m, 256); // Hardwired output length
		return m.doFinal();
		update32(m, OUTPUT_LENGTH * 8); // Hardwired output length
		return doFinal(m);
		}

		// Same as m.doFinal(), but returns the output in a non-movable byte array.
		private byte[] doFinal(Mac m) {
		final byte[] mac = ArrayUtils.newNonMovableByteArray(OUTPUT_LENGTH);
		try {
		m.doFinal(mac, 0);
		return mac;
		} catch (ShortBufferException e) {
		throw new RuntimeException(e);
		}
		}
		}

services/tests/servicestests/src/com/android/server/locksettings/SP800DeriveTests.java

+14 −0

Original line number	Diff line number	Diff line
		@@ -49,4 +49,18 @@ public class SP800DeriveTests {
		"770dfab6a6a4a4bee0257ff335213f78"
		+ "d8287b4fd537d5c1fffa956910e7c779").toUpperCase(), HexDump.toHexString(res));
		}

		@Test
		public void testWithContext() throws Exception {
		byte[] keyBytes = HexDump.hexStringToByteArray(
		"e204d6d466aad507ffaf6d6dab0a5b26"
		+ "152c9e21e764370464e360c8fbc765c6");
		SP800Derive sk = new SP800Derive(keyBytes);
		byte[] label = HexDump.hexStringToByteArray("ed8282442dbfe03aaa1799faa5");
		byte[] context = HexDump.hexStringToByteArray("6c0b857412ef52");
		byte[] res = sk.withContext(label, context);
		assertEquals((
		"21658822e750a33d9ed743627697f0ea"
		+ "12543b5edef19cc453f01da949e5e37f").toUpperCase(), HexDump.toHexString(res));
		}
		}