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Commit dd36d037 authored by Tianjie Xu's avatar Tianjie Xu Committed by Automerger Merge Worker
Browse files

Merge "Support parsing legacy reboot escrow data" am: 8d380420 

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1563080

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I85de3f465b440b14ce0535bbd22ed6b76001c553
parents c9ba08c6 8d380420

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

+32 −10
Original line number Diff line number Diff line
@@ -35,6 +35,12 @@ class RebootEscrowData { 
     */

    private static final int CURRENT_VERSION = 2;



    /**

    * This is the legacy version of the escrow data format for R builds. The escrow data is only

    * encrypted by the escrow key, without additional wrap of another key from keystore.

    */

    private static final int LEGACY_SINGLE_ENCRYPTED_VERSION = 1;



    private RebootEscrowData(byte spVersion, byte[] syntheticPassword, byte[] blob,

            RebootEscrowKey key) {

        mSpVersion = spVersion;
@@ -64,6 +70,19 @@ class RebootEscrowData { 
        return mKey;

    }



    private static byte[] decryptBlobCurrentVersion(SecretKey kk, RebootEscrowKey ks,

            DataInputStream dis) throws IOException {

        if (kk == null) {

            throw new IOException("Failed to find wrapper key in keystore, cannot decrypt the"

                    + " escrow data");

        }



        // Decrypt the blob with the key from keystore first, then decrypt again with the reboot

        // escrow key.

        byte[] ksEncryptedBlob = AesEncryptionUtil.decrypt(kk, dis);

        return AesEncryptionUtil.decrypt(ks.getKey(), ksEncryptedBlob);

    }



    static RebootEscrowData fromEncryptedData(RebootEscrowKey ks, byte[] blob, SecretKey kk)

            throws IOException {

        Objects.requireNonNull(ks);
@@ -71,18 +90,21 @@ class RebootEscrowData { 


        DataInputStream dis = new DataInputStream(new ByteArrayInputStream(blob));

        int version = dis.readInt();

        if (version != CURRENT_VERSION) {

            throw new IOException("Unsupported version " + version);

        }

        byte spVersion = dis.readByte();



        // Decrypt the blob with the key from keystore first, then decrypt again with the reboot

        // escrow key.

        byte[] ksEncryptedBlob = AesEncryptionUtil.decrypt(kk, dis);

        final byte[] syntheticPassword = AesEncryptionUtil.decrypt(ks.getKey(), ksEncryptedBlob);



        switch (version) {

            case CURRENT_VERSION: {

                byte[] syntheticPassword = decryptBlobCurrentVersion(kk, ks, dis);

                return new RebootEscrowData(spVersion, syntheticPassword, blob, ks);

            }

            case LEGACY_SINGLE_ENCRYPTED_VERSION: {

                // Decrypt the blob with the escrow key directly.

                byte[] syntheticPassword = AesEncryptionUtil.decrypt(ks.getKey(), dis);

                return new RebootEscrowData(spVersion, syntheticPassword, blob, ks);

            }

            default:

                throw new IOException("Unsupported version " + version);

        }

    }



    static RebootEscrowData fromSyntheticPassword(RebootEscrowKey ks, byte spVersion,

            byte[] syntheticPassword, SecretKey kk)

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

+6 −1
Original line number Diff line number Diff line
@@ -146,6 +146,7 @@ class RebootEscrowManager { 
            RebootEscrowProviderInterface rebootEscrowProvider;

            if (DeviceConfig.getBoolean(DeviceConfig.NAMESPACE_OTA,

                    "server_based_ror_enabled", false)) {

                Slog.i(TAG, "Using server based resume on reboot");

                rebootEscrowProvider = new RebootEscrowProviderServerBasedImpl(mContext, mStorage);

            } else {

                rebootEscrowProvider = new RebootEscrowProviderHalImpl();
@@ -272,6 +273,10 @@ class RebootEscrowManager { 
        // generated before reboot. Note that we will clear the escrow key even if the keystore key

        // is null.

        SecretKey kk = mKeyStoreManager.getKeyStoreEncryptionKey();

        if (kk == null) {

            Slog.i(TAG, "Failed to load the key for resume on reboot from key store.");

        }



        RebootEscrowKey escrowKey;

        try {

            escrowKey = getAndClearRebootEscrowKey(kk);
@@ -281,7 +286,7 @@ class RebootEscrowManager { 
            return;

        }



        if (kk == null || escrowKey == null) {

        if (escrowKey == null) {

            onGetRebootEscrowKeyFailed(users);

            return;

        }

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

+5 −0
Original line number Diff line number Diff line
@@ -136,6 +136,11 @@ class RebootEscrowProviderServerBasedImpl implements RebootEscrowProviderInterfa 
            Slog.w(TAG, "Failed to read reboot escrow server blob from storage");

            return null;

        }

        if (decryptionKey == null) {

            Slog.w(TAG, "Failed to decrypt the escrow key; decryption key from keystore is"

                    + " null.");

            return null;

        }



        Slog.i(TAG, "Loaded reboot escrow server blob from storage");

        try {

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

+30 −17
Original line number Diff line number Diff line
@@ -19,19 +19,17 @@ package com.android.server.locksettings; 
import static org.hamcrest.CoreMatchers.is;

import static org.junit.Assert.assertThat;



import android.security.keystore.KeyGenParameterSpec;

import android.security.keystore.KeyProperties;



import androidx.test.runner.AndroidJUnit4;



import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;



import java.security.GeneralSecurityException;

import java.io.ByteArrayOutputStream;

import java.io.DataOutputStream;



import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;



/**

 * atest FrameworksServicesTests:RebootEscrowDataTest
@@ -41,22 +39,18 @@ public class RebootEscrowDataTest { 
    private RebootEscrowKey mKey;

    private SecretKey mKeyStoreEncryptionKey;



    private SecretKey generateNewRebootEscrowEncryptionKey() throws GeneralSecurityException {

        KeyGenerator generator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES);

        generator.init(new KeyGenParameterSpec.Builder(

                "reboot_escrow_data_test_key",

                KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)

                .setKeySize(256)

                .setBlockModes(KeyProperties.BLOCK_MODE_GCM)

                .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)

                .build());

        return generator.generateKey();

    }

    // Hex encoding of a randomly generated AES key for test.

    private static final byte[] TEST_AES_KEY = new byte[] {

            0x44, 0x74, 0x61, 0x54, 0x29, 0x74, 0x37, 0x61,

            0x48, 0x19, 0x12, 0x54, 0x13, 0x13, 0x52, 0x31,

            0x70, 0x70, 0x75, 0x25, 0x27, 0x31, 0x49, 0x09,

            0x26, 0x52, 0x72, 0x63, 0x63, 0x61, 0x78, 0x23,

    };



    @Before

    public void generateKey() throws Exception {

        mKey = RebootEscrowKey.generate();

        mKeyStoreEncryptionKey = generateNewRebootEscrowEncryptionKey();

        mKeyStoreEncryptionKey = new SecretKeySpec(TEST_AES_KEY, "AES");

    }



    private static byte[] getTestSp() {
@@ -114,4 +108,23 @@ public class RebootEscrowDataTest { 
        assertThat(decrypted, is(testSp));

    }



    @Test

    public void fromEncryptedData_legacyVersion_success() throws Exception {

        byte[] testSp = getTestSp();

        byte[] ksEncryptedBlob = AesEncryptionUtil.encrypt(mKey.getKey(), testSp);



        // Write a legacy blob encrypted only by k_s.

        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        DataOutputStream dos = new DataOutputStream(bos);

        dos.writeInt(1);

        dos.writeByte(3);

        dos.write(ksEncryptedBlob);

        byte[] legacyBlob = bos.toByteArray();



        RebootEscrowData actual = RebootEscrowData.fromEncryptedData(mKey, legacyBlob, null);



        assertThat(actual.getSpVersion(), is((byte) 3));

        assertThat(actual.getKey().getKeyBytes(), is(mKey.getKeyBytes()));

        assertThat(actual.getSyntheticPassword(), is(testSp));

    }

}