Use RecoverySession object to hide session IDs (redux) (2bcdad95) · Commits · e / os / android_frameworks_base

core/java/android/security/keystore/RecoveryClaim.java

0 → 100644

+54 −0

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		/*
		* Copyright (C) 2018 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.security.keystore;

		/**
		* An attempt to recover a keychain protected by remote secure hardware.
		*
		* @hide
		*/
		public class RecoveryClaim {

		private final RecoverySession mRecoverySession;
		private final byte[] mClaimBytes;

		RecoveryClaim(RecoverySession recoverySession, byte[] claimBytes) {
		mRecoverySession = recoverySession;
		mClaimBytes = claimBytes;
		}

		/**
		* Returns the session associated with the recovery attempt. This is used to match the symmetric
		* key, which remains internal to the framework, for decrypting the claim response.
		*
		* @return The session data.
		*/
		public RecoverySession getRecoverySession() {
		return mRecoverySession;
		}

		/**
		* Returns the encrypted claim's bytes.
		*
		* <p>This should be sent by the recovery agent to the remote secure hardware, which will use
		* it to decrypt the keychain, before sending it re-encrypted with the session's symmetric key
		* to the device.
		*/
		public byte[] getClaimBytes() {
		return mClaimBytes;
		}
		}

core/java/android/security/keystore/RecoveryManager.java

+28 −11

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		@@ -23,6 +23,7 @@ import android.content.pm.PackageManager.NameNotFoundException;
		import android.os.RemoteException;
		import android.os.ServiceManager;
		import android.os.ServiceSpecificException;
		import android.util.Log;

		import com.android.internal.widget.ILockSettings;

		@@ -36,6 +37,7 @@ import java.util.Map;
		* @hide
		*/
		public class RecoveryManager {
		private static final String TAG = "RecoveryController";

		/** Key has been successfully synced. */
		public static final int RECOVERY_STATUS_SYNCED = 0;
		@@ -380,30 +382,31 @@ public class RecoveryManager {
		* @param vaultChallenge Data passed from server for this recovery session and used to prevent
		* replay attacks
		* @param secrets Secrets provided by user, the method only uses type and secret fields.
		* @return Binary blob with recovery claim. It is encrypted with verifierPublicKey and contains
		* a proof of user secrets, session symmetric key and parameters necessary to identify the
		* counter with the number of failed recovery attempts.
		* @return The recovery claim. Claim provides a b binary blob with recovery claim. It is
		* encrypted with verifierPublicKey and contains a proof of user secrets, session symmetric
		* key and parameters necessary to identify the counter with the number of failed recovery
		* attempts.
		* @throws BadCertificateFormatException if the {@code verifierPublicKey} is in an incorrect
		* format.
		* @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery
		* service.
		*/
		public @NonNull byte[] startRecoverySession(
		@NonNull String sessionId,
		@NonNull public RecoveryClaim startRecoverySession(
		@NonNull byte[] verifierPublicKey,
		@NonNull byte[] vaultParams,
		@NonNull byte[] vaultChallenge,
		@NonNull List<KeychainProtectionParams> secrets)
		throws BadCertificateFormatException, InternalRecoveryServiceException {
		try {
		RecoverySession recoverySession = RecoverySession.newInstance(this);
		byte[] recoveryClaim =
		mBinder.startRecoverySession(
		sessionId,
		recoverySession.getSessionId(),
		verifierPublicKey,
		vaultParams,
		vaultChallenge,
		secrets);
		return recoveryClaim;
		return new RecoveryClaim(recoverySession, recoveryClaim);
		} catch (RemoteException e) {
		throw e.rethrowFromSystemServer();
		} catch (ServiceSpecificException e) {
		@@ -417,8 +420,8 @@ public class RecoveryManager {
		/**
		* Imports keys.
		*
		* @param sessionId Id for recovery session, same as in
		* {@link #startRecoverySession(String, byte[], byte[], byte[], List)}.
		* @param session Related recovery session, as originally created by invoking
		* {@link #startRecoverySession(byte[], byte[], byte[], List)}.
		* @param recoveryKeyBlob Recovery blob encrypted by symmetric key generated for this session.
		* @param applicationKeys Application keys. Key material can be decrypted using recoveryKeyBlob
		* and session. KeyStore only uses package names from the application info in {@link
		@@ -429,14 +432,14 @@ public class RecoveryManager {
		* @throws InternalRecoveryServiceException if an error occurs internal to the recovery service.
		*/
		public Map<String, byte[]> recoverKeys(
		@NonNull String sessionId,
		@NonNull RecoverySession session,
		@NonNull byte[] recoveryKeyBlob,
		@NonNull List<WrappedApplicationKey> applicationKeys)
		throws SessionExpiredException, DecryptionFailedException,
		InternalRecoveryServiceException {
		try {
		return (Map<String, byte[]>) mBinder.recoverKeys(
		sessionId, recoveryKeyBlob, applicationKeys);
		session.getSessionId(), recoveryKeyBlob, applicationKeys);
		} catch (RemoteException e) {
		throw e.rethrowFromSystemServer();
		} catch (ServiceSpecificException e) {
		@@ -450,6 +453,20 @@ public class RecoveryManager {
		}
		}

		/**
		* Deletes all data associated with {@code session}. Should not be invoked directly but via
		* {@link RecoverySession#close()}.
		*
		* @hide
		*/
		void closeSession(RecoverySession session) {
		try {
		mBinder.closeSession(session.getSessionId());
		} catch (RemoteException \| ServiceSpecificException e) {
		Log.e(TAG, "Unexpected error trying to close session", e);
		}
		}

		/**
		* Generates a key called {@code alias} and loads it into the recoverable key store. Returns the
		* raw material of the key.

core/java/android/security/keystore/RecoverySession.java

0 → 100644

+71 −0

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		/*
		* Copyright (C) 2018 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.security.keystore;

		import java.security.SecureRandom;

		/**
		* Session to recover a {@link KeychainSnapshot} from the remote trusted hardware, initiated by a
		* recovery agent.
		*
		* @hide
		*/
		public class RecoverySession implements AutoCloseable {

		private static final int SESSION_ID_LENGTH_BYTES = 16;

		private final String mSessionId;
		private final RecoveryManager mRecoveryManager;

		private RecoverySession(RecoveryManager recoveryManager, String sessionId) {
		mRecoveryManager = recoveryManager;
		mSessionId = sessionId;
		}

		/**
		* A new session, started by {@code recoveryManager}.
		*/
		static RecoverySession newInstance(RecoveryManager recoveryManager) {
		return new RecoverySession(recoveryManager, newSessionId());
		}

		/**
		* Returns a new random session ID.
		*/
		private static String newSessionId() {
		SecureRandom secureRandom = new SecureRandom();
		byte[] sessionId = new byte[SESSION_ID_LENGTH_BYTES];
		secureRandom.nextBytes(sessionId);
		StringBuilder sb = new StringBuilder();
		for (byte b : sessionId) {
		sb.append(Byte.toHexString(b, /upperCase=/ false));
		}
		return sb.toString();
		}

		/**
		* An internal session ID, used by the framework to match recovery claims to snapshot responses.
		*/
		String getSessionId() {
		return mSessionId;
		}

		@Override
		public void close() {
		mRecoveryManager.closeSession(this);
		}
		}

core/java/com/android/internal/widget/ILockSettings.aidl

+1 −0

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		@@ -81,4 +81,5 @@ interface ILockSettings {
		in List<KeychainProtectionParams> secrets);
		Map/<String, byte[]>/ recoverKeys(in String sessionId, in byte[] recoveryKeyBlob,
		in List<WrappedApplicationKey> applicationKeys);
		void closeSession(in String sessionId);
		}

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

+4 −0

Original line number	Diff line number	Diff line
		@@ -2028,6 +2028,10 @@ public class LockSettingsService extends ILockSettings.Stub {
		vaultParams, vaultChallenge, secrets);
		}

		public void closeSession(@NonNull String sessionId) throws RemoteException {
		mRecoverableKeyStoreManager.closeSession(sessionId);
		}

		@Override
		public Map<String, byte[]> recoverKeys(@NonNull String sessionId,
		@NonNull byte[] recoveryKeyBlob, @NonNull List<WrappedApplicationKey> applicationKeys)