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[CDM] remove platform version exchange protocol

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Bug: 280846138
Test: Tested manually from raven (U) -> r11 (T)
Change-Id: I78d4b6cd334963d44e1081f97f190e83da8ea5ee
This commit is contained in:
Raphael Kim
2023-05-05 10:17:44 -07:00
parent 0bdf223f49
commit 83e2e0e82b
4 changed files with 25 additions and 120 deletions
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121
services/companion/java/com/android/server/companion/transport/CompanionTransportManager.java
View File

@@ -19,10 +19,8 @@ package com.android.server.companion.transport;
import static android.Manifest.permission.DELIVER_COMPANION_MESSAGES;
import static com.android.server.companion.transport.Transport.MESSAGE_REQUEST_PERMISSION_RESTORE;
import static com.android.server.companion.transport.Transport.MESSAGE_REQUEST_PLATFORM_INFO;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.SuppressLint;
import android.app.ActivityManagerInternal;
import android.companion.AssociationInfo;
@@ -33,7 +31,6 @@ import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Binder;
import android.os.Build;
import android.os.IBinder;
import android.os.ParcelFileDescriptor;
import android.os.RemoteCallbackList;
import android.os.RemoteException;
@@ -46,7 +43,6 @@ import com.android.server.companion.AssociationStore;
import java.io.FileDescriptor;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
@@ -58,19 +54,8 @@ public class CompanionTransportManager {
private static final String TAG = "CDM_CompanionTransportManager";
private static final boolean DEBUG = false;
private static final int SECURE_CHANNEL_AVAILABLE_SDK = Build.VERSION_CODES.UPSIDE_DOWN_CAKE;
private static final int NON_ANDROID = -1;
private boolean mSecureTransportEnabled = true;
private static boolean isRequest(int message) {
return (message & 0xFF000000) == 0x63000000;
}
private static boolean isResponse(int message) {
return (message & 0xFF000000) == 0x33000000;
}
private final Context mContext;
private final AssociationStore mAssociationStore;
@@ -84,10 +69,6 @@ public class CompanionTransportManager {
@NonNull
private final SparseArray<IOnMessageReceivedListener> mMessageListeners = new SparseArray<>();
@Nullable
private Transport mTempTransport;
public CompanionTransportManager(Context context, AssociationStore associationStore) {
mContext = context;
mAssociationStore = associationStore;
@@ -199,7 +180,8 @@ public class CompanionTransportManager {
detachSystemDataTransport(packageName, userId, associationId);
}
initializeTransport(associationId, fd);
// TODO: Implement new API to pass a PSK
initializeTransport(associationId, fd, null);
notifyOnTransportsChanged();
}
@@ -237,107 +219,36 @@ public class CompanionTransportManager {
});
}
private void initializeTransport(int associationId, ParcelFileDescriptor fd) {
private void initializeTransport(int associationId,
ParcelFileDescriptor fd,
byte[] preSharedKey) {
Slog.i(TAG, "Initializing transport");
Transport transport;
if (!isSecureTransportEnabled()) {
Transport transport = new RawTransport(associationId, fd, mContext);
addMessageListenersToTransport(transport);
transport.start();
synchronized (mTransports) {
mTransports.put(associationId, transport);
}
Slog.i(TAG, "RawTransport is created");
return;
}
// Exchange platform info to decide which transport should be created
mTempTransport = new RawTransport(associationId, fd, mContext);
addMessageListenersToTransport(mTempTransport);
IOnMessageReceivedListener listener = new IOnMessageReceivedListener() {
@Override
public void onMessageReceived(int associationId, byte[] data) throws RemoteException {
synchronized (mTransports) {
onPlatformInfoReceived(associationId, data);
}
}
@Override
public IBinder asBinder() {
return null;
}
};
mTempTransport.addListener(MESSAGE_REQUEST_PLATFORM_INFO, listener);
mTempTransport.start();
int sdk = Build.VERSION.SDK_INT;
String release = Build.VERSION.RELEASE;
// data format: | SDK_INT (int) | release length (int) | release |
final ByteBuffer data = ByteBuffer.allocate(4 + 4 + release.getBytes().length)
.putInt(sdk)
.putInt(release.getBytes().length)
.put(release.getBytes());
// TODO: it should check if preSharedKey is given
try {
mTempTransport.sendMessage(MESSAGE_REQUEST_PLATFORM_INFO, data.array());
} catch (IOException e) {
Slog.e(TAG, "Failed to exchange platform info");
}
}
/**
* Depending on the remote platform info to decide which transport should be created
*/
private void onPlatformInfoReceived(int associationId, byte[] data) {
if (mTempTransport.getAssociationId() != associationId) {
return;
}
// TODO: it should check if preSharedKey is given
ByteBuffer buffer = ByteBuffer.wrap(data);
int remoteSdk = buffer.getInt();
byte[] remoteRelease = new byte[buffer.getInt()];
buffer.get(remoteRelease);
Slog.i(TAG, "Remote device SDK: " + remoteSdk + ", release:" + new String(remoteRelease));
Transport transport = mTempTransport;
mTempTransport.stop();
int sdk = Build.VERSION.SDK_INT;
String release = Build.VERSION.RELEASE;
if (sdk < SECURE_CHANNEL_AVAILABLE_SDK || remoteSdk < SECURE_CHANNEL_AVAILABLE_SDK) {
// If either device is Android T or below, use raw channel
// TODO: depending on the release version, either
// 1) using a RawTransport for old T versions
// 2) or an Ukey2 handshaked transport for UKey2 backported T versions
Slog.d(TAG, "Secure channel is not supported. Using raw transport");
transport = new RawTransport(transport.getAssociationId(), transport.getFd(), mContext);
// If secure transport is explicitly disabled for testing, use raw transport
Slog.i(TAG, "Secure channel is disabled. Creating raw transport");
transport = new RawTransport(associationId, fd, mContext);
} else if (Build.isDebuggable()) {
// If device is debug build, use hardcoded test key for authentication
Slog.d(TAG, "Creating an unauthenticated secure channel");
final byte[] testKey = "CDM".getBytes(StandardCharsets.UTF_8);
transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),
mContext, testKey, null);
} else if (sdk == NON_ANDROID || remoteSdk == NON_ANDROID) {
transport = new SecureTransport(associationId, fd, mContext, testKey, null);
} else if (preSharedKey != null) {
// If either device is not Android, then use app-specific pre-shared key
// TODO: pass in a real preSharedKey
Slog.d(TAG, "Creating a PSK-authenticated secure channel");
transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),
mContext, new byte[0], null);
transport = new SecureTransport(associationId, fd, mContext, preSharedKey, null);
} else {
// If none of the above applies, then use secure channel with attestation verification
Slog.d(TAG, "Creating a secure channel");
transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),
mContext);
transport = new SecureTransport(associationId, fd, mContext);
}
addMessageListenersToTransport(transport);
transport.start();
synchronized (mTransports) {
mTransports.put(transport.getAssociationId(), transport);
mTransports.put(associationId, transport);
}
// Doesn't need to notifyTransportsChanged here, it'll be done in attachSystemDataTransport
}
public Future<?> requestPermissionRestore(int associationId, byte[] data) {

6
services/companion/java/com/android/server/companion/transport/RawTransport.java
View File

@@ -35,7 +35,7 @@ class RawTransport extends Transport {
}
@Override
public void start() {
void start() {
if (DEBUG) {
Slog.d(TAG, "Starting raw transport.");
}
@@ -54,7 +54,7 @@ class RawTransport extends Transport {
}
@Override
public void stop() {
void stop() {
if (DEBUG) {
Slog.d(TAG, "Stopping raw transport.");
}
@@ -62,7 +62,7 @@ class RawTransport extends Transport {
}
@Override
public void close() {
void close() {
stop();
if (DEBUG) {

6
services/companion/java/com/android/server/companion/transport/SecureTransport.java
View File

@@ -51,18 +51,18 @@ class SecureTransport extends Transport implements SecureChannel.Callback {
}
@Override
public void start() {
void start() {
mSecureChannel.start();
}
@Override
public void stop() {
void stop() {
mSecureChannel.stop();
mShouldProcessRequests = false;
}
@Override
public void close() {
void close() {
mSecureChannel.close();
mShouldProcessRequests = false;
}

12
services/companion/java/com/android/server/companion/transport/Transport.java
View File

@@ -47,7 +47,6 @@ public abstract class Transport {
protected static final boolean DEBUG = Build.IS_DEBUGGABLE;
static final int MESSAGE_REQUEST_PING = 0x63807378; // ?PIN
public static final int MESSAGE_REQUEST_PLATFORM_INFO = 0x63807073; // ?PFI
public static final int MESSAGE_REQUEST_CONTEXT_SYNC = 0x63678883; // ?CXS
public static final int MESSAGE_REQUEST_PERMISSION_RESTORE = 0x63826983; // ?RES
@@ -113,17 +112,17 @@ public abstract class Transport {
/**
* Start listening to messages.
*/
public abstract void start();
abstract void start();
/**
* Soft stop listening to the incoming data without closing the streams.
*/
public abstract void stop();
abstract void stop();
/**
* Stop listening to the incoming data and close the streams.
*/
public abstract void close();
abstract void close();
protected abstract void sendMessage(int message, int sequence, @NonNull byte[] data)
throws IOException;
@@ -183,11 +182,6 @@ public abstract class Transport {
sendMessage(MESSAGE_RESPONSE_SUCCESS, sequence, data);
break;
}
case MESSAGE_REQUEST_PLATFORM_INFO: {
callback(message, data);
// DO NOT SEND A RESPONSE!
break;
}
case MESSAGE_REQUEST_CONTEXT_SYNC: {
callback(message, data);
sendMessage(MESSAGE_RESPONSE_SUCCESS, sequence, EmptyArray.BYTE);