DO NOT MERGE: Don't trust callers to supply app info to bindBackupAgent()

Get the canonical identity and metadata about the package from the
Package Manager at time of usage rather than rely on the caller to
have gotten things right, even when the caller has the system uid.

Bug 28795098

Change-Id: I62710b15bb601fdfedd68e32349168c10725eb45

diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index 74266cc..be204c1 100644 (file)
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -1434,9 +1434,10 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
         
         case START_BACKUP_AGENT_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
-            ApplicationInfo info = ApplicationInfo.CREATOR.createFromParcel(data);
+            String packageName = data.readString();
             int backupRestoreMode = data.readInt();
-            boolean success = bindBackupAgent(info, backupRestoreMode);
+            int userId = data.readInt();
+            boolean success = bindBackupAgent(packageName, backupRestoreMode, userId);
             reply.writeNoException();
             reply.writeInt(success ? 1 : 0);
             return true;
@@ -3125,13 +3126,14 @@ class ActivityManagerProxy implements IActivityManager
         return binder;
     }
 
-    public boolean bindBackupAgent(ApplicationInfo app, int backupRestoreMode)
+    public boolean bindBackupAgent(String packageName, int backupRestoreMode, int userId)
             throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
-        app.writeToParcel(data, 0);
+        data.writeString(packageName);
         data.writeInt(backupRestoreMode);
+        data.writeInt(userId);
         mRemote.transact(START_BACKUP_AGENT_TRANSACTION, data, reply, 0);
         reply.readException();
         boolean success = reply.readInt() != 0;

diff --git a/core/java/android/app/IActivityManager.java b/core/java/android/app/IActivityManager.java
index 77c2ea0..8c174c8 100644 (file)
--- a/core/java/android/app/IActivityManager.java
+++ b/core/java/android/app/IActivityManager.java
@@ -163,7 +163,7 @@ public interface IActivityManager extends IInterface {
             int res) throws RemoteException;
     public IBinder peekService(Intent service, String resolvedType) throws RemoteException;
 
-    public boolean bindBackupAgent(ApplicationInfo appInfo, int backupRestoreMode)
+    public boolean bindBackupAgent(String packageName, int backupRestoreMode, int userId)
             throws RemoteException;
     public void clearPendingBackup() throws RemoteException;
     public void backupAgentCreated(String packageName, IBinder agent) throws RemoteException;

diff --git a/services/java/com/android/server/BackupManagerService.java b/services/java/com/android/server/BackupManagerService.java
index 1c88a46..d1b8ad5 100644 (file)
--- a/services/java/com/android/server/BackupManagerService.java
+++ b/services/java/com/android/server/BackupManagerService.java
@@ -1780,7 +1780,8 @@ class BackupManagerService extends IBackupManager.Stub {
             mConnecting = true;
             mConnectedAgent = null;
             try {
-                if (mActivityManager.bindBackupAgent(app, mode)) {
+                if (mActivityManager.bindBackupAgent(app.packageName, mode,
+                        UserHandle.USER_OWNER)) {
                     Slog.d(TAG, "awaiting agent for " + app);
 
                     // success; wait for the agent to arrive

diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index be37b01..0c229d9 100644 (file)
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -12823,10 +12823,22 @@ public final class ActivityManagerService extends ActivityManagerNative
     // Cause the target app to be launched if necessary and its backup agent
     // instantiated.  The backup agent will invoke backupAgentCreated() on the
     // activity manager to announce its creation.
-    public boolean bindBackupAgent(ApplicationInfo app, int backupMode) {
-        if (DEBUG_BACKUP) Slog.v(TAG, "bindBackupAgent: app=" + app + " mode=" + backupMode);
+    public boolean bindBackupAgent(String packageName, int backupMode, int userId) {
+        if (DEBUG_BACKUP) Slog.v(TAG, "bindBackupAgent: app=" + packageName + " mode=" + backupMode);
         enforceCallingPermission("android.permission.CONFIRM_FULL_BACKUP", "bindBackupAgent");
 
+        IPackageManager pm = AppGlobals.getPackageManager();
+        ApplicationInfo app = null;
+        try {
+            app = pm.getApplicationInfo(packageName, 0, userId);
+        } catch (RemoteException e) {
+            // can't happen; package manager is process-local
+        }
+        if (app == null) {
+            Slog.w(TAG, "Unable to bind backup agent for " + packageName);
+            return false;
+        }
+
         synchronized(this) {
             // !!! TODO: currently no check here that we're already bound
             BatteryStatsImpl.Uid.Pkg.Serv ss = null;