Preventing a shortcut which requires permissions from being added to

homescreen

A shortcut can be added by any app as INSTALL_SHORTCUT is a normal
level permission. But the intent is actually launched by the launcher
app which can have other permission as well.

> When adding a shortcut from the broadcast, verify that the intent does
not require any permission
> When adding a shortcut using the two-step drop process, verify that
the source app also has the permission to create such a shortcut

Bug: 30778130
Change-Id: I33a391bc0af81248aaff4459aaa79d1adc77926b
(cherry picked from commit fb5096d07b)

src/com/android/launcher3/InstallShortcutReceiver.java

@@ -33,6 +33,7 @@ import com.android.launcher3.compat.LauncherActivityInfoCompat;
 import com.android.launcher3.compat.LauncherAppsCompat;
 import com.android.launcher3.compat.UserHandleCompat;
 import com.android.launcher3.compat.UserManagerCompat;
+import com.android.launcher3.util.PackageManagerHelper;
 import com.android.launcher3.util.Thunk;
 
 import org.json.JSONException;
@@ -146,6 +147,15 @@ public class InstallShortcutReceiver extends BroadcastReceiver {
         }
         PendingInstallShortcutInfo info = createPendingInfo(context, data);
         if (info != null) {
+            if (!info.isLauncherActivity()) {
+                // Since its a custom shortcut, verify that it is safe to launch.
+                if (!PackageManagerHelper.hasPermissionForActivity(
+                        context, info.launchIntent, null)) {
+                    // Target cannot be launched, or requires some special permission to launch
+                    Log.e(TAG, "Ignoring malicious intent " + info.launchIntent.toUri(0));
+                    return;
+                }
+            }
             queuePendingShortcutInfo(info, context);
         }
     }

src/com/android/launcher3/Launcher.java

@@ -106,6 +106,7 @@ import com.android.launcher3.compat.UserManagerCompat;
 import com.android.launcher3.model.WidgetsModel;
 import com.android.launcher3.util.ComponentKey;
 import com.android.launcher3.util.LongArrayMap;
+import com.android.launcher3.util.PackageManagerHelper;
 import com.android.launcher3.util.TestingUtils;
 import com.android.launcher3.util.Thunk;
 import com.android.launcher3.widget.PendingAddWidgetInfo;
@@ -191,6 +192,8 @@ public class Launcher extends Activity
     private static final String RUNTIME_STATE_PENDING_ADD_SPAN_X = "launcher.add_span_x";
     // Type: int
     private static final String RUNTIME_STATE_PENDING_ADD_SPAN_Y = "launcher.add_span_y";
+    // Type: int
+    private static final String RUNTIME_STATE_PENDING_ADD_COMPONENT = "launcher.add_component";
     // Type: parcelable
     private static final String RUNTIME_STATE_PENDING_ADD_WIDGET_INFO = "launcher.add_widget_info";
     // Type: parcelable
@@ -242,7 +245,7 @@ public class Launcher extends Activity
     private AppWidgetManagerCompat mAppWidgetManager;
     private LauncherAppWidgetHost mAppWidgetHost;
 
-    @Thunk ItemInfo mPendingAddInfo = new ItemInfo();
+    @Thunk PendingAddItemInfo mPendingAddInfo = new PendingAddItemInfo();
     private LauncherAppWidgetProviderInfo mPendingAddWidgetInfo;
     private int mPendingAddWidgetId = -1;
 
@@ -1312,6 +1315,8 @@ public class Launcher extends Activity
             mPendingAddInfo.cellY = savedState.getInt(RUNTIME_STATE_PENDING_ADD_CELL_Y);
             mPendingAddInfo.spanX = savedState.getInt(RUNTIME_STATE_PENDING_ADD_SPAN_X);
             mPendingAddInfo.spanY = savedState.getInt(RUNTIME_STATE_PENDING_ADD_SPAN_Y);
+            mPendingAddInfo.componentName =
+                    savedState.getParcelable(RUNTIME_STATE_PENDING_ADD_COMPONENT);
             AppWidgetProviderInfo info = savedState.getParcelable(
                     RUNTIME_STATE_PENDING_ADD_WIDGET_INFO);
             mPendingAddWidgetInfo = info == null ?
@@ -1499,7 +1504,13 @@ public class Launcher extends Activity
         CellLayout layout = getCellLayout(container, screenId);
 
         ShortcutInfo info = InstallShortcutReceiver.fromShortcutIntent(this, data);
-        if (info == null) {
+        if (info == null || mPendingAddInfo.componentName == null) {
+            return;
+        }
+        if (!PackageManagerHelper.hasPermissionForActivity(
+                this, info.intent, mPendingAddInfo.componentName.getPackageName())) {
+            // The app is trying to add a shortcut without sufficient permissions
+            Log.e(TAG, "Ignoring malicious intent " + info.intent.toUri(0));
             return;
         }
         final View view = createShortcut(info);
@@ -1966,6 +1977,8 @@ public class Launcher extends Activity
             outState.putInt(RUNTIME_STATE_PENDING_ADD_CELL_Y, mPendingAddInfo.cellY);
             outState.putInt(RUNTIME_STATE_PENDING_ADD_SPAN_X, mPendingAddInfo.spanX);
             outState.putInt(RUNTIME_STATE_PENDING_ADD_SPAN_Y, mPendingAddInfo.spanY);
+            outState.putParcelable(RUNTIME_STATE_PENDING_ADD_COMPONENT,
+                    mPendingAddInfo.componentName);
             outState.putParcelable(RUNTIME_STATE_PENDING_ADD_WIDGET_INFO, mPendingAddWidgetInfo);
             outState.putInt(RUNTIME_STATE_PENDING_ADD_WIDGET_ID, mPendingAddWidgetId);
         }
@@ -2198,6 +2211,7 @@ public class Launcher extends Activity
         mPendingAddInfo.spanX = mPendingAddInfo.spanY = -1;
         mPendingAddInfo.minSpanX = mPendingAddInfo.minSpanY = 1;
         mPendingAddInfo.dropPos = null;
+        mPendingAddInfo.componentName = null;
     }
 
     void addAppWidgetFromDropImpl(final int appWidgetId, final ItemInfo info, final
@@ -2273,6 +2287,7 @@ public class Launcher extends Activity
         mPendingAddInfo.container = container;
         mPendingAddInfo.screenId = screenId;
         mPendingAddInfo.dropPos = null;
+        mPendingAddInfo.componentName = componentName;
 
         if (cell != null) {
             mPendingAddInfo.cellX = cell[0];

src/com/android/launcher3/util/PackageManagerHelper.java

@@ -16,8 +16,15 @@
 
 package com.android.launcher3.util;
 
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.content.Intent;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.ResolveInfo;
+import android.os.Build;
+import android.text.TextUtils;
 
 import com.android.launcher3.Utilities;
 
@@ -68,4 +75,53 @@ public class PackageManagerHelper {
             return false;
         }
     }
+
+    /**
+     * Returns true if {@param srcPackage} has the permission required to start the activity from
+     * {@param intent}. If {@param srcPackage} is null, then the activity should not need
+     * any permissions
+     */
+    public static boolean hasPermissionForActivity(Context context, Intent intent,
+            String srcPackage) {
+        PackageManager pm = context.getPackageManager();
+        ResolveInfo target = pm.resolveActivity(intent, 0);
+        if (target == null) {
+            // Not a valid target
+            return false;
+        }
+        if (TextUtils.isEmpty(target.activityInfo.permission)) {
+            // No permission is needed
+            return true;
+        }
+        if (TextUtils.isEmpty(srcPackage)) {
+            // The activity requires some permission but there is no source.
+            return false;
+        }
+
+        // Source does not have sufficient permissions.
+        if(pm.checkPermission(target.activityInfo.permission, srcPackage) !=
+                PackageManager.PERMISSION_GRANTED) {
+            return false;
+        }
+
+        if (!Utilities.ATLEAST_MARSHMALLOW) {
+            // These checks are sufficient for below M devices.
+            return true;
+        }
+
+        // On M and above also check AppOpsManager for compatibility mode permissions.
+        if (TextUtils.isEmpty(AppOpsManager.permissionToOp(target.activityInfo.permission))) {
+            // There is no app-op for this permission, which could have been disabled.
+            return true;
+        }
+
+        // There is no direct way to check if the app-op is allowed for a particular app. Since
+        // app-op is only enabled for apps running in compatibility mode, simply block such apps.
+
+        try {
+            return pm.getApplicationInfo(srcPackage, 0).targetSdkVersion >= Build.VERSION_CODES.M;
+        } catch (NameNotFoundException e) { }
+
+        return false;
+    }
 }