From d2b132fac44c38aea685db9170f24cf93a25ca99 Mon Sep 17 00:00:00 2001
From: Michael Wachenschwanz <mwachens@google.com>
Date: Wed, 1 Apr 2020 16:28:46 -0700
Subject: [PATCH] Add permission check to UsageStatsManager#isAppInactive

UsageStatsManager#isAppInactive provides usage information that is
usually gated by the PACKAGE_USAGE_STATS permission in similar API.
This updates isAppInactive to also check for the PACKAGE_USAGE_STATS
permission.

Test: atest android.app.usage.cts android.app.usage.cts.UsageStatsTest#testIsAppInactive
Fixes: 148991455

Change-Id: I8ff8eb5d2e887bc164095f38d374e3992808fe79
---
 .../android/app/usage/IUsageStatsManager.aidl  |  2 +-
 .../android/app/usage/UsageStatsManager.java   |  9 +++++++--
 .../server/am/ActivityManagerShellCommand.java |  2 +-
 .../server/usage/UsageStatsService.java        | 18 +++++++++++++++---
 4 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/core/java/android/app/usage/IUsageStatsManager.aidl b/core/java/android/app/usage/IUsageStatsManager.aidl
index 1211c731e2e1d..ed6ba0c5efa47 100644
--- a/core/java/android/app/usage/IUsageStatsManager.aidl
+++ b/core/java/android/app/usage/IUsageStatsManager.aidl
@@ -43,7 +43,7 @@ interface IUsageStatsManager {
     @UnsupportedAppUsage
     void setAppInactive(String packageName, boolean inactive, int userId);
     @UnsupportedAppUsage
-    boolean isAppInactive(String packageName, int userId);
+    boolean isAppInactive(String packageName, int userId, String callingPackage);
     void onCarrierPrivilegedAppsChanged();
     void reportChooserSelection(String packageName, int userId, String contentType,
             in String[] annotations, String action);
diff --git a/core/java/android/app/usage/UsageStatsManager.java b/core/java/android/app/usage/UsageStatsManager.java
index 2c701b48455cf..5c6f07fd5100c 100644
--- a/core/java/android/app/usage/UsageStatsManager.java
+++ b/core/java/android/app/usage/UsageStatsManager.java
@@ -601,12 +601,17 @@ public final class UsageStatsManager {
      * app hasn't been used directly or indirectly for a period of time defined by the system. This
      * could be of the order of several hours or days. Apps are not considered inactive when the
      * device is charging.
+     * <p> The caller must have {@link android.Manifest.permission#PACKAGE_USAGE_STATS} to query the
+     * inactive state of other apps</p>
+     *
      * @param packageName The package name of the app to query
-     * @return whether the app is currently considered inactive
+     * @return whether the app is currently considered inactive or false if querying another app
+     * without {@link android.Manifest.permission#PACKAGE_USAGE_STATS}
      */
     public boolean isAppInactive(String packageName) {
         try {
-            return mService.isAppInactive(packageName, mContext.getUserId());
+            return mService.isAppInactive(packageName, mContext.getUserId(),
+                    mContext.getOpPackageName());
         } catch (RemoteException e) {
             // fall through and return default
         }
diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index bf797291380a2..19b084b74a8f8 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -2493,7 +2493,7 @@ final class ActivityManagerShellCommand extends ShellCommand {
 
         IUsageStatsManager usm = IUsageStatsManager.Stub.asInterface(ServiceManager.getService(
                 Context.USAGE_STATS_SERVICE));
-        boolean isIdle = usm.isAppInactive(packageName, userId);
+        boolean isIdle = usm.isAppInactive(packageName, userId, SHELL_PACKAGE_NAME);
         pw.println("Idle=" + isIdle);
         return 0;
     }
diff --git a/services/usage/java/com/android/server/usage/UsageStatsService.java b/services/usage/java/com/android/server/usage/UsageStatsService.java
index 0d1b3523bf9b2..a2b15f323e180 100644
--- a/services/usage/java/com/android/server/usage/UsageStatsService.java
+++ b/services/usage/java/com/android/server/usage/UsageStatsService.java
@@ -1578,15 +1578,27 @@ public class UsageStatsService extends SystemService implements
         }
 
         @Override
-        public boolean isAppInactive(String packageName, int userId) {
+        public boolean isAppInactive(String packageName, int userId, String callingPackage) {
+            final int callingUid = Binder.getCallingUid();
             try {
                 userId = ActivityManager.getService().handleIncomingUser(Binder.getCallingPid(),
-                        Binder.getCallingUid(), userId, false, false, "isAppInactive", null);
+                        callingUid, userId, false, false, "isAppInactive", null);
             } catch (RemoteException re) {
                 throw re.rethrowFromSystemServer();
             }
+
+            // If the calling app is asking about itself, continue, else check for permission.
+            if (packageName.equals(callingPackage)) {
+                final int actualCallingUid = mPackageManagerInternal.getPackageUidInternal(
+                        callingPackage, 0, userId);
+                if (actualCallingUid != callingUid) {
+                    return false;
+                }
+            } else if (!hasPermission(callingPackage)) {
+                return false;
+            }
             final boolean obfuscateInstantApps = shouldObfuscateInstantAppsForCaller(
-                    Binder.getCallingUid(), userId);
+                    callingUid, userId);
             final long token = Binder.clearCallingIdentity();
             try {
                 return mAppStandby.isAppIdleFiltered(