DO NOT MERGE: ActivityManager#killBackgroundProcesses can kill caller's own app only
unless it's a system app.
Bug: 239423414
Bug: 223376078
Test: atest CtsAppTestCases:ActivityManagerTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:fa94ce5c7738e449cb6bd68c77af4858018e49e0)
Merged-In: Iac6baa889965b8ffecd9a43179a4c96632ad1d02
Change-Id: Iac6baa889965b8ffecd9a43179a4c96632ad1d02
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 5d1d225..68a42d1 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -3934,6 +3934,9 @@
* processes to reclaim memory; the system will take care of restarting
* these processes in the future as needed.
*
+ * <p class="note">Third party applications can only use this API to kill their own processes.
+ * </p>
+ *
* @param packageName The name of the package whose processes are to
* be killed.
*/
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 7439b2f..cb00011 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -3123,7 +3123,11 @@
android:protectionLevel="normal" />
<!-- Allows an application to call
- {@link android.app.ActivityManager#killBackgroundProcesses}.
+ {@link android.app.ActivityManager#killBackgroundProcesses}.
+
+ <p class="note">Third party applications can only use this API to kill their own
+ processes.</p>
+
<p>Protection level: normal
-->
<permission android:name="android.permission.KILL_BACKGROUND_PROCESSES"
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index a70a01f..cd221a8 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -3837,8 +3837,20 @@
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
+ final int callingUid = Binder.getCallingUid();
+ final int callingPid = Binder.getCallingPid();
+ final int callingAppId = UserHandle.getAppId(callingUid);
- userId = mUserController.handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(),
+ ProcessRecord proc;
+ synchronized (mPidsSelfLocked) {
+ proc = mPidsSelfLocked.get(callingPid);
+ }
+ final boolean hasKillAllPermission = PERMISSION_GRANTED == checkPermission(
+ android.Manifest.permission.FORCE_STOP_PACKAGES, callingPid, callingUid)
+ || UserHandle.isCore(callingUid)
+ || (proc != null && proc.info.isSystemApp());
+
+ userId = mUserController.handleIncomingUser(callingPid, callingUid,
userId, true, ALLOW_FULL_ONLY, "killBackgroundProcesses", null);
final int[] userIds = mUserController.expandUserId(userId);
@@ -3853,7 +3865,7 @@
targetUserId));
} catch (RemoteException e) {
}
- if (appId == -1) {
+ if (appId == -1 || (!hasKillAllPermission && appId != callingAppId)) {
Slog.w(TAG, "Invalid packageName: " + packageName);
return;
}
@@ -3881,6 +3893,22 @@
throw new SecurityException(msg);
}
+ final int callingUid = Binder.getCallingUid();
+ final int callingPid = Binder.getCallingPid();
+
+ ProcessRecord proc;
+ synchronized (mPidsSelfLocked) {
+ proc = mPidsSelfLocked.get(callingPid);
+ }
+ if (callingUid >= FIRST_APPLICATION_UID
+ && (proc == null || !proc.info.isSystemApp())) {
+ final String msg = "Permission Denial: killAllBackgroundProcesses() from pid="
+ + callingPid + ", uid=" + callingUid + " is not allowed";
+ Slog.w(TAG, msg);
+ // Silently return to avoid existing apps from crashing.
+ return;
+ }
+
final long callingId = Binder.clearCallingIdentity();
try {
synchronized (this) {
