Prevent non-admin users from deleting system apps. am: 6c870e1579 am: 15ab50ec29 am: d719add201 am: a6038bd5cc

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17408864

Change-Id: I688f747552cc32683f855c777762bf135291eaf7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

services/core/java/com/android/server/pm/PackageManagerService.java

@@ -21657,6 +21657,16 @@ public class PackageManagerService extends IPackageManager.Stub
                 return PackageManager.DELETE_FAILED_INTERNAL_ERROR;
             }
 
+            if (isSystemApp(uninstalledPs)) {
+                UserInfo userInfo = mUserManager.getUserInfo(userId);
+                if (userInfo == null || !userInfo.isAdmin()) {
+                    Slog.w(TAG, "Not removing package " + packageName
+                            + " as only admin user may downgrade system apps");
+                    EventLog.writeEvent(0x534e4554, "170646036", -1, packageName);
+                    return PackageManager.DELETE_FAILED_USER_RESTRICTED;
+                }
+            }
+
             disabledSystemPs = mSettings.getDisabledSystemPkgLPr(packageName);
             // Static shared libs can be declared by any package, so let us not
             // allow removing a package if it provides a lib others depend on.