Add helper method to enfore a package name belongs to an uid

This is no-op refactor to move utility methods from
ConnectivityService to a common place.

Test: atest NetworkStaticLibTests#com.android.net.moduletests.util.PermissionUtilsTest#testEnforcePackageNameMatchesUid
Bug: N/A
Change-Id: I5802dedcc91fa6e130a5c534bba5080ca37dbeec
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 7339d08..66e10a2 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -3004,26 +3004,6 @@
         return false;
     }
 
-    private int getAppUid(final String app, final UserHandle user) {
-        final PackageManager pm =
-                mContext.createContextAsUser(user, 0 /* flags */).getPackageManager();
-        final long token = Binder.clearCallingIdentity();
-        try {
-            return pm.getPackageUid(app, 0 /* flags */);
-        } catch (PackageManager.NameNotFoundException e) {
-            return -1;
-        } finally {
-            Binder.restoreCallingIdentity(token);
-        }
-    }
-
-    private void verifyCallingUidAndPackage(String packageName, int callingUid) {
-        final UserHandle user = UserHandle.getUserHandleForUid(callingUid);
-        if (getAppUid(packageName, user) != callingUid) {
-            throw new SecurityException(packageName + " does not belong to uid " + callingUid);
-        }
-    }
-
     /**
      * Ensure that a network route exists to deliver traffic to the specified
      * host via the specified network interface.
@@ -3039,7 +3019,8 @@
         if (disallowedBecauseSystemCaller()) {
             return false;
         }
-        verifyCallingUidAndPackage(callingPackageName, mDeps.getCallingUid());
+        PermissionUtils.enforcePackageNameMatchesUid(
+                mContext, mDeps.getCallingUid(), callingPackageName);
         enforceChangePermission(callingPackageName, callingAttributionTag);
         if (mProtectedNetworks.contains(networkType)) {
             enforceConnectivityRestrictedNetworksPermission(true /* checkUidsAllowedList */);