diff --git a/services/core/java/com/android/server/pm/permission/LegacyPermissionManagerService.java b/services/core/java/com/android/server/pm/permission/LegacyPermissionManagerService.java
index b1676d0..ea554d3 100644
--- a/services/core/java/com/android/server/pm/permission/LegacyPermissionManagerService.java
+++ b/services/core/java/com/android/server/pm/permission/LegacyPermissionManagerService.java
@@ -30,6 +30,7 @@
 import android.os.ServiceManager;
 import android.os.UserHandle;
 import android.permission.ILegacyPermissionManager;
+import android.util.EventLog;
 import android.util.Log;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -187,10 +188,25 @@
     private void verifyCallerCanCheckAccess(String packageName, String message, int pid, int uid) {
         // If the check is being requested by an app then only allow the app to query its own
         // access status.
+        boolean reportError = false;
         int callingUid = mInjector.getCallingUid();
         int callingPid = mInjector.getCallingPid();
         if (UserHandle.getAppId(callingUid) >= Process.FIRST_APPLICATION_UID && (callingUid != uid
                 || callingPid != pid)) {
+            reportError = true;
+        }
+        // If the query is against an app on the device, then the check should only be allowed if
+        // the provided uid matches that of the specified package.
+        if (packageName != null && UserHandle.getAppId(uid) >= Process.FIRST_APPLICATION_UID) {
+            int packageUid = mInjector.getPackageUidForUser(packageName, UserHandle.getUserId(uid));
+            if (uid != packageUid) {
+                EventLog.writeEvent(0x534e4554, "193441322",
+                        UserHandle.getAppId(callingUid) >= Process.FIRST_APPLICATION_UID
+                                ? callingUid : uid, "Package uid mismatch");
+                reportError = true;
+            }
+        }
+        if (reportError) {
             String response = String.format(
                     "Calling uid %d, pid %d cannot access for package %s (uid=%d, pid=%d): %s",
                     callingUid, callingPid, packageName, uid, pid, message);
@@ -385,12 +401,14 @@
     @VisibleForTesting
     public static class Injector {
         private final Context mContext;
+        private final PackageManagerInternal mPackageManagerInternal;
 
         /**
          * Public constructor that accepts a {@code context} within which to operate.
          */
         public Injector(@NonNull Context context) {
             mContext = context;
+            mPackageManagerInternal = LocalServices.getService(PackageManagerInternal.class);
         }
 
         /**
@@ -453,5 +471,12 @@
             return mContext.getPackageManager().getApplicationInfoAsUser(packageName, 0,
                     UserHandle.getUserHandleForUid(uid));
         }
+
+        /**
+         * Returns the uid for the specified {@code packageName} under the provided {@code userId}.
+         */
+        public int getPackageUidForUser(String packageName, int userId) {
+            return mPackageManagerInternal.getPackageUid(packageName, 0, userId);
+        }
     }
 }
diff --git a/services/tests/servicestests/src/com/android/server/pm/permission/LegacyPermissionManagerServiceTest.java b/services/tests/servicestests/src/com/android/server/pm/permission/LegacyPermissionManagerServiceTest.java
index acd3fca..3261dfa 100644
--- a/services/tests/servicestests/src/com/android/server/pm/permission/LegacyPermissionManagerServiceTest.java
+++ b/services/tests/servicestests/src/com/android/server/pm/permission/LegacyPermissionManagerServiceTest.java
@@ -125,7 +125,7 @@
     public void checkDeviceIdentifierAccess_hasPrivilegedPermission_returnsGranted() {
         // Apps with the READ_PRIVILEGED_PHONE_STATE permission should have access to device
         // identifiers.
-        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID);
+        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID);
         when(mInjector.checkPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
                 APP_PID, APP_UID)).thenReturn(PackageManager.PERMISSION_GRANTED);
 
@@ -140,7 +140,7 @@
     public void checkDeviceIdentifierAccess_hasAppOp_returnsGranted() {
         // Apps that have been granted the READ_DEVICE_IDENTIFIERS appop should have access to
         // device identifiers.
-        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID);
+        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID);
         when(mAppOpsManager.noteOpNoThrow(eq(AppOpsManager.OPSTR_READ_DEVICE_IDENTIFIERS),
                 eq(APP_UID), eq(mPackageName), any(), any())).thenReturn(
                 AppOpsManager.MODE_ALLOWED);
@@ -156,7 +156,7 @@
     public void checkDeviceIdentifierAccess_hasDpmAccess_returnsGranted() {
         // Apps that pass a DevicePolicyManager device / profile owner check should have access to
         // device identifiers.
-        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID);
+        setupCheckDeviceIdentifierAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID);
         when(mDevicePolicyManager.hasDeviceIdentifierAccess(mPackageName, APP_PID,
                 APP_UID)).thenReturn(true);
 
@@ -236,7 +236,7 @@
         // both the permission and the appop must be granted. If the permission is granted but the
         // appop is not then AppOpsManager#MODE_IGNORED should be returned to indicate that this
         // should be a silent failure.
-        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID);
+        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID);
         setPackageTargetSdk(Build.VERSION_CODES.Q);
 
         grantPermissionAndAppop(android.Manifest.permission.READ_PHONE_STATE, null);
@@ -256,7 +256,7 @@
         // Apps targeting R+ with just the READ_PHONE_STATE permission granted should not have
         // access to the phone number; PERMISSION_DENIED should be returned both with and without
         // the appop granted since this check should be skipped for target SDK R+.
-        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID);
+        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID);
 
         grantPermissionAndAppop(android.Manifest.permission.READ_PHONE_STATE, null);
         int resultWithoutAppop = mLegacyPermissionManagerService.checkPhoneNumberAccess(
@@ -319,12 +319,79 @@
         assertEquals(PackageManager.PERMISSION_GRANTED, resultWithAppop);
     }
 
+    @Test
+    public void checkPhoneNumberAccess_providedUidDoesNotMatchPackageUid_throwsException()
+            throws Exception {
+        // An app can directly interact with one of the services that accepts a package name and
+        // returns a protected resource via a direct binder transact. This app could then provide
+        // the name of another app that targets pre-R, then determine if the app is installed based
+        // on whether the service throws an exception or not. While the app can provide the package
+        // name of another app, it cannot specify the package uid which is passed to the
+        // LegacyPermissionManager using Binder#getCallingUid. Ultimately this uid should then be
+        // compared against the actual uid of the package to ensure information about packages
+        // installed on the device is not leaked.
+        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID, APP_UID + 1);
+
+        assertThrows(SecurityException.class,
+                () -> mLegacyPermissionManagerService.checkPhoneNumberAccess(mPackageName,
+                        CHECK_PHONE_NUMBER_MESSAGE, null, APP_PID, APP_UID));
+    }
+
+    @Test
+    public void checkPhoneNumberAccess_nullPackageNameSystemUid_returnsGranted() throws Exception {
+        // The platform can pass a null package name when checking if the platform itself has
+        // access to the device phone number(s) / identifier(s). This test ensures if a null package
+        // is provided, then the package uid check is skipped and the test is based on whether the
+        // the provided uid / pid has been granted the privileged permission.
+        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID, -1);
+        when(mInjector.checkPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
+                SYSTEM_PID, SYSTEM_UID)).thenReturn(PackageManager.PERMISSION_GRANTED);
+
+        int result = mLegacyPermissionManagerService.checkPhoneNumberAccess(null,
+                CHECK_PHONE_NUMBER_MESSAGE, null, SYSTEM_PID, SYSTEM_UID);
+
+        assertEquals(PackageManager.PERMISSION_GRANTED, result);
+    }
+
+    @Test
+    public void checkPhoneNumberAccess_systemUidMismatchPackageUid_returnsGranted()
+            throws Exception {
+        // When the platform is checking device phone number / identifier access checks for other
+        // components on the platform, a uid less than the first application UID is provided; this
+        // test verifies the package uid check is skipped and access is still granted with the
+        // privileged permission.
+        int telephonyUid = SYSTEM_UID + 1;
+        int telephonyPid = SYSTEM_PID + 1;
+        setupCheckPhoneNumberAccessTest(SYSTEM_PID, SYSTEM_UID, -1);
+        when(mInjector.checkPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
+                telephonyPid, telephonyUid)).thenReturn(PackageManager.PERMISSION_GRANTED);
+
+        int result = mLegacyPermissionManagerService.checkPhoneNumberAccess(mPackageName,
+                CHECK_PHONE_NUMBER_MESSAGE, null, telephonyPid, telephonyUid);
+
+        assertEquals(PackageManager.PERMISSION_GRANTED, result);
+    }
+
     /**
      * Configures device identifier access tests to fail; tests verifying access should individually
      * set an access check to succeed to verify access when that condition is met.
      */
     private void setupCheckDeviceIdentifierAccessTest(int callingPid, int callingUid) {
-        setupAccessTest(callingPid, callingUid);
+        setupCheckDeviceIdentifierAccessTest(callingPid, callingUid, callingUid);
+    }
+
+    /**
+     * Configures device identifier access tests to fail; tests verifying access should individually
+     * set an access check to succeed to verify access when that condition is met.
+     *
+     * <p>To prevent leaking package information, access checks for package UIDs >= {@link
+     * android.os.Process#FIRST_APPLICATION_UID} must ensure the provided uid matches the uid of
+     * the package being checked; to ensure this check is successful, this method accepts the
+     * {@code packageUid} to be used for the package being checked.
+     */
+    public void setupCheckDeviceIdentifierAccessTest(int callingPid, int callingUid,
+            int packageUid) {
+        setupAccessTest(callingPid, callingUid, packageUid);
 
         when(mDevicePolicyManager.hasDeviceIdentifierAccess(anyString(), anyInt(),
                 anyInt())).thenReturn(false);
@@ -333,11 +400,26 @@
     }
 
     /**
-     * Configures phone number access tests to fail; tests verifying access should individually set
-     * an access check to succeed to verify access when that condition is met.
+     * Configures phone number access tests to fail; tests verifying access should individually
+     * set an access check to succeed to verify access when that condition is set.
+     *
      */
     private void setupCheckPhoneNumberAccessTest(int callingPid, int callingUid) throws Exception {
-        setupAccessTest(callingPid, callingUid);
+        setupCheckPhoneNumberAccessTest(callingPid, callingUid, callingUid);
+    }
+
+    /**
+     * Configures phone number access tests to fail; tests verifying access should individually set
+     * an access check to succeed to verify access when that condition is met.
+     *
+     * <p>To prevent leaking package information, access checks for package UIDs >= {@link
+     * android.os.Process#FIRST_APPLICATION_UID} must ensure the provided uid matches the uid of
+     * the package being checked; to ensure this check is successful, this method accepts the
+     * {@code packageUid} to be used for the package being checked.
+     */
+    private void setupCheckPhoneNumberAccessTest(int callingPid, int callingUid, int packageUid)
+            throws Exception {
+        setupAccessTest(callingPid, callingUid, packageUid);
         setPackageTargetSdk(Build.VERSION_CODES.R);
     }
 
@@ -345,9 +427,10 @@
      * Configures the common mocks for any access tests using the provided {@code callingPid}
      * and {@code callingUid}.
      */
-    private void setupAccessTest(int callingPid, int callingUid) {
+    private void setupAccessTest(int callingPid, int callingUid, int packageUid) {
         when(mInjector.getCallingPid()).thenReturn(callingPid);
         when(mInjector.getCallingUid()).thenReturn(callingUid);
+        when(mInjector.getPackageUidForUser(anyString(), anyInt())).thenReturn(packageUid);
 
         when(mInjector.checkPermission(anyString(), anyInt(), anyInt())).thenReturn(
                 PackageManager.PERMISSION_DENIED);