From 0c1a37b7ad9ebe9554afaf5e39cd29e83c3a4276 Mon Sep 17 00:00:00 2001
From: Lorenzo Colitti <lorenzo@google.com>
Date: Thu, 18 Mar 2021 15:54:31 +0900
Subject: [PATCH] Expose isUidNetworkingBlocked and
 isUidRestrictedOnMeteredNetworks

These methods are used by ConnectivityService for synchronous
calls such as getActiveNetworkInfo, isActiveNetworkMetered, etc.

These calls must call into NPMS and acquire the NPMS lock because
they are synchronous. They cannot use the stale copy of the
policy rules maintained by ConnectivityService, because if they
did, races like the following could occur:

1. App gets broadcast/callback/....
2. App calls isActiveNetworkMetered or other synchronous method.
3. ConnectivityService's copy of the rules is out of date, so the
   call returns stale information that the UID is still blocked.
4. The app thinks it has no networking, and does not call the
   synchronous method again until some other event occurs,
   potentially much later.

Bug: 176289731
Test: passes existing tests in ConnectivityServiceTest
Change-Id: I4ad0ca60431fe3702be85332530b6e93728d55e7
---
 core/api/module-lib-current.txt                 | 2 ++
 core/api/test-current.txt                       | 2 ++
 core/java/android/net/NetworkPolicyManager.java | 6 ++----
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/core/api/module-lib-current.txt b/core/api/module-lib-current.txt
index 42892a5f3ad99..a8f4ddc713f5e 100644
--- a/core/api/module-lib-current.txt
+++ b/core/api/module-lib-current.txt
@@ -196,6 +196,8 @@ package android.net {
     method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public int getMultipathPreference(@NonNull android.net.Network);
     method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public int getRestrictBackgroundStatus(int);
     method public static boolean isUidBlocked(int, boolean);
+    method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public boolean isUidNetworkingBlocked(int, boolean);
+    method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public boolean isUidRestrictedOnMeteredNetworks(int);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public void registerNetworkPolicyCallback(@Nullable java.util.concurrent.Executor, @NonNull android.net.NetworkPolicyManager.NetworkPolicyCallback);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public void unregisterNetworkPolicyCallback(@NonNull android.net.NetworkPolicyManager.NetworkPolicyCallback);
     field public static final int BLOCKED_METERED_REASON_ADMIN_DISABLED = 262144; // 0x40000
diff --git a/core/api/test-current.txt b/core/api/test-current.txt
index e486fa2c2e29f..efb413e029b32 100644
--- a/core/api/test-current.txt
+++ b/core/api/test-current.txt
@@ -1480,6 +1480,8 @@ package android.net {
 
   public class NetworkPolicyManager {
     method public boolean getRestrictBackground();
+    method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public boolean isUidNetworkingBlocked(int, boolean);
+    method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public boolean isUidRestrictedOnMeteredNetworks(int);
     method @NonNull public static String resolveNetworkId(@NonNull android.net.wifi.WifiConfiguration);
     method public void setRestrictBackground(boolean);
   }
diff --git a/core/java/android/net/NetworkPolicyManager.java b/core/java/android/net/NetworkPolicyManager.java
index 78ad781158a27..3da1227f1bac3 100644
--- a/core/java/android/net/NetworkPolicyManager.java
+++ b/core/java/android/net/NetworkPolicyManager.java
@@ -630,9 +630,8 @@ public class NetworkPolicyManager {
      * @param meteredNetwork True if the network is metered.
      * @return true if networking is blocked for the given uid according to current networking
      *         policies.
-     *
-     * @hide
      */
+    @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY)
     public boolean isUidNetworkingBlocked(int uid, boolean meteredNetwork) {
         try {
             return mService.isUidNetworkingBlocked(uid, meteredNetwork);
@@ -671,9 +670,8 @@ public class NetworkPolicyManager {
      *
      * @param uid The target uid.
      * @return true if the given uid is restricted from doing networking on metered networks.
-     *
-     * @hide
      */
+    @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY)
     public boolean isUidRestrictedOnMeteredNetworks(int uid) {
         try {
             return mService.isUidRestrictedOnMeteredNetworks(uid);