From bbadec37d215190583d260d5e1d4ab1df00009d2 Mon Sep 17 00:00:00 2001
From: Lorenzo Colitti <lorenzo@google.com>
Date: Mon, 16 Aug 2021 15:30:05 +0900
Subject: [PATCH] Add a unit test for a bug in registerDefaultNetworkCallback.

Currently, when a VPN app calls registerDefaultNetworkCallback,
it will always get its own VPN, even if the VPN app called
VpnService.Builder#addDisallowedApplication to take itself out
of the VPN's UID ranges.

Add a test for the current incorrect behaviour.

Also fix an indentation error elsewhere.

Bug: 195265065
Test: test-only change
Change-Id: Id9648ea71fc7ae10855aa311beeb7975569d17f2
---
 .../server/ConnectivityServiceTest.java       | 50 ++++++++++++++++++-
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index c19ed611fa..06d5e0045f 100644
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -7739,8 +7739,8 @@ public class ConnectivityServiceTest {
         mMockVpn.disconnect();
     }
 
-   @Test
-   public void testIsActiveNetworkMeteredOverVpnSpecifyingUnderlyingNetworks() throws Exception {
+    @Test
+    public void testIsActiveNetworkMeteredOverVpnSpecifyingUnderlyingNetworks() throws Exception {
         // Returns true by default when no network is available.
         assertTrue(mCm.isActiveNetworkMetered());
         mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
@@ -8305,6 +8305,52 @@ public class ConnectivityServiceTest {
         mCm.unregisterNetworkCallback(vpnDefaultCallbackAsUid);
     }
 
+    @Test
+    public void testVpnExcludesOwnUid() throws Exception {
+        // required for registerDefaultNetworkCallbackForUid.
+        mServiceContext.setPermission(NETWORK_SETTINGS, PERMISSION_GRANTED);
+
+        // Connect Wi-Fi.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connect(true /* validated */);
+
+        // Connect a VPN that excludes its UID from its UID ranges.
+        final LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(VPN_IFNAME);
+        final int myUid = Process.myUid();
+        final Set<UidRange> ranges = new ArraySet<>();
+        ranges.add(new UidRange(0, myUid - 1));
+        ranges.add(new UidRange(myUid + 1, UserHandle.PER_USER_RANGE - 1));
+        mMockVpn.setUnderlyingNetworks(new Network[]{mWiFiNetworkAgent.getNetwork()});
+        mMockVpn.establish(lp, myUid, ranges);
+
+        // Wait for validation before registering callbacks.
+        waitForIdle();
+
+        final int otherUid = myUid + 1;
+        final Handler h = new Handler(ConnectivityThread.getInstanceLooper());
+        final TestNetworkCallback otherUidCb = new TestNetworkCallback();
+        final TestNetworkCallback defaultCb = new TestNetworkCallback();
+        final TestNetworkCallback perUidCb = new TestNetworkCallback();
+        registerDefaultNetworkCallbackAsUid(otherUidCb, otherUid);
+        mCm.registerDefaultNetworkCallback(defaultCb, h);
+        doAsUid(Process.SYSTEM_UID,
+                () -> mCm.registerDefaultNetworkCallbackForUid(myUid, perUidCb, h));
+
+        otherUidCb.expectAvailableCallbacksValidated(mMockVpn);
+        // BUG (b/195265065): the default network for the VPN app is actually Wi-Fi, not the VPN.
+        defaultCb.expectAvailableCallbacksValidated(mMockVpn);
+        perUidCb.expectAvailableCallbacksValidated(mMockVpn);
+        // getActiveNetwork is not affected by this bug.
+        assertEquals(mMockVpn.getNetwork(), mCm.getActiveNetworkForUid(myUid + 1));
+        assertEquals(mWiFiNetworkAgent.getNetwork(), mCm.getActiveNetwork());
+        assertEquals(mWiFiNetworkAgent.getNetwork(), mCm.getActiveNetworkForUid(myUid));
+
+        doAsUid(otherUid, () -> mCm.unregisterNetworkCallback(otherUidCb));
+        mCm.unregisterNetworkCallback(defaultCb);
+        doAsUid(Process.SYSTEM_UID, () -> mCm.unregisterNetworkCallback(perUidCb));
+    }
+
     private void setupLegacyLockdownVpn() {
         final String profileName = "testVpnProfile";
         final byte[] profileTag = profileName.getBytes(StandardCharsets.UTF_8);