Enforce restricted user, getConnectionOwnerUid checks

This CL adds checks to ensure restricted users cannot change or
start/stop platform VPNs. In addition, this also adds checks to the
ConnectivityManager#getConnectionOwnerUid() to ensure that only
VpnService based VPNs can identify connections

Bug: 148040659
Test: FrameworksNetTests run
Change-Id: Id47ada5766036bfc84f3ba47f66f2d2683af916d
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index cb31404..5405ad3 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -4716,19 +4716,19 @@
     /**
      * Returns the {@code uid} of the owner of a network connection.
      *
-     * @param protocol The protocol of the connection. Only {@code IPPROTO_TCP} and
-     * {@code IPPROTO_UDP} currently supported.
+     * @param protocol The protocol of the connection. Only {@code IPPROTO_TCP} and {@code
+     *     IPPROTO_UDP} currently supported.
      * @param local The local {@link InetSocketAddress} of a connection.
      * @param remote The remote {@link InetSocketAddress} of a connection.
-     *
      * @return {@code uid} if the connection is found and the app has permission to observe it
-     * (e.g., if it is associated with the calling VPN app's tunnel) or
-     * {@link android.os.Process#INVALID_UID} if the connection is not found.
-     * Throws {@link SecurityException} if the caller is not the active VPN for the current user.
-     * Throws {@link IllegalArgumentException} if an unsupported protocol is requested.
+     *     (e.g., if it is associated with the calling VPN app's VpnService tunnel) or {@link
+     *     android.os.Process#INVALID_UID} if the connection is not found.
+     * @throws {@link SecurityException} if the caller is not the active VpnService for the current
+     *     user.
+     * @throws {@link IllegalArgumentException} if an unsupported protocol is requested.
      */
-    public int getConnectionOwnerUid(int protocol, @NonNull InetSocketAddress local,
-            @NonNull InetSocketAddress remote) {
+    public int getConnectionOwnerUid(
+            int protocol, @NonNull InetSocketAddress local, @NonNull InetSocketAddress remote) {
         ConnectionInfo connectionInfo = new ConnectionInfo(protocol, local, remote);
         try {
             return mService.getConnectionOwnerUid(connectionInfo);
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 1b43fc0..6351f34 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -7486,6 +7486,13 @@
      */
     public int getConnectionOwnerUid(ConnectionInfo connectionInfo) {
         final Vpn vpn = enforceActiveVpnOrNetworkStackPermission();
+
+        // Only VpnService based VPNs should be able to get this information.
+        if (vpn != null && vpn.getActiveAppVpnType() != VpnManager.TYPE_VPN_SERVICE) {
+            throw new SecurityException(
+                    "getConnectionOwnerUid() not allowed for non-VpnService VPNs");
+        }
+
         if (connectionInfo.protocol != IPPROTO_TCP && connectionInfo.protocol != IPPROTO_UDP) {
             throw new IllegalArgumentException("Unsupported protocol " + connectionInfo.protocol);
         }
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index f40e57f..e233651 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -78,6 +78,7 @@
 import static android.net.NetworkPolicyManager.RULE_REJECT_ALL;
 import static android.net.NetworkPolicyManager.RULE_REJECT_METERED;
 import static android.net.RouteInfo.RTN_UNREACHABLE;
+import static android.system.OsConstants.IPPROTO_TCP;
 
 import static com.android.server.ConnectivityServiceTestUtilsKt.transportToLegacyType;
 import static com.android.testutils.ConcurrentUtilsKt.await;
@@ -138,6 +139,7 @@
 import android.content.res.Resources;
 import android.location.LocationManager;
 import android.net.CaptivePortalData;
+import android.net.ConnectionInfo;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
 import android.net.ConnectivityManager.PacketKeepalive;
@@ -153,6 +155,7 @@
 import android.net.INetworkPolicyListener;
 import android.net.INetworkPolicyManager;
 import android.net.INetworkStatsService;
+import android.net.InetAddresses;
 import android.net.InterfaceConfiguration;
 import android.net.IpPrefix;
 import android.net.IpSecManager;
@@ -176,6 +179,7 @@
 import android.net.SocketKeepalive;
 import android.net.UidRange;
 import android.net.Uri;
+import android.net.VpnManager;
 import android.net.metrics.IpConnectivityLog;
 import android.net.shared.NetworkMonitorUtils;
 import android.net.shared.PrivateDnsConfig;
@@ -272,6 +276,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 
 import kotlin.reflect.KClass;
 
@@ -445,15 +450,21 @@
             return mPackageManager;
         }
 
+        private int checkMockedPermission(String permission, Supplier<Integer> ifAbsent) {
+            final Integer granted = mMockedPermissions.get(permission);
+            return granted != null ? granted : ifAbsent.get();
+        }
+
         @Override
         public int checkPermission(String permission, int pid, int uid) {
-            final Integer granted = mMockedPermissions.get(permission);
-            if (granted == null) {
-                // All non-mocked permissions should be held by the test or unnecessary: check as
-                // normal to make sure the code does not rely on unexpected permissions.
-                return super.checkPermission(permission, pid, uid);
-            }
-            return granted;
+            return checkMockedPermission(
+                    permission, () -> super.checkPermission(permission, pid, uid));
+        }
+
+        @Override
+        public int checkCallingOrSelfPermission(String permission) {
+            return checkMockedPermission(
+                    permission, () -> super.checkCallingOrSelfPermission(permission));
         }
 
         @Override
@@ -994,6 +1005,7 @@
         // Careful ! This is different from mNetworkAgent, because MockNetworkAgent does
         // not inherit from NetworkAgent.
         private TestNetworkAgentWrapper mMockNetworkAgent;
+        private int mVpnType = VpnManager.TYPE_VPN_SERVICE;
 
         private VpnInfo mVpnInfo;
 
@@ -1014,6 +1026,10 @@
             updateCapabilities(null /* defaultNetwork */);
         }
 
+        public void setVpnType(int vpnType) {
+            mVpnType = vpnType;
+        }
+
         @Override
         public int getNetId() {
             if (mMockNetworkAgent == null) {
@@ -1032,6 +1048,11 @@
             return mConnected;  // Similar trickery
         }
 
+        @Override
+        public int getActiveAppVpnType() {
+            return mVpnType;
+        }
+
         private void connect(boolean isAlwaysMetered) {
             mNetworkCapabilities.set(mMockNetworkAgent.getNetworkCapabilities());
             mConnected = true;
@@ -6382,6 +6403,90 @@
         assertEquals(Process.INVALID_UID, newNc.getOwnerUid());
     }
 
+    private void setupConnectionOwnerUid(int vpnOwnerUid, @VpnManager.VpnType int vpnType)
+            throws Exception {
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(VPN_USER));
+        establishVpn(new LinkProperties(), vpnOwnerUid, vpnRange);
+        mMockVpn.setVpnType(vpnType);
+
+        final VpnInfo vpnInfo = new VpnInfo();
+        vpnInfo.ownerUid = vpnOwnerUid;
+        mMockVpn.setVpnInfo(vpnInfo);
+    }
+
+    private void setupConnectionOwnerUidAsVpnApp(int vpnOwnerUid, @VpnManager.VpnType int vpnType)
+            throws Exception {
+        setupConnectionOwnerUid(vpnOwnerUid, vpnType);
+
+        // Test as VPN app
+        mServiceContext.setPermission(android.Manifest.permission.NETWORK_STACK, PERMISSION_DENIED);
+        mServiceContext.setPermission(
+                NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, PERMISSION_DENIED);
+    }
+
+    private ConnectionInfo getTestConnectionInfo() throws Exception {
+        return new ConnectionInfo(
+                IPPROTO_TCP,
+                new InetSocketAddress(InetAddresses.parseNumericAddress("1.2.3.4"), 1234),
+                new InetSocketAddress(InetAddresses.parseNumericAddress("2.3.4.5"), 2345));
+    }
+
+    @Test
+    public void testGetConnectionOwnerUidPlatformVpn() throws Exception {
+        final int myUid = Process.myUid();
+        setupConnectionOwnerUidAsVpnApp(myUid, VpnManager.TYPE_VPN_PLATFORM);
+
+        try {
+            mService.getConnectionOwnerUid(getTestConnectionInfo());
+            fail("Expected SecurityException for non-VpnService app");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
+    public void testGetConnectionOwnerUidVpnServiceWrongUser() throws Exception {
+        final int myUid = Process.myUid();
+        setupConnectionOwnerUidAsVpnApp(myUid + 1, VpnManager.TYPE_VPN_SERVICE);
+
+        try {
+            mService.getConnectionOwnerUid(getTestConnectionInfo());
+            fail("Expected SecurityException for non-VpnService app");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
+    public void testGetConnectionOwnerUidVpnServiceDoesNotThrow() throws Exception {
+        final int myUid = Process.myUid();
+        setupConnectionOwnerUidAsVpnApp(myUid, VpnManager.TYPE_VPN_SERVICE);
+
+        // TODO: Test the returned UID
+        mService.getConnectionOwnerUid(getTestConnectionInfo());
+    }
+
+    @Test
+    public void testGetConnectionOwnerUidVpnServiceNetworkStackDoesNotThrow() throws Exception {
+        final int myUid = Process.myUid();
+        setupConnectionOwnerUid(myUid, VpnManager.TYPE_VPN_SERVICE);
+        mServiceContext.setPermission(
+                android.Manifest.permission.NETWORK_STACK, PERMISSION_GRANTED);
+
+        // TODO: Test the returned UID
+        mService.getConnectionOwnerUid(getTestConnectionInfo());
+    }
+
+    @Test
+    public void testGetConnectionOwnerUidVpnServiceMainlineNetworkStackDoesNotThrow()
+            throws Exception {
+        final int myUid = Process.myUid();
+        setupConnectionOwnerUid(myUid, VpnManager.TYPE_VPN_SERVICE);
+        mServiceContext.setPermission(
+                NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, PERMISSION_GRANTED);
+
+        // TODO: Test the returned UID
+        mService.getConnectionOwnerUid(getTestConnectionInfo());
+    }
+
     private TestNetworkAgentWrapper establishVpn(
             LinkProperties lp, int ownerUid, Set<UidRange> vpnRange) throws Exception {
         final TestNetworkAgentWrapper
diff --git a/tests/net/java/com/android/server/connectivity/VpnTest.java b/tests/net/java/com/android/server/connectivity/VpnTest.java
index eb78529..ac1c518 100644
--- a/tests/net/java/com/android/server/connectivity/VpnTest.java
+++ b/tests/net/java/com/android/server/connectivity/VpnTest.java
@@ -656,8 +656,12 @@
     }
 
     private Vpn createVpnAndSetupUidChecks(int... grantedOps) throws Exception {
-        final Vpn vpn = createVpn(primaryUser.id);
-        setMockedUsers(primaryUser);
+        return createVpnAndSetupUidChecks(primaryUser, grantedOps);
+    }
+
+    private Vpn createVpnAndSetupUidChecks(UserInfo user, int... grantedOps) throws Exception {
+        final Vpn vpn = createVpn(user.id);
+        setMockedUsers(user);
 
         when(mPackageManager.getPackageUidAsUser(eq(TEST_VPN_PKG), anyInt()))
                 .thenReturn(Process.myUid());
@@ -726,6 +730,19 @@
     }
 
     @Test
+    public void testProvisionVpnProfileRestrictedUser() throws Exception {
+        final Vpn vpn =
+                createVpnAndSetupUidChecks(
+                        restrictedProfileA, AppOpsManager.OP_ACTIVATE_PLATFORM_VPN);
+
+        try {
+            vpn.provisionVpnProfile(TEST_VPN_PKG, mVpnProfile, mKeyStore);
+            fail("Expected SecurityException due to restricted user");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
     public void testDeleteVpnProfile() throws Exception {
         final Vpn vpn = createVpnAndSetupUidChecks();
 
@@ -736,6 +753,19 @@
     }
 
     @Test
+    public void testDeleteVpnProfileRestrictedUser() throws Exception {
+        final Vpn vpn =
+                createVpnAndSetupUidChecks(
+                        restrictedProfileA, AppOpsManager.OP_ACTIVATE_PLATFORM_VPN);
+
+        try {
+            vpn.deleteVpnProfile(TEST_VPN_PKG, mKeyStore);
+            fail("Expected SecurityException due to restricted user");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
     public void testGetVpnProfilePrivileged() throws Exception {
         final Vpn vpn = createVpnAndSetupUidChecks();
 
@@ -820,6 +850,32 @@
     }
 
     @Test
+    public void testStartVpnProfileRestrictedUser() throws Exception {
+        final Vpn vpn =
+                createVpnAndSetupUidChecks(
+                        restrictedProfileA, AppOpsManager.OP_ACTIVATE_PLATFORM_VPN);
+
+        try {
+            vpn.startVpnProfile(TEST_VPN_PKG, mKeyStore);
+            fail("Expected SecurityException due to restricted user");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
+    public void testStopVpnProfileRestrictedUser() throws Exception {
+        final Vpn vpn =
+                createVpnAndSetupUidChecks(
+                        restrictedProfileA, AppOpsManager.OP_ACTIVATE_PLATFORM_VPN);
+
+        try {
+            vpn.stopVpnProfile(TEST_VPN_PKG);
+            fail("Expected SecurityException due to restricted user");
+        } catch (SecurityException expected) {
+        }
+    }
+
+    @Test
     public void testSetPackageAuthorizationVpnService() throws Exception {
         final Vpn vpn = createVpnAndSetupUidChecks();