Merge "Re-implement NetworkUtils#queryUserAccess."

core/jni/android_net_NetworkUtils.cpp

@@ -102,11 +102,6 @@ static jint android_net_utils_bindSocketToNetwork(JNIEnv *env, jobject thiz, job
     return setNetworkForSocket(netId, AFileDescriptor_getFD(env, javaFd));
 }
 
-static jboolean android_net_utils_queryUserAccess(JNIEnv *env, jobject thiz, jint uid, jint netId)
-{
-    return (jboolean) !queryUserAccess(uid, netId);
-}
-
 static bool checkLenAndCopy(JNIEnv* env, const jbyteArray& addr, int len, void* dst)
 {
     if (env->GetArrayLength(addr) != len) {
@@ -246,7 +241,6 @@ static const JNINativeMethod gNetworkUtilMethods[] = {
     { "getBoundNetworkForProcess", "()I", (void*) android_net_utils_getBoundNetworkForProcess },
     { "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },
     { "bindSocketToNetwork", "(Ljava/io/FileDescriptor;I)I", (void*) android_net_utils_bindSocketToNetwork },
-    { "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess },
     { "attachDropAllBPFFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDropAllBPFFilter },
     { "detachBPFFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_detachBPFFilter },
     { "getTcpRepairWindow", "(Ljava/io/FileDescriptor;)Landroid/net/TcpRepairWindow;", (void*) android_net_utils_getTcpRepairWindow },

framework/src/android/net/NetworkUtils.java

@@ -92,7 +92,10 @@ public class NetworkUtils {
      * Determine if {@code uid} can access network designated by {@code netId}.
      * @return {@code true} if {@code uid} can access network, {@code false} otherwise.
      */
-    public native static boolean queryUserAccess(int uid, int netId);
+    public static boolean queryUserAccess(int uid, int netId) {
+        // TODO (b/183485986): remove this method
+        return false;
+    }
 
     /**
      * DNS resolver series jni method.

services/core/java/com/android/server/ConnectivityService.java

@@ -1149,8 +1149,8 @@ public class ConnectivityService extends IConnectivityManager.Stub
         /**
          * @see NetworkUtils#queryUserAccess(int, int)
          */
-        public boolean queryUserAccess(int uid, int netId) {
-            return NetworkUtils.queryUserAccess(uid, netId);
+        public boolean queryUserAccess(int uid, Network network, ConnectivityService cs) {
+            return cs.queryUserAccess(uid, network);
         }
 
         /**
@@ -4843,6 +4843,42 @@ public class ConnectivityService extends IConnectivityManager.Stub
         nai.networkMonitor().forceReevaluation(uid);
     }
 
+    // TODO: call into netd.
+    private boolean queryUserAccess(int uid, Network network) {
+        final NetworkAgentInfo nai = getNetworkAgentInfoForNetwork(network);
+        if (nai == null) return false;
+
+        // Any UID can use its default network.
+        if (nai == getDefaultNetworkForUid(uid)) return true;
+
+        // Privileged apps can use any network.
+        if (mPermissionMonitor.hasRestrictedNetworksPermission(uid)) {
+            return true;
+        }
+
+        // An unprivileged UID can use a VPN iff the VPN applies to it.
+        if (nai.isVPN()) {
+            return nai.networkCapabilities.appliesToUid(uid);
+        }
+
+        // An unprivileged UID can bypass the VPN that applies to it only if it can protect its
+        // sockets, i.e., if it is the owner.
+        final NetworkAgentInfo vpn = getVpnForUid(uid);
+        if (vpn != null && !vpn.networkAgentConfig.allowBypass
+                && uid != vpn.networkCapabilities.getOwnerUid()) {
+            return false;
+        }
+
+        // The UID's permission must be at least sufficient for the network. Since the restricted
+        // permission was already checked above, that just leaves background networks.
+        if (!nai.networkCapabilities.hasCapability(NET_CAPABILITY_FOREGROUND)) {
+            return mPermissionMonitor.hasUseBackgroundNetworksPermission(uid);
+        }
+
+        // Unrestricted network. Anyone gets to use it.
+        return true;
+    }
+
     /**
      * Returns information about the proxy a certain network is using. If given a null network, it
      * it will return the proxy for the bound network for the caller app or the default proxy if
@@ -4863,7 +4899,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 return null;
             }
             return getLinkPropertiesProxyInfo(activeNetwork);
-        } else if (mDeps.queryUserAccess(mDeps.getCallingUid(), network.getNetId())) {
+        } else if (mDeps.queryUserAccess(mDeps.getCallingUid(), network, this)) {
             // Don't call getLinkProperties() as it requires ACCESS_NETWORK_STATE permission, which
             // caller may not have.
             return getLinkPropertiesProxyInfo(network);

services/core/java/com/android/server/connectivity/PermissionMonitor.java

@@ -271,6 +271,13 @@ public class PermissionMonitor {
         return mApps.containsKey(uid);
     }
 
+    /**
+     * Returns whether the given uid has permission to use restricted networks.
+     */
+    public synchronized boolean hasRestrictedNetworksPermission(int uid) {
+        return Boolean.TRUE.equals(mApps.get(uid));
+    }
+
     private void update(Set<UserHandle> users, Map<Integer, Boolean> apps, boolean add) {
         List<Integer> network = new ArrayList<>();
         List<Integer> system = new ArrayList<>();

tests/net/java/com/android/server/ConnectivityServiceTest.java

@@ -1571,7 +1571,7 @@ public class ConnectivityServiceTest {
         doReturn(mNetworkStack).when(deps).getNetworkStack();
         doReturn(mSystemProperties).when(deps).getSystemProperties();
         doReturn(mock(ProxyTracker.class)).when(deps).makeProxyTracker(any(), any());
-        doReturn(true).when(deps).queryUserAccess(anyInt(), anyInt());
+        doReturn(true).when(deps).queryUserAccess(anyInt(), any(), any());
         doAnswer(inv -> {
             mPolicyTracker = new WrappedMultinetworkPolicyTracker(
                     inv.getArgument(0), inv.getArgument(1), inv.getArgument(2));