Merge "Add new methods to redact NetworkCapabilities & LinkProperties"

framework/api/module-lib-current.txt

@@ -10,6 +10,8 @@ package android.net {
     method @NonNull @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public java.util.List<android.net.NetworkStateSnapshot> getAllNetworkStateSnapshots();
     method @Nullable public android.net.ProxyInfo getGlobalProxy();
     method @NonNull public static android.util.Range<java.lang.Integer> getIpSecNetIdRange();
+    method @Nullable @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public android.net.LinkProperties redactLinkPropertiesForPackage(@NonNull android.net.LinkProperties, int, @NonNull String);
+    method @Nullable @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public android.net.NetworkCapabilities redactNetworkCapabilitiesForPackage(@NonNull android.net.NetworkCapabilities, int, @NonNull String);
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerDefaultNetworkCallbackForUid(int, @NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerSystemDefaultNetworkCallback(@NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void replaceFirewallChain(int, @NonNull int[]);

framework/src/android/net/ConnectivityManager.java

@@ -1625,16 +1625,45 @@ public class ConnectivityManager {
     }
 
     /**
-     * Get the {@link NetworkCapabilities} for the given {@link Network}.  This
+     * Redact {@link LinkProperties} for a given package
-     * will return {@code null} if the network is unknown or if the |network| argument is null.
      *
-     * This will remove any location sensitive data in {@link TransportInfo} embedded in
+     * Returns an instance of the given {@link LinkProperties} appropriately redacted to send to the
-     * {@link NetworkCapabilities#getTransportInfo()}. Some transport info instances like
+     * given package, considering its permissions.
-     * {@link android.net.wifi.WifiInfo} contain location sensitive information. Retrieving
+     *
-     * this location sensitive information (subject to app's location permissions) will be
+     * @param lp A {@link LinkProperties} which will be redacted.
-     * noted by system. To include any location sensitive data in {@link TransportInfo},
+     * @param uid The target uid.
-     * use a {@link NetworkCallback} with
+     * @param packageName The name of the package, for appops logging.
-     * {@link NetworkCallback#FLAG_INCLUDE_LOCATION_INFO} flag.
+     * @return A redacted {@link LinkProperties} which is appropriate to send to the given uid,
+     *         or null if the uid lacks the ACCESS_NETWORK_STATE permission.
+     * @hide
+     */
+    @RequiresPermission(anyOf = {
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+            android.Manifest.permission.NETWORK_STACK,
+            android.Manifest.permission.NETWORK_SETTINGS})
+    @SystemApi(client = MODULE_LIBRARIES)
+    @Nullable
+    public LinkProperties redactLinkPropertiesForPackage(@NonNull LinkProperties lp, int uid,
+            @NonNull String packageName) {
+        try {
+            return mService.redactLinkPropertiesForPackage(
+                    lp, uid, packageName, getAttributionTag());
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Get the {@link NetworkCapabilities} for the given {@link Network}, or null.
+     *
+     * This will remove any location sensitive data in the returned {@link NetworkCapabilities}.
+     * Some {@link TransportInfo} instances like {@link android.net.wifi.WifiInfo} contain location
+     * sensitive information. To retrieve this location sensitive information (subject to
+     * the caller's location permissions), use a {@link NetworkCallback} with the
+     * {@link NetworkCallback#FLAG_INCLUDE_LOCATION_INFO} flag instead.
+     *
+     * This method returns {@code null} if the network is unknown or if the |network| argument
+     * is null.
      *
      * @param network The {@link Network} object identifying the network in question.
      * @return The {@link NetworkCapabilities} for the network, or {@code null}.
@@ -1650,6 +1679,38 @@ public class ConnectivityManager {
         }
     }
 
+    /**
+     * Redact {@link NetworkCapabilities} for a given package.
+     *
+     * Returns an instance of {@link NetworkCapabilities} that is appropriately redacted to send
+     * to the given package, considering its permissions. Calling this method will blame the UID for
+     * retrieving the device location if the passed capabilities contain location-sensitive
+     * information.
+     *
+     * @param nc A {@link NetworkCapabilities} instance which will be redacted.
+     * @param uid The target uid.
+     * @param packageName The name of the package, for appops logging.
+     * @return A redacted {@link NetworkCapabilities} which is appropriate to send to the given uid,
+     *         or null if the uid lacks the ACCESS_NETWORK_STATE permission.
+     * @hide
+     */
+    @RequiresPermission(anyOf = {
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+            android.Manifest.permission.NETWORK_STACK,
+            android.Manifest.permission.NETWORK_SETTINGS})
+    @SystemApi(client = MODULE_LIBRARIES)
+    @Nullable
+    public NetworkCapabilities redactNetworkCapabilitiesForPackage(
+            @NonNull NetworkCapabilities nc,
+            int uid, @NonNull String packageName) {
+        try {
+            return mService.redactNetworkCapabilitiesForPackage(nc, uid, packageName,
+                    getAttributionTag());
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
     /**
      * Gets a URL that can be used for resolving whether a captive portal is present.
      * 1. This URL should respond with a 204 response to a GET request to indicate no captive
@@ -3547,7 +3608,20 @@ public class ConnectivityManager {
          * @hide
          */
         public static final int FLAG_NONE = 0;
+
         /**
+         * Inclusion of this flag means location-sensitive redaction requests keeping location info.
+         *
+         * Some objects like {@link NetworkCapabilities} may contain location-sensitive information.
+         * Prior to Android 12, this information is always returned to apps holding the appropriate
+         * permission, possibly noting that the app has used location.
+         * <p>In Android 12 and above, by default the sent objects do not contain any location
+         * information, even if the app holds the necessary permissions, and the system does not
+         * take note of location usage by the app. Apps can request that location information is
+         * included, in which case the system will check location permission and the location
+         * toggle state, and take note of location usage by the app if any such information is
+         * returned.
+         *
          * Use this flag to include any location sensitive data in {@link NetworkCapabilities} sent
          * via {@link #onCapabilitiesChanged(Network, NetworkCapabilities)}.
          * <p>
@@ -3564,8 +3638,7 @@ public class ConnectivityManager {
          * <li> Retrieving this location sensitive information (subject to app's location
          * permissions) will be noted by system. </li>
          * <li> Without this flag any {@link NetworkCapabilities} provided via the callback does
-         * not include location sensitive info.
+         * not include location sensitive information.
-         * </p>
          */
         // Note: Some existing fields which are location sensitive may still be included without
         // this flag if the app targets SDK < S (to maintain backwards compatibility).

framework/src/android/net/IConnectivityManager.aidl

@@ -76,10 +76,15 @@ interface IConnectivityManager
     LinkProperties getActiveLinkProperties();
     LinkProperties getLinkPropertiesForType(int networkType);
     LinkProperties getLinkProperties(in Network network);
+    LinkProperties redactLinkPropertiesForPackage(in LinkProperties lp, int uid, String packageName,
+            String callingAttributionTag);
 
     NetworkCapabilities getNetworkCapabilities(in Network network, String callingPackageName,
             String callingAttributionTag);
 
+    NetworkCapabilities redactNetworkCapabilitiesForPackage(in NetworkCapabilities nc, int uid,
+            String callingPackageName, String callingAttributionTag);
+
     @UnsupportedAppUsage(maxTargetSdk = 30, trackingBug = 170729553)
     NetworkState[] getAllNetworkState();
 

service/src/com/android/server/ConnectivityService.java

@@ -2164,6 +2164,19 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
     }
 
+    @Override
+    @Nullable
+    public LinkProperties redactLinkPropertiesForPackage(@NonNull LinkProperties lp, int uid,
+            @NonNull String packageName, @Nullable String callingAttributionTag) {
+        Objects.requireNonNull(packageName);
+        Objects.requireNonNull(lp);
+        enforceNetworkStackOrSettingsPermission();
+        if (!checkAccessPermission(-1 /* pid */, uid)) {
+            return null;
+        }
+        return linkPropertiesRestrictedForCallerPermissions(lp, -1 /* callerPid */, uid);
+    }
+
     private NetworkCapabilities getNetworkCapabilitiesInternal(Network network) {
         return getNetworkCapabilitiesInternal(getNetworkAgentInfoForNetwork(network));
     }
@@ -2187,13 +2200,34 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 getCallingPid(), mDeps.getCallingUid(), callingPackageName, callingAttributionTag);
     }
 
+    @Override
+    public NetworkCapabilities redactNetworkCapabilitiesForPackage(@NonNull NetworkCapabilities nc,
+            int uid, @NonNull String packageName, @Nullable String callingAttributionTag) {
+        Objects.requireNonNull(nc);
+        Objects.requireNonNull(packageName);
+        enforceNetworkStackOrSettingsPermission();
+        if (!checkAccessPermission(-1 /* pid */, uid)) {
+            return null;
+        }
+        return createWithLocationInfoSanitizedIfNecessaryWhenParceled(
+                networkCapabilitiesRestrictedForCallerPermissions(nc, -1 /* callerPid */, uid),
+                true /* includeLocationSensitiveInfo */, -1 /* callingPid */, uid, packageName,
+                callingAttributionTag);
+    }
+
     @VisibleForTesting
     NetworkCapabilities networkCapabilitiesRestrictedForCallerPermissions(
             NetworkCapabilities nc, int callerPid, int callerUid) {
+        // Note : here it would be nice to check ACCESS_NETWORK_STATE and return null, but
+        // this would be expensive (one more permission check every time any NC callback is
+        // sent) and possibly dangerous : apps normally can't lose ACCESS_NETWORK_STATE, if
+        // it happens for some reason (e.g. the package is uninstalled while CS is trying to
+        // send the callback) it would crash the system server with NPE.
         final NetworkCapabilities newNc = new NetworkCapabilities(nc);
         if (!checkSettingsPermission(callerPid, callerUid)) {
             newNc.setUids(null);
             newNc.setSSID(null);
+            // TODO: Processes holding NETWORK_FACTORY should be able to see the underlying networks
             newNc.setUnderlyingNetworks(null);
         }
         if (newNc.getNetworkSpecifier() != null) {
@@ -2211,7 +2245,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
 
     /**
      * Wrapper used to cache the permission check results performed for the corresponding
-     * app. This avoid performing multiple permission checks for different fields in
+     * app. This avoids performing multiple permission checks for different fields in
      * NetworkCapabilities.
      * Note: This wrapper does not support any sort of invalidation and thus must not be
      * persistent or long-lived. It may only be used for the time necessary to
@@ -2339,6 +2373,8 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 includeLocationSensitiveInfo);
         final NetworkCapabilities newNc = new NetworkCapabilities(nc, redactions);
         // Reset owner uid if not destined for the owner app.
+        // TODO : calling UID is redacted because apps should generally not know what UID is
+        // bringing up the VPN, but this should not apply to some very privileged apps like settings
         if (callingUid != nc.getOwnerUid()) {
             newNc.setOwnerUid(INVALID_UID);
             return newNc;
@@ -2364,9 +2400,15 @@ public class ConnectivityService extends IConnectivityManager.Stub
         return newNc;
     }
 
+    @NonNull
     private LinkProperties linkPropertiesRestrictedForCallerPermissions(
             LinkProperties lp, int callerPid, int callerUid) {
         if (lp == null) return new LinkProperties();
+        // Note : here it would be nice to check ACCESS_NETWORK_STATE and return null, but
+        // this would be expensive (one more permission check every time any LP callback is
+        // sent) and possibly dangerous : apps normally can't lose ACCESS_NETWORK_STATE, if
+        // it happens for some reason (e.g. the package is uninstalled while CS is trying to
+        // send the callback) it would crash the system server with NPE.
 
         // Only do a permission check if sanitization is needed, to avoid unnecessary binder calls.
         final boolean needsSanitization =
@@ -2737,6 +2779,11 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 "ConnectivityService");
     }
 
+    private boolean checkAccessPermission(int pid, int uid) {
+        return mContext.checkPermission(android.Manifest.permission.ACCESS_NETWORK_STATE, pid, uid)
+                == PERMISSION_GRANTED;
+    }
+
     /**
      * Performs a strict and comprehensive check of whether a calling package is allowed to
      * change the state of network, as the condition differs for pre-M, M+, and

tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java

@@ -16,9 +16,15 @@
 
 package android.net.cts;
 
+import static android.Manifest.permission.ACCESS_COARSE_LOCATION;
+import static android.Manifest.permission.ACCESS_FINE_LOCATION;
+import static android.Manifest.permission.ACCESS_NETWORK_STATE;
 import static android.Manifest.permission.CONNECTIVITY_INTERNAL;
 import static android.Manifest.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS;
+import static android.Manifest.permission.NETWORK_FACTORY;
 import static android.Manifest.permission.NETWORK_SETTINGS;
+import static android.Manifest.permission.NETWORK_SETUP_WIZARD;
+import static android.Manifest.permission.NETWORK_STACK;
 import static android.Manifest.permission.READ_DEVICE_CONFIG;
 import static android.content.pm.PackageManager.FEATURE_BLUETOOTH;
 import static android.content.pm.PackageManager.FEATURE_ETHERNET;
@@ -54,7 +60,9 @@ import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_PARTIAL_CONNECTIVITY;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED;
 import static android.net.NetworkCapabilities.TRANSPORT_TEST;
+import static android.net.NetworkCapabilities.TRANSPORT_VPN;
 import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
+import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
 import static android.net.cts.util.CtsNetUtils.ConnectivityActionReceiver;
 import static android.net.cts.util.CtsNetUtils.HTTP_PORT;
 import static android.net.cts.util.CtsNetUtils.NETWORK_CALLBACK_ACTION;
@@ -64,6 +72,7 @@ import static android.net.cts.util.CtsTetheringUtils.TestTetheringEventCallback;
 import static android.net.util.NetworkStackUtils.TEST_CAPTIVE_PORTAL_HTTPS_URL;
 import static android.net.util.NetworkStackUtils.TEST_CAPTIVE_PORTAL_HTTP_URL;
 import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
+import static android.os.Process.INVALID_UID;
 import static android.provider.Settings.Global.NETWORK_METERED_MULTIPATH_PREFERENCE;
 import static android.system.OsConstants.AF_INET;
 import static android.system.OsConstants.AF_INET6;
@@ -76,6 +85,7 @@ import static com.android.modules.utils.build.SdkLevel.isAtLeastS;
 import static com.android.networkstack.apishim.ConstantsShim.BLOCKED_REASON_LOCKDOWN_VPN;
 import static com.android.networkstack.apishim.ConstantsShim.BLOCKED_REASON_NONE;
 import static com.android.testutils.Cleanup.testAndCleanup;
+import static com.android.testutils.DevSdkIgnoreRuleKt.SC_V2;
 import static com.android.testutils.MiscAsserts.assertThrows;
 import static com.android.testutils.TestNetworkTrackerKt.initTestNetwork;
 import static com.android.testutils.TestPermissionUtil.runAsShell;
@@ -103,6 +113,7 @@ import android.content.IntentFilter;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.res.Resources;
+import android.net.CaptivePortalData;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
 import android.net.ConnectivitySettingsManager;
@@ -132,6 +143,7 @@ import android.net.Uri;
 import android.net.cts.util.CtsNetUtils;
 import android.net.cts.util.CtsTetheringUtils;
 import android.net.util.KeepaliveUtils;
+import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 import android.os.Binder;
 import android.os.Build;
@@ -160,6 +172,7 @@ import androidx.test.runner.AndroidJUnit4;
 
 import com.android.internal.util.ArrayUtils;
 import com.android.modules.utils.build.SdkLevel;
+import com.android.net.module.util.CollectionUtils;
 import com.android.networkstack.apishim.ConnectivityManagerShimImpl;
 import com.android.networkstack.apishim.ConstantsShim;
 import com.android.networkstack.apishim.NetworkInformationShimImpl;
@@ -554,6 +567,223 @@ public class ConnectivityManagerTest {
         }
     }
 
+    private boolean checkPermission(String perm, int uid) {
+        return mContext.checkPermission(perm, -1 /* pid */, uid) == PERMISSION_GRANTED;
+    }
+
+    private String findPackageByPermissions(@NonNull List<String> requiredPermissions,
+                @NonNull List<String> forbiddenPermissions) throws Exception {
+        final List<PackageInfo> packageInfos =
+                mPackageManager.getInstalledPackages(GET_PERMISSIONS);
+        for (PackageInfo packageInfo : packageInfos) {
+            final int uid = mPackageManager.getPackageUid(packageInfo.packageName, 0 /* flags */);
+            if (!CollectionUtils.all(requiredPermissions, perm -> checkPermission(perm, uid))) {
+                continue;
+            }
+            if (CollectionUtils.any(forbiddenPermissions, perm -> checkPermission(perm, uid))) {
+                continue;
+            }
+
+            return packageInfo.packageName;
+        }
+        return null;
+    }
+
+    @DevSdkIgnoreRule.IgnoreUpTo(SC_V2)
+    @Test
+    public void testRedactLinkPropertiesForPackage() throws Exception {
+        final String groundedPkg = findPackageByPermissions(
+                List.of(), /* requiredPermissions */
+                List.of(ACCESS_NETWORK_STATE) /* forbiddenPermissions */);
+        assertNotNull("Couldn't find any package without ACCESS_NETWORK_STATE", groundedPkg);
+        final int groundedUid = mPackageManager.getPackageUid(groundedPkg, 0 /* flags */);
+
+        final String normalPkg = findPackageByPermissions(
+                List.of(ACCESS_NETWORK_STATE) /* requiredPermissions */,
+                List.of(NETWORK_SETTINGS, NETWORK_STACK,
+                        PERMISSION_MAINLINE_NETWORK_STACK) /* forbiddenPermissions */);
+        assertNotNull("Couldn't find any package with ACCESS_NETWORK_STATE but"
+                + " without NETWORK_SETTINGS", normalPkg);
+        final int normalUid = mPackageManager.getPackageUid(normalPkg, 0 /* flags */);
+
+        // There are some privileged packages on the system, like the phone process, the network
+        // stack and the system server.
+        final String privilegedPkg = findPackageByPermissions(
+                List.of(ACCESS_NETWORK_STATE, NETWORK_SETTINGS), /* requiredPermissions */
+                List.of() /* forbiddenPermissions */);
+        assertNotNull("Couldn't find a package with sufficient permissions", privilegedPkg);
+        final int privilegedUid = mPackageManager.getPackageUid(privilegedPkg, 0);
+
+        // Set parcelSensitiveFields to true to preserve CaptivePortalApiUrl & CaptivePortalData
+        // when parceling.
+        final LinkProperties lp = new LinkProperties(new LinkProperties(),
+                true /* parcelSensitiveFields */);
+        final Uri capportUrl = Uri.parse("https://capport.example.com/api");
+        final CaptivePortalData capportData = new CaptivePortalData.Builder().build();
+        final int mtu = 12345;
+        lp.setMtu(mtu);
+        lp.setCaptivePortalApiUrl(capportUrl);
+        lp.setCaptivePortalData(capportData);
+
+        // No matter what the given uid is, a SecurityException will be thrown if the caller
+        // doesn't hold the NETWORK_SETTINGS permission.
+        assertThrows(SecurityException.class,
+                () -> mCm.redactLinkPropertiesForPackage(lp, groundedUid, groundedPkg));
+        assertThrows(SecurityException.class,
+                () -> mCm.redactLinkPropertiesForPackage(lp, normalUid, normalPkg));
+        assertThrows(SecurityException.class,
+                () -> mCm.redactLinkPropertiesForPackage(lp, privilegedUid, privilegedPkg));
+
+        runAsShell(NETWORK_SETTINGS, () -> {
+            // No matter what the given uid is, if the given LinkProperties is null, then
+            // NullPointerException will be thrown.
+            assertThrows(NullPointerException.class,
+                    () -> mCm.redactLinkPropertiesForPackage(null, groundedUid, groundedPkg));
+            assertThrows(NullPointerException.class,
+                    () -> mCm.redactLinkPropertiesForPackage(null, normalUid, normalPkg));
+            assertThrows(NullPointerException.class,
+                    () -> mCm.redactLinkPropertiesForPackage(null, privilegedUid, privilegedPkg));
+
+            // Make sure null is returned for a UID without ACCESS_NETWORK_STATE.
+            assertNull(mCm.redactLinkPropertiesForPackage(lp, groundedUid, groundedPkg));
+
+            // CaptivePortalApiUrl & CaptivePortalData will be set to null if given uid doesn't hold
+            // the NETWORK_SETTINGS permission.
+            assertNull(mCm.redactLinkPropertiesForPackage(lp, normalUid, normalPkg)
+                    .getCaptivePortalApiUrl());
+            assertNull(mCm.redactLinkPropertiesForPackage(lp, normalUid, normalPkg)
+                    .getCaptivePortalData());
+            // MTU is not sensitive and is not redacted.
+            assertEquals(mtu, mCm.redactLinkPropertiesForPackage(lp, normalUid, normalPkg)
+                    .getMtu());
+
+            // CaptivePortalApiUrl & CaptivePortalData will be preserved if the given uid holds the
+            // NETWORK_SETTINGS permission.
+            assertEquals(capportUrl,
+                    mCm.redactLinkPropertiesForPackage(lp, privilegedUid, privilegedPkg)
+                            .getCaptivePortalApiUrl());
+            assertEquals(capportData,
+                    mCm.redactLinkPropertiesForPackage(lp, privilegedUid, privilegedPkg)
+                            .getCaptivePortalData());
+        });
+    }
+
+    private NetworkCapabilities redactNc(@NonNull final NetworkCapabilities nc, int uid,
+            @NonNull String packageName) {
+        return mCm.redactNetworkCapabilitiesForPackage(nc, uid, packageName);
+    }
+
+    @DevSdkIgnoreRule.IgnoreUpTo(SC_V2)
+    @Test
+    public void testRedactNetworkCapabilitiesForPackage() throws Exception {
+        final String groundedPkg = findPackageByPermissions(
+                List.of(), /* requiredPermissions */
+                List.of(ACCESS_NETWORK_STATE) /* forbiddenPermissions */);
+        assertNotNull("Couldn't find any package without ACCESS_NETWORK_STATE", groundedPkg);
+        final int groundedUid = mPackageManager.getPackageUid(groundedPkg, 0 /* flags */);
+
+        // A package which doesn't have any of the permissions below, but has NETWORK_STATE.
+        // There should be a number of packages like this on the device; AOSP has many,
+        // including contacts, webview, the keyboard, pacprocessor, messaging.
+        final String normalPkg = findPackageByPermissions(
+                List.of(ACCESS_NETWORK_STATE) /* requiredPermissions */,
+                List.of(NETWORK_SETTINGS, NETWORK_FACTORY, NETWORK_SETUP_WIZARD,
+                        NETWORK_STACK, PERMISSION_MAINLINE_NETWORK_STACK,
+                        ACCESS_FINE_LOCATION, ACCESS_COARSE_LOCATION) /* forbiddenPermissions */);
+        assertNotNull("Can't find a package with ACCESS_NETWORK_STATE but without any of"
+                + " the forbidden permissions", normalPkg);
+        final int normalUid = mPackageManager.getPackageUid(normalPkg, 0 /* flags */);
+
+        // There are some privileged packages on the system, like the phone process, the network
+        // stack and the system server.
+        final String privilegedPkg = findPackageByPermissions(
+                List.of(ACCESS_NETWORK_STATE, NETWORK_SETTINGS, NETWORK_FACTORY,
+                        ACCESS_FINE_LOCATION), /* requiredPermissions */
+                List.of() /* forbiddenPermissions */);
+        assertNotNull("Couldn't find a package with sufficient permissions", privilegedPkg);
+        final int privilegedUid = mPackageManager.getPackageUid(privilegedPkg, 0);
+
+        final Set<Range<Integer>> uids = new ArraySet<>();
+        uids.add(new Range<>(10000, 10100));
+        uids.add(new Range<>(10200, 10300));
+        final String ssid = "My-WiFi";
+        // This test will set underlying networks in the capabilities to redact to see if they
+        // are appropriately redacted, so fetch the default network to put in there as an example.
+        final Network defaultNetwork = mCm.getActiveNetwork();
+        assertNotNull("CTS requires a working Internet connection", defaultNetwork);
+        final int subId1 = 1;
+        final int subId2 = 2;
+        final int[] administratorUids = {normalUid};
+        final String bssid = "location sensitive";
+        final int rssi = 43; // not location sensitive
+        final WifiInfo wifiInfo = new WifiInfo.Builder()
+                .setBssid(bssid)
+                .setRssi(rssi)
+                .build();
+        final NetworkCapabilities nc = new NetworkCapabilities.Builder()
+                .setUids(uids)
+                .setSsid(ssid)
+                .setUnderlyingNetworks(List.of(defaultNetwork))
+                .setSubscriptionIds(Set.of(subId1, subId2))
+                .setAdministratorUids(administratorUids)
+                .setOwnerUid(normalUid)
+                .setTransportInfo(wifiInfo)
+                .build();
+
+        // No matter what the given uid is, a SecurityException will be thrown if the caller
+        // doesn't hold the NETWORK_SETTINGS permission.
+        assertThrows(SecurityException.class, () -> redactNc(nc, groundedUid, groundedPkg));
+        assertThrows(SecurityException.class, () -> redactNc(nc, normalUid, normalPkg));
+        assertThrows(SecurityException.class, () -> redactNc(nc, privilegedUid, privilegedPkg));
+
+        runAsShell(NETWORK_SETTINGS, () -> {
+            // Make sure that the NC is null if the package doesn't hold ACCESS_NETWORK_STATE.
+            assertNull(redactNc(nc, groundedUid, groundedPkg));
+
+            // Uids, ssid, underlying networks & subscriptionIds will be redacted if the given uid
+            // doesn't hold the associated permissions. The wifi transport info is also suitably
+            // redacted.
+            final NetworkCapabilities redactedNormal = redactNc(nc, normalUid, normalPkg);
+            assertNull(redactedNormal.getUids());
+            assertNull(redactedNormal.getSsid());
+            assertNull(redactedNormal.getUnderlyingNetworks());
+            assertEquals(0, redactedNormal.getSubscriptionIds().size());
+            assertEquals(WifiInfo.DEFAULT_MAC_ADDRESS,
+                    ((WifiInfo) redactedNormal.getTransportInfo()).getBSSID());
+            assertEquals(rssi, ((WifiInfo) redactedNormal.getTransportInfo()).getRssi());
+
+            // Uids, ssid, underlying networks & subscriptionIds will be preserved if the given uid
+            // holds the associated permissions.
+            final NetworkCapabilities redactedPrivileged =
+                    redactNc(nc, privilegedUid, privilegedPkg);
+            assertEquals(uids, redactedPrivileged.getUids());
+            assertEquals(ssid, redactedPrivileged.getSsid());
+            assertEquals(List.of(defaultNetwork), redactedPrivileged.getUnderlyingNetworks());
+            assertEquals(Set.of(subId1, subId2), redactedPrivileged.getSubscriptionIds());
+            assertEquals(bssid, ((WifiInfo) redactedPrivileged.getTransportInfo()).getBSSID());
+            assertEquals(rssi, ((WifiInfo) redactedPrivileged.getTransportInfo()).getRssi());
+
+            // The owner uid is only preserved when the network is a VPN and the uid is the
+            // same as the owner uid.
+            nc.addTransportType(TRANSPORT_VPN);
+            assertEquals(normalUid, redactNc(nc, normalUid, normalPkg).getOwnerUid());
+            assertEquals(INVALID_UID, redactNc(nc, privilegedUid, privilegedPkg).getOwnerUid());
+            nc.removeTransportType(TRANSPORT_VPN);
+
+            // If the given uid doesn't hold location permissions, the owner uid will be set to
+            // INVALID_UID even when sent to that UID (this avoids a wifi suggestor knowing where
+            // the device is by virtue of the device connecting to its own network).
+            assertEquals(INVALID_UID, redactNc(nc, normalUid, normalPkg).getOwnerUid());
+
+            // If the given uid holds location permissions, the owner uid is preserved. This works
+            // because the shell holds ACCESS_FINE_LOCATION.
+            final int[] administratorUids2 = { privilegedUid };
+            nc.setAdministratorUids(administratorUids2);
+            nc.setOwnerUid(privilegedUid);
+            assertEquals(privilegedUid, redactNc(nc, privilegedUid, privilegedPkg).getOwnerUid());
+        });
+    }
+
     /**
      * Tests that connections can be opened on WiFi and cellphone networks,
      * and that they are made from different IP addresses.