Refactor VPN interface filtering necessity check
Bug: 206482423
Test: atest ConnectivityServiceTest
Change-Id: Iedf344f6275d4c6b23716eb11e3eecf54c6a2f9a
(cherry picked from commit 77a794868fd478dadb90e5e1fa71debd7257db4d)
Merged-In: Iedf344f6275d4c6b23716eb11e3eecf54c6a2f9a
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 67a64d5..d17ff0f 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -7737,10 +7737,10 @@
private void updateVpnFiltering(LinkProperties newLp, LinkProperties oldLp,
NetworkAgentInfo nai) {
- final String oldIface = oldLp != null ? oldLp.getInterfaceName() : null;
- final String newIface = newLp != null ? newLp.getInterfaceName() : null;
- final boolean wasFiltering = requiresVpnIsolation(nai, nai.networkCapabilities, oldLp);
- final boolean needsFiltering = requiresVpnIsolation(nai, nai.networkCapabilities, newLp);
+ final String oldIface = getVpnIsolationInterface(nai, nai.networkCapabilities, oldLp);
+ final String newIface = getVpnIsolationInterface(nai, nai.networkCapabilities, newLp);
+ final boolean wasFiltering = requiresVpnAllowRule(oldIface);
+ final boolean needsFiltering = requiresVpnAllowRule(newIface);
if (!wasFiltering && !needsFiltering) {
// Nothing to do.
@@ -8046,15 +8046,14 @@
}
/**
- * Returns whether VPN isolation (ingress interface filtering) should be applied on the given
- * network.
+ * Returns the interface which requires VPN isolation (ingress interface filtering).
*
* Ingress interface filtering enforces that all apps under the given network can only receive
* packets from the network's interface (and loopback). This is important for VPNs because
* apps that cannot bypass a fully-routed VPN shouldn't be able to receive packets from any
* non-VPN interfaces.
*
- * As a result, this method should return true iff
+ * As a result, this method should return Non-null interface iff
* 1. the network is an app VPN (not legacy VPN)
* 2. the VPN does not allow bypass
* 3. the VPN is fully-routed
@@ -8063,16 +8062,28 @@
* @see INetd#firewallAddUidInterfaceRules
* @see INetd#firewallRemoveUidInterfaceRules
*/
- private boolean requiresVpnIsolation(@NonNull NetworkAgentInfo nai, NetworkCapabilities nc,
+ @Nullable
+ private String getVpnIsolationInterface(@NonNull NetworkAgentInfo nai, NetworkCapabilities nc,
LinkProperties lp) {
- if (nc == null || lp == null) return false;
- return nai.isVPN()
+ if (nc == null || lp == null) return null;
+ if (nai.isVPN()
&& !nai.networkAgentConfig.allowBypass
&& nc.getOwnerUid() != Process.SYSTEM_UID
&& lp.getInterfaceName() != null
&& (lp.hasIpv4DefaultRoute() || lp.hasIpv4UnreachableDefaultRoute())
&& (lp.hasIpv6DefaultRoute() || lp.hasIpv6UnreachableDefaultRoute())
- && !lp.hasExcludeRoute();
+ && !lp.hasExcludeRoute()) {
+ return lp.getInterfaceName();
+ }
+ return null;
+ }
+
+ /**
+ * Returns whether we need to set interface filtering rule or not
+ */
+ private boolean requiresVpnAllowRule(String filterIface) {
+ // Allow rules are only needed if VPN isolation is enabled.
+ return filterIface != null;
}
private static UidRangeParcel[] toUidRangeStableParcels(final @NonNull Set<UidRange> ranges) {
@@ -8200,9 +8211,10 @@
if (!prevRanges.isEmpty()) {
updateVpnUidRanges(false, nai, prevRanges);
}
- final boolean wasFiltering = requiresVpnIsolation(nai, prevNc, nai.linkProperties);
- final boolean shouldFilter = requiresVpnIsolation(nai, newNc, nai.linkProperties);
- final String iface = nai.linkProperties.getInterfaceName();
+ final String oldIface = getVpnIsolationInterface(nai, prevNc, nai.linkProperties);
+ final String newIface = getVpnIsolationInterface(nai, newNc, nai.linkProperties);
+ final boolean wasFiltering = requiresVpnAllowRule(oldIface);
+ final boolean shouldFilter = requiresVpnAllowRule(newIface);
// For VPN uid interface filtering, old ranges need to be removed before new ranges can
// be added, due to the range being expanded and stored as individual UIDs. For example
// the UIDs might be updated from [0, 99999] to ([0, 10012], [10014, 99999]) which means
@@ -8215,10 +8227,11 @@
// TODO Fix this window by computing an accurate diff on Set<UidRange>, so the old range
// to be removed will never overlap with the new range to be added.
if (wasFiltering && !prevRanges.isEmpty()) {
- mPermissionMonitor.onVpnUidRangesRemoved(iface, prevRanges, prevNc.getOwnerUid());
+ mPermissionMonitor.onVpnUidRangesRemoved(oldIface, prevRanges,
+ prevNc.getOwnerUid());
}
if (shouldFilter && !newRanges.isEmpty()) {
- mPermissionMonitor.onVpnUidRangesAdded(iface, newRanges, newNc.getOwnerUid());
+ mPermissionMonitor.onVpnUidRangesAdded(newIface, newRanges, newNc.getOwnerUid());
}
} catch (Exception e) {
// Never crash!