commit cf7744dc1e2707ff2f25aa572428fea329c2d95e
author Benedict Wong <benedictwong@google.com> Tue Apr 14 18:17:16 2020 -0700
committer Benedict Wong <benedictwong@google.com> Wed Apr 29 23:05:51 2020 -0700
tree 05079b26ff473d7f07299ada20d45bc319682f7e
parent 4fab2954464cf8645bccc3641b1c470962ef5db0

Update MODP groups for IKEv2/IPsec VPNs

This commit improves security by removing MODP groups that are
considered to be breakable in the near-future, and adding support for
ones that are more highly recommended.

3072 and 4096 are added based on the IANA constants, and are already
supported in the IKEv2 library.

This commit is made in line with recommendations in RFC 8247:
https://tools.ietf.org/html/rfc8247#section-2.4

Bug: 154056830
Test: FrameworksNetTests, FrameworksIkeTests passing, manually tested.
Change-Id: I941dbbfc2d6be693869ba6213590a07f3eac4bc7
Merged-In: I941dbbfc2d6be693869ba6213590a07f3eac4bc7
(cherry picked from commit f33cf5bd76a0e6a4a105bd606a94b24dfbbc86ef)

services/core/java/com/android/server/connectivity/VpnIkev2Utils.java

diff --git a/services/core/java/com/android/server/connectivity/VpnIkev2Utils.java b/services/core/java/com/android/server/connectivity/VpnIkev2Utils.java
index 228966c..103f659 100644
--- a/services/core/java/com/android/server/connectivity/VpnIkev2Utils.java
+++ b/services/core/java/com/android/server/connectivity/VpnIkev2Utils.java
@@ -17,7 +17,6 @@
 package com.android.server.connectivity;
 
 import static android.net.ConnectivityManager.NetworkCallback;
-import static android.net.ipsec.ike.SaProposal.DH_GROUP_1024_BIT_MODP;
 import static android.net.ipsec.ike.SaProposal.DH_GROUP_2048_BIT_MODP;
 import static android.net.ipsec.ike.SaProposal.ENCRYPTION_ALGORITHM_AES_CBC;
 import static android.net.ipsec.ike.SaProposal.ENCRYPTION_ALGORITHM_AES_GCM_12;
@@ -85,6 +84,12 @@
 public class VpnIkev2Utils {
     private static final String TAG = VpnIkev2Utils.class.getSimpleName();
 
+    // TODO: Use IKE library exposed constants when @SystemApi is updated.
+    /** IANA-defined 3072 group for use in IKEv2 */
+    private static final int DH_GROUP_3072_BIT_MODP = 15;
+    /** IANA-defined 4096 group for use in IKEv2 */
+    private static final int DH_GROUP_4096_BIT_MODP = 16;
+
     static IkeSessionParams buildIkeSessionParams(
             @NonNull Context context, @NonNull Ikev2VpnProfile profile, @NonNull Network network) {
         final IkeIdentification localId = parseIkeIdentification(profile.getUserIdentity());
@@ -177,8 +182,9 @@
 
         // Add dh, prf for both builders
         for (final IkeSaProposal.Builder builder : Arrays.asList(normalModeBuilder, aeadBuilder)) {
+            builder.addDhGroup(DH_GROUP_4096_BIT_MODP);
+            builder.addDhGroup(DH_GROUP_3072_BIT_MODP);
             builder.addDhGroup(DH_GROUP_2048_BIT_MODP);
-            builder.addDhGroup(DH_GROUP_1024_BIT_MODP);
             builder.addPseudorandomFunction(PSEUDORANDOM_FUNCTION_AES128_XCBC);
             builder.addPseudorandomFunction(PSEUDORANDOM_FUNCTION_HMAC_SHA1);
         }