From 9cd977f9f469bba280e7875d0fac0b1565da4f17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bram=20Bonn=C3=A9?= <brambonne@google.com>
Date: Wed, 15 Apr 2020 18:19:34 +0200
Subject: Use EUI64 IPv6 link-local address generation when randomizing MAC

When connected MAC address randomization is used, generate IPv6
link-local addresses using EUI64 with the per-network defined MAC
address.
Networks that do not use MAC address randomization keep using RFC7217
stable privacy address generation instead.

Bug: 154114734

Test: atest ClientModeImplTest
Test: atest WifiManagerTest
Test: Connect to network
Test: Set up hotspot
Test: Cast from device
Test: Observe that IPv6 link-local address differs for two networks
using randomization
Test: Observe that stable-privacy link-local address is used for network
when not using randomization

Change-Id: Iefb027b17657031116e068bbccdb7b2231a65238
(cherry picked from commit d870eee583e9300fbdaa1620325fe3c13d30817d)
---
 .../com/android/server/wifi/ClientModeImpl.java    | 30 ++++++++++++++--------
 1 file changed, 20 insertions(+), 10 deletions(-)

(limited to 'service')

diff --git a/service/java/com/android/server/wifi/ClientModeImpl.java b/service/java/com/android/server/wifi/ClientModeImpl.java
index 5b616dd0a..b5bd479db 100644
--- a/service/java/com/android/server/wifi/ClientModeImpl.java
+++ b/service/java/com/android/server/wifi/ClientModeImpl.java
@@ -6447,12 +6447,17 @@ public class ClientModeImpl extends StateMachine {
 
         final boolean isUsingStaticIp =
                 (config.getIpAssignment() == IpConfiguration.IpAssignment.STATIC);
+        final boolean isUsingMacRandomization =
+                config.macRandomizationSetting
+                        == WifiConfiguration.RANDOMIZATION_PERSISTENT
+                        && isConnectedMacRandomizationEnabled();
         if (mVerboseLoggingEnabled) {
             final String key = config.getKey();
             log("startIpClient netId=" + Integer.toString(mLastNetworkId)
                     + " " + key + " "
                     + " roam=" + mIsAutoRoaming
                     + " static=" + isUsingStaticIp
+                    + " randomMac=" + isUsingMacRandomization
                     + " isFilsConnection=" + isFilsConnection);
         }
 
@@ -6471,15 +6476,18 @@ public class ClientModeImpl extends StateMachine {
                 return false;
             }
             setConfigurationsPriorToIpClientProvisioning(config);
-            final ProvisioningConfiguration prov =
+            final ProvisioningConfiguration.Builder prov =
                     new ProvisioningConfiguration.Builder()
                     .withPreDhcpAction()
                     .withPreconnection()
                     .withApfCapabilities(
                     mWifiNative.getApfCapabilities(mInterfaceName))
-                    .withLayer2Information(layer2Info)
-                    .build();
-            mIpClient.startProvisioning(prov);
+                    .withLayer2Information(layer2Info);
+            if (isUsingMacRandomization) {
+                // Use EUI64 address generation for link-local IPv6 addresses.
+                prov.withRandomMacAddress();
+            }
+            mIpClient.startProvisioning(prov.build());
         } else {
             sendNetworkChangeBroadcast(DetailedState.OBTAINING_IPADDR);
             // We must clear the config BSSID, as the wifi chipset may decide to roam
@@ -6521,7 +6529,7 @@ public class ClientModeImpl extends StateMachine {
                 }
             }
 
-            final ProvisioningConfiguration prov;
+            final ProvisioningConfiguration.Builder prov;
             ProvisioningConfiguration.ScanResultInfo scanResultInfo = null;
             if (scanResult != null) {
                 final List<ScanResultInfo.InformationElement> ies =
@@ -6542,8 +6550,7 @@ public class ClientModeImpl extends StateMachine {
                     .withNetwork(getCurrentNetwork())
                     .withDisplayName(config.SSID)
                     .withScanResultInfo(scanResultInfo)
-                    .withLayer2Information(layer2Info)
-                    .build();
+                    .withLayer2Information(layer2Info);
             } else {
                 StaticIpConfiguration staticIpConfig = config.getStaticIpConfiguration();
                 prov = new ProvisioningConfiguration.Builder()
@@ -6551,10 +6558,13 @@ public class ClientModeImpl extends StateMachine {
                         .withApfCapabilities(mWifiNative.getApfCapabilities(mInterfaceName))
                         .withNetwork(getCurrentNetwork())
                         .withDisplayName(config.SSID)
-                        .withLayer2Information(layer2Info)
-                        .build();
+                        .withLayer2Information(layer2Info);
+            }
+            if (isUsingMacRandomization) {
+                // Use EUI64 address generation for link-local IPv6 addresses.
+                prov.withRandomMacAddress();
             }
-            mIpClient.startProvisioning(prov);
+            mIpClient.startProvisioning(prov.build());
         }
 
         return true;
-- 
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