From becf46bfdff50dab319210b69d30185f87db7f17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bram=20Bonn=C3=A9?= <brambonne@google.com>
Date: Mon, 19 Oct 2020 18:08:55 +0200
Subject: Use EUI64 IPv6 link-local address generation only 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: 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

Merged-In: Iefb027b17657031116e068bbccdb7b2231a65238
Merged-In: I0a59c750511aacddb38b19bf64b56fd18ff545c5
Change-Id: I4512b87459d036630925ca5ac5ea42179c42ea71
---
 .../com/android/server/wifi/ClientModeImpl.java     | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/service/java/com/android/server/wifi/ClientModeImpl.java b/service/java/com/android/server/wifi/ClientModeImpl.java
index d98d022b7..cd6d8b269 100644
--- a/service/java/com/android/server/wifi/ClientModeImpl.java
+++ b/service/java/com/android/server/wifi/ClientModeImpl.java
@@ -5300,12 +5300,17 @@ public class ClientModeImpl extends StateMachine {
             final WifiConfiguration currentConfig = getCurrentWifiConfiguration();
             final boolean isUsingStaticIp =
                     (currentConfig.getIpAssignment() == IpConfiguration.IpAssignment.STATIC);
+            final boolean isUsingMacRandomization =
+                    currentConfig.macRandomizationSetting
+                            == WifiConfiguration.RANDOMIZATION_PERSISTENT
+                            && isConnectedMacRandomizationEnabled();
             if (mVerboseLoggingEnabled) {
                 final String key = currentConfig.configKey();
                 log("enter ObtainingIpState netId=" + Integer.toString(mLastNetworkId)
                         + " " + key + " "
                         + " roam=" + mIsAutoRoaming
-                        + " static=" + isUsingStaticIp);
+                        + " static=" + isUsingStaticIp
+                        + " randomMac=" + isUsingMacRandomization);
             }
 
             // Send event to CM & network change broadcast
@@ -5334,26 +5339,26 @@ public class ClientModeImpl extends StateMachine {
                     mIpClient.setTcpBufferSizes(mTcpBufferSizes);
                 }
             }
-            final ProvisioningConfiguration prov;
+            final ProvisioningConfiguration.Builder prov;
             if (!isUsingStaticIp) {
                 prov = new ProvisioningConfiguration.Builder()
                             .withPreDhcpAction()
                             .withApfCapabilities(mWifiNative.getApfCapabilities(mInterfaceName))
                             .withNetwork(getCurrentNetwork())
-                            .withDisplayName(currentConfig.SSID)
-                            .withRandomMacAddress()
-                            .build();
+                            .withDisplayName(currentConfig.SSID);
+                if (isUsingMacRandomization) {
+                    prov.withRandomMacAddress();
+                }
             } else {
                 StaticIpConfiguration staticIpConfig = currentConfig.getStaticIpConfiguration();
                 prov = new ProvisioningConfiguration.Builder()
                             .withStaticConfiguration(staticIpConfig)
                             .withApfCapabilities(mWifiNative.getApfCapabilities(mInterfaceName))
                             .withNetwork(getCurrentNetwork())
-                            .withDisplayName(currentConfig.SSID)
-                            .build();
+                            .withDisplayName(currentConfig.SSID);
             }
             if (mIpClient != null) {
-                mIpClient.startProvisioning(prov);
+                mIpClient.startProvisioning(prov.build());
             }
             // Get Link layer stats so as we get fresh tx packet counters
             getWifiLinkLayerStats();
-- 
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