Connect the DHCP UDP socket to the server.

This makes it so that the socket cannot receive datagrams from
anybody except the DHCP server. This does not improve security,
because we never read from the UDP socket anyway, but it does
make ListeningPortsTest pass.

Bug: 23906864
Bug: 23933386
Change-Id: Ib090273a417f7eb2ac1ee3309260249b72fb8345

1 files changed, 4 insertions, 5 deletions

diff --git a/core/java/android/net/DhcpResults.java b/core/java/android/net/DhcpResults.java
index 87c063f..97bd5d2 100644
--- a/core/java/android/net/DhcpResults.java
+++ b/core/java/android/net/DhcpResults.java
@@ -21,7 +21,6 @@ import android.os.Parcel;
 import android.text.TextUtils;
 import android.util.Log;
 
-import java.net.InetAddress;
 import java.net.Inet4Address;
 import java.util.Objects;
 
@@ -34,7 +33,7 @@ import java.util.Objects;
 public class DhcpResults extends StaticIpConfiguration {
     private static final String TAG = "DhcpResults";
 
-    public InetAddress serverAddress;
+    public Inet4Address serverAddress;
 
     /** Vendor specific information (from RFC 2132). */
     public String vendorInfo;
@@ -142,7 +141,7 @@ public class DhcpResults extends StaticIpConfiguration {
     private static void readFromParcel(DhcpResults dhcpResults, Parcel in) {
         StaticIpConfiguration.readFromParcel(dhcpResults, in);
         dhcpResults.leaseDuration = in.readInt();
-        dhcpResults.serverAddress = NetworkUtils.unparcelInetAddress(in);
+        dhcpResults.serverAddress = (Inet4Address) NetworkUtils.unparcelInetAddress(in);
         dhcpResults.vendorInfo = in.readString();
     }
 
@@ -183,8 +182,8 @@ public class DhcpResults extends StaticIpConfiguration {
 
     public boolean setServerAddress(String addrString) {
         try {
-            serverAddress = NetworkUtils.numericToInetAddress(addrString);
-        } catch (IllegalArgumentException e) {
+            serverAddress = (Inet4Address) NetworkUtils.numericToInetAddress(addrString);
+        } catch (IllegalArgumentException|ClassCastException e) {
             Log.e(TAG, "setServerAddress failed with addrString " + addrString);
             return true;
         }