Fix the potential NullPointerException.

The networkAttributesParcelable retrieved from IpMemoryStore might be
null, it might cause crash with NullPointerException when attepmting
to read from the field on a null object reference.

Bug: 135174345
Test: atest FrameworksNetTests NetworkStackTests
Merged-In: I658fbba3e18c5c640ed7d445d2cd59c4221e055f
Merged-In: Ie6b5c293b4ca17622674d5f735a9d62e04410088

(cherry picked from commit 4769936f59)

Change-Id: I3be6e57f6f8c56f828b025828aae0640248d23a9

services/net/java/android/net/ipmemorystore/NetworkAttributes.java

@@ -127,6 +127,7 @@ public class NetworkAttributes {
 
     @Nullable
     private static InetAddress getByAddressOrNull(@Nullable final byte[] address) {
+        if (null == address) return null;
         try {
             return InetAddress.getByAddress(address);
         } catch (UnknownHostException e) {
@@ -227,7 +228,9 @@ public class NetworkAttributes {
         }
 
         /**
-         * Set the lease expiry timestamp of assigned v4 address.
+         * Set the lease expiry timestamp of assigned v4 address. Long.MAX_VALUE is used
+         * to represent "infinite lease".
+         *
          * @param assignedV4AddressExpiry The lease expiry timestamp of assigned v4 address.
          * @return This builder.
          */

services/net/java/android/net/ipmemorystore/OnNetworkAttributesRetrievedListener.java

@@ -40,8 +40,8 @@ public interface OnNetworkAttributesRetrievedListener {
                 // NonNull, but still don't crash the system server if null
                 if (null != listener) {
                     listener.onNetworkAttributesRetrieved(
-                            new Status(statusParcelable), l2Key,
-                            new NetworkAttributes(networkAttributesParcelable));
+                            new Status(statusParcelable), l2Key, null == networkAttributesParcelable
+                                ? null : new NetworkAttributes(networkAttributesParcelable));
                 }
             }