fix: Invalid subscription plan cause NPE

If someone setup a invalid subscription plan with
subId:INVALID_SUBSCRIPTION_ID. (For instance, test code).
It will cause NPE when WiFi connected because WiFi network doesn't own
subscriberId. (Happened on API call: buildTemplateCarrierMetered with
null subscriberId.)

Fix:
1. Add null check before calling buildTemplateCarrierMetered
2. Add invalid subId check before saving subscription plan.

Bug: 191938713
Test: atest -c NetworkPolicyManagerServiceTest

Change-Id: I835a7b8890035975e187ca0a70ec2f30ca56455a

services/core/java/com/android/server/net/NetworkPolicyManagerService.java

@@ -2139,6 +2139,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
             if (!quotaEnabled) continue;
             if (snapshot.getNetwork() == null) continue;
             final int subId = getSubIdLocked(snapshot.getNetwork());
+            if (subId == INVALID_SUBSCRIPTION_ID) continue;
             final SubscriptionPlan plan = getPrimarySubscriptionPlanLocked(subId);
             if (plan == null) continue;
 
@@ -2161,9 +2162,10 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
                 final long startOfDay = ZonedDateTime.ofInstant(now, cycle.getLower().getZone())
                         .truncatedTo(ChronoUnit.DAYS)
                         .toInstant().toEpochMilli();
-                final long totalBytes = getTotalBytes(
-                        buildTemplateCarrierMetered(snapshot.getSubscriberId()),
-                        start, startOfDay);
+                final String subscriberId = snapshot.getSubscriberId();
+                final long totalBytes = subscriberId == null
+                        ? 0 : getTotalBytes(
+                                buildTemplateCarrierMetered(subscriberId), start, startOfDay);
                 final long remainingBytes = limitBytes - totalBytes;
                 // Number of remaining days including current day
                 final long remainingDays =
@@ -2679,6 +2681,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
             // write all known subscription plans
             for (int i = 0; i < mSubscriptionPlans.size(); i++) {
                 final int subId = mSubscriptionPlans.keyAt(i);
+                if (subId == INVALID_SUBSCRIPTION_ID) continue;
                 final String ownerPackage = mSubscriptionPlansOwner.get(subId);
                 final SubscriptionPlan[] plans = mSubscriptionPlans.valueAt(i);
                 if (ArrayUtils.isEmpty(plans)) continue;
@@ -5572,7 +5575,8 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
 
         // Turn carrier/mobile data limit off
         NetworkPolicy[] policies = getNetworkPolicies(mContext.getOpPackageName());
-        NetworkTemplate templateCarrier = buildTemplateCarrierMetered(subscriber);
+        NetworkTemplate templateCarrier = subscriber != null
+                ? buildTemplateCarrierMetered(subscriber) : null;
         NetworkTemplate templateMobile = buildTemplateMobileAll(subscriber);
         for (NetworkPolicy policy : policies) {
             //  All policies loaded from disk will be carrier templates, and setting will also only