From afc800274caaecf3647db2f04cd0635285eb675b Mon Sep 17 00:00:00 2001
From: Tayrtahn <tayrtahn@gmail.com>
Date: Thu, 20 Jun 2024 20:17:16 -0400
Subject: [PATCH] Fix null exceptions in SurveillanceCameraMonitorSystem
 (#29275)

* Add IsNullOrEmpty checks before indexing KnownSubnets

* actor
---
 .../Systems/SurveillanceCameraMonitorSystem.cs           | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Content.Server/SurveillanceCamera/Systems/SurveillanceCameraMonitorSystem.cs b/Content.Server/SurveillanceCamera/Systems/SurveillanceCameraMonitorSystem.cs
index ca0f59cd14..f61c57a4a6 100644
--- a/Content.Server/SurveillanceCamera/Systems/SurveillanceCameraMonitorSystem.cs
+++ b/Content.Server/SurveillanceCamera/Systems/SurveillanceCameraMonitorSystem.cs
@@ -90,7 +90,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
     private void OnSubnetRequest(EntityUid uid, SurveillanceCameraMonitorComponent component,
         SurveillanceCameraMonitorSubnetRequestMessage args)
     {
-        if (args.Actor != null)
+        if (args.Actor is { Valid: true } actor && !Deleted(actor))
         {
             SetActiveSubnet(uid, args.Subnet, component);
         }
@@ -146,6 +146,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
                     break;
                 case SurveillanceCameraSystem.CameraSubnetData:
                     if (args.Data.TryGetValue(SurveillanceCameraSystem.CameraSubnetData, out string? subnet)
+                        && !string.IsNullOrEmpty(subnet)
                         && !component.KnownSubnets.ContainsKey(subnet))
                     {
                         component.KnownSubnets.Add(subnet, args.SenderAddress);
@@ -217,6 +218,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
     {
         if (!Resolve(uid, ref monitor)
             || monitor.LastHeartbeatSent < _heartbeatDelay
+            || string.IsNullOrEmpty(monitor.ActiveSubnet)
             || !monitor.KnownSubnets.TryGetValue(monitor.ActiveSubnet, out var subnetAddress))
         {
             return;
@@ -278,6 +280,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
         SurveillanceCameraMonitorComponent? monitor = null)
     {
         if (!Resolve(uid, ref monitor)
+            || string.IsNullOrEmpty(subnet)
             || !monitor.KnownSubnets.ContainsKey(subnet))
         {
             return;
@@ -295,6 +298,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
     private void RequestActiveSubnetInfo(EntityUid uid, SurveillanceCameraMonitorComponent? monitor = null)
     {
         if (!Resolve(uid, ref monitor)
+            || string.IsNullOrEmpty(monitor.ActiveSubnet)
             || !monitor.KnownSubnets.TryGetValue(monitor.ActiveSubnet, out var address))
         {
             return;
@@ -310,6 +314,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
     private void ConnectToSubnet(EntityUid uid, string subnet, SurveillanceCameraMonitorComponent? monitor = null)
     {
         if (!Resolve(uid, ref monitor)
+            || string.IsNullOrEmpty(subnet)
             || !monitor.KnownSubnets.TryGetValue(subnet, out var address))
         {
             return;
@@ -327,6 +332,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
     private void DisconnectFromSubnet(EntityUid uid, string subnet, SurveillanceCameraMonitorComponent? monitor = null)
     {
         if (!Resolve(uid, ref monitor)
+            || string.IsNullOrEmpty(subnet)
             || !monitor.KnownSubnets.TryGetValue(subnet, out var address))
         {
             return;
@@ -415,6 +421,7 @@ public sealed class SurveillanceCameraMonitorSystem : EntitySystem
         SurveillanceCameraMonitorComponent? monitor = null)
     {
         if (!Resolve(uid, ref monitor)
+            || string.IsNullOrEmpty(monitor.ActiveSubnet)
             || !monitor.KnownSubnets.TryGetValue(monitor.ActiveSubnet, out var subnetAddress))
         {
             return;
-- 
2.51.2