Address ClientUUID issue as per GHSA-hvm9-wc8j-mgrc

With credits to original contributors and TShock team, see advisory for more details.
SignatureBeef · Dec 19, 2024 · 24d30d3 · 24d30d3
1 parent a74e49f
commit 24d30d3
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Showing 2 changed files with 113 additions and 139 deletions.
diff --git a/OTAPI.Scripts/Mods/PatchClientUUID.Server.cs b/OTAPI.Scripts/Mods/PatchClientUUID.Server.cs
diff --git a/OTAPI.Scripts/Patches/Terraria.RemoteClient.Server.cs b/OTAPI.Scripts/Patches/Terraria.RemoteClient.Server.cs
@@ -19,8 +19,65 @@ You should have received a copy of the GNU General Public License
 #pragma warning disable CS0108 // Member hides inherited member; missing new keyword
 #pragma warning disable CS0626 // Method, operator, or accessor is marked external and has no attributes on it
 
+using ModFramework;
+using Mono.Cecil.Cil;
+using MonoMod;
+using System;
 using System.Collections.Generic;
 
+/// <summary>
+/// @doc Adds additional properties to Terraria.RemoteClient. 
+/// </summary>
+[MonoModIgnore]
+partial class Patch
+{
+    [Modification(ModType.PostPatch, "Patching in Client UUID")]
+    public static void PatchClientUUID(MonoModder modder)
+    {
+        const int PacketID = 68;
+        int messageType = 0;
+        var GetData = modder.GetILCursor(() => new Terraria.MessageBuffer().GetData(0, 0, out messageType));
+        var Callback = modder.GetMethodDefinition(() => OTAPI.Hooks.MessageBuffer.InvokeClientUUIDReceived(default, default, default, default, ref messageType));
+
+        GetData.GotoNext(i => i.OpCode == OpCodes.Switch);
+
+        var instructions = (Instruction[])GetData.Next.Operand;
+
+        var packet = instructions[PacketID - 1];
+
+        GetData.Goto(packet);
+
+        /*
+         *  Replace the ReadString call with the callback. Reference il:
+
+            // reader.ReadString();
+            IL_655e: ldarg.0        == GetData.Next
+            IL_655f: ldfld class [mscorlib]System.IO.BinaryReader Terraria.MessageBuffer::reader
+            IL_6564: callvirt instance string [mscorlib]System.IO.BinaryReader::ReadString()
+            IL_6569: pop
+            IL_656a: ret
+        */
+
+        GetData.Index++;
+        GetData.Emit(OpCodes.Ldarg_0);
+
+        GetData.Index++;
+
+        foreach (var parameter in GetData.Method.Parameters)
+        {
+            GetData.Emit(OpCodes.Ldarg, parameter);
+        }
+
+        System.Diagnostics.Debug.Assert(GetData.Next.OpCode == OpCodes.Callvirt);
+        GetData.Next.OpCode = OpCodes.Call;
+        GetData.Next.Operand = Callback;
+
+        GetData.Index++;
+        System.Diagnostics.Debug.Assert(GetData.Next.OpCode == OpCodes.Pop);
+        GetData.Next.OpCode = OpCodes.Nop;
+    }
+}
+
 /// <summary>
 /// @doc Adds a Terraria.RemoteClient.Data variable for data storage.
 /// </summary>
@@ -29,6 +86,7 @@ namespace Terraria
     partial class patch_RemoteClient : Terraria.RemoteClient
     {
         public Dictionary<string, object> Data { get; set; }
+        public string ClientUUID { get; set; }
 
         [MonoMod.MonoModConstructor]
         patch_RemoteClient()
@@ -39,8 +97,60 @@ partial class patch_RemoteClient : Terraria.RemoteClient
         public extern void orig_Reset();
         public void Reset()
         {
-            orig_Reset();
-            Data.Clear();
+            // clear before possible socket exceptions
+            Data.Clear();
+            ClientUUID = null;
+            orig_Reset();
+        }
+    }
+}
+
+namespace OTAPI
+{
+    public static partial class Hooks
+    {
+        public static partial class MessageBuffer
+        {
+            public class ClientUUIDReceivedEventArgs : EventArgs
+            {
+                public HookEvent Event { get; set; }
+                public HookResult? Result { get; set; }
+
+                public Terraria.MessageBuffer Instance { get; set; }
+                public System.IO.BinaryReader Reader { get; set; }
+                public int Start { get; set; }
+                public int Length { get; set; }
+                public int MessageType { get; set; }
+                public string ClientUUID { get; set; }
+            }
+            public static event EventHandler<ClientUUIDReceivedEventArgs> ClientUUIDReceived;
+
+            /// <summary>
+            /// Called when Terraria receives a ClientUUID(#68) packet from a connection
+            /// </summary>
+            public static void InvokeClientUUIDReceived(Terraria.MessageBuffer instance, System.IO.BinaryReader reader, int start, int length, ref int messageType)
+            {
+                var args = new ClientUUIDReceivedEventArgs()
+                {
+                    Event = HookEvent.Before,
+                    Instance = instance,
+                    Reader = reader,
+                    Start = start,
+                    Length = length,
+                    MessageType = messageType
+                };
+
+                ClientUUIDReceived?.Invoke(null, args);
+                if (args.Result != HookResult.Cancel)
+                {
+                    args.ClientUUID = reader.ReadString();
+
+                    ((Terraria.patch_RemoteClient)Terraria.Netplay.Clients[args.Instance.whoAmI]).ClientUUID = args.ClientUUID;
+
+                    args.Event = HookEvent.After;
+                    ClientUUIDReceived?.Invoke(null, args);
+                }
+            }
         }
     }
-}
+}