Add small overhead for event size constraints

Server/mods/deathmatch/logic/CGame.cpp

@@ -1131,7 +1131,7 @@ bool CGame::StaticProcessNetworkPacket(unsigned char ucPacketID, const NetServer
 {
     if (ucPacketID == PACKET_ID_LUA_EVENT)
     {
-        if (pBitStream->GetNumberOfUnreadBits() > CLuaEventPacket::MAX_LUA_EVENT_ARGUMENTS_SIZE * 8)
+        if (pBitStream->GetNumberOfUnreadBits() > (CLuaEventPacket::MAX_LUA_EVENT_ARGUMENTS_SIZE + CLuaEventPacket::LUA_EVENT_ENVELOPE_HEADROOM) * 8)
             return false;
     }
 

Server/mods/deathmatch/logic/packets/CLuaEventPacket.cpp

@@ -32,7 +32,7 @@ bool CLuaEventPacket::Read(NetBitStreamInterface& BitStream)
     {
         if (usNameLength < (MAX_EVENT_NAME_LENGTH - 1) && BitStream.ReadStringCharacters(m_strName, usNameLength) && BitStream.Read(m_ElementID))
         {
-            if (BitStream.GetNumberOfUnreadBits() > MAX_LUA_LATENT_EVENT_ARGUMENTS_SIZE * 8)
+            if (BitStream.GetNumberOfUnreadBits() > (MAX_LUA_LATENT_EVENT_ARGUMENTS_SIZE + LUA_EVENT_ENVELOPE_HEADROOM) * 8)
                 return false;
 
             // Faster than using a constructor

Server/mods/deathmatch/logic/packets/CLuaEventPacket.h

@@ -17,6 +17,7 @@
 class CLuaEventPacket final : public CPacket
 {
 public:
+    static constexpr int LUA_EVENT_ENVELOPE_HEADROOM = 64 * 1024;
     // Limit for the size of the arguments in a single triggerEvent. (1MB)
     static constexpr int MAX_LUA_EVENT_ARGUMENTS_SIZE = 1024 * 1024;
     // Limit for the size of the arguments in a single triggerLatentEvent. (10MB)

Shared/mods/deathmatch/logic/CLatentReceiver.cpp

@@ -128,12 +128,10 @@ void CLatentReceiver::OnReceive(NetBitStreamInterface* pBitStream)
         if (uiFinalSize > 100 * 1024 * 1024)
             return OnReceiveError("uiFinalSize too large");
 
-        // CATEGORY_PACKET reassembles raw packet data and feeds it into
-        // the main packet dispatch (CGame::StaticProcessPacket). Without
-        // a tighter cap, an attacker can craft a 100MB payload targeting
-        // packet handlers that scale poorly with input size (e.g.
-        // CPlayerModInfoPacket). 10MB is well above any legitimate use.
-        constexpr uint LATENT_PACKET_MAX_SIZE = 10 * 1024 * 1024;
+        // uiFinalSize includes the 5-byte CATEGORY_PACKET wrapper and the
+        // serialized event envelope. Keep 10 MiB available for argument data
+        // while allowing a small amount of protocol overhead.
+        constexpr uint LATENT_PACKET_MAX_SIZE = 10 * 1024 * 1024 + 64 * 1024;
         if (usCategory == CATEGORY_PACKET && uiFinalSize > LATENT_PACKET_MAX_SIZE)
             return OnReceiveError("CATEGORY_PACKET payload too large");
 
@@ -159,8 +157,10 @@ void CLatentReceiver::OnReceive(NetBitStreamInterface* pBitStream)
     //
     // Read body
     //
-    if (activeRx.uiWritePosition + usSizeSent > activeRx.buffer.GetSize())
-        return OnReceiveError("Buffer would overflow");
+    if (activeRx.uiWritePosition > activeRx.buffer.GetSize() || usSizeSent > activeRx.buffer.GetSize() - activeRx.uiWritePosition)
+    {
+        return OnReceiveError(SString("Buffer would overflow (size:%u pos:%u chunk:%u)", activeRx.buffer.GetSize(), activeRx.uiWritePosition, usSizeSent));
+    }
 
     if (bIsTail && activeRx.uiWritePosition + usSizeSent != activeRx.buffer.GetSize())
         return OnReceiveError("Buffer size wrong");