From 07e90754ab86f7d56df2f813ceb93de12d4aa0d5 Mon Sep 17 00:00:00 2001
From: Emma Miler <27428383+emma-miler@users.noreply.github.com>
Date: Fri, 13 May 2022 01:53:22 +0200
Subject: Block `emit` command when sv_cheats is disabled (#170)

---
 .../NorthstarDedicatedTest.vcxproj                 |  2 ++
 .../NorthstarDedicatedTest.vcxproj.filters         | 21 ++++++++++++-----
 NorthstarDedicatedTest/dllmain.cpp                 |  2 ++
 NorthstarDedicatedTest/emit_blocker.cpp            | 26 ++++++++++++++++++++++
 NorthstarDedicatedTest/emit_blocker.h              |  3 +++
 5 files changed, 48 insertions(+), 6 deletions(-)
 create mode 100644 NorthstarDedicatedTest/emit_blocker.cpp
 create mode 100644 NorthstarDedicatedTest/emit_blocker.h

diff --git a/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj b/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj
index 1d065006..8f969d3e 100644
--- a/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj
+++ b/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj
@@ -115,6 +115,7 @@
     <ClInclude Include="chatcommand.h" />
     <ClInclude Include="clientchathooks.h" />
     <ClInclude Include="clientvideooverrides.h" />
+    <ClInclude Include="emit_blocker.h" />
     <ClInclude Include="localchatwriter.h" />
     <ClInclude Include="ns_version.h" />
     <ClInclude Include="plugins.h" />
@@ -582,6 +583,7 @@
     <ClCompile Include="dedicated.cpp" />
     <ClCompile Include="dedicatedmaterialsystem.cpp" />
     <ClCompile Include="dllmain.cpp" />
+    <ClCompile Include="emit_blocker.cpp" />
     <ClCompile Include="filesystem.cpp" />
     <ClCompile Include="gameutils.cpp" />
     <ClCompile Include="hooks.cpp" />
diff --git a/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj.filters b/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj.filters
index c6815227..0424fcf6 100644
--- a/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj.filters
+++ b/NorthstarDedicatedTest/NorthstarDedicatedTest.vcxproj.filters
@@ -133,6 +133,9 @@
     <Filter Include="Source Files\Shared\Exploit Fixes\UTF8Parser">
       <UniqueIdentifier>{b30e08b1-b962-4264-8cbb-a0a31924b93e}</UniqueIdentifier>
     </Filter>
+    <Filter Include="Header Files\Shared\ExploitFixes">
+      <UniqueIdentifier>{7f609cee-d2c0-46a2-b06e-83b9f0511915}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="pch.h">
@@ -1491,12 +1494,6 @@
     <ClInclude Include="clientvideooverrides.h">
       <Filter>Header Files\Client</Filter>
     </ClInclude>
-    <ClInclude Include="ExploitFixes.h">
-      <Filter>Source Files\Shared\Exploit Fixes</Filter>
-    </ClInclude>
-    <ClInclude Include="NSMem.h">
-      <Filter>Source Files\Shared\Exploit Fixes</Filter>
-    </ClInclude>
     <ClInclude Include="ExploitFixes_UTF8Parser.h">
       <Filter>Source Files\Shared\Exploit Fixes\UTF8Parser</Filter>
     </ClInclude>
@@ -1506,6 +1503,15 @@
     <ClInclude Include="ns_version.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="ExploitFixes.h">
+      <Filter>Header Files\Shared\ExploitFixes</Filter>
+    </ClInclude>
+    <ClInclude Include="NSMem.h">
+      <Filter>Header Files\Shared\ExploitFixes</Filter>
+    </ClInclude>
+    <ClInclude Include="emit_blocker.h">
+      <Filter>Header Files\Shared\ExploitFixes</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="dllmain.cpp">
@@ -1667,6 +1673,9 @@
     <ClCompile Include="version.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="emit_blocker.cpp">
+      <Filter>Source Files\Shared\Exploit Fixes</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <MASM Include="audio_asm.asm">
diff --git a/NorthstarDedicatedTest/dllmain.cpp b/NorthstarDedicatedTest/dllmain.cpp
index c0674d94..1b98105c 100644
--- a/NorthstarDedicatedTest/dllmain.cpp
+++ b/NorthstarDedicatedTest/dllmain.cpp
@@ -49,6 +49,7 @@
 #include "rapidjson/writer.h"
 #include "rapidjson/error/en.h"
 #include "ExploitFixes.h"
+#include "emit_blocker.h"
 
 typedef void (*initPluginFuncPtr)(void* getPluginObject);
 
@@ -283,6 +284,7 @@ bool InitialiseNorthstar()
 
 	// activate exploit fixes
 	AddDllLoadCallback("server.dll", ExploitFixes::LoadCallback);
+	AddDllLoadCallback("server.dll", InitialiseServerEmit_Blocker);
 
 	// run callbacks for any libraries that are already loaded by now
 	CallAllPendingDLLLoadCallbacks();
diff --git a/NorthstarDedicatedTest/emit_blocker.cpp b/NorthstarDedicatedTest/emit_blocker.cpp
new file mode 100644
index 00000000..3f996c69
--- /dev/null
+++ b/NorthstarDedicatedTest/emit_blocker.cpp
@@ -0,0 +1,26 @@
+#include "pch.h"
+#include "cvar.h"
+
+ConVar* sv_cheats;
+
+typedef char(__fastcall* function_containing_emit_t)(uint64_t a1, uint64_t a2);
+function_containing_emit_t function_containing_emit;
+
+char function_containing_emit_hook(uint64_t unknown_value, uint64_t command_ptr)
+{
+	char* command_string = *(char**)(command_ptr + 1040); // From decompile
+	if (!sv_cheats->m_Value.m_nValue && !strncmp(command_string, "emit", 5))
+	{
+		spdlog::info("Blocking command \"emit\" because sv_cheats was 0");
+		return 1;
+	}
+	return function_containing_emit(unknown_value, command_ptr);
+}
+
+void InitialiseServerEmit_Blocker(HMODULE baseAddress)
+{
+	HookEnabler hook;
+	sv_cheats = g_pCVar->FindVar("sv_cheats");
+	ENABLER_CREATEHOOK(
+		hook, (char*)baseAddress + 0x5889A0, &function_containing_emit_hook, reinterpret_cast<LPVOID*>(&function_containing_emit));
+}
\ No newline at end of file
diff --git a/NorthstarDedicatedTest/emit_blocker.h b/NorthstarDedicatedTest/emit_blocker.h
new file mode 100644
index 00000000..43991927
--- /dev/null
+++ b/NorthstarDedicatedTest/emit_blocker.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void InitialiseServerEmit_Blocker(HMODULE baseAddress);
\ No newline at end of file
-- 
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