switch to live patching MSIL approach

.github/workflows/ci.yml

@@ -35,6 +35,11 @@ jobs:
         cd build
         cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
         cmake --build .
+    
+    - name: Generate patched MSIL
+      shell: cmd
+      run: |
+        msil\patch.bat
 
     - name: Build installer
       shell: cmd

bin/ildasm/ildasm.exe.config

@@ -0,0 +1,6 @@
+<?xml version ="1.0"?>
+<configuration>
+    <startup useLegacyV2RuntimeActivationPolicy="true">
+        <requiredRuntime safemode="true" imageVersion="v4.0.30319" version="v4.0.30319"/>
+    </startup>
+</configuration>

msil/README.md

@@ -1,5 +1,5 @@
 # Patched MSIL/managed code DLLs
 
-This folder contains managed code DLLs that have been manually patched to redirect or remove references to Win32 APIs that do not exist on Windows 95. They have been edited with [https://github.com/dnSpy/dnSpy](dnSpy).
+This folder contains patches for managed code DLLs to redirect or remove references to Win32 APIs that do not exist on Windows 95. They are applied to the MSIL that can be generated using `ildisasm` (in the `bin` folder) and reassembled with `ilasm` (in `bin/dotnetfx20/URTInstallPath`). For ease of use, a `patch.bat` script is provided which should automate this process.
 
 .NET appears to use a hashing/signing system that will prevent these DLLs from getting installed into the Global Assembly Cache (GAC) by any normal means. Instead, the installer installs the original DLLs into the GAC and then clobbers them with these patched DLLs at the end. The hash/signing check is never done again so this ends up working, even though it is a hacky solution. There may be a better one I'm not aware of.

msil/System.Windows.Forms.patch

@@ -0,0 +1,20 @@
+--- System.Windows.Forms.asm.original	2024-04-19 12:15:06.880649435 -0700
++++ System.Windows.Forms.asm	2024-04-19 12:16:01.487091612 -0700
+@@ -58528,7 +58528,7 @@
+     IL_000f:  ret
+   } // end of method UnsafeNativeMethods::CreateMenu
+ 
+-  .method public hidebysig static pinvokeimpl("comdlg32.dll" autochar lasterr winapi) 
++  .method public hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi) 
+           bool  GetOpenFileName([in][out] class System.Windows.Forms.NativeMethods/OPENFILENAME_I ofn) cil managed preservesig
+   {
+   }
+@@ -59879,7 +59879,7 @@
+                                            [in][out] object&  marshal( interface ) pAcc) cil managed preservesig
+   {
+   }
+-  .method public hidebysig static pinvokeimpl("user32.dll" nomangle autochar winapi) 
++  .method public hidebysig static pinvokeimpl("corusr.dll" nomangle autochar winapi) 
+           void  NotifyWinEvent(int32 winEvent,
+                                valuetype [mscorlib]System.Runtime.InteropServices.HandleRef hwnd,
+                                int32 objType,

msil/System.configuration.patch

@@ -0,0 +1,19 @@
+--- System.configuration.asm.original	2024-04-19 13:20:09.458249700 -0700
++++ System.configuration.asm	2024-04-19 13:22:09.844507556 -0700
+@@ -8,6 +8,7 @@
+ .module extern kernel32.dll
+ .module extern crypt32.dll
+ .module extern advapi32.dll
++.module extern corkel32.dll
+ .assembly extern mscorlib
+ {
+   .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+@@ -71914,7 +71915,7 @@
+ 
+   .field static assembly literal int32 GetFileExInfoStandard = int32(0x00000000)
+   .field static assembly literal int32 MOVEFILE_REPLACE_EXISTING = int32(0x00000001)
+-  .method assembly hidebysig static pinvokeimpl("kernel32.dll" autochar lasterr winapi bestfit:off) 
++  .method assembly hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi bestfit:off) 
+           bool  GetFileAttributesEx(string name,
+                                     int32 fileInfoLevel,
+                                     [out] valuetype Microsoft.Win32.UnsafeNativeMethods/WIN32_FILE_ATTRIBUTE_DATA& data) cil managed preservesig

msil/mscorlib.patch

@@ -0,0 +1,42 @@
+--- mscorlib.asm.original	2024-04-19 12:55:04.782157988 -0700
++++ mscorlib.asm	2024-04-19 12:57:54.287832486 -0700
+@@ -11,6 +11,7 @@
+ .module extern kernel32.dll
+ .module extern mscorwks.dll
+ .module extern oleaut32.dll
++.module extern corkel32.dll
+ .module extern advapi32.dll
+ .module extern ole32.dll
+ .module extern user32.dll
+@@ -367275,19 +367276,19 @@
+                                  native int mustBeZero) cil managed preservesig
+   {
+   }
+-  .method assembly hidebysig static pinvokeimpl("kernel32.dll" autochar lasterr winapi bestfit:off) 
++  .method assembly hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi bestfit:off) 
+           int32  GetLongPathName(string path,
+                                  class System.Text.StringBuilder longPathBuffer,
+                                  int32 bufferLength) cil managed preservesig
+   {
+   }
+-  .method assembly hidebysig static pinvokeimpl("kernel32.dll" autochar lasterr winapi bestfit:off) 
++  .method assembly hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi bestfit:off) 
+           int32  GetLongPathName([in] char[] path,
+                                  [out] char[] longPathBuffer,
+                                  int32 bufferLength) cil managed preservesig
+   {
+   }
+-  .method assembly hidebysig static pinvokeimpl("kernel32.dll" autochar lasterr winapi bestfit:off) 
++  .method assembly hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi bestfit:off) 
+           int32  GetLongPathName(char* path,
+                                  char* longPathBuffer,
+                                  int32 bufferLength) cil managed preservesig
+@@ -367675,7 +367676,7 @@
+                                      class System.Text.StringBuilder lpBuffer) cil managed preservesig
+   {
+   }
+-  .method assembly hidebysig static pinvokeimpl("kernel32.dll" autochar lasterr winapi bestfit:off) 
++  .method assembly hidebysig static pinvokeimpl("corkel32.dll" autochar lasterr winapi bestfit:off) 
+           bool  GetFileAttributesEx(string name,
+                                     int32 fileInfoLevel,
+                                     valuetype Microsoft.Win32.Win32Native/WIN32_FILE_ATTRIBUTE_DATA& lpFileInformation) cil managed preservesig

msil/patch.bat

@@ -0,0 +1,20 @@
+@echo off
+setlocal
+cd /d %~dp0
+mkdir build
+mkdir temp
+cd temp
+
+goto patchFiles
+
+:doPatch
+..\..\bin\ildasm\ildasm.exe /out=%~1.asm ../../bin/dotnetfx20/URTInstallPath/%~1.dll
+..\..\bin\patch\patch %~1.asm ..\%~1.patch
+..\..\bin\dotnetfx20\URTInstallPath\ilasm.exe /dll %~1.asm
+copy %~1.dll ..\build
+goto :eof
+
+:patchFiles
+call:doPatch System.Windows.Forms
+call:doPatch mscorlib
+call:doPatch System.configuration

setup/dotnet9x.nsi

@@ -5583,11 +5583,11 @@ File /r "..\wrappers\build\*.dll"
 !insertmacro Check95 0 SkipNET20MSILPatches
 
 SetOutPath $WINDIR\assembly\GAC_MSIL\System.Windows.Forms\2.0.0.0__b77a5c561934e089
-File "..\msil\System.Windows.Forms.dll"
+File "..\msil\build\System.Windows.Forms.dll"
 SetOutPath $WINDIR\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089
-File "..\msil\mscorlib.dll"
+File "..\msil\build\mscorlib.dll"
 SetOutPath $WINDIR\assembly\GAC_MSIL\System.Configuration\2.0.0.0__b03f5f7f11d50a3a
-File "..\msil\System.configuration.dll"
+File "..\msil\build\System.configuration.dll"
 
 SkipNET20MSILPatches: