[PATCH v3 0/3] MR3855: Fixes for ntlea

[Yuxuan Shui (＠yshui)]

Make functions ntlea needs to patch hotpatchable. And add a asm wrapper for `GetWindowLongA` to workaround an assumption ntlea made.

--
  v3: user32: add hotpatchable wrapper for GetWindowLongA

https://gitlab.winehq.org/wine/wine/-/merge_requests/3855

[PATCH v3 1/3] gdi32: make GetStockObject hotpatchable

[Yuxuan Shui]

From: Yuxuan Shui

Needed for ntlea.
---
 dlls/gdi32/objects.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/gdi32/objects.c b/dlls/gdi32/objects.c
index 42bf6fcf111..070ce9c3885 100644
--- a/dlls/gdi32/objects.c
+++ b/dlls/gdi32/objects.c
@@ -418,7 +418,7 @@ HGDIOBJ WINAPI GetCurrentObject( HDC hdc, UINT type )
 /***********************************************************************
  *           GetStockObject    (GDI32.@)
  */
-HGDIOBJ WINAPI GetStockObject( INT obj )
+HGDIOBJ WINAPI DECLSPEC_HOTPATCH GetStockObject( INT obj )
 {
     if (obj < 0 || obj > STOCK_LAST + 1 || obj == 9) return 0;

[PATCH v3 2/3] user32: make CallWindowProcA hotpatchable

[Yuxuan Shui]

From: Yuxuan Shui

Needed for ntlea.
---
 dlls/user32/winproc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index 5ab85eb81cd..8804199aed1 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -860,7 +860,7 @@ BOOL WINAPI User32CallSendAsyncCallback( const struct send_async_params *params,
  *
  *   ECMA-234, Win32
  */
-LRESULT WINAPI CallWindowProcA( WNDPROC func, HWND hwnd, UINT msg, WPARAM wParam,  LPARAM lParam )
+LRESULT WINAPI DECLSPEC_HOTPATCH CallWindowProcA( WNDPROC func, HWND hwnd, UINT msg, WPARAM wParam,  LPARAM lParam )
 {
     struct win_proc_params params;

[PATCH v3 3/3] user32: add hotpatchable wrapper for GetWindowLongA

[Yuxuan Shui]

From: Yuxuan Shui

ntlea for some reason expects GetWindowLongA to start with a "push $-2", and
will try to skip over this instruction. If we don't anticipate this, it will
ended up either skipping over critical instructions, or on a desync address.
Either way, it would be bad.
---
 dlls/user32/win.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/dlls/user32/win.c b/dlls/user32/win.c
index 28cf40441d9..895b222cceb 100644
--- a/dlls/user32/win.c
+++ b/dlls/user32/win.c
@@ -884,11 +884,33 @@ WORD WINAPI GetWindowWord( HWND hwnd, INT offset )
     return NtUserGetWindowWord( hwnd, offset );
 }

-
 /**********************************************************************
  *		GetWindowLongA (USER32.@)
  */
-LONG WINAPI GetWindowLongA( HWND hwnd, INT offset )
+
+#ifdef __i386__
+
+/* This wrapper is here to workaround a ntlea quirk. First of all, ntlea
+ * checks whether GetWindowLongA starts with the Win32 hotpatchable prologue,
+ * if it can find that, it will use a hooking strategy more difficult for us
+ * to deal with. Secondly, it assumes what follows the prologue is a `pushl $-2`,
+ * and will try to skip over this instruction when calling `GetWindowLongA`,
+ * (i.e. it tries to jump to `GetWindowLongA + 7`, 5 bytes for the prologue, 2
+ * bytes for the `pushl`.). We have to anticipate that and make sure the result
+ * of doing this won't be a messed up stack, or a desynced PC.
+ */
+__ASM_STDCALL_FUNC(GetWindowLongA, 8,
+        "movl.s %edi, %edi\n"
+        "pushl %ebp\n"
+        "movl.s %esp, %ebp\n"
+        "pushl $-2\n"
+        "addl $4, %esp\n"
+        "popl %ebp\n"
+        "jmp " __ASM_STDCALL("get_window_longA", 8) "\n")
+LONG WINAPI get_window_longA( HWND hwnd, INT offset )
+#else
+LONG WINAPI DECLSPEC_HOTPATCH GetWindowLongA(HWND hwnd, INT offset)
+#endif
 {
     switch (offset)
     {
@@ -910,7 +932,6 @@ LONG WINAPI GetWindowLongA( HWND hwnd, INT offset )
     }
 }

-
 /**********************************************************************
  *		GetWindowLongW (USER32.@)
  */

[Yuxuan Shui (＠yshui)]

update: added a comment explaining the wrapper, and picked a better name.

[Alex Henrie (＠alexhenrie)]

Alex Henrie (@alexhenrie) commented about dlls/user32/win.c:
> -
> - and will try to skip over this instruction when calling `GetWindowLongA`,
> -
> - (i.e. it tries to jump to `GetWindowLongA + 7`, 5 bytes for the prologue, 2
> -
> - bytes for the `pushl`.). We have to anticipate that and make sure the result
> -
> - of doing this won't be a messed up stack, or a desynced PC.
> - */
>
> +__ASM_STDCALL_FUNC(GetWindowLongA, 8,
> -
>    "movl.s %edi, %edi\n"
> -
>    "pushl %ebp\n"
> -
>    "movl.s %esp, %ebp\n"
> -
>    "pushl $-2\n"
> -
>    "addl $4, %esp\n"
> -
>    "popl %ebp\n"
> -
>    "jmp " __ASM_STDCALL("get_window_longA", 8) "\n")
>
> +LONG WINAPI get_window_longA( HWND hwnd, INT offset )
> +#else
> +LONG WINAPI DECLSPEC_HOTPATCH GetWindowLongA(HWND hwnd, INT offset)

Could you please use a consistent style here, either with extra spaces in the parentheses in both argument lists or without extra spaces in both?

[Yuxuan Shui (＠yshui)]

On Mon Sep 18 17:25:40 2023 +0000, Alex Henrie wrote:
> Could you please use a consistent style here, either with extra spaces
> in the parentheses in both argument lists or without extra spaces in both?

I thought I wasn't supposed to put spaces there. example: https://gitlab.winehq.org/wine/wine/-/blob/master/dlls/ntdll/thread.c?ref_ty...