[PATCH v2 0/1] MR4434: winex11: Free correct pointer when using xf86vm

[Fabian Maurer (＠DarkShadow44)]

After allocation the pointer gets shifted by sizeof(xf86vm_modes),
so we have to undo that before calling free.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55909

--
  v2: winex11: Free correct pointer when using xf86vm

https://gitlab.winehq.org/wine/wine/-/merge_requests/4434

[PATCH v2 1/1] winex11: Free correct pointer when using xf86vm

[Fabian Maurer]

From: Fabian Maurer

After allocation the pointer gets shifted by sizeof(xf86vm_modes),
so we have to undo that before calling free.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55909
---
 dlls/winex11.drv/xvidmode.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/winex11.drv/xvidmode.c b/dlls/winex11.drv/xvidmode.c
index 399d5e90e1e..fd9b1e7e8b1 100644
--- a/dlls/winex11.drv/xvidmode.c
+++ b/dlls/winex11.drv/xvidmode.c
@@ -159,11 +159,12 @@ static void xf86vm_free_modes(DEVMODEW *modes)

if (modes)
     {
+        BYTE *ptr = (BYTE *)modes - sizeof(xf86vm_modes);
         assert(modes[0].dmDriverExtra == sizeof(XF86VidModeModeInfo *));
-        memcpy(&xf86vm_modes, (BYTE *)modes - sizeof(xf86vm_modes), sizeof(xf86vm_modes));
+        memcpy(&xf86vm_modes, ptr, sizeof(xf86vm_modes));
         XFree(xf86vm_modes);
+        free(ptr);
     }
-    free(modes);
 }

static BOOL xf86vm_get_current_mode(x11drv_settings_id id, DEVMODEW *mode)

[Fabian Maurer (＠DarkShadow44)]

On Mon Nov 20 02:08:33 2023 +0000, Zhiyi Zhang wrote:
> Let's move free(ptr) into the if (modes) branch or return early if modes
> is NULL.

Good catch, thanks. Pushed an update.

[PATCH v2 0/1] MR4434: winex11: Free correct pointer when using xf86vm - approved

[Zhiyi Zhang (＠zhiyi)]

This merge request was approved by Zhiyi Zhang.