Arkadiusz Hiler : user32: Fix WM_DEVICECHANGE handling.

[Alexandre Julliard]

Module: wine
Branch: oldstable
Commit: 01f17546c491d0709012e96a55e1c5ac175dba72
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=01f17546c491d0709012e96a5...

Author: Arkadiusz Hiler 
Date:   Wed Nov 25 17:04:14 2020 +0200

user32: Fix WM_DEVICECHANGE handling.

WM_DEVICECHANGE's lParam can be either a pointer to a variant of
DEV_BROADCAST_HDR or an immediate value (usually 0) depending on
the wParam's value.

This fixes a crash when broadcasting WM_DEVICECHANGE with
wParam = DBT_DEVNODES_CHANGED, lParam = 0.

Signed-off-by: Arkadiusz Hiler 
Signed-off-by: Alexandre Julliard 
(cherry picked from commit b4abe3889f95e74df77f9fac117b30d236b2b2cc)
Signed-off-by: Michael Stefaniuc

---

dlls/user32/message.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dlls/user32/message.c b/dlls/user32/message.c
index 2ab82837d1b..37e7cb7735d 100644
--- a/dlls/user32/message.c
+++ b/dlls/user32/message.c
@@ -1028,7 +1028,7 @@ static size_t pack_message( HWND hwnd, UINT message, WPARAM wparam, LPARAM lpara
     case WM_DEVICECHANGE:
     {
         DEV_BROADCAST_HDR *header = (DEV_BROADCAST_HDR *)lparam;
-        push_data( data, header, header->dbch_size );
+        if ((wparam & 0x8000) && header) push_data( data, header, header->dbch_size );
         return 0;
     }
     case WM_WINE_KEYBOARD_LL_HOOK:
@@ -1431,6 +1431,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa
         if (!get_buffer_space( buffer, sizeof(BOOL) )) return FALSE;
         break;
     case WM_DEVICECHANGE:
+        if (!(*wparam & 0x8000)) return TRUE;
         minsize = sizeof(DEV_BROADCAST_HDR);
         break;
     case WM_WINE_KEYBOARD_LL_HOOK: