Rémi Bernon : winex11.drv: Fix invalid range when reading GTK_WORKAREAS_D0 (valgrind).

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 99088fe17b4ea6c627a8c3d377c39bd48c68ccef
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=99088fe17b4ea6c627a8c3d37...

Author: Rémi Bernon <rbernon(a)codeweavers.com>
Date:   Mon Mar  8 09:14:22 2021 +0100

winex11.drv: Fix invalid range when reading GTK_WORKAREAS_D0 (valgrind).

  Invalid read of size 8
     at 0x559B816: get_work_area (display.c:296)
     by 0x55DC8C1: query_screens (xinerama.c:103)
     by 0x55DC8C1: xinerama_init (xinerama.c:275)
     by 0x55D6F47: process_attach (x11drv_main.c:602)
     by 0x55D6F47: DllMain (x11drv_main.c:721)
     by 0x7BC35819: call_dll_entry_point (loader.c:285)
     by 0x7BC35819: MODULE_InitDLL (loader.c:1317)
     by 0x7BC362ED: process_attach.part.0 (loader.c:1411)
     by 0x7BC3B843: process_attach (loader.c:1382)
     by 0x7BC3B843: LdrLoadDll (loader.c:2765)
     by 0x7B025C85: load_library (loader.c:172)
     by 0x7B026B72: LoadLibraryExW (loader.c:522)
     by 0x7B026BE5: LoadLibraryW (loader.c:492)
     by 0x40990D: load_graphics_driver (desktop.c:844)
     by 0x40990D: manage_desktop (desktop.c:1010)
     by 0x40C6B3: parse_command_line (explorer.c:836)
     by 0x40C6B3: wWinMain (explorer.c:865)
     by 0x4103F2: wmain (crt_wwinmain.c:55)
   Address 0x5272370 is 16 bytes before an unallocated block of size 3,132,512 in arena "client"

Signed-off-by: Rémi Bernon <rbernon(a)codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard(a)winehq.org>

---

 dlls/winex11.drv/display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dlls/winex11.drv/display.c b/dlls/winex11.drv/display.c
index 0f61f9f7b2e..b647455a01f 100644
--- a/dlls/winex11.drv/display.c
+++ b/dlls/winex11.drv/display.c
@@ -289,9 +289,9 @@ RECT get_work_area(const RECT *monitor_rect)
                             x11drv_atom(_GTK_WORKAREAS_D0), 0, ~0, False, XA_CARDINAL, &type,
                             &format, &count, &remaining, (unsigned char **)&work_area))
     {
-        if (type == XA_CARDINAL && format == 32 && count >= 4)
+        if (type == XA_CARDINAL && format == 32)
         {
-            for (i = 0; i + 3 < count; i += 4)
+            for (i = 0; i < count / 4; ++i)
             {
                 work_rect.left = work_area[i * 4];
                 work_rect.top = work_area[i * 4 + 1];