Bernhard Übelacker : wing32: Avoid crash in WinGGetDIBPointer when called with NULL bitmap info.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 0f6a66e91967cfd53f90975b172d8f06c31f8be1
URL:    https://gitlab.winehq.org/wine/wine/-/commit/0f6a66e91967cfd53f90975b172d8f0...

Author: Bernhard Übelacker <bernhardu(a)mailbox.org>
Date:   Sun Jan 14 10:24:45 2024 +0100

wing32: Avoid crash in WinGGetDIBPointer when called with NULL bitmap info.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=56135

---

 dlls/wing32/tests/wing32.c | 3 +++
 dlls/wing32/wing32.c       | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/dlls/wing32/tests/wing32.c b/dlls/wing32/tests/wing32.c
index 1a3c958ff02..e3f01ff22bc 100644
--- a/dlls/wing32/tests/wing32.c
+++ b/dlls/wing32/tests/wing32.c
@@ -51,6 +51,9 @@ static void test_WinGGetDIBPointer(void)
     dib = WinGGetDIBPointer(NULL, NULL);
     ok(dib == NULL, "WinGGetDIBPointer returned unexpected value %p\n", dib);
 
+    dib = WinGGetDIBPointer(bmp, NULL);
+    ok(dib != NULL, "WinGGetDIBPointer failed\n");
+
     dib = WinGGetDIBPointer(bmp, &bmi);
     ok(dib != NULL, "WinGGetDIBPointer failed\n");
 
diff --git a/dlls/wing32/wing32.c b/dlls/wing32/wing32.c
index b6702ba8017..14012206286 100644
--- a/dlls/wing32/wing32.c
+++ b/dlls/wing32/wing32.c
@@ -72,7 +72,7 @@ void * WINAPI WinGGetDIBPointer( HBITMAP hbmp, BITMAPINFO *bmi )
 
     if (GetObjectW( hbmp, sizeof(ds), &ds ) == sizeof(ds))
     {
-        bmi->bmiHeader = ds.dsBmih;
+        if (bmi) bmi->bmiHeader = ds.dsBmih;
         return ds.dsBm.bmBits;
     }
     return NULL;