[PATCH v5 0/1] MR10929: gdi32: Validate count parameter in ExtCreateRegion

[Bartosz Kosiorek (＠gang65)]

--
  v5: gdi32: Validate count parameter in ExtCreateRegion
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10929

[PATCH v5 1/1] gdi32: Validate count parameter in ExtCreateRegion

[Bartosz Kosiorek]

From: Bartosz Kosiorek <[e-mail]>

---
 dlls/ddraw/clipper.c        | 2 +-
 dlls/gdi32/objects.c        | 2 +-
 dlls/gdi32/tests/clipping.c | 4 +---
 dlls/win32u/region.c        | 3 ++-
 4 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/dlls/ddraw/clipper.c b/dlls/ddraw/clipper.c
index 3159a34cb5a..2b13b0ee766 100644
--- a/dlls/ddraw/clipper.c
+++ b/dlls/ddraw/clipper.c
@@ -299,7 +299,7 @@ static HRESULT WINAPI ddraw_clipper_SetClipList(IDirectDrawClipper *iface, RGNDA
         DeleteObject(clipper->region);
     if (!region)
         clipper->region = NULL;
-    else if (!(clipper->region = ExtCreateRegion(NULL, 0, region)))
+    else if (!(clipper->region = ExtCreateRegion(NULL, region->rdh.dwSize + region->rdh.nRgnSize, region)))
     {
         wined3d_mutex_unlock();
         ERR("Failed to create region.\n");
diff --git a/dlls/gdi32/objects.c b/dlls/gdi32/objects.c
index f2b353cff27..12eaddcd623 100644
--- a/dlls/gdi32/objects.c
+++ b/dlls/gdi32/objects.c
@@ -642,7 +642,7 @@ HBITMAP WINAPI CreateDiscardableBitmap( HDC hdc, INT width, INT height )
  */
 HRGN WINAPI ExtCreateRegion( const XFORM *xform, DWORD count, const RGNDATA *data )
 {
-    if (!data)
+    if (!data || count < sizeof(RGNDATAHEADER))
     {
         SetLastError( ERROR_INVALID_PARAMETER );
         return 0;
diff --git a/dlls/gdi32/tests/clipping.c b/dlls/gdi32/tests/clipping.c
index ce66f9cad09..0ae467dbfdc 100644
--- a/dlls/gdi32/tests/clipping.c
+++ b/dlls/gdi32/tests/clipping.c
@@ -219,15 +219,14 @@ static void test_ExtCreateRegion(void)
     SetLastError(0xdeadbeef);
     hrgn = ExtCreateRegion(NULL, sizeof(RGNDATAHEADER), &rgn.data);
     ok(hrgn != 0, "ExtCreateRegion error %lu\n", GetLastError());
+    ok(GetLastError() == 0xdeadbeef, "0xdeadbeef, got %lu\n", GetLastError());
     verify_region(hrgn, &empty_rect);
     DeleteObject(hrgn);
 
     /* Cannot be smaller than sizeof(RGNDATAHEADER) */
     SetLastError(0xdeadbeef);
     hrgn = ExtCreateRegion(NULL, sizeof(RGNDATAHEADER) - 1, &rgn.data);
-    todo_wine
     ok(!hrgn, "ExtCreateRegion should fail\n");
-    todo_wine
     ok(GetLastError() == ERROR_INVALID_PARAMETER ||
        broken(GetLastError() == 0xdeadbeef), "0xdeadbeef, got %lu\n", GetLastError());
 
@@ -267,7 +266,6 @@ static void test_ExtCreateRegion(void)
     /* Buffer cannot be smaller than sizeof(RGNDATAHEADER) + 2 * sizeof(RECT) */
     SetLastError(0xdeadbeef);
     hrgn = ExtCreateRegion(NULL, sizeof(RGNDATAHEADER) + 2 * sizeof(RECT) - 1, &rgn.data);
-    todo_wine
     ok(!hrgn, "ExtCreateRegion should fail\n");
     ok(GetLastError() == 0xdeadbeef, "0xdeadbeef, got %lu\n", GetLastError());
 
diff --git a/dlls/win32u/region.c b/dlls/win32u/region.c
index 35ef4a22256..3c1a8bc0953 100644
--- a/dlls/win32u/region.c
+++ b/dlls/win32u/region.c
@@ -896,7 +896,8 @@ HRGN WINAPI NtGdiExtCreateRegion( const XFORM *xform, DWORD count, const RGNDATA
     WINEREGION *obj;
     const RECT *pCurRect, *pEndRect;
 
-    if (!rgndata || rgndata->rdh.dwSize < sizeof(RGNDATAHEADER))
+    if (!rgndata || rgndata->rdh.dwSize < sizeof(RGNDATAHEADER) ||
+        count < sizeof(RGNDATAHEADER) + rgndata->rdh.nCount * sizeof(RECT))
         return 0;
 
     /* XP doesn't care about the type */
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10929

[Bartosz Kosiorek (＠gang65)]

Bartosz Kosiorek (@gang65) commented about dlls/ddraw/clipper.c:
> DeleteObject(clipper->region);
>      if (!region)
>          clipper->region = NULL;
> -    else if (!(clipper->region = ExtCreateRegion(NULL, 0, region)))
> +    else if (!(clipper->region = ExtCreateRegion(NULL, region->rdh.dwSize + region->rdh.nRgnSize, region)))

From now we need to always specify valid value of number of bytes pointed by buffer.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10929#note_140326