RFC - oleaut32: Cope with invalid icon data

[Bruno Jesus]

While testing bug [1] I noticed that invalid data is sent to
OLEPictureImpl_LoadIcon. This patch is meant to resist these kind of
issues and makes the game goes on a little further until other crash.

I'm sending this as RFC because I don't know then icon structure but
my tests seem very straight forward from what I can guess from the
function.

[1] https://bugs.winehq.org/show_bug.cgi?id=21012

Thanks in advance and best regards,
Bruno
-------------- next part --------------
diff --git a/dlls/oleaut32/olepicture.c b/dlls/oleaut32/olepicture.c
index 5d0d801..5ce83e0 100644
--- a/dlls/oleaut32/olepicture.c
+++ b/dlls/oleaut32/olepicture.c
@@ -1210,6 +1210,8 @@ static HRESULT OLEPictureImpl_LoadIcon(OLEPictureImpl *This, BYTE *xbuf, ULONG x
     HDC hdcRef;
     int	i;
 
+    TRACE("(this %p, xbuf %p, xread %u)\n", This, xbuf, xread);
+
     /*
     FIXME("icon.idReserved=%d\n",cifd->idReserved);
     FIXME("icon.idType=%d\n",cifd->idType);
@@ -1226,6 +1228,13 @@ static HRESULT OLEPictureImpl_LoadIcon(OLEPictureImpl *This, BYTE *xbuf, ULONG x
 	FIXME("[%d] dwDIBOffset %d\n",i,cifd->idEntries[i].dwDIBOffset);
     }
     */
+
+    /* Need at least one icon to do something. */
+    if (!cifd->idCount)
+    {
+        ERR("Invalid icon count of zero.\n");
+        return E_FAIL;
+    }
     i=0;
     /* If we have more than one icon, try to find the best.
      * this currently means '32 pixel wide'.
@@ -1237,6 +1246,12 @@ static HRESULT OLEPictureImpl_LoadIcon(OLEPictureImpl *This, BYTE *xbuf, ULONG x
 	}
 	if (i==cifd->idCount) i=0;
     }
+    if (xread < cifd->idEntries[i].dwDIBOffset + cifd->idEntries[i].dwDIBSize)
+    {
+        ERR("Icon data address %u is over %u bytes available.\n",
+            cifd->idEntries[i].dwDIBOffset + cifd->idEntries[i].dwDIBSize, xread);
+        return E_FAIL;
+    }
     if (cifd->idType == 2)
     {
         LPBYTE buf = HeapAlloc(GetProcessHeap(), 0, cifd->idEntries[i].dwDIBSize + 4);