[PATCH] Bug #22804: Reject out of bounds XGetImage requests

[Keith Packard]

On Fri, 2009-07-17 at 10:51 -0700, Aaron Plattner wrote:
> The XGetImage man page states:
> 
>     If the drawable is a window, the window must be viewable, and it must be the
>     case that if there were no inferiors or overlapping windows, the specified
>     rectangle of the window would be fully visible on the screen and wholly
>     contained within the outside edges of the window, or a BadMatch error
>     results.  Note that the borders of the window can be included and read with
>     this request.

How about leaving the semantics as similar as we can; clip GetImage to
the pixmap containing the window (GetWindowPixmap)? That means that in
the absence of compositing, you get the same result as before.

'visible on the screen' could easily be interpreted to mean 'contained
within the frame buffer holding the window' here, and clearly was in the
existing implementation.

-- 
keith.packard at intel.com
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