[PATCH resend] dix: Reinstate GetImage window size check

[Jeremy Huddleston]

Reviewed-by: Jeremy Huddleston <jeremyhu at apple.com>

On Oct 27, 2011, at 22:07, Aaron Plattner wrote:

> Commit 587c3a2d1961834558193e8e14e8e381a077a253 fixed DoGetImage to
> check windows against their backing drawables, rather than against the
> screen dimensions, to prevent reading outside the bounds of redirected
> windows' backing pixmaps (see bug #22804).  Unfortunately, while
> making that change I also removed the check that the rectangle is
> contained within the bounds of the source window, which is a violation
> of the specification:
> 
>    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 Match error results). Note that the
>    borders of the window can be included and read with this request.
> 
>    (emphasis mine)
> 
> Reinstate the window dimension check, to return BadMatch if the
> GetImage request falls outside the bounds of the window.
> 
> Fixes X Test Suite test XGetImage-15:
> 
>    400|0 15 1 11:05:41|IC Start
>    200|0 15 11:05:41|TP Start
>    520|0 15 00005146 1 1|VSW5TESTSUITE PURPOSE 15
>    520|0 15 00005146 1 2|Assertion XGetImage-15.(A)
>    520|0 15 00005146 1 3|When the drawable is a window and the window is viewable
>    520|0 15 00005146 1 4|and it is not the case that given there were no inferiors or
>    520|0 15 00005146 1 5|overlapping windows the specified rectangle of the window
>    520|0 15 00005146 1 6|would be fully visible on the screen and wholly contained
>    520|0 15 00005146 1 7|within the outside edges of the window, then a BadMatch
>    520|0 15 00005146 1 8|error occurs.
>    520|0 15 00005146 1 9|METH: Create window which is not fully visible on the screen.
>    520|0 15 00005146 1 10|METH: Call XMapWindow to make sure the window is viewable.
>    520|0 15 00005146 1 11|METH: Call XGetImage with rectangle extending beyond edge of screen.
>    520|0 15 00005146 1 12|METH: Verify XGetImage return value is null.
>    520|0 15 00005146 1 13|METH: Verify that BadMatch error occurred.
>    520|0 15 00005146 1 14|METH: Create window which is fully visible on the screen.
>    520|0 15 00005146 1 15|METH: Call XMapWindow to make sure the window is viewable.
>    520|0 15 00005146 1 16|METH: Call XGetImage with rectangle extending beyond edge of window.
>    520|0 15 00005146 1 17|METH: Verify XGetImage return value is null.
>    520|0 15 00005146 1 18|METH: Verify that BadMatch error occurred.
>    520|0 15 00005146 1 19|REPORT: Got Success, Expecting BadMatch
>    520|0 15 00005146 1 20|REPORT: Null image not returned.
>    220|0 15 1 11:05:41|FAIL
> 
> Signed-off-by: Aaron Plattner <aplattner at nvidia.com>
> ---
> This change has been sitting on my queue for a while.  It should be pretty easy
> to review.
> 
> dix/dispatch.c |    8 ++++++++
> 1 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/dix/dispatch.c b/dix/dispatch.c
> index 43cb4d1..2b6cb82 100644
> --- a/dix/dispatch.c
> +++ b/dix/dispatch.c
> @@ -2029,6 +2029,14 @@ DoGetImage(ClientPtr client, int format, Drawable drawable,
> 	if (!pWin->viewable)
> 	    return BadMatch;
> 
> +	/* If the drawable is a window, the rectangle must be contained within
> +	 * its bounds (including the border). */
> +	if (x < -wBorderWidth(pWin) ||
> +	    x + width > wBorderWidth(pWin) + (int)pDraw->width ||
> +	    y < -wBorderWidth(pWin) ||
> +	    y + height > wBorderWidth(pWin) + (int)pDraw->height)
> +	    return BadMatch;
> +
> 	relx += pDraw->x;
> 	rely += pDraw->y;
> 
> -- 
> 1.7.5.4
> 
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