Re: [PATCH v2] red-parse-qxl: Check consistency of QXL_DRAW_COPY operations

[Frediano Ziglio <fziglio@xxxxxxxxxx>]

> On Fri, 27 May 2016, Frediano Ziglio wrote:
> 
> > > 
> > > The source area should not extend outside the source bitmap, or have
> > > swapped coordinates.
> > > 
> > > Signed-off-by: Francois Gouget <fgouget@xxxxxxxxxxxxxxx>
> > > ---
> > >  server/red-parse-qxl.c | 12 ++++++++++++
> > >  1 file changed, 12 insertions(+)
> > > 
> > 
> > I checked and if this function return error the resource is correctly
> > released.
> 
> Yes. So the original patch was correct.
> 
> 
> > > +        (red->src_area.left < 0 ||
> > > +         red->src_area.left > red->src_area.right ||
> > > +         red->src_area.right > red->src_bitmap->u.bitmap.x ||
> > > +         red->src_area.top < 0 || red->src_area.top >
> > > red->src_area.bottom
> > > ||
> > > +         red->src_area.bottom > red->src_bitmap->u.bitmap.y)) {
> > > +        red_put_image(red->src_bitmap);
> > 
> > Mm... this make me think you didn't test the code.. this cause
> > a double free in the current code
> 
> I tested the original patch but I failed to retest the error condition
> after adding the red_put_image() call. I have now done that, found the
> double free, and so I recommend going back to the original patch.
> 

Can I suggest 

@@ -682,6 +682,20 @@ static int red_get_copy_ptr(RedMemSlotInfo *slots, int group_id,
         return 1;
     }
     red_get_rect_ptr(&red->src_area, &qxl->src_area);
+    /* The source area should not extend outside the source bitmap or have
+     * swapped coordinates.
+     */
+    if (red->src_area.left < 0 ||
+        red->src_area.left > red->src_area.right ||
+        red->src_area.top < 0 ||
+        red->src_area.top > red->src_area.bottom) {
+        return 1;
+    }
+    if (red->src_bitmap->descriptor.type == SPICE_IMAGE_TYPE_BITMAP &&
+        (red->src_area.right > red->src_bitmap->u.bitmap.x ||
+         red->src_area.bottom > red->src_bitmap->u.bitmap.y)) {
+        return 1;
+    }
     red->rop_descriptor  = qxl->rop_descriptor;
     red->scale_mode      = qxl->scale_mode;
     red_get_qmask_ptr(slots, group_id, &red->mask, &qxl->mask, flags);

?

Frediano
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