[PATCH 1.9.2.902 1/1] dix: GetPointerEvents: added valuator range checking
Peter Hutterer
peter.hutterer at who-t.net
Mon Jan 24 16:34:33 PST 2011
On Mon, Jan 24, 2011 at 10:03:30PM +0200, Oliver McFadden wrote:
> Button events may be sent with no valuators (e.g. to simply indicate
> ButtonPress or ButtonRelease without any coordinates); when this happens
> the server would read uninitialized memory.
>
> ==9999== Conditional jump or move depends on uninitialised value(s)
> ==9999== at 0x48E87E8: pixman_f_transform_point (in /usr/lib/libpixman-1.so.0.18.2)
> ==9999== Uninitialised value was created by a stack allocation
> ==9999== at 0x37524: GetPointerEvents (getevents.c:1074)
> ==9999==
> ==9999== Conditional jump or move depends on uninitialised value(s)
> ==9999== at 0x496D074: lround (s_lround.c:40)
> ==9999== by 0x3773B: GetPointerEvents (getevents.c:1048)
> ==9999== by 0x683BB: xf86PostButtonEventP (xf86Xinput.c:1162)
> ==9999== by 0x6853B: xf86PostButtonEvent (xf86Xinput.c:1126)
> ==9999== by 0x5779037: process_state (multitouch.c:321) (xf86-input-mtev)
> ==9999== by 0x577908F: read_input (multitouch.c:331)) (xf86-input-mtev)
> ==9999== by 0x66B4F: xf86SigioReadInput (xf86Events.c:298)
> ==9999== by 0x112697: xf86SIGIO (sigio.c:118)
> ==9999== by 0x4A12B2F: ??? (sigrestorer.S:51)
> ==9999== Uninitialised value was created by a stack allocation
> ==9999== at 0x37524: GetPointerEvents (getevents.c:1074)
>
> Signed-off-by: Oliver McFadden <oliver.mcfadden at nokia.com>
Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>
Jeremy, feel free to pick this up
Cheers,
Peter
> ---
> I'm not sure anyone actually cares about this patch anymore, since this code has
> changed completely due to the valuator rework. If someone wants to apply it to
> the 1.9.2(.xxx) branches, then please be my guest.
>
> dix/getevents.c | 18 ++++++++++--------
> 1 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/dix/getevents.c b/dix/getevents.c
> index e5134d3..f1e5514 100644
> --- a/dix/getevents.c
> +++ b/dix/getevents.c
> @@ -1034,19 +1034,21 @@ FreeEventList(EventListPtr list, int num_events)
> }
>
> static void
> -transformAbsolute(DeviceIntPtr dev, int v[MAX_VALUATORS])
> +transformAbsolute(DeviceIntPtr dev, int first, int num, int *valuators)
> {
> - struct pixman_f_vector p;
> + struct pixman_f_vector p = { .v = {0.0, 0.0, 1.0} };
>
> /* p' = M * p in homogeneous coordinates */
> - p.v[0] = v[0];
> - p.v[1] = v[1];
> - p.v[2] = 1.0;
> + if (num >= 1 && first == 0)
> + p.v[0] = *(valuators + 0);
> +
> + if (first <= 1 && num >= (2 - first))
> + p.v[1] = *(valuators + 1 - first);
>
> pixman_f_transform_point(&dev->transform, &p);
>
> - v[0] = lround(p.v[0]);
> - v[1] = lround(p.v[1]);
> + valuators[0] = lround(p.v[0]);
> + valuators[1] = lround(p.v[1]);
> }
>
> /**
> @@ -1124,7 +1126,7 @@ GetPointerEvents(EventList *events, DeviceIntPtr pDev, int type, int buttons,
> scr->height);
> }
>
> - transformAbsolute(pDev, valuators);
> + transformAbsolute(pDev, first_valuator, num_valuators, valuators);
> moveAbsolute(pDev, &x, &y, first_valuator, num_valuators, valuators);
> } else {
> if (flags & POINTER_ACCELERATE) {
> --
> 1.7.1.245.g7c42e
>
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