diff options
| author | Olivier Fourdan <ofourdan@redhat.com> | 2017-12-05 09:59:06 +0100 |
|---|---|---|
| committer | Adam Jackson <ajax@redhat.com> | 2017-12-13 10:09:11 -0500 |
| commit | 072dff82817bc02bb4bdb2dad594e6090586bf58 (patch) | |
| tree | 0927841e7fa3189c17bb69ed981ce23fd06f0a35 | |
| parent | f9a55653721980e3921083015ffb39f777606828 (diff) | |
dix: avoid deferencing NULL PtrCtrl
PtrCtrl really makes sense for relative pointing device only, absolute
devices such as touch devices do not have any PtrCtrl set.
In some cases, if the client issues a XGetPointerControl() immediatlely
after a ChangeMasterDeviceClasses() copied the touch device to the VCP,
a NULL pointer dereference will occur leading to a crash of Xwayland.
Check whether the PtrCtrl is not NULL in ProcGetPointerControl() and
return the default control values otherwise, to avoid the NULL pointer
dereference.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1519533
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
(cherry picked from commit 9f7a9be13d6449c00c86d3035374f4f543654b3f)
| -rw-r--r-- | dix/devices.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/dix/devices.c b/dix/devices.c index ea3c6c8a9..4a628afb0 100644 --- a/dix/devices.c +++ b/dix/devices.c @@ -2329,10 +2329,15 @@ int ProcGetPointerControl(ClientPtr client) { DeviceIntPtr ptr = PickPointer(client); - PtrCtrl *ctrl = &ptr->ptrfeed->ctrl; + PtrCtrl *ctrl; xGetPointerControlReply rep; int rc; + if (ptr->ptrfeed) + ctrl = &ptr->ptrfeed->ctrl; + else + ctrl = &defaultPointerControl; + REQUEST_SIZE_MATCH(xReq); rc = XaceHook(XACE_DEVICE_ACCESS, client, ptr, DixGetAttrAccess); |