Introduced in xorg-server-1.13.99.901-2-g9ad0fdb. Storing the grab pointer in the listener turns out to be a bad idea. If the grab is not an active grab or an implicit grab, the pointer stored is the one to the grab attached on the window. This grab may be removed if the client calls UngrabButton or similar while the touch is still active, leaving a dangling pointer.
To avoid this, copy the grab wherever we need to reference it later. This is also what we do for pointer/keyboard grabs, where we copy the grab as soon as it becomes active. Reported-by: Maarten Lankhorst <maarten.lankho...@canonical.com> Signed-off-by: Peter Hutterer <peter.hutte...@who-t.net> --- Xi/exevents.c | 7 +++++-- dix/events.c | 3 ++- dix/touch.c | 19 +++++++++++++++++-- 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/Xi/exevents.c b/Xi/exevents.c index 2feddd3..ae2e5ae 100644 --- a/Xi/exevents.c +++ b/Xi/exevents.c @@ -1429,8 +1429,11 @@ DeliverTouchEmulatedEvent(DeviceIntPtr dev, TouchPointInfoPtr ti, */ if (!devgrab && dev->deviceGrab.grab && dev->deviceGrab.implicitGrab) { TouchListener *l; + GrabPtr g; devgrab = dev->deviceGrab.grab; + g = AllocGrab(devgrab); + BUG_WARN(!g); *dev->deviceGrab.sync.event = ev->device_event; @@ -1439,8 +1442,8 @@ DeliverTouchEmulatedEvent(DeviceIntPtr dev, TouchPointInfoPtr ti, * event selection. Thus, we update the last listener in the array. */ l = &ti->listeners[ti->num_listeners - 1]; - l->listener = devgrab->resource; - l->grab = devgrab; + l->listener = g->resource; + l->grab = g; //l->resource_type = RT_NONE; if (devgrab->grabtype != XI2 || devgrab->type != XI_TouchBegin) diff --git a/dix/events.c b/dix/events.c index cd2d939..76bc555 100644 --- a/dix/events.c +++ b/dix/events.c @@ -1442,7 +1442,8 @@ UpdateTouchesForGrab(DeviceIntPtr mouse) listener->type = LISTENER_POINTER_GRAB; else listener->type = LISTENER_GRAB; - listener->grab = grab; + FreeGrab(listener->grab); + listener->grab = AllocGrab(grab); } } } diff --git a/dix/touch.c b/dix/touch.c index 01a554e..fb218d4 100644 --- a/dix/touch.c +++ b/dix/touch.c @@ -365,6 +365,8 @@ TouchBeginTouch(DeviceIntPtr dev, int sourceid, uint32_t touchid, void TouchEndTouch(DeviceIntPtr dev, TouchPointInfoPtr ti) { + int i; + if (ti->emulate_pointer) { GrabPtr grab; @@ -376,6 +378,9 @@ TouchEndTouch(DeviceIntPtr dev, TouchPointInfoPtr ti) } } + for (i = 0; i < ti->num_listeners; i++) + TouchRemoveListener(ti, ti->listeners[0].listener); + ti->active = FALSE; ti->pending_finish = FALSE; ti->sprite.spriteTraceGood = 0; @@ -692,15 +697,23 @@ void TouchAddListener(TouchPointInfoPtr ti, XID resource, int resource_type, enum InputLevel level, enum TouchListenerType type, enum TouchListenerState state, WindowPtr window, - GrabPtr grab) + const GrabPtr grab) { + GrabPtr g = NULL; + + /* We need a copy of the grab, not the grab itself since that may be + * deleted by a UngrabButton request and leaves us with a dangling + * pointer */ + if (grab) + g = AllocGrab(grab); + ti->listeners[ti->num_listeners].listener = resource; ti->listeners[ti->num_listeners].resource_type = resource_type; ti->listeners[ti->num_listeners].level = level; ti->listeners[ti->num_listeners].state = state; ti->listeners[ti->num_listeners].type = type; ti->listeners[ti->num_listeners].window = window; - ti->listeners[ti->num_listeners].grab = grab; + ti->listeners[ti->num_listeners].grab = g; if (grab) ti->num_grabs++; ti->num_listeners++; @@ -725,6 +738,7 @@ TouchRemoveListener(TouchPointInfoPtr ti, XID resource) continue; if (listener->grab) { + FreeGrab(listener->grab); listener->grab = NULL; ti->num_grabs--; } @@ -734,6 +748,7 @@ TouchRemoveListener(TouchPointInfoPtr ti, XID resource) ti->num_listeners--; ti->listeners[ti->num_listeners].listener = 0; ti->listeners[ti->num_listeners].state = LISTENER_AWAITING_BEGIN; + return TRUE; } return FALSE; -- 1.8.1.4 _______________________________________________ xorg-devel@lists.x.org: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel