From 061eb684996627347acdf87ec11d108cedee71b6 Mon Sep 17 00:00:00 2001 From: Peter Hutterer Date: Thu, 21 Dec 2023 13:48:10 +1000 Subject: [PATCH xserver] Xi: when creating a new ButtonClass, set the number of buttons There's a racy sequence where a master device may copy the button class from the slave, without ever initializing numButtons. This leads to a device with zero buttons but a button class which is invalid. Let's copy the numButtons value from the source - by definition if we don't have a button class yet we do not have any other slave devices with more than this number of buttons anyway. CVE-2024-0229, ZDI-CAN-22678 This vulnerability was discovered by: Jan-Niklas Sohn working with Trend Micro Zero Day Initiative --- Xi/exevents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/Xi/exevents.c b/Xi/exevents.c index 54ea11a938..e161714682 100644 --- a/Xi/exevents.c +++ b/Xi/exevents.c @@ -605,6 +605,7 @@ DeepCopyPointerClasses(DeviceIntPtr from, DeviceIntPtr to) to->button = calloc(1, sizeof(ButtonClassRec)); if (!to->button) FatalError("[Xi] no memory for class shift.\n"); + to->button->numButtons = from->button->numButtons; } else classes->button = NULL; -- 2.43.0