From 1b0d63f15fb79d0cb840f8b701f343548b5640e8 Mon Sep 17 00:00:00 2001 From: Henrique de Moraes Holschuh Date: Thu, 25 Feb 2010 22:22:22 -0300 Subject: thinkpad-acpi: lock down video output state access commit b525c06cdbd8a3963f0173ccd23f9147d4c384b5 upstream. Given the right combination of ThinkPad and X.org, just reading the video output control state is enough to hard-crash X.org. Until the day I somehow find out a model or BIOS cut date to not provide this feature to ThinkPads that can do video switching through X RandR, change permissions so that only processes with CAP_SYS_ADMIN can access any sort of video output control state. This bug could be considered a local DoS I suppose, as it allows any non-privledged local user to cause some versions of X.org to hard-crash some ThinkPads. Reported-by: Jidanni Signed-off-by: Henrique de Moraes Holschuh Signed-off-by: Greg Kroah-Hartman --- drivers/platform/x86/Kconfig | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'drivers/platform/x86/Kconfig') diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 55ca39dea42e..6e2a4ca4162e 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -291,9 +291,15 @@ config THINKPAD_ACPI_VIDEO server running, phase of the moon, and the current mood of Schroedinger's cat. If you can use X.org's RandR to control your ThinkPad's video output ports instead of this feature, - don't think twice: do it and say N here to save some memory. + don't think twice: do it and say N here to save memory and avoid + bad interactions with X.org. - If you are not sure, say Y here. + NOTE: access to this feature is limited to processes with the + CAP_SYS_ADMIN capability, to avoid local DoS issues in platforms + where it interacts badly with X.org. + + If you are not sure, say Y here but do try to check if you could + be using X.org RandR instead. config THINKPAD_ACPI_HOTKEY_POLL bool "Support NVRAM polling for hot keys" -- cgit v1.2.3