ACPI: Split out custom_method functionality into an own driver
With /sys/kernel/debug/acpi/custom_method root can write
to arbitrary memory and increase his priveleges, even if
these are restricted.
-> Make this an own debug .config option and warn about the
security issue in the config description.
-> Still keep acpi/debugfs.c which now only creates an empty
/sys/kernel/debug/acpi directory. There might be other
users of it later.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: rui.zhang@intel.com
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 3a17ca5..d918e13 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -380,6 +380,21 @@
which is used to report some hardware errors notified via
SCI, mainly the corrected errors.
+config ACPI_CUSTOM_METHOD
+ tristate "Allow ACPI methods to be inserted/replaced at run time"
+ depends on DEBUG_FS
+ default n
+ help
+ This debug facility allows ACPI AML methods to me inserted and/or
+ replaced without rebooting the system. For details refer to:
+ Documentation/acpi/method-customizing.txt.
+
+ NOTE: This option is security sensitive, because it allows arbitrary
+ kernel memory to be written to by root (uid=0) users, allowing them
+ to bypass certain security measures (e.g. if root is not allowed to
+ load additional kernel modules after boot, this feature may be used
+ to override that restriction).
+
source "drivers/acpi/apei/Kconfig"
endif # ACPI