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/Documentation/acpi/method-customizing.txt b/Documentation/acpi/method-customizing.txt
index 3e1d25a..5f55373 100644
--- a/Documentation/acpi/method-customizing.txt
+++ b/Documentation/acpi/method-customizing.txt
@@ -66,3 +66,8 @@
But each individual write to debugfs can implement a SINGLE
method override. i.e. if we want to insert/override multiple
ACPI methods, we need to redo step c) ~ g) for multiple times.
+
+Note: Be aware that root can mis-use this driver to modify arbitrary
+ memory and gain additional rights, if root's privileges got
+ restricted (for example if root is not allowed to load additional
+ modules after boot).