From bfa10bc7193d6309dc8029e18fe7d844f9a3a1c0 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Wed, 5 Apr 2017 17:40:30 +0100
Subject: [PATCH 53/62] asus-wmi: Restrict debugfs interface when the kernel is
 locked down
Patch-mainline: No, submitted

References: fate#314486

We have no way of validating what all of the Asus WMI methods do on a given
machine - and there's a risk that some will allow hardware state to be
manipulated in such a way that arbitrary code can be executed in the
kernel, circumventing module loading restrictions.  Prevent that if the
kernel is locked down.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/platform/x86/asus-wmi.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -1914,6 +1914,9 @@ static int show_dsts(struct seq_file *m,
 	int err;
 	u32 retval = -1;
 
+	if (kernel_is_locked_down())
+		return -EPERM;
+
 	err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval);
 
 	if (err < 0)
@@ -1930,6 +1933,9 @@ static int show_devs(struct seq_file *m,
 	int err;
 	u32 retval = -1;
 
+	if (kernel_is_locked_down())
+		return -EPERM;
+
 	err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param,
 				    &retval);
 
@@ -1954,6 +1960,9 @@ static int show_call(struct seq_file *m,
 	union acpi_object *obj;
 	acpi_status status;
 
+	if (kernel_is_locked_down())
+		return -EPERM;
+
 	status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID,
 				     0, asus->debug.method_id,
 				     &input, &output);