From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Mon, 9 Sep 2013 22:49:45 +0000 (-0700)
Subject: asus-wmi: Restrict debugfs interface when securelevel is set
X-Git-Tag: v4.1.12-92~310^2~4
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=16f61bd6608338962a768c4dbacd764843223ddc;p=users%2Fjedix%2Flinux-maple.git

asus-wmi: Restrict debugfs interface when securelevel is set

Orabug: 21539498

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. Prevent that if securelevel is set.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
---

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 7543a56e0f45..08d54b499e82 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -45,6 +45,7 @@
 #include <linux/seq_file.h>
 #include <linux/platform_device.h>
 #include <linux/thermal.h>
+#include <linux/security.h>
 #include <linux/acpi.h>
 #include <linux/dmi.h>
 #include <acpi/video.h>
@@ -1589,6 +1590,9 @@ static int show_dsts(struct seq_file *m, void *data)
 	int err;
 	u32 retval = -1;
 
+	if (get_securelevel() > 0)
+		return -EPERM;
+
 	err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval);
 
 	if (err < 0)
@@ -1605,6 +1609,9 @@ static int show_devs(struct seq_file *m, void *data)
 	int err;
 	u32 retval = -1;
 
+	if (get_securelevel() > 0)
+		return -EPERM;
+
 	err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param,
 				    &retval);
 
@@ -1629,6 +1636,9 @@ static int show_call(struct seq_file *m, void *data)
 	union acpi_object *obj;
 	acpi_status status;
 
+	if (get_securelevel() > 0)
+		return -EPERM;
+
 	status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID,
 				     1, asus->debug.method_id,
 				     &input, &output);