From: Matthew Garrett <mjg59@srcf.ucam.org>
Date: Tue, 3 Sep 2013 11:23:29 -0400
Subject: [09/18] uswsusp: Disable when securelevel is set
Origin: https://github.com/mjg59/linux/commit/504f45f7cc9b4265a4d89728c4f8254295e81977

uswsusp allows a user process to dump and then restore kernel state, which
makes it possible to modify the running kernel. Disable this if securelevel
has been set.

Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org>
---
 kernel/power/user.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 526e8911460a..40618bf41620 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -24,6 +24,7 @@
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/security.h>
 
 #include <asm/uaccess.h>
 
@@ -52,6 +53,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	if (!hibernation_available())
 		return -EPERM;
 
+	if (get_securelevel() > 0)
+		return -EPERM;
+
 	lock_system_sleep();
 
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
