[PATCH 09/12] uswsusp: Disable when securelevel is set

Matthew Garrett
2013-09-09T15:54:30Z

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 <matthew.garrett@nebula.com>
---
kernel/power/user.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 4ed81e7..520a9c4 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>

@@ -48,6 +49,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
struct snapshot_data *data;
int error;

+ if (get_securelevel() > 0)
+ return -EPERM;
+
lock_system_sleep();

if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
--
1.8.3.1