[PATCH V33 11/30] uswsusp: Disable when the kernel is locked down

[Matthew Garrett]

From: Matthew Garrett <mjg59@xxxxxxxxxxxxx>

uswsusp allows a user process to dump and then restore kernel state, which
makes it possible to modify the running kernel.  Disable this if the kernel
is locked down.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx>
cc: linux-pm@xxxxxxxxxxxxxxx
Cc: pavel@xxxxxx
Cc: rjw@xxxxxxxxxxxxx
---
 kernel/power/user.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 2d8b60a3c86b..8a8d7f1c8fbb 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 <linux/uaccess.h>
 
@@ -52,6 +53,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	if (!hibernation_available())
 		return -EPERM;
 
+	if (security_is_locked_down(LOCKDOWN_HIBERNATION))
+		return -EPERM;
+
 	lock_system_sleep();
 
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
-- 
2.22.0.410.gd8fdbe21b5-goog