[PATCH 08/24] uswsusp: Disable when the kernel is locked down

From: David Howells
Date: Wed Apr 11 2018 - 12:25:40 EST


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: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Reviewed-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
Reviewed-by: James Morris <james.l.morris@xxxxxxxxxx>
cc: linux-pm@xxxxxxxxxxxxxxx
---

kernel/power/user.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 75c959de4b29..959b336d8eca 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -52,6 +52,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
if (!hibernation_available())
return -EPERM;

+ if (kernel_is_locked_down("/dev/snapshot"))
+ return -EPERM;
+
lock_system_sleep();

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