From: Matthew Garrett <mjg59@srcf.ucam.org>
Date: Wed, 5 Apr 2017 16:40:30 +0000 (+0100)
Subject: uswsusp: Disable when the kernel is locked down
X-Git-Tag: archive/raspbian/4.15.4-1+rpi1~1^2^2^2~49
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=7bbcf420ddf5ffe19ca2f631def4f7a682882e83;p=linux.git

uswsusp: Disable when the kernel is locked down

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@srcf.ucam.org>
Signed-off-by: David Howells <dhowells@redhat.com>

Gbp-Pq: Topic features/all/lockdown
Gbp-Pq: Name 0048-uswsusp-Disable-when-the-kernel-is-locked-down.patch
---

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 22df9f7ff67..e4b926d329b 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())
+		return -EPERM;
+
 	lock_system_sleep();
 
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {