[PATCH V31 09/25] uswsusp: Disable when the kernel is locked down

Matthew Garrett matthewgarrett at google.com
Tue Mar 26 18:27:25 UTC 2019

From: Matthew Garrett <mjg59 at srcf.ucam.org>

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 at redhat.com>
Signed-off-by: Matthew Garrett <mjg59 at google.com>
cc: linux-pm at vger.kernel.org
Cc: pavel at ucw.cz
Cc: rjw at rjwysocki.net
 kernel/power/user.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 2d8b60a3c86b..99e13fd13237 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", LOCKDOWN_INTEGRITY))
+		return -EPERM;
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {

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