BACKPORT: lockdown: Allow unprivileged users to see lockdown status

A number of userspace tools, such as systemtap, need a way to see the
current lockdown state so they can gracefully deal with the kernel being
locked down. The state is already exposed in
/sys/kernel/security/lockdown, but is only readable by root. Adjust the
permissions so unprivileged users can read the state.

Fixes: 000d388ed3bb ("security: Add a static lockdown policy LSM")
Cc: Frank Ch. Eigler <fche@redhat.com>
Change-Id: I9eb77e97933780ec1e5f1656e135c171deccd8e7
Signed-off-by: Jeremy Cline <jcline@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/lockdown/lockdown.c

@@ -153,7 +153,7 @@ static int __init lockdown_secfs_init(void)
 {
 	struct dentry *dentry;
 
-	dentry = securityfs_create_file("lockdown", 0600, NULL, NULL,
+	dentry = securityfs_create_file("lockdown", 0644, NULL, NULL,
 					&lockdown_ops);
 	return PTR_ERR_OR_ZERO(dentry);
 }