[PATCH 02/27] Add a SysRq option to lift kernel lockdown
From: Thiago Jung Bauermann <hidden>
Date: 2017-11-07 17:39:18
Also in:
linux-efi, lkml
Hello David, David Howells [off-list ref] writes:
+static struct sysrq_key_op lockdown_lift_sysrq_op = {
+ .handler = sysrq_handle_lockdown_lift,
+ .help_msg = "unSB(x)",
+ .action_msg = "Disabling Secure Boot restrictions",
+ .enable_mask = SYSRQ_DISABLE_USERSPACE,
+};
+
+static int __init lockdown_lift_sysrq(void)
+{
+ if (kernel_locked_down) {
+ lockdown_lift_sysrq_op.help_msg[5] = LOCKDOWN_LIFT_KEY;
+ register_sysrq_key(LOCKDOWN_LIFT_KEY, &lockdown_lift_sysrq_op);
+ }
+ return 0;
+}
+
+late_initcall(lockdown_lift_sysrq);
+
+#endif /* CONFIG_ALLOW_LOCKDOWN_LIFT_BY_KEY */
On non-x86 platforms (tested on powerpc) this fails to build with:
security/lock_down.c: In function ?lockdown_lift_sysrq?:
security/lock_down.c:100:40: error: ?LOCKDOWN_LIFT_KEY? undeclared (first use in this function)
lockdown_lift_sysrq_op.help_msg[5] = LOCKDOWN_LIFT_KEY;
^~~~~~~~~~~~~~~~~
security/lock_down.c:100:40: note: each undeclared identifier is reported only once for each function it appears in
--
Thiago Jung Bauermann
IBM Linux Technology Center
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