[PATCH 01/24] Add the ability to lock down access to the running kernel image
rdunlap at infradead.org
Wed Apr 11 17:37:38 UTC 2018
On 04/11/2018 09:24 AM, David Howells wrote:
> arch/x86/kernel/setup.c | 2 +
> include/linux/kernel.h | 32 +++++++++++++++++++++++
> security/Kconfig | 23 ++++++++++++++++-
> security/Makefile | 3 ++
> security/lock_down.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 124 insertions(+), 1 deletion(-)
> create mode 100644 security/lock_down.c
> diff --git a/security/Kconfig b/security/Kconfig
> index c4302067a3ad..a68e5bdebad5 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -231,6 +231,28 @@ config STATIC_USERMODEHELPER_PATH
> If you wish for all usermode helper programs to be disabled,
> specify an empty string here (i.e. "").
> +config LOCK_DOWN_KERNEL
> + bool "Allow the kernel to be 'locked down'"
> + help
> + Allow the kernel to be locked down. Locking down the kernel turns
> + off various features that might otherwise allow access to the kernel
> + image (eg. setting MSR registers).
> + Note, however, that locking down your kernel will prevent some
> + drivers from functioning because allowing manual configuration of
> + hardware parameters is forbidden, lest a device be used to access the
> + kernel by DMA. This mostly applies to ISA devices.
Is DMA from non-ISA devices OK, or did I miss seeing that patch?
> + The kernel lockdown can be triggered by adding lockdown=1 to the
> + kernel command line.
> diff --git a/security/lock_down.c b/security/lock_down.c
> new file mode 100644
> index 000000000000..f35ffdd096ad
> --- /dev/null
> +++ b/security/lock_down.c
> @@ -0,0 +1,65 @@
> +/* Lock down the kernel
> + *
> + * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
> + * Written by David Howells (dhowells at redhat.com)
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public Licence
> + * as published by the Free Software Foundation; either version
> + * 2 of the Licence, or (at your option) any later version.
fsf.org spells that Licence word as License. :)
> + */
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