From: Jann Horn <jannh@google.com>
To: David Howells <dhowells@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-man <linux-man@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
James Morris <jmorris@namei.org>,
kernel list <linux-kernel@vger.kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH 01/24] Add the ability to lock down access to the running kernel image
Date: Wed, 11 Apr 2018 18:44:54 +0200 [thread overview]
Message-ID: <CAG48ez3U3pf4O8Yc1y-+T=Dcc-N-KP0Zd_1GS44p--zxockJ1Q@mail.gmail.com> (raw)
In-Reply-To: <152346388583.4030.15146667041427303547.stgit@warthog.procyon.org.uk>
On Wed, Apr 11, 2018 at 6:24 PM, David Howells <dhowells@redhat.com> wrote:
> Provide a single call to allow kernel code to determine whether the system
> should be locked down, thereby disallowing various accesses that might
> allow the running kernel image to be changed, including:
>
> - /dev/mem and similar
> - Loading of unauthorised modules
> - Fiddling with MSR registers
> - Suspend to disk managed by the kernel
> - Use of device DMA
>
> Two kernel configuration options are provided:
>
> (*) CONFIG_LOCK_DOWN_KERNEL
>
> This makes lockdown available and applies it to all the points that
> need to be locked down if the mode is set. Lockdown mode can be
> enabled by providing:
>
> lockdown=1
>
> on the command line.
>
> (*) CONFIG_LOCK_DOWN_MANDATORY
>
> This forces lockdown on at compile time, overriding the command line
> option.
>
> init_lockdown() is used as a hook from which lockdown can be managed in
> future. It has to be called from arch setup code before things like ACPI
> are enabled.
>
> Note that, with the other changes in this series, if lockdown mode is
> enabled, the kernel will not be able to use certain drivers as the ability
> to manually configure hardware parameters would then be prohibited. This
> primarily applies to ISA hardware devices.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
[...]
> 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
[...]
> +/*
> + * Lock the kernel down from very early in the arch setup. This must happen
> + * prior to things like ACPI being initialised.
> + */
Pedantic nit: I think this comment is wrong now? This function
actually just prints stuff.
> +void __init init_lockdown(void)
> +{
> +#ifdef CONFIG_LOCK_DOWN_MANDATORY
> + pr_notice("Kernel is locked down from config; see man kernel_lockdown.7\n");
> +#endif
> +}
next prev parent reply other threads:[~2018-04-11 16:45 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-11 16:24 [PATCH 00/24] security: Add kernel lockdown David Howells
2018-04-11 16:24 ` [PATCH 01/24] Add the ability to lock down access to the running kernel image David Howells
2018-04-11 16:44 ` Jann Horn [this message]
2018-04-11 17:37 ` Randy Dunlap
2018-04-11 18:50 ` Miguel Ojeda
2018-04-11 19:56 ` Greg KH
2018-04-11 17:49 ` David Howells
2018-04-11 18:09 ` Linus Torvalds
2018-04-11 18:35 ` Justin Forbes
2018-04-11 21:05 ` Jordan Glover
2018-04-11 22:38 ` Linus Torvalds
2018-04-12 13:09 ` Justin Forbes
2018-04-12 16:52 ` Linus Torvalds
2018-04-12 2:57 ` Andy Lutomirski
2018-04-11 16:24 ` [PATCH 02/24] Add a SysRq option to lift kernel lockdown David Howells
2018-04-11 17:05 ` Jann Horn
2018-04-13 20:22 ` Pavel Machek
2018-04-11 16:24 ` [PATCH 03/24] ima: require secure_boot rules in lockdown mode David Howells
2018-04-11 16:25 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells
2018-04-11 16:25 ` [PATCH 05/24] Restrict /dev/{mem, kmem, port} when " David Howells
2018-04-11 16:25 ` [PATCH 06/24] kexec_load: Disable at runtime if " David Howells
2018-04-11 19:00 ` Eric W. Biederman
2018-04-11 20:09 ` Mimi Zohar
2018-04-12 11:38 ` Mimi Zohar
2018-04-11 20:05 ` David Howells
2018-04-11 16:25 ` [PATCH 07/24] hibernate: Disable when " David Howells
2018-04-13 20:22 ` Pavel Machek
2018-04-19 14:38 ` David Howells
2018-04-22 14:34 ` Andy Lutomirski
2018-04-26 7:26 ` Pavel Machek
2018-04-26 7:34 ` Rafael J. Wysocki
2018-04-26 8:20 ` Jiri Kosina
2018-05-23 8:46 ` joeyli
2018-04-11 16:25 ` [PATCH 08/24] uswsusp: " David Howells
2018-04-11 16:25 ` [PATCH 09/24] PCI: Lock down BAR access " David Howells
2018-04-11 16:25 ` [PATCH 10/24] x86: Lock down IO port " David Howells
2018-04-11 16:25 ` [PATCH 11/24] x86/msr: Restrict MSR " David Howells
2018-04-11 16:25 ` [PATCH 12/24] ACPI: Limit access to custom_method " David Howells
2018-04-11 16:26 ` [PATCH 13/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2018-04-11 16:26 ` [PATCH 14/24] acpi: Disable ACPI table override if the kernel is " David Howells
2018-04-11 16:26 ` [PATCH 15/24] acpi: Disable APEI error injection " David Howells
2018-04-11 16:26 ` [PATCH 16/24] Prohibit PCMCIA CIS storage when " David Howells
2018-04-11 16:26 ` [PATCH 17/24] Lock down TIOCSSERIAL David Howells
2018-04-11 16:26 ` [PATCH 18/24] Lock down module params that specify hardware parameters (eg. ioport) David Howells
2018-04-11 17:22 ` Randy Dunlap
2018-04-11 16:26 ` [PATCH 19/24] x86/mmiotrace: Lock down the testmmiotrace module David Howells
2018-04-11 16:26 ` [PATCH 20/24] Lock down /proc/kcore David Howells
2018-04-11 16:26 ` [PATCH 21/24] Lock down kprobes David Howells
2018-04-11 16:27 ` [PATCH 22/24] bpf: Restrict kernel image access functions when the kernel is locked down David Howells
2018-04-11 16:27 ` [PATCH 23/24] Lock down perf David Howells
2018-04-11 16:27 ` [PATCH 24/24] debugfs: Restrict debugfs when the kernel is locked down David Howells
2018-04-11 17:26 ` Randy Dunlap
2018-04-11 18:50 ` Eric W. Biederman
2018-04-11 19:54 ` Greg KH
2018-04-11 20:08 ` David Howells
2018-04-11 20:09 ` David Howells
2018-04-11 20:33 ` Greg KH
2018-04-12 2:54 ` Andy Lutomirski
2018-04-12 8:23 ` Greg KH
2018-04-12 14:19 ` Andy Lutomirski
2018-04-13 20:22 ` Pavel Machek
2018-04-19 14:35 ` David Howells
2018-05-10 11:01 ` Pavel Machek
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