linux-kernel - Re: [PATCH 07/11] kexec: Disable in a secure boot environment

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <871uihozqc.fsf@xmission.com>
Date:	Tue, 04 Sep 2012 21:33:31 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org, linux-efi@...r.kernel.org
Subject: Re: [PATCH 07/11] kexec: Disable in a secure boot environment

Matthew Garrett <mjg59@...f.ucam.org> writes:

> On Tue, Sep 04, 2012 at 03:12:52PM -0700, Eric W. Biederman wrote:
>> Matthew Garrett <mjg59@...f.ucam.org> writes:
>> > The driving force behind this code right now is that our choices are 
>> > either (1) do something like this, or (2) disable kexec entirely.
>> 
>> Actually there is an interesting question here. Why does even EFI secure
>> boot justify this?  If I install my own key in EFI I should be able to
>> boot a kernel that does anything I want it to.   My machine doing what I
>> want it to is the point of trusted boot is it not?
>
> The full implementation should trust keys that are trusted by the 
> platform, so it'd boot any kexec image you cared to sign. Or simply 
> patch this code out and rebuild and self-sign, or disable the code that 
> turns off the capability when in secure boot mode. I've no objection to 
> putting that behind an #ifdef.

I will be happy to see a version of kexec that accepts signed images,
allowing the functionality to work in your brave new world where
everything must be signed.

Until then I don't see a point in merging anything else.

I will be happy to see some reasonable patchs for signing support on the
kexec path.

Eric
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/