linux-kernel - Re: [PATCH 0/3] KEXEC_SIG with appended signature

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Message-ID: <87czneeurr.fsf@dja-thinkpad.axtens.net>
Date:   Fri, 05 Nov 2021 21:55:52 +1100
From:   Daniel Axtens <dja@...ens.net>
To:     Michal Suchanek <msuchanek@...e.de>, keyrings@...r.kernel.org
Cc:     Rob Herring <robh@...nel.org>, linux-s390@...r.kernel.org,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Jessica Yu <jeyu@...nel.org>, linux-kernel@...r.kernel.org,
        David Howells <dhowells@...hat.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Paul Mackerras <paulus@...ba.org>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Michal Suchanek <msuchanek@...e.de>,
        linuxppc-dev@...ts.ozlabs.org,
        Frank van der Linden <fllinden@...zon.com>,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Subject: Re: [PATCH 0/3] KEXEC_SIG with appended signature

Michal Suchanek <msuchanek@...e.de> writes:

> S390 uses appended signature for kernel but implements the check
> separately from module loader.
>
> Support for secure boot on powerpc with appended signature is planned -
> grub patches submitted upstream but not yet merged.

Power Non-Virtualised / OpenPower already supports secure boot via kexec
with signature verification via IMA. I think you have now sent a
follow-up series that merges some of the IMA implementation, I just
wanted to make sure it was clear that we actually already have support
for this in the kernel, it's just grub that is getting new support.

> This is an attempt at unified appended signature verification.

I am always in favour of fewer reimplementations of the same feature in
the kernel :)

Regards,
Daniel

>
> Thanks
>
> Michal
>
> Michal Suchanek (3):
>   s390/kexec_file: Don't opencode appended signature verification.
>   module: strip the signature marker in the verification function.
>   powerpc/kexec_file: Add KEXEC_SIG support.
>
>  arch/powerpc/Kconfig                  | 11 +++++++
>  arch/powerpc/kexec/elf_64.c           | 14 +++++++++
>  arch/s390/kernel/machine_kexec_file.c | 42 +++------------------------
>  include/linux/verification.h          |  3 ++
>  kernel/module-internal.h              |  2 --
>  kernel/module.c                       | 11 +++----
>  kernel/module_signing.c               | 32 ++++++++++++++------
>  7 files changed, 59 insertions(+), 56 deletions(-)
>
> -- 
> 2.31.1