linux-kernel - Re: [PATCH v3 0/2] let kexec_file_load use platform keyring to verify the kernel image

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Date:   Thu, 17 Jan 2019 20:08:04 -0500
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Kairui Song <kasong@...hat.com>, linux-kernel@...r.kernel.org,
        Dave Young <dyoung@...hat.com>
Cc:     dhowells@...hat.com, dwmw2@...radead.org,
        jwboyer@...oraproject.org, keyrings@...r.kernel.org,
        jmorris@...ei.org, serge@...lyn.com, bauerman@...ux.ibm.com,
        ebiggers@...gle.com, nayna@...ux.ibm.com, dyoung@...hat.com,
        linux-integrity@...r.kernel.org, kexec@...ts.infradead.org
Subject: Re: [PATCH v3 0/2] let kexec_file_load use platform keyring to
 verify the kernel image

On Wed, 2019-01-16 at 18:16 +0800, Kairui Song wrote:
> This patch series adds a .platform_trusted_keys in system_keyring as the
> reference to .platform keyring in integrity subsystem, when platform
> keyring is being initialized it will be updated. So other component could
> use this keyring as well.

Remove "other component could use ...".
> 
> This patch series also let kexec_file_load use platform keyring as fall
> back if it failed to verify the image against secondary keyring, make it
> possible to load kernel signed by third part key if third party key is
> imported in the firmware.

This is the only reason for these patches.  Please remove "also".

> 
> After this patch kexec_file_load will be able to verify a signed PE
> bzImage using keys in platform keyring.
> 
> Tested in a VM with locally signed kernel with pesign and imported the
> cert to EFI's MokList variable.

It's taken so long for me to review/test this patch set due to a
regression in sanity_check_segment_list(), introduced somewhere
between 4.20 and 5.0.0-rc1.  The sgement overlap test - "if ((mend >
pstart) && (mstart < pend))" - fails, returning a -EINVAL.

Is anyone else seeing this?

Mimi


> 
> Kairui Song (2):
>   integrity, KEYS: add a reference to platform keyring
>   kexec, KEYS: Make use of platform keyring for signature verify
> 
> Update from V2:
>   - Use IS_ENABLED in kexec_file_load to judge if platform_trusted_keys
>     should be used for verifying image as suggested by Mimi Zohar
> 
> Update from V1:
>   - Make platform_trusted_keys static, and update commit message as suggested
>     by Mimi Zohar
>   - Always check if platform keyring is initialized before use it
> 
> Kairui Song (2):
>   integrity, KEYS: add a reference to platform keyring
>   kexec, KEYS: Make use of platform keyring for signature verify
> 
>  arch/x86/kernel/kexec-bzimage64.c | 13 ++++++++++---
>  certs/system_keyring.c            | 22 +++++++++++++++++++++-
>  include/keys/system_keyring.h     |  5 +++++
>  include/linux/verification.h      |  1 +
>  security/integrity/digsig.c       |  6 ++++++
>  5 files changed, 43 insertions(+), 4 deletions(-)
>