Re: [PATCH v2] integrity: Always reference the blacklist keyring with apprasial

From: Eric Snowberg
Date: Wed Jul 12 2023 - 17:15:24 EST




> On Jul 12, 2023, at 11:40 AM, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote:
>
> On Wed, 2023-07-05 at 18:52 -0400, Eric Snowberg wrote:
>> Commit 273df864cf746 ("ima: Check against blacklisted hashes for files with
>> modsig") introduced an appraise_flag option for referencing the blacklist
>> keyring. Any matching binary found on this keyring fails signature
>> validation. This flag only works with module appended signatures.
>>
>> An important part of a PKI infrastructure is to have the ability to do
>> revocation at a later time should a vulnerability be found. Expand the
>> revocation flag usage to all appraisal functions. The flag is now
>> enabled by default. Setting the flag with an IMA policy has been
>> deprecated. Without a revocation capability like this in place, only
>> authenticity can be maintained. With this change, integrity can now be
>> achieved with digital signature based IMA appraisal.
>>
>> Signed-off-by: Eric Snowberg <eric.snowberg@xxxxxxxxxx>
>
> Thanks, Eric. Other than including "appraise_flag=check_blacklist"
> when displaying the measurement list, it looks good.

Thanks for your review.

I want to make sure I understand the request here. Do you mean you
don’t want to see “appraise_flag=check_blacklist” when you cat
/sys/kernel/security/ima/policy? Or are you referencing a change in the
/sys/kernel/security/ima/ascii_runtime_measurements list? Thanks.