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

From: Eric Snowberg
Date: Thu Jul 13 2023 - 11:27:29 EST




> On Jul 12, 2023, at 3:33 PM, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote:
>
> On Wed, 2023-07-12 at 21:12 +0000, Eric Snowberg wrote:
>>
>>> 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.
>
> The IMA policy rules as displayed via <securityfs>/ima/policy should
> not contain “appraise_flag=check_blacklist".

Ok, I will fix this in v3, thanks.