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

Eric Snowberg eric.snowberg at oracle.com
Thu Jul 13 15:25:53 UTC 2023



> On Jul 12, 2023, at 3:33 PM, Mimi Zohar <zohar at linux.ibm.com> wrote:
> 
> On Wed, 2023-07-12 at 21:12 +0000, Eric Snowberg wrote:
>> 
>>> On Jul 12, 2023, at 11:40 AM, Mimi Zohar <zohar at linux.ibm.com> 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 at oracle.com>
>>> 
>>> 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.



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