Re: [PATCH v9 2/8] integrity: Introduce a Linux keyring called machine

[Eric Snowberg]

> On Jan 11, 2022, at 11:16 AM, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote:
> 
> On Mon, 2022-01-10 at 23:25 +0000, Eric Snowberg wrote:
>>> Jarkko, my concern is that once this version of the patch set is
>>> upstreamed, would limiting which keys may be loaded onto the .machine
>>> keyring be considered a regression?
>> 
>> 
>> Currently certificates built into the kernel do not have a CA restriction on them.  
>> IMA will trust anything in this keyring even if the CA bit is not set.  While it would 
>> be advisable for a kernel to be built with a CA, nothing currently enforces it. 
>> 
>> My thinking for the dropped CA restriction patches was to introduce a new Kconfig.  
>> This Kconfig would do the CA enforcement on the machine keyring.  However if the 
>> Kconfig option was not set for enforcement, it would work as it does in this series, 
>> plus it would allow IMA to work with non-CA keys.  This would be done by removing 
>> the restriction placed in this patch. Let me know your thoughts on whether this would 
>> be an appropriate solution.  I believe this would get around what you are identifying as 
>> a possible regression.
> 
> True the problem currently exists with the builtin keys, but there's a
> major difference between trusting the builtin keys and those being
> loading via MOK.  This is an integrity gap that needs to be closed and
> shouldn't be expanded to keys on the .machine keyring.
> 
> "plus it would allow IMA to work with non-CA keys" is unacceptable.

Ok, I’ll leave that part out.  Could you clarify the wording I should include in the future 
cover letter, which adds IMA support, on why it is unacceptable for the end-user to
make this decision?