linux-kernel - Re: [RFC PATCH v3 08/13] clavis: Introduce new LSM called clavis

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Message-ID: <F911D28D-F8EC-4773-8143-2B4E207DA202@oracle.com>
Date: Wed, 23 Oct 2024 19:25:21 +0000
From: Eric Snowberg <eric.snowberg@...cle.com>
To: "sergeh@...nel.org" <sergeh@...nel.org>
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Subject: Re: [RFC PATCH v3 08/13] clavis: Introduce new LSM called clavis



> On Oct 22, 2024, at 8:25 PM, sergeh@...nel.org wrote:
> 
> On Thu, Oct 17, 2024 at 09:55:11AM -0600, Eric Snowberg wrote:
>> 
>> +The Clavis LSM contains a system keyring call .clavis.  It contains a single
> 
> s/call/called/

I will change that, thanks.

>> +asymmetric key that is used to validate anything added to it.  This key can
>> +be added during boot and must be a preexisting system kernel key.  If the
>> +``clavis=`` boot parameter is not used, any asymmetric key the user owns
> 
> Who is "the user", and precisely what does "owns' mean here?  Is it just
> restating that it must be a key already in one of the builtin or secondary
> or platform keyrings?

In the case where Clavis was not provided a key id during boot, root can 
add a single public key to the .clavis keyring anytime afterwards.  This 
key does not need to be in any of the system keyrings.  Once the key is 
added, the Clavis LSM is enabled. The root user must also own the private 
key, since this is required to do the ACL signing. I will try to clarify this better 
in the documentation. 

I wouldn't expect this to be the typical way Clavis would be used. I would 
also be interested in any feedback if enabling the Clavis LSM this way 
following boot should be removed.  If this were removed, Clavis could 
only be enabled when using the boot parameter.

> And this is done by simply loading it into the clavis keyring, right?

Correct.