Re: [RFC 6/8] KEYS: PGP data parser

[H. Peter Anvin]

On February 16, 2024 8:53:01 AM PST, Roberto Sassu <roberto.sassu@xxxxxxxxxxxxxxx> wrote:
>On Fri, 2024-02-16 at 16:44 +0000, Matthew Wilcox wrote:
>> On Fri, Feb 16, 2024 at 04:24:33PM +0100, Petr Tesarik wrote:
>> > From: David Howells <dhowells@xxxxxxxxxx>
>> > 
>> > Implement a PGP data parser for the crypto key type to use when
>> > instantiating a key.
>> > 
>> > This parser attempts to parse the instantiation data as a PGP packet
>> > sequence (RFC 4880) and if it parses okay, attempts to extract a public-key
>> > algorithm key or subkey from it.
>> 
>> I don't understand why we want to do this in-kernel instead of in
>> userspace and then pass in the actual key.
>
>Sigh, this is a long discussion.
>
>PGP keys would be used as a system-wide trust anchor to verify RPM
>package headers, which already contain file digests that can be used as
>reference values for kernel-enforced integrity appraisal.
>
>With the assumptions that:
>
>- In a locked-down system the kernel has more privileges than root
>- The kernel cannot offload this task to an user space process due to
>  insufficient isolation
>
>the only available option is to do it in the kernel (that is what I got
>as suggestion).
>
>Roberto
>
>

Ok, at least one of those assumptions is false, and *definitely* this approach seems to be a solution in search of a problem.