Re: LPC 2021 presentation - Kernel cgroups and namespaces: Can they contribute to FFI claims?


Paul Albertella
 

Hi Elana,

On 29/09/2021 06:50, elana.copperman@... wrote:
And in a more general sense, what are the criteria for acceptance of such kernel features as the basis for safety claims such as FFI?
@Paul Albertella <mailto:paul.albertella@...> – I would hope that your new WG will be helpful to make clear guidelines on such questions.
Yes, that's very much my intention!

There are really two broad sets of criteria, which can be summarised in the following two questions:

1) What role does the feature have in achieving a safety goal?
2) What gives us confidence that the feature can fulfil that role?

In my opinion, there's nothing to *prevent* us from using any Linux feature as the basis for a safety claim, provided that we can:

* Document our answers to these questions (Assertions)
* Provide material to support these answers (Evidence)

The challenge is that we then have to satisfy a safety assessor that these are valid and sufficient!

One of the issues we face when answering these questions for Linux (and open source software in general) is that the 'traditional' answers (as described in safety standards like ISO 26262) are not always well-supported by either assertions or evidence from open source communities.

However, it's vitally important to recognise that safety standards do allow for 'non-traditional' answers and evidence, provided that we are prepared to make a reasoned argument to support these.

My goal with the OSEP WG is to explore specific examples of this, to understand what Linux contributors (or maintainers) and safety system developers (or integrators) can do to both frame better answers and provide better evidence.

Regards,

Paul

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