Re: [RFC PATCH] rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto

[David Howells <dhowells@redhat.com>]

Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> Given that this part of the driver only uses synchronous crypto, and
> only using a hardcoded algo and mode [pcbc(fcrypt)], of which only a
> generic C implementation exists, may I suggest that we switch to a
> library based approach instead?
> 
> That way, we can get rid of the crypto API overhead here, and IMO, we
> can drop support for this cipher from the crypto API entirely.

Ummm...  I'm not entirely sure.  At some point, I need to look at implementing
the rxgk security class to allow gss to be used.  That can in theory support
any kerberos cipher suite (which don't include pcbc or fcrypt).  I don't yet
know how much code I could theoretically share with rxkad.c.

However, since pcbc and fcrypt are only used by rxkad.c, it might make sense
to move them to net/rxrpc/ and hard code them in rxkad.c - though I'd prefer
to make an attempt on rxgk first.

David