Re: [kernel-hardening] Re: Remaining crypto API regressions with CONFIG_VMAP_STACK

[Jason A. Donenfeld]

Hi Herbert,

On Sat, Dec 10, 2016 at 6:37 AM, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> As for AEAD we never had a sync interface to begin with and I
> don't think I'm going to add one.

That's too bad to hear. I hope you'll reconsider. Modern cryptographic
design is heading more and more in the direction of using AEADs for
interesting things, and having a sync interface would be a lot easier
for implementing these protocols. In the same way many protocols need
a hash of some data, now protocols often want some particular data
encrypted with an AEAD using a particular key and nonce and AD. One
protocol that comes to mind is Noise [1].

I know that in my own [currently external to the tree] kernel code, I
just forego the use of the crypto API all together, and one of the
primary reasons for that is lack of a sync interface for AEADs. When I
eventually send this upstream, presumably everyone will want me to use
the crypto API, and having a sync AEAD interface would be personally
helpful for that. I guess I could always write the sync interface
myself, but I imagine you'd prefer having the design control etc.

Jason


[1] http://noiseprotocol.org/