Re: [PATCH v2 01/23] crypto: provide single place for hash algoinformation

From: Mimi Zohar
Date: Tue Oct 22 2013 - 08:50:28 EST


On Tue, 2013-10-22 at 20:07 +0800, Herbert Xu wrote:
> On Tue, Oct 22, 2013 at 12:57:02PM +0100, Dmitry Kasatkin wrote:
> > On Tue, Oct 22, 2013 at 12:32 PM, Herbert Xu
> > <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> > > On Tue, Oct 22, 2013 at 12:29:56PM +0100, Dmitry Kasatkin wrote:
> > >>
> > >> We are not adding user-space interface.
> > >> We just need to algo definitions which are in sync between user space,
> > >> IMA/EVM and kernel module signing.
> > >> Module signing perl script uses hard coded values. We want to improve
> > >> it export them to user space.
> > >>
> > >> But please give us a hint, what crypto user-space API helps for us?
> > >
> > > OK, if you're not exporting the kernel asymmetric key code then
> > > that's fine.
> >
> > Can we take this to mean acked-by you?
>
> FWIW I'm against introducing new interfaces using integer IDs
> for crypto algorithms. Especially if such an interface is exposed
> to user-space.
>
> You said that you're not currently using this as a kernel/user-space
> interface, which I can live with grudgingly.

> However, the fact that you've placed this file in uapi leads me to
> believe that at some future point in time there will be some sort
> of kernel/user-space interface using this. Why else would they need
> to be in sync?

Files, including kernel modules, are already signed in userspace and
verified by the kernel. So they already need to be in sync. Up to now,
IMA was limited to a 20 byte digest. This patch set adds support in IMA
for larger digests.

thanks,

Mimi

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