Re: [RFC PATCH 5/8] KEYS: Provide software public key query function [ver 3]

[Mat Martineau]

On Thu, 12 May 2016, David Howells wrote:

> Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> wrote:
>
> > > +	len = crypto_akcipher_maxsize(tfm);
> > > +	info->key_size = len * 8;
> > > +	info->max_data_size = len;
> > > +	info->max_sig_size = len;
> > > +	info->max_enc_size = len;
> > > +	info->max_dec_size = len;
> >
> > If len > UINT16_MAX, should UINT16_MAX be reported as the max size? Similar
> > question for len*8 and key_size.
>
> key_size is 32 bits, but the other sizes are all 16 bits, so you would need a
> 524288-bit key to exceed their capacity.  I'm not sure that's likely anytime
> soon, but should I just make all the sizes 32-bit anyway?

Given that cryto_akcipher_maxsize() returns an int and keyctl_pkey_query 
is part of the userspace API, I support bumping the sizes to 32-bit.

--
Mat Martineau
Intel OTC