Re: [PATCH v2] crypto: AF_ALG - add support for keys/asymmetric-type

From: Tadeusz Struk
Date: Wed Jan 13 2016 - 09:09:19 EST

Hi David,
On 01/13/2016 05:31 AM, David Howells wrote:
>> > + pkey = keyring->[asym_crypto];
>> > + if (!pkey) {
>> > + key_put(keyring);
>> > + goto out;
>> > + }
>> > +
>> > + err = setkey(private, pkey->key, pkey->keylen);
>> > + key_put(keyring);
> Note that you may not assume that there's data there that you can use in this
> manner. The key might be a pointer to some hardware device such as a TPM. I
> have a TPM asymmetric subtype in progress.

So is there anything in place that can be used to tell what the key actually is?
The security/integrity/digsig_asymmetric.c is using this api in a similar way, so
if it is incorrect digsig_asymmetric shouldn't work neither.

> I think this really needs to be driven from a keyctl() because you need to let
> the asymmetric subtype decide how it wants to handle this. I would suggest
> to pass sufficient arguments, how to decrypt the private key and what metadata
> needs to be passed vs what is inline with the data.

I agree, ideally keyctl should do the job for all the cases and request_key()
should just return a key data.