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

[Tadeusz Struk]

Hi David,
On 01/13/2016 05:31 AM, David Howells wrote:
>> > +	pkey = keyring->payload.data[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
> adding KEYCTL_{ASYM_GETINFO,SIGN,VERIFY,ENCRYPT,DECRYPT} - the problem is how
> 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.
Thanks,
-- 
TS