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From:   Richard Weinberger <richard.weinberger@gmail.com>
Date:   Mon, 14 Sep 2020 08:38:37 +0200
Message-ID: <CAFLxGvw4zvL0N5+wChKq3=_xLuuCYLKDOyKKnKFy3UiWMUwf-g@mail.gmail.com>
Subject: Re: [PATCH 2/2] crypto: caam - support tagged keys for skcipher algorithms
To:     Iuliana Prodan <iuliana.prodan@nxp.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        Horia Geanta <horia.geanta@nxp.com>,
        Aymen Sghaier <aymen.sghaier@nxp.com>,
        "David S. Miller" <davem@davemloft.net>,
        Silvano Di Ninno <silvano.dininno@nxp.com>,
        Franck Lenormand <franck.lenormand@nxp.com>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-imx <linux-imx@nxp.com>, David Gstir <david@sigma-star.at>
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On Thu, Jul 16, 2020 at 4:12 PM Richard Weinberger
<richard.weinberger@gmail.com> wrote:
>
> On Mon, Jul 13, 2020 at 12:09 AM Iuliana Prodan <iuliana.prodan@nxp.com> wrote:
> >
> > Tagged keys are keys that contain metadata indicating what
> > they are and how to handle them using tag_object API.
> >
> > Add support, for tagged keys, to skcipher algorithms by
> > adding new transformations, with _tk_ prefix to distinguish
> > between plaintext and tagged keys.
> >
> > For job descriptors a new option (key_cmd_opt) was added for KEY command.
> > Tagged keys can be loaded using only a KEY command with ENC=1
> > and the proper setting of the EKT bit. The EKT bit in the
> > KEY command indicates which encryption algorithm (AES-ECB or
> > AES-CCM) should be used to decrypt the key. These options will be kept in
> > key_cmd_opt.
> >
> > The tk_ transformations can be used directly by their name:
> > struct sockaddr_alg sa = {
> >     .salg_family = AF_ALG,
> >     .salg_type = "skcipher", /* this selects the symmetric cipher */
> >     .salg_name = "tk(cbc(aes))" /* this is the cipher name */
> > };
> > or for dm-crypt, e.g. using dmsetup:
> > dmsetup -v create encrypted --table "0 $(blockdev --getsz /dev/mmcblk2p10)
> > crypt capi:tk(cbc(aes))-plain :32:logon:seckey 0 /dev/mmcblk2p10 0 1
> > sector_size:512".
>
> How to use it with cryptsetup?
> I'm asking because it is not clear to me why you are not implementing
> a new kernel key type (KEYS subsystem)
> to utilize tagged keys.
> Many tools already support the keyctl userspace interface (cryptsetup,
> fscrypt, ...).

*friendly ping*

-- 
Thanks,
//richard