RE: [EXT] Re: [PATCH v5 4/5] crypto: caam - add in-kernel interface for blob generator

From: Pankaj Gupta <pankaj.gupta@nxp.com>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>,
	Jarkko Sakkinen <jarkko@kernel.org>
Cc: Horia Geanta <horia.geanta@nxp.com>,
	Aymen Sghaier <aymen.sghaier@nxp.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	David Gstir <david@sigma-star.at>,
	"tharvey@gateworks.com" <tharvey@gateworks.com>,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>,
	James Bottomley <jejb@linux.ibm.com>,
	Mimi Zohar <zohar@linux.ibm.com>,
	David Howells <dhowells@redhat.com>,
	James Morris <jmorris@namei.org>,
	Eric Biggers <ebiggers@kernel.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Jan Luebbe <j.luebbe@pengutronix.de>,
	Richard Weinberger <richard@nod.at>,
	Franck Lenormand <franck.lenormand@nxp.com>,
	Sumit Garg <sumit.garg@linaro.org>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"keyrings@vger.kernel.org" <keyrings@vger.kernel.org>,
	"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>
Subject: RE: [EXT] Re: [PATCH v5 4/5] crypto: caam - add in-kernel interface for blob generator
Date: Fri, 25 Feb 2022 12:20:54 +0000	[thread overview]
Message-ID: <DU2PR04MB863084B70239A69E4DE9D65B953E9@DU2PR04MB8630.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <a8cb99e0-fe01-2234-9839-fea28ca09f6d@pengutronix.de>


> -----Original Message-----
> From: Ahmad Fatoum <a.fatoum@pengutronix.de>
> Sent: Wednesday, February 23, 2022 9:50 PM
> To: Jarkko Sakkinen <jarkko@kernel.org>
> Cc: Horia Geanta <horia.geanta@nxp.com>; Aymen Sghaier
> <aymen.sghaier@nxp.com>; Herbert Xu <herbert@gondor.apana.org.au>;
> David S. Miller <davem@davemloft.net>; kernel@pengutronix.de; David Gstir
> <david@sigma-star.at>; Pankaj Gupta <pankaj.gupta@nxp.com>;
> tharvey@gateworks.com; Matthias Schiffer <matthias.schiffer@ew.tq-
> group.com>; James Bottomley <jejb@linux.ibm.com>; Mimi Zohar
> <zohar@linux.ibm.com>; David Howells <dhowells@redhat.com>; James Morris
> <jmorris@namei.org>; Eric Biggers <ebiggers@kernel.org>; Serge E. Hallyn
> <serge@hallyn.com>; Jan Luebbe <j.luebbe@pengutronix.de>; Richard
> Weinberger <richard@nod.at>; Franck Lenormand
> <franck.lenormand@nxp.com>; Sumit Garg <sumit.garg@linaro.org>; linux-
> integrity@vger.kernel.org; keyrings@vger.kernel.org; linux-
> crypto@vger.kernel.org; linux-kernel@vger.kernel.org; linux-security-
> module@vger.kernel.org
> Subject: [EXT] Re: [PATCH v5 4/5] crypto: caam - add in-kernel interface for blob
> generator
> 
> Caution: EXT Email
> 
> On 23.02.22 16:41, Jarkko Sakkinen wrote:
> > On Tue, Feb 22, 2022 at 08:58:18PM +0100, Ahmad Fatoum wrote:
> >> The NXP Cryptographic Acceleration and Assurance Module (CAAM) can be
> >> used to protect user-defined data across system reboot:
> >>
> >>   - When the system is fused and boots into secure state, the master
> >>     key is a unique never-disclosed device-specific key
> >>   - random key is encrypted by key derived from master key
> >>   - data is encrypted using the random key
> >>   - encrypted data and its encrypted random key are stored alongside
> >>   - This blob can now be safely stored in non-volatile memory
> >>
> >> On next power-on:
> >>   - blob is loaded into CAAM
> >>   - CAAM writes decrypted data either into memory or key register
> >>
> >> Add functions to realize encrypting and decrypting into memory
> >> alongside the CAAM driver.
> >>
> >> They will be used in a later commit as a source for the trusted key
> >> seal/unseal mechanism.
> >>
> >> Reviewed-by: David Gstir <david@sigma-star.at>
> >> Reviewed-by: Pankaj Gupta <pankaj.gupta@nxp.com>
> >> Tested-By: Tim Harvey <tharvey@gateworks.com>
> >> Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> >> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> >> ---
> >> To: "Horia Geantă" <horia.geanta@nxp.com>
> >> To: Aymen Sghaier <aymen.sghaier@nxp.com>
> >> To: Herbert Xu <herbert@gondor.apana.org.au>
> >> To: "David S. Miller" <davem@davemloft.net>
> >> Cc: James Bottomley <jejb@linux.ibm.com>
> >> Cc: Jarkko Sakkinen <jarkko@kernel.org>
> >> Cc: Mimi Zohar <zohar@linux.ibm.com>
> >> Cc: David Howells <dhowells@redhat.com>
> >> Cc: James Morris <jmorris@namei.org>
> >> Cc: Eric Biggers <ebiggers@kernel.org>
> >> Cc: "Serge E. Hallyn" <serge@hallyn.com>
> >> Cc: Jan Luebbe <j.luebbe@pengutronix.de>
> >> Cc: David Gstir <david@sigma-star.at>
> >> Cc: Richard Weinberger <richard@nod.at>
> >> Cc: Franck LENORMAND <franck.lenormand@nxp.com>
> >> Cc: Sumit Garg <sumit.garg@linaro.org>
> >> Cc: Tim Harvey <tharvey@gateworks.com>
> >> Cc: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> >> Cc: Pankaj Gupta <pankaj.gupta@nxp.com>
> >> Cc: linux-integrity@vger.kernel.org
> >> Cc: keyrings@vger.kernel.org
> >> Cc: linux-crypto@vger.kernel.org
> >> Cc: linux-kernel@vger.kernel.org
> >> Cc: linux-security-module@vger.kernel.org
> >> ---
> >>  drivers/crypto/caam/Kconfig    |   3 +
> >>  drivers/crypto/caam/Makefile   |   1 +
> >>  drivers/crypto/caam/blob_gen.c | 230
> +++++++++++++++++++++++++++++++++
> >>  include/soc/fsl/caam-blob.h    |  56 ++++++++
> >>  4 files changed, 290 insertions(+)
> >>  create mode 100644 drivers/crypto/caam/blob_gen.c  create mode
> >> 100644 include/soc/fsl/caam-blob.h
> >>
> >> diff --git a/drivers/crypto/caam/Kconfig
> >> b/drivers/crypto/caam/Kconfig index 84ea7cba5ee5..ea9f8b1ae981 100644
> >> --- a/drivers/crypto/caam/Kconfig
> >> +++ b/drivers/crypto/caam/Kconfig
> >> @@ -151,6 +151,9 @@ config CRYPTO_DEV_FSL_CAAM_RNG_API
> >>        Selecting this will register the SEC4 hardware rng to
> >>        the hw_random API for supplying the kernel entropy pool.
> >>
> >> +config CRYPTO_DEV_FSL_CAAM_BLOB_GEN
> >> +    bool
> >> +
> >>  endif # CRYPTO_DEV_FSL_CAAM_JR
> >>
> >>  endif # CRYPTO_DEV_FSL_CAAM
> >> diff --git a/drivers/crypto/caam/Makefile
> >> b/drivers/crypto/caam/Makefile index 3570286eb9ce..25f7ae5a4642
> >> 100644
> >> --- a/drivers/crypto/caam/Makefile
> >> +++ b/drivers/crypto/caam/Makefile
> >> @@ -21,6 +21,7 @@ caam_jr-
> $(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI)
> >> += caamalg_qi.o
> >>  caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_AHASH_API) += caamhash.o
> >>  caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API) += caamrng.o
> >>  caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_PKC_API) += caampkc.o
> >> pkc_desc.o
> >> +caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_BLOB_GEN) += blob_gen.o
> >>
> >>  caam-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI) += qi.o  ifneq
> >> ($(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI),)
> >> diff --git a/drivers/crypto/caam/blob_gen.c
> >> b/drivers/crypto/caam/blob_gen.c new file mode 100644 index
> >> 000000000000..513d3f90e438
> >> --- /dev/null
> >> +++ b/drivers/crypto/caam/blob_gen.c
> >> @@ -0,0 +1,230 @@
> >> +// SPDX-License-Identifier: GPL-2.0-only
> >> +/*
> >> + * Copyright (C) 2015 Pengutronix, Steffen Trumtrar
> >> +<kernel@pengutronix.de>
> >> + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum
> >> +<kernel@pengutronix.de>  */
> >> +
> >> +#include <linux/device.h>
> >> +#include <soc/fsl/caam-blob.h>
> >> +
> >> +#include "compat.h"
> >> +#include "desc_constr.h"
> >> +#include "desc.h"
> >> +#include "error.h"
> >> +#include "intern.h"
> >> +#include "jr.h"
> >> +#include "regs.h"
> >> +
> >> +struct caam_blob_priv {
> >> +    struct device jrdev;
> >> +};
> >> +
> >> +struct caam_blob_job_result {
> >> +    int err;
> >> +    struct completion completion;
> >> +};
> >> +
> >> +static void caam_blob_job_done(struct device *dev, u32 *desc, u32
> >> +err, void *context) {
> >> +    struct caam_blob_job_result *res = context;
> >> +    int ecode = 0;
> >> +
> >> +    dev_dbg(dev, "%s %d: err 0x%x\n", __func__, __LINE__, err);
> >> +
> >> +    if (err)
> >> +            ecode = caam_jr_strstatus(dev, err);
> >> +
> >> +    res->err = ecode;
> >> +
> >> +    /*
> >> +     * Upon completion, desc points to a buffer containing a CAAM job
> >> +     * descriptor which encapsulates data into an externally-storable
> >> +     * blob.
> >> +     */
> >> +    complete(&res->completion);
> >> +}
> >> +
> >> +static u32 *caam_blob_alloc_desc(size_t keymod_len) {
> >> +    size_t len;
> >> +
> >> +    /* header + (key mod immediate) + 2x pointers + op */
> >> +    len = 4 + (4 + ALIGN(keymod_len, 4)) + 2*(4 + 4 +
> >> + CAAM_PTR_SZ_MAX) + 4;
> >
> > Nit: the amount of magic numbers is overwhelming here. I neither
> > understand the statement nor how that comment should help me to
> understand it.
> 
> header              =  4
> (key mod immediate) = (4 + ALIGN(keymod_len, 4))
> 2x pointer          =  2 * (4 + 4 + CAAM_PTR_SZ_MAX)
> op                  =  4

Instead of the function caam_blob_alloc_desc(), it will be great if the caller functions caam_encap_blob()/caam_encap_blob (), could add local array:
uint32_t desc[CAAM_DESC_BYTES_MAX];

> 
> I haven't heard back from the CAAM maintainers yet since v1. Perhaps now is a
> good occasion to chime in? :-)
> 
> @Jarkko, could you take a look at patch 5? That's the gist of the series and I
> have yet to get maintainer feedback on that one.
> 
> Cheers,
> Ahmad
> 
> 
> >
> > BR, Jarkko
> >
> 
> 
> --
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       |
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.pen
> gutronix.de%2F&amp;data=04%7C01%7Cpankaj.gupta%40nxp.com%7Cc97e9d4
> aaf304124407908d9f6e87101%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%
> 7C0%7C637812300459173929%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wL
> jAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;s
> data=CvnfIXR68DPRCaYrOYQKSv2eSBSNSSJYx2BQJee4yLg%3D&amp;reserved=0
> |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |