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@xxxxxxxxxxxxx>
>> Reviewed-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
>> Tested-By: Tim Harvey <tharvey@xxxxxxxxxxxxx>
>> Tested-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
>> Signed-off-by: Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
>> ---
>> To: "Horia Geantă" <horia.geanta@xxxxxxx>
>> To: Aymen Sghaier <aymen.sghaier@xxxxxxx>
>> To: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>> To: "David S. Miller" <davem@xxxxxxxxxxxxx>
>> Cc: James Bottomley <jejb@xxxxxxxxxxxxx>
>> Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
>> Cc: Mimi Zohar <zohar@xxxxxxxxxxxxx>
>> Cc: David Howells <dhowells@xxxxxxxxxx>
>> Cc: James Morris <jmorris@xxxxxxxxx>
>> Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
>> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
>> Cc: Jan Luebbe <j.luebbe@xxxxxxxxxxxxxx>
>> Cc: David Gstir <david@xxxxxxxxxxxxx>
>> Cc: Richard Weinberger <richard@xxxxxx>
>> Cc: Franck LENORMAND <franck.lenormand@xxxxxxx>
>> Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
>> Cc: Tim Harvey <tharvey@xxxxxxxxxxxxx>
>> Cc: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
>> Cc: Pankaj Gupta <pankaj.gupta@xxxxxxx>
>> Cc: linux-integrity@xxxxxxxxxxxxxxx
>> Cc: keyrings@xxxxxxxxxxxxxxx
>> Cc: linux-crypto@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: linux-security-module@xxxxxxxxxxxxxxx
>> ---
>> 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@xxxxxxxxxxxxxx>
>> + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@xxxxxxxxxxxxxx>
>> + */
>> +
>> +#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
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
>
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