[PATCH v1 0/3] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

Ahmad Fatoum
2021-03-16T17:03:38Z

The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
built into many newer i.MX and QorIQ SoCs by NXP.

Its blob mechanism can AES encrypt/decrypt user data using a unique
never-disclosed device-specific key. There has been multiple
discussions on how to represent this within the kernel:

- [RFC] crypto: caam - add red blobifier
Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
best integrate the blob mechanism.
Mimi suggested that it could be used to implement trusted keys.
Trusted keys back then were a TPM-only feature.

- security/keys/secure_key: Adds the secure key support based on CAAM.
Udit added[2] a new "secure" key type with the CAAM as backend. The key
material stays within the kernel only.
Mimi and James agreed that this needs a generic interface, not specific
to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
basis for TEE-backed keys.

- [RFC] drivers: crypto: caam: key: Add caam_tk key type
Franck added[3] a new "caam_tk" key type based on Udit's work. The key
material stays within the kernel only, but can optionally be user-set
instead of coming from RNG. James voiced the opinion that there should
be just one user-facing generic wrap/unwrap key type with multiple
possible handlers. David suggested trusted keys.

- Introduce TEE based Trusted Keys support
Sumit reworked[4] trusted keys to support multiple possible backends with
one chosen at boot time and added a new TEE backend along with TPM.
This now sits in Jarkko's master branch to be sent out for v5.13

This patch series builds on top of Sumit's rework to have the CAAM as yet another
trusted key backend.

The CAAM bits are based on Steffen's initial patch from 2015. His work had been
used in the field for some years now, so I preferred not to deviate too much from it.

This series has been tested with dmcrypt[5] on an i.MX6DL.

Looking forward to your feedback.

Cheers,
Ahmad

[1]: https://lore.kernel.org/linux-crypto/1447082306-19946-2-git-send-email-s.trumtrar@pengutronix.de/
[2]: https://lore.kernel.org/linux-integrity/20180723111432.26830-1-udit.agarwal@nxp.com/
[3]: https://lore.kernel.org/lkml/1551456599-10603-2-git-send-email-franck.lenormand@nxp.com/
[4]: https://lore.kernel.org/lkml/1604419306-26105-1-git-send-email-sumit.garg@linaro.org/
[5]: https://lore.kernel.org/linux-integrity/20210122084321.24012-2-a.fatoum@pengutronix.de/

---
To: Jarkko Sakkinen <jarkko@kernel.org>
To: "Horia Geantă" <horia.geanta@nxp.com>
To: Mimi Zohar <zohar@linux.ibm.com>
To: Aymen Sghaier <aymen.sghaier@nxp.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
To: "David S. Miller" <davem@davemloft.net>
To: James Bottomley <jejb@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Udit Agarwal <udit.agarwal@nxp.com>
Cc: Jan Luebbe <j.luebbe@penutronix.de>
Cc: David Gstir <david@sigma-star.at>
Cc: Franck LENORMAND <franck.lenormand@nxp.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
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

Ahmad Fatoum (3):
crypto: caam - add in-kernel interface for blob generator
KEYS: trusted: implement fallback to kernel RNG
KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

Documentation/admin-guide/kernel-parameters.txt | 1 +-
drivers/crypto/caam/Kconfig | 4 +-
drivers/crypto/caam/Makefile | 1 +-
drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++++-
include/keys/trusted-type.h | 2 +-
include/keys/trusted_caam.h | 11 +-
include/soc/fsl/caam-blob.h | 54 ++++-
security/keys/trusted-keys/Makefile | 1 +-
security/keys/trusted-keys/trusted_caam.c | 74 +++++-
security/keys/trusted-keys/trusted_core.c | 17 +-
10 files changed, 392 insertions(+), 3 deletions(-)
create mode 100644 drivers/crypto/caam/blob_gen.c
create mode 100644 include/keys/trusted_caam.h
create mode 100644 include/soc/fsl/caam-blob.h
create mode 100644 security/keys/trusted-keys/trusted_caam.c

base-commit: 8a3fa8ade8a35d8f7c178f5680f07f223da41b87
--
git-series 0.9.1