Re: [PATCH v2 0/6] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

From: Ahmad Fatoum
Date: Wed Jul 14 2021 - 02:37:18 EST


Dear Trusted Keys and CAAM maintainers/reviewers,

On 22.06.21 14:37, Ahmad Fatoum wrote:
> The first three patches are new and are applicable regardless of this
> series, but the rest won't apply cleanly without them. I chose to
> include them this time, but I can split them up for v3 if that's
> preferred.
>
> v1 -> v2:
> - Added new commit to make trusted key Kconfig option independent
> of TPM and added new Kconfig file and symbols for trusted keys
> - Add new commit for importing existing key material (Jan)
> - Allow users to force use of kernel RNG (Jarkko)
> - Enforce maximum keymod size (Horia)
> - Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
> (Horia)
> - Make blobifier handle private to CAAM glue code file (Horia)
> - Extend trusted keys documentation for CAAM
> - Rebased on v5.12-rc7 and updated cover letter:
>
> 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:
>
> 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. This time
> it uses CAAM "black blobs" instead of "red blobs", so key material stays
> within the CAAM and isn't exposed to kernel in plaintext.
> 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.

Gentle Ping.

> Cheers,
> Ahmad
>
> [1]: https://lore.kernel.org/linux-crypto/1447082306-19946-2-git-send-email-s.trumtrar@xxxxxxxxxxxxxx/
> [2]: https://lore.kernel.org/linux-integrity/20180723111432.26830-1-udit.agarwal@xxxxxxx/
> [3]: https://lore.kernel.org/lkml/1551456599-10603-2-git-send-email-franck.lenormand@xxxxxxx/
> [4]: https://lore.kernel.org/lkml/1604419306-26105-1-git-send-email-sumit.garg@xxxxxxxxxx/
> [5]: https://lore.kernel.org/linux-integrity/20210122084321.24012-2-a.fatoum@xxxxxxxxxxxxxx/
>
> ---
> To: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> To: "Horia Geantă" <horia.geanta@xxxxxxx>
> To: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> To: Aymen Sghaier <aymen.sghaier@xxxxxxx>
> To: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> To: "David S. Miller" <davem@xxxxxxxxxxxxx>
> To: James Bottomley <jejb@xxxxxxxxxxxxx>
> Cc: David Howells <dhowells@xxxxxxxxxx>
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
> Cc: Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx>
> Cc: Udit Agarwal <udit.agarwal@xxxxxxx>
> Cc: Jan Luebbe <j.luebbe@xxxxxxxxxxxxxx>
> Cc: David Gstir <david@xxxxxxxxxxxxx>
> Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
> Cc: Richard Weinberger <richard@xxxxxx>
> Cc: Franck LENORMAND <franck.lenormand@xxxxxxx>
> Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
> Cc: linux-integrity@xxxxxxxxxxxxxxx
> Cc: keyrings@xxxxxxxxxxxxxxx
> Cc: linux-crypto@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
>
> Ahmad Fatoum (6):
> KEYS: trusted: allow use of TEE as backend without TCG_TPM support
> KEYS: trusted: Allow import from existing key material for development
> KEYS: trusted: allow users to use kernel RNG for key material
> KEYS: trusted: allow trust sources to use kernel RNG for key material
> crypto: caam - add in-kernel interface for blob generator
> KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
>
> Documentation/admin-guide/kernel-parameters.txt | 8 +-
> Documentation/security/keys/trusted-encrypted.rst | 74 ++++-
> drivers/crypto/caam/Kconfig | 3 +-
> 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 | 56 ++++-
> security/keys/Kconfig | 14 +-
> security/keys/trusted-keys/Kconfig | 49 +++-
> security/keys/trusted-keys/Makefile | 10 +-
> security/keys/trusted-keys/trusted_caam.c | 74 +++++-
> security/keys/trusted-keys/trusted_core.c | 48 ++-
> 13 files changed, 554 insertions(+), 26 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/Kconfig
> create mode 100644 security/keys/trusted-keys/trusted_caam.c
>
> base-commit: 13311e74253fe64329390df80bed3f07314ddd61
>


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