[v6,0/4] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

Message

Ahmad Fatoum March 16, 2022, 4:43 p.m. UTC

Series applies on top of current linux-tpmdd/master

v5 was here:
https://lore.kernel.org/linux-integrity/[e-mail]/

Changelog was moved beneath each individual patch.


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 Agarwal 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.MX6Q/DL and an i.MX8M[6].

Looking forward to your feedback.

Cheers,
Ahmad

 [1]: https://lore.kernel.org/linux-crypto/[e-mail]/
 [2]: https://lore.kernel.org/linux-integrity/[e-mail]/
 [3]: https://lore.kernel.org/lkml/[e-mail]/
 [4]: https://lore.kernel.org/lkml/[e-mail]/
 [5]: https://lore.kernel.org/linux-integrity/[e-mail]/
 [6]: https://lore.kernel.org/linux-integrity/[e-mail]/

---
To: Jarkko Sakkinen <[e-mail]>
To: "Horia Geantă" <[e-mail]>
To: Mimi Zohar <[e-mail]>
To: Pankaj Gupta <[e-mail]>
To: Herbert Xu <[e-mail]>
To: "David S. Miller" <[e-mail]>
To: James Bottomley <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: James Morris <[e-mail]>
Cc: "Serge E. Hallyn" <[e-mail]>
Cc: Steffen Trumtrar <[e-mail]>
Cc: Jan Luebbe <[e-mail]>
Cc: David Gstir <[e-mail]>
Cc: Eric Biggers <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: Franck LENORMAND <[e-mail]>
Cc: Sumit Garg <[e-mail]>
Cc: Andreas Rammhold <[e-mail]>
Cc: Tim Harvey <[e-mail]>
Cc: Matthias Schiffer <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]

Ahmad Fatoum (4):
  KEYS: trusted: allow use of TEE as backend without TCG_TPM support
  KEYS: trusted: allow use of kernel RNG for key material
  crypto: caam - add in-kernel interface for blob generator
  KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

 .../admin-guide/kernel-parameters.txt         |  11 ++
 .../security/keys/trusted-encrypted.rst       |  60 ++++++-
 MAINTAINERS                                   |   9 +
 drivers/crypto/caam/Kconfig                   |   3 +
 drivers/crypto/caam/Makefile                  |   1 +
 drivers/crypto/caam/blob_gen.c                | 160 ++++++++++++++++++
 include/keys/trusted-type.h                   |   2 +-
 include/keys/trusted_caam.h                   |  11 ++
 include/soc/fsl/caam-blob.h                   |  79 +++++++++
 security/keys/Kconfig                         |  18 +-
 security/keys/trusted-keys/Kconfig            |  38 +++++
 security/keys/trusted-keys/Makefile           |  10 +-
 security/keys/trusted-keys/trusted_caam.c     |  74 ++++++++
 security/keys/trusted-keys/trusted_core.c     |  45 ++++-
 14 files changed, 492 insertions(+), 29 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