Series applies on top of v5.18-rc5. Would be great if this could make
it
into v5.19.
v8 was here:
https://lore.kernel.org/linux-integrity/09e2552c-7392-e1da-926b-53c7db0b118d@xxxxxxxxxxxxxx
Changelog is beneath each individual patch. Compared to v8, only code
change is checking whether CAAM can support blobbing at init-time as
apparently some Layerscape SoCs are available in a non-E(ncryption)
variant that doesn't do AES. Previously, adding trusted keys on such
SoCs would return an error with a cryptic error message.
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.
