Re: [PATCH v9 0/7] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

[Michael Walle <michael@walle.cc>]

Am 2022-05-06 08:25, schrieb Ahmad Fatoum:
> 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@pengutronix.de
> 
> 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.

For the whole series:

Tested-by: Michael Walle <michael@walle.cc> # on ls1028a (non-E and E)

-michael