Hi David,
> -Original Message-
> From: David Gstir
> Sent: Wednesday, April 3, 2024 12:51 PM
> To: Mimi Zohar ; James Bottomley
> ; Jarkko Sakkinen ; Herbert Xu
> ; David S. Miller
> Cc: David Gstir ; Shawn Guo ;
> Jonathan Corbet ; Sascha Hauer
> ; Pengutronix Kernel Team
> ; Fabio Estevam ; dl-linux-
> imx ; Ahmad Fatoum ;
> sigma star Kernel Team ; David Howells
> ; Li Yang ; Paul Moore
> ; James Morris ; Serge E.
> Hallyn ; Paul E. McKenney ;
> Randy Dunlap ; Catalin Marinas
> ; Rafael J. Wysocki
> ; Tejun Heo ; Steven Rostedt
> (Google) ; linux-...@vger.kernel.org; linux-
> ker...@vger.kernel.org; linux-integr...@vger.kernel.org;
> keyri...@vger.kernel.org; linux-cry...@vger.kernel.org; linux-arm-
> ker...@lists.infradead.org; linuxppc-dev@lists.ozlabs.org; linux-security-
> mod...@vger.kernel.org; Richard Weinberger ; David
> Oberhollenzer
> Subject: [EXT] [PATCH v8 3/6] KEYS: trusted: Introduce NXP DCP-backed
> trusted keys
>
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>
> DCP (Data Co-Processor) is the little brother of NXP's CAAM IP.
> Beside of accelerated crypto operations, it also offers support for hardware-
> bound keys. Using this feature it is possible to implement a blob
> mechanism similar to what CAAM offers. Unlike on CAAM, constructing and
> parsing the blob has to happen in software (i.e. the kernel).
>
> The software-based blob format used by DCP trusted keys encrypts the
> payload using AES-128-GCM with a freshly generated random key and
> nonce.
> The random key itself is AES-128-ECB encrypted using the DCP unique or
> OTP key.
>
> The DCP trusted key blob format is:
> /*
> * struct dcp_blob_fmt - DCP BLOB format.
> *
> * @fmt_version: Format version, currently being %1
> * @blob_key: Random AES 128 key which is used to encrypt @payload,
> *@blob_key itself is encrypted with OTP or UNIQUE device key in
> *AES-128-ECB mode by DCP.
> * @nonce: Random nonce used for @payload encryption.
> * @payload_len: Length of the plain text @payload.
> * @payload: The payload itself, encrypted using AES-128-GCM and
> @blob_key,
> * GCM auth tag of size AES_BLOCK_SIZE is attached at the end of it.
> *
> * The total size of a DCP BLOB is sizeof(struct dcp_blob_fmt) +
> @payload_len +
> * AES_BLOCK_SIZE.
> */
> struct dcp_blob_fmt {
> __u8 fmt_version;
> __u8 blob_key[AES_KEYSIZE_128];
> __u8 nonce[AES_KEYSIZE_128];
> __le32 payload_len;
> __u8 payload[];
> } __packed;
>
> By default the unique key is used. It is also possible to use the OTP key.
> While the unique key should be unique it is not documented how this key is
> derived. Therefore selection the OTP key is supported as well via the
> use_otp_key module parameter.
>
> Co-developed-by: Richard Weinberger
> Signed-off-by: Richard Weinberger
> Co-developed-by: David Oberhollenzer
> Signed-off-by: David Oberhollenzer
> Signed-off-by: David Gstir
> Reviewed-by: Jarkko Sakkinen
> ---
> include/keys/trusted_dcp.h| 11 +
> security/keys/trusted-keys/Kconfig| 8 +
> security/keys/trusted-keys/Makefile | 2 +
> security/keys/trusted-keys/trusted_core.c | 6 +-
> security/keys/trusted-keys/trusted_dcp.c | 313
> ++
> 5 files changed, 339 insertions(+), 1 deletion(-) create mode 100644
> include/keys/trusted_dcp.h create mode 100644 security/keys/trusted-
> keys/trusted_dcp.c
>
> diff --git a/include/keys/trusted_dcp.h b/include/keys/trusted_dcp.h new
> file mode 100644 index ..9aaa42075b40
> --- /dev/null
> +++ b/include/keys/trusted_dcp.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 sigma star gmbh
> + */
> +
> +#ifndef TRUSTED_DCP_H
> +#define TRUSTED_DCP_H
> +
> +extern struct trusted_key_ops dcp_trusted_key_ops;
> +
> +#endif
> diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-
> keys/Kconfig
> index 553dc117f385..1fb8aa001995 100644
> --- a/security/keys/trusted-keys/Kconfig
> +++ b/security/keys/trusted-keys/Kconfig
> @@ -39,6 +39,14 @@ config TRUSTED_KEYS_CAAM
> Enable use of NXP's Cryptographic Accelerator and Assurance Module
> (CAAM) as trusted key backend.
>
> +config TRUSTED_KEYS_DCP
> + bool "DCP-based trusted keys"
> + depends on CRYPTO_DEV_MXS_DCP >= TRUSTED_KEYS
> + default y
> + select HAVE_TRUSTED_KEYS
> + help
> + Enable use of NXP's DCP (Data Co-Processor) as trusted key backend.
> +
> if !HAVE_TRUSTED_KEYS
> comment "No trust source selected!"
> endif
> diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-
> keys/Makefile
> index 735aa0bc08ef..f0f3b27f688b 100644
> --- a/security/keys/trusted-keys/Makefile
> +++ b/security/keys/trusted-keys/Makefile
> @@
