linux/include/keys/trusted_dcp.h

/* 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
KEYS: trusted: Introduce NXP DCP-backed trusted keys 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 <richard@nod.at> Signed-off-by: Richard Weinberger <richard@nod.at> Co-developed-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at> Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at> Signed-off-by: David Gstir <david@sigma-star.at> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> 2024-04-03 09:21:19 +02:00			`/* 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`