On Fri, 2022-04-15 at 22:56 +0200, Ahmad Fatoum wrote:
> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> built into many newer i.MX and QorIQ SoCs by NXP.
>
> The CAAM does crypto acceleration, hardware number generation and
> has a blob mechanism for encapsulation/decapsulation of sensitive material.
>
> This blob mechanism depends on a device specific random 256-bit One Time
> Programmable Master Key that is fused in each SoC at manufacturing
> time. This key is unreadable and can only be used by the CAAM for AES
> encryption/decryption of user data.
>
> This makes it a suitable backend (source) for kernel trusted keys.
>
> Previous commits generalized trusted keys to support multiple backends
> and added an API to access the CAAM blob mechanism. Based on these,
> provide the necessary glue to use the CAAM for trusted keys.
>
> Reviewed-by: David Gstir <david@xxxxxxxxxxxxx>
> Reviewed-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> Tested-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> Tested-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
> Tested-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> v6 -> v7:
> - Split off MAINTAINERS and documentation chanes into separate patches
> (Jarkko)
> - Use new struct caam_blob_info API (Pankaj)
> v5 -> v6:
> - Rename caam_trusted_key_ops to trusted_key_caam_ops for symmetry
> with other trust sources (Pankaj)
> - Collected Pankaj's Reviewed-by
> v4 -> v5:
> - Collected Reviewed-by's and Tested-by's
> - Changed modifier to SECURE_KEY for compatibility with linux-imx
> (Matthias)
> v3 -> v4:
> - Collected Acked-by's, Reviewed-by's and Tested-by
> v2 -> v3:
> - add MAINTAINERS entry
> v1 -> v2:
> - Extend trusted keys documentation for CAAM
>
> To: David Howells <dhowells@xxxxxxxxxx>
> To: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> To: James Bottomley <jejb@xxxxxxxxxxxxx>
> To: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> To: Jonathan Corbet <corbet@xxxxxxx>
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
> Cc: "Horia Geantă" <horia.geanta@xxxxxxx>
> Cc: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
> Cc: Jan Luebbe <j.luebbe@xxxxxxxxxxxxxx>
> Cc: David Gstir <david@xxxxxxxxxxxxx>
> Cc: Richard Weinberger <richard@xxxxxx>
> Cc: Franck LENORMAND <franck.lenormand@xxxxxxx>
> Cc: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
> Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
> Cc: keyrings@xxxxxxxxxxxxxxx
> Cc: linux-crypto@xxxxxxxxxxxxxxx
> Cc: linux-doc@xxxxxxxxxxxxxxx
> Cc: linux-integrity@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> ---
> .../admin-guide/kernel-parameters.txt | 1 +
> include/keys/trusted_caam.h | 11 +++
> security/keys/trusted-keys/Kconfig | 11 ++-
> security/keys/trusted-keys/Makefile | 2 +
> security/keys/trusted-keys/trusted_caam.c | 82 +++++++++++++++++++
> security/keys/trusted-keys/trusted_core.c | 6 +-
> 6 files changed, 111 insertions(+), 2 deletions(-)
> create mode 100644 include/keys/trusted_caam.h
> create mode 100644 security/keys/trusted-keys/trusted_caam.c
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4deed1908a75..9afb7046ce97 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5958,6 +5958,7 @@
> sources:
> - "tpm"
> - "tee"
> + - "caam"
> If not specified then it defaults to iterating through
> the trust source list starting with TPM and assigns the
> first trust source as a backend which is initialized
> diff --git a/include/keys/trusted_caam.h b/include/keys/trusted_caam.h
> new file mode 100644
> index 000000000000..73fe2f32f65e
> --- /dev/null
> +++ b/include/keys/trusted_caam.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@xxxxxxxxxxxxxx>
> + */
> +
> +#ifndef __CAAM_TRUSTED_KEY_H
> +#define __CAAM_TRUSTED_KEY_H
> +
> +extern struct trusted_key_ops trusted_key_caam_ops;
> +
> +#endif
> diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig
> index fc4abd581abb..dbfdd8536468 100644
> --- a/security/keys/trusted-keys/Kconfig
> +++ b/security/keys/trusted-keys/Kconfig
> @@ -24,6 +24,15 @@ config TRUSTED_KEYS_TEE
> Enable use of the Trusted Execution Environment (TEE) as trusted
> key backend.
>
> -if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE
> +config TRUSTED_KEYS_CAAM
> + bool "CAAM-based trusted keys"
> + depends on CRYPTO_DEV_FSL_CAAM_JR >= TRUSTED_KEYS
> + select CRYPTO_DEV_FSL_CAAM_BLOB_GEN
> + default y
> + help
> + Enable use of NXP's Cryptographic Accelerator and Assurance Module
> + (CAAM) as trusted key backend.
> +
> +if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE && !TRUSTED_KEYS_CAAM
> comment "No trust source selected!"
> endif
> diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
> index 2e2371eae4d5..735aa0bc08ef 100644
> --- a/security/keys/trusted-keys/Makefile
> +++ b/security/keys/trusted-keys/Makefile
> @@ -12,3 +12,5 @@ trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o
> trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o
>
> trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o
> +
> +trusted-$(CONFIG_TRUSTED_KEYS_CAAM) += trusted_caam.o
> diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c
> new file mode 100644
> index 000000000000..46cb2484ec36
> --- /dev/null
> +++ b/security/keys/trusted-keys/trusted_caam.c
> @@ -0,0 +1,82 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@xxxxxxxxxxxxxx>
> + */
> +
> +#include <keys/trusted_caam.h>
> +#include <keys/trusted-type.h>
> +#include <linux/build_bug.h>
> +#include <linux/key-type.h>
> +#include <soc/fsl/caam-blob.h>
> +
> +static struct caam_blob_priv *blobifier;
> +
> +#define KEYMOD "SECURE_KEY"
> +
> +static_assert(MAX_KEY_SIZE + CAAM_BLOB_OVERHEAD <= CAAM_BLOB_MAX_LEN);
> +static_assert(MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN);
> +
> +static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
> +{
> + int ret;
> + struct caam_blob_info info = {
> + .input = p->key, .input_len = p->key_len,
> + .output = p->blob, .output_len = MAX_BLOB_SIZE,
> + .key_mod = KEYMOD, .key_mod_len = sizeof(KEYMOD) - 1,
> + };
> +
> + ret = caam_encap_blob(blobifier, &info);
> + if (ret)
> + return ret;
> +
> + p->blob_len = info.output_len;
> + return 0;
> +}
> +
> +static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob)
> +{
> + int ret;
> + struct caam_blob_info info = {
> + .input = p->blob, .input_len = p->blob_len,
> + .output = p->key, .output_len = MAX_KEY_SIZE,
> + .key_mod = KEYMOD, .key_mod_len = sizeof(KEYMOD) - 1,
> + };
> +
> + ret = caam_decap_blob(blobifier, &info);
> + if (ret)
> + return ret;
> +
> + p->key_len = info.output_len;
> + return 0;
> +}
> +
> +static int trusted_caam_init(void)
> +{
> + int ret;
> +
> + blobifier = caam_blob_gen_init();
> + if (IS_ERR(blobifier)) {
> + pr_err("Job Ring Device allocation for transform failed\n");
> + return PTR_ERR(blobifier);
> + }
> +
> + ret = register_key_type(&key_type_trusted);
> + if (ret)
> + caam_blob_gen_exit(blobifier);
> +
> + return ret;
> +}
> +
> +static void trusted_caam_exit(void)
> +{
> + unregister_key_type(&key_type_trusted);
> + caam_blob_gen_exit(blobifier);
> +}
> +
> +struct trusted_key_ops trusted_key_caam_ops = {
> + .migratable = 0, /* non-migratable */
> + .init = trusted_caam_init,
> + .seal = trusted_caam_seal,
> + .unseal = trusted_caam_unseal,
> + .exit = trusted_caam_exit,
> +};
> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> index 9235fb7d0ec9..c6fc50d67214 100644
> --- a/security/keys/trusted-keys/trusted_core.c
> +++ b/security/keys/trusted-keys/trusted_core.c
> @@ -9,6 +9,7 @@
> #include <keys/user-type.h>
> #include <keys/trusted-type.h>
> #include <keys/trusted_tee.h>
> +#include <keys/trusted_caam.h>
> #include <keys/trusted_tpm.h>
> #include <linux/capability.h>
> #include <linux/err.h>
> @@ -29,7 +30,7 @@ MODULE_PARM_DESC(rng, "Select trusted key RNG");
>
> static char *trusted_key_source;
> module_param_named(source, trusted_key_source, charp, 0);
> -MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
> +MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee or caam)");
>
> static const struct trusted_key_source trusted_key_sources[] = {
> #if defined(CONFIG_TRUSTED_KEYS_TPM)
> @@ -38,6 +39,9 @@ static const struct trusted_key_source trusted_key_sources[] = {
> #if defined(CONFIG_TRUSTED_KEYS_TEE)
> { "tee", &trusted_key_tee_ops },
> #endif
> +#if defined(CONFIG_TRUSTED_KEYS_CAAM)
> + { "caam", &trusted_key_caam_ops },
> +#endif
> };
>
> DEFINE_STATIC_CALL_NULL(trusted_key_init, *trusted_key_sources[0].ops->init);
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
