Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9C69C433F5 for ; Wed, 24 Nov 2021 07:53:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240894AbhKXH4w (ORCPT ); Wed, 24 Nov 2021 02:56:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240440AbhKXH4u (ORCPT ); Wed, 24 Nov 2021 02:56:50 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE8D0C06173E for ; Tue, 23 Nov 2021 23:53:40 -0800 (PST) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1mpn5z-0000rb-9a; Wed, 24 Nov 2021 08:53:35 +0100 Subject: Re: [PATCH v4 5/5] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys To: Jonathan Corbet , David Howells , Jarkko Sakkinen , James Bottomley , Mimi Zohar Cc: kernel@pengutronix.de, David Gstir , Tim Harvey , James Morris , "Serge E. Hallyn" , =?UTF-8?Q?Horia_Geant=c4=83?= , Aymen Sghaier , Herbert Xu , "David S. Miller" , Udit Agarwal , Eric Biggers , Jan Luebbe , Richard Weinberger , Franck LENORMAND , Sumit Garg , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org References: From: Ahmad Fatoum Message-ID: <4a3a9f12-1588-81f2-1471-5faae4b660d3@pengutronix.de> Date: Wed, 24 Nov 2021 08:53:32 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-crypto@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Hello Jarkko, Mimi and James, On 11.10.21 12:02, 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 > Tested-By: Tim Harvey > Signed-off-by: Ahmad Fatoum Is there anything I can do to make this patch more palatable to you? Thanks, Ahmad > --- > To: Jonathan Corbet > To: David Howells > To: Jarkko Sakkinen > To: James Bottomley > To: Mimi Zohar > Cc: James Morris > Cc: "Serge E. Hallyn" > Cc: "Horia Geantă" > Cc: Aymen Sghaier > Cc: Herbert Xu > Cc: "David S. Miller" > Cc: Udit Agarwal > Cc: Eric Biggers > Cc: Jan Luebbe > Cc: David Gstir > Cc: Richard Weinberger > Cc: Franck LENORMAND > Cc: Sumit Garg > Cc: keyrings@vger.kernel.org > Cc: linux-crypto@vger.kernel.org > Cc: linux-doc@vger.kernel.org > Cc: linux-integrity@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-security-module@vger.kernel.org > --- > Documentation/admin-guide/kernel-parameters.txt | 1 +- > Documentation/security/keys/trusted-encrypted.rst | 42 ++++++++- > MAINTAINERS | 9 ++- > 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 | 74 ++++++++++++++++- > security/keys/trusted-keys/trusted_core.c | 6 +- > 8 files changed, 152 insertions(+), 4 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 d5969452f063..0ed1165e0f55 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5767,6 +5767,7 @@ > 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/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst > index 1d4b4b8f12f0..ad66573ca6fd 100644 > --- a/Documentation/security/keys/trusted-encrypted.rst > +++ b/Documentation/security/keys/trusted-encrypted.rst > @@ -35,6 +35,13 @@ safe. > Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip > fuses and is accessible to TEE only. > > + (3) CAAM (Cryptographic Acceleration and Assurance Module: IP on NXP SoCs) > + > + When High Assurance Boot (HAB) is enabled and the CAAM is in secure > + mode, trust is rooted to the OTPMK, a never-disclosed 256-bit key > + randomly generated and fused into each SoC at manufacturing time. > + Otherwise, a common fixed test key is used instead. > + > * Execution isolation > > (1) TPM > @@ -46,6 +53,10 @@ safe. > Customizable set of operations running in isolated execution > environment verified via Secure/Trusted boot process. > > + (3) CAAM > + > + Fixed set of operations running in isolated execution environment. > + > * Optional binding to platform integrity state > > (1) TPM > @@ -63,6 +74,11 @@ safe. > Relies on Secure/Trusted boot process for platform integrity. It can > be extended with TEE based measured boot process. > > + (3) CAAM > + > + Relies on the High Assurance Boot (HAB) mechanism of NXP SoCs > + for platform integrity. > + > * Interfaces and APIs > > (1) TPM > @@ -74,10 +90,13 @@ safe. > TEEs have well-documented, standardized client interface and APIs. For > more details refer to ``Documentation/staging/tee.rst``. > > + (3) CAAM > + > + Interface is specific to silicon vendor. > > * Threat model > > - The strength and appropriateness of a particular TPM or TEE for a given > + The strength and appropriateness of a particular trust source for a given > purpose must be assessed when using them to protect security-relevant data. > > > @@ -104,8 +123,14 @@ selected trust source: > from platform specific hardware RNG or a software based Fortuna CSPRNG > which can be seeded via multiple entropy sources. > > + * CAAM: Kernel RNG > + > + The normal kernel random number generator is used. To seed it from the > + CAAM HWRNG, enable CRYPTO_DEV_FSL_CAAM_RNG_API and ensure the device > + can be probed. > + > Optionally, users may specify ``trusted.kernel_rng=1`` on the kernel > -command-line to override the used RNG with the kernel's random number pool. > +command-line to force use of the kernel's random number pool. > > Encrypted Keys > -------------- > @@ -192,6 +217,19 @@ Usage:: > specific to TEE device implementation. The key length for new keys is always > in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). > > +Trusted Keys usage: CAAM > +------------------------ > + > +Usage:: > + > + keyctl add trusted name "new keylen" ring > + keyctl add trusted name "load hex_blob" ring > + keyctl print keyid > + > +"keyctl print" returns an ASCII hex copy of the sealed key, which is in format > +specific to CAAM device implementation. The key length for new keys is always > +in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). > + > Encrypted Keys usage > -------------------- > > diff --git a/MAINTAINERS b/MAINTAINERS > index a4a0c2baaf27..2c6514759222 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -10364,6 +10364,15 @@ S: Supported > F: include/keys/trusted_tee.h > F: security/keys/trusted-keys/trusted_tee.c > > +KEYS-TRUSTED-CAAM > +M: Ahmad Fatoum > +R: Pengutronix Kernel Team > +L: linux-integrity@vger.kernel.org > +L: keyrings@vger.kernel.org > +S: Supported > +F: include/keys/trusted_caam.h > +F: security/keys/trusted-keys/trusted_caam.c > + > KEYS/KEYRINGS > M: David Howells > M: Jarkko Sakkinen > diff --git a/include/keys/trusted_caam.h b/include/keys/trusted_caam.h > new file mode 100644 > index 000000000000..2fba0996b0b0 > --- /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 > + */ > + > +#ifndef __CAAM_TRUSTED_KEY_H > +#define __CAAM_TRUSTED_KEY_H > + > +extern struct trusted_key_ops caam_trusted_key_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..01adfd18adda > --- /dev/null > +++ b/security/keys/trusted-keys/trusted_caam.c > @@ -0,0 +1,74 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum > + */ > + > +#include > +#include > +#include > +#include > +#include > + > +static struct caam_blob_priv *blobifier; > + > +#define KEYMOD "kernel:trusted" > + > +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 length = p->key_len + CAAM_BLOB_OVERHEAD; > + int ret; > + > + ret = caam_encap_blob(blobifier, KEYMOD, p->key, p->blob, length); > + if (ret) > + return ret; > + > + p->blob_len = length; > + return 0; > +} > + > +static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob) > +{ > + int length = p->blob_len; > + int ret; > + > + ret = caam_decap_blob(blobifier, KEYMOD, p->blob, p->key, length); > + if (ret) > + return ret; > + > + p->key_len = length - CAAM_BLOB_OVERHEAD; > + 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 caam_trusted_key_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 d2b7626cde8b..305e44651180 100644 > --- a/security/keys/trusted-keys/trusted_core.c > +++ b/security/keys/trusted-keys/trusted_core.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -29,7 +30,7 @@ MODULE_PARM_DESC(kernel_rng, "Generate key material from kernel 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", &caam_trusted_key_ops }, > +#endif > }; > > DEFINE_STATIC_CALL_NULL(trusted_key_init, *trusted_key_sources[0].ops->init); > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |