From patchwork Fri Apr 15 20:56:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Ahmad Fatoum X-Patchwork-Id: 12815306 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 91EE6C4332F for ; Fri, 15 Apr 2022 20:58:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352970AbiDOVAk (ORCPT ); Fri, 15 Apr 2022 17:00:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345862AbiDOVAe (ORCPT ); Fri, 15 Apr 2022 17:00:34 -0400 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 6BF1860DAD for ; Fri, 15 Apr 2022 13:57:42 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nfT0A-0002iH-W7; Fri, 15 Apr 2022 22:57:11 +0200 Received: from [2a0a:edc0:0:1101:1d::ac] (helo=dude04.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1nfT0A-003FIt-BG; Fri, 15 Apr 2022 22:57:08 +0200 Received: from afa by dude04.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1nfT07-000C0M-J0; Fri, 15 Apr 2022 22:57:07 +0200 From: Ahmad Fatoum To: Jonathan Corbet , David Howells , Jarkko Sakkinen , James Bottomley , Mimi Zohar Cc: kernel@pengutronix.de, Ahmad Fatoum , James Morris , "Serge E. Hallyn" , =?utf-8?q?Horia_Geant=C4=83?= , Pankaj Gupta , Herbert Xu , "David S. Miller" , Eric Biggers , Jan Luebbe , David Gstir , Richard Weinberger , Franck LENORMAND , Matthias Schiffer , 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 Subject: [PATCH v7 5/6] doc: trusted-encrypted: describe new CAAM trust source Date: Fri, 15 Apr 2022 22:56:46 +0200 Message-Id: <20220415205647.46056-6-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220415205647.46056-1-a.fatoum@pengutronix.de> References: <20220415205647.46056-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: afa@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-security-module@vger.kernel.org Precedence: bulk List-ID: Update documentation for trusted key use with the Cryptographic Acceleration and Assurance Module (CAAM), an IP on NXP SoCs. Signed-off-by: Ahmad Fatoum --- v6 -> v7: - docs update split off as new Patch (Jarkko) - fixed typo in "Trusted Keys usage: CAAM" section 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: Pankaj Gupta Cc: Herbert Xu Cc: "David S. Miller" Cc: Eric Biggers Cc: Jan Luebbe Cc: David Gstir Cc: Richard Weinberger Cc: Franck LENORMAND Cc: Matthias Schiffer 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 --- .../security/keys/trusted-encrypted.rst | 40 ++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 2fe6fd1a2bbd..0bfb4c339748 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. @@ -104,6 +123,12 @@ 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 + is probed. + Users may override this by specifying ``trusted.rng=kernel`` on the kernel command-line to override the used RNG with the kernel's random number pool. @@ -193,6 +218,19 @@ 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 a +CAAM-specific format. The key length for new keys is always in bytes. +Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). + Encrypted Keys usage --------------------