From patchwork Wed Mar 16 16:43:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ahmad Fatoum X-Patchwork-Id: 12782962 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 86992C433EF for ; Wed, 16 Mar 2022 16:44:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357512AbiCPQpY (ORCPT ); Wed, 16 Mar 2022 12:45:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357477AbiCPQpT (ORCPT ); Wed, 16 Mar 2022 12:45:19 -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 76F2929C86 for ; Wed, 16 Mar 2022 09:44:04 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nUWkM-0003gT-6s; Wed, 16 Mar 2022 17:43:38 +0100 Received: from afa by dude.hi.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1nUWkJ-007DX5-Tf; Wed, 16 Mar 2022 17:43:35 +0100 From: Ahmad Fatoum To: Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , James Bottomley , Mimi Zohar , Sumit Garg , David Howells , Herbert Xu , "David S. Miller" Cc: kernel@pengutronix.de, Andreas Rammhold , Tim Harvey , Ahmad Fatoum , David Gstir , Richard Weinberger , Matthias Schiffer , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org Subject: [PATCH v6 1/4] KEYS: trusted: allow use of TEE as backend without TCG_TPM support Date: Wed, 16 Mar 2022 17:43:32 +0100 Message-Id: <20220316164335.1720255-2-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220316164335.1720255-1-a.fatoum@pengutronix.de> References: <20220316164335.1720255-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 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: With recent rework, trusted keys are no longer limited to TPM as trust source. The Kconfig symbol is unchanged however leading to a few issues: - TCG_TPM is required, even if only TEE is to be used - Enabling TCG_TPM, but excluding it from available trusted sources is not possible - TEE=m && TRUSTED_KEYS=y will lead to TEE support being silently dropped, which is not the best user experience Remedy these issues by introducing two new boolean Kconfig symbols: TRUSTED_KEYS_TPM and TRUSTED_KEYS_TEE with the appropriate dependencies. Any new code depending on the TPM trusted key backend in particular or symbols exported by it will now need to explicitly state that it depends on TRUSTED_KEYS && TRUSTED_KEYS_TPM The latter to ensure the dependency is built and the former to ensure it's reachable for module builds. There are no such users yet. Reviewed-by: Sumit Garg Reviewed-by: Jarkko Sakkinen Tested-By: Andreas Rammhold Tested-By: Tim Harvey Signed-off-by: Ahmad Fatoum --- v5 -> v6: - Rebased on asym_tpm removal v4 -> v5: - collected Jarkko's Reviewed-by v3 -> v4: - rebased on top of Andreas' regression fix and pulled it back into series v2 -> v3: - factored this patch out as a fix for backporting v1 -> v2: - Move rest of TPM-related selects from TRUSTED_KEYS to TRUSTED_KEYS_TPM (Sumit) - Remove left-over line in Makefile (Sumit) - added Fixes: tag - adjust commit message to reference the regression reported by Andreas - have ASYMMETRIC_TPM_KEY_SUBTYPE depend on TRUSTED_KEYS_TPM, because it references global symbols that are exported by the trusted key TPM backend. [1]: https://lore.kernel.org/linux-integrity/f8285eb0135ba30c9d846cf9dd395d1f5f8b1efc.1624364386.git-series.a.fatoum@pengutronix.de/ [2]: https://lore.kernel.org/linux-integrity/20210719091335.vwfebcpkf4pag3wm@wrt/T/#t To: Jarkko Sakkinen To: James Morris To: "Serge E. Hallyn" To: James Bottomley To: Mimi Zohar To: Sumit Garg To: David Howells To: Herbert Xu To: "David S. Miller" Cc: David Gstir Cc: Richard Weinberger Cc: Matthias Schiffer Cc: keyrings@vger.kernel.org Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: linux-integrity@vger.kernel.org --- security/keys/Kconfig | 18 ++++++-------- security/keys/trusted-keys/Kconfig | 29 +++++++++++++++++++++++ security/keys/trusted-keys/Makefile | 8 +++---- security/keys/trusted-keys/trusted_core.c | 4 ++-- 4 files changed, 42 insertions(+), 17 deletions(-) create mode 100644 security/keys/trusted-keys/Kconfig diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 969122c7b92f..826cd0904f9a 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -70,23 +70,19 @@ config BIG_KEYS config TRUSTED_KEYS tristate "TRUSTED KEYS" - depends on KEYS && TCG_TPM - select CRYPTO - select CRYPTO_HMAC - select CRYPTO_SHA1 - select CRYPTO_HASH_INFO - select ASN1_ENCODER - select OID_REGISTRY - select ASN1 + depends on KEYS help This option provides support for creating, sealing, and unsealing keys in the kernel. Trusted keys are random number symmetric keys, - generated and RSA-sealed by the TPM. The TPM only unseals the keys, - if the boot PCRs and other criteria match. Userspace will only ever - see encrypted blobs. + generated and sealed by a trust source selected at kernel boot-time. + Userspace will only ever see encrypted blobs. If you are unsure as to whether this is required, answer N. +if TRUSTED_KEYS +source "security/keys/trusted-keys/Kconfig" +endif + config ENCRYPTED_KEYS tristate "ENCRYPTED KEYS" depends on KEYS diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig new file mode 100644 index 000000000000..fc4abd581abb --- /dev/null +++ b/security/keys/trusted-keys/Kconfig @@ -0,0 +1,29 @@ +config TRUSTED_KEYS_TPM + bool "TPM-based trusted keys" + depends on TCG_TPM >= TRUSTED_KEYS + default y + select CRYPTO + select CRYPTO_HMAC + select CRYPTO_SHA1 + select CRYPTO_HASH_INFO + select ASN1_ENCODER + select OID_REGISTRY + select ASN1 + help + Enable use of the Trusted Platform Module (TPM) as trusted key + backend. Trusted keys are random number symmetric keys, + which will be generated and RSA-sealed by the TPM. + The TPM only unseals the keys, if the boot PCRs and other + criteria match. + +config TRUSTED_KEYS_TEE + bool "TEE-based trusted keys" + depends on TEE >= TRUSTED_KEYS + default y + help + Enable use of the Trusted Execution Environment (TEE) as trusted + key backend. + +if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE +comment "No trust source selected!" +endif diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index feb8b6c3cc79..2e2371eae4d5 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -5,10 +5,10 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_core.o -trusted-y += trusted_tpm1.o +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o $(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h -trusted-y += trusted_tpm2.o -trusted-y += tpm2key.asn1.o +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o -trusted-$(CONFIG_TEE) += trusted_tee.o +trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c index 9b9d3ef79cbe..7cdbd16aed30 100644 --- a/security/keys/trusted-keys/trusted_core.c +++ b/security/keys/trusted-keys/trusted_core.c @@ -27,10 +27,10 @@ module_param_named(source, trusted_key_source, charp, 0); MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)"); static const struct trusted_key_source trusted_key_sources[] = { -#if IS_REACHABLE(CONFIG_TCG_TPM) +#if defined(CONFIG_TRUSTED_KEYS_TPM) { "tpm", &trusted_key_tpm_ops }, #endif -#if IS_REACHABLE(CONFIG_TEE) +#if defined(CONFIG_TRUSTED_KEYS_TEE) { "tee", &trusted_key_tee_ops }, #endif };