From patchwork Mon Oct 11 10:02:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ahmad Fatoum X-Patchwork-Id: 12549621 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA177C433EF for ; Mon, 11 Oct 2021 10:03:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEC6961038 for ; Mon, 11 Oct 2021 10:03:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235781AbhJKKFT (ORCPT ); Mon, 11 Oct 2021 06:05:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235762AbhJKKFP (ORCPT ); Mon, 11 Oct 2021 06:05:15 -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 7762DC061745 for ; Mon, 11 Oct 2021 03:03:15 -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 1mZs8v-0006Sj-Kj; Mon, 11 Oct 2021 12:02:49 +0200 Received: from afa by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mZs8r-0002cg-Rq; Mon, 11 Oct 2021 12:02:45 +0200 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 , 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 v4 1/5] KEYS: trusted: allow use of TEE as backend without TCG_TPM support Date: Mon, 11 Oct 2021 12:02:34 +0200 Message-Id: X-Mailer: git-send-email 2.30.2 In-Reply-To: References: 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-integrity@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org 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 code depending on the TPM trusted key backend 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. This currently only affects CONFIG_ASYMMETRIC_TPM_KEY_SUBTYPE, so it's fixed up here as well. Reviewed-by: Sumit Garg Tested-By: Andreas Rammhold Tested-By: Tim Harvey Signed-off-by: Ahmad Fatoum Reviewed-by: Jarkko Sakkinen --- 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: 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 --- crypto/asymmetric_keys/Kconfig | 2 +- security/keys/Kconfig | 18 +++++---------- security/keys/trusted-keys/Kconfig | 29 ++++++++++++++++++++++++- security/keys/trusted-keys/Makefile | 8 +++---- security/keys/trusted-keys/trusted_core.c | 4 +-- 5 files changed, 43 insertions(+), 18 deletions(-) create mode 100644 security/keys/trusted-keys/Kconfig diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index 1f1f004dc757..8886eddbf881 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -25,7 +25,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE config ASYMMETRIC_TPM_KEY_SUBTYPE tristate "Asymmetric TPM backed private key subtype" depends on TCG_TPM - depends on TRUSTED_KEYS + depends on TRUSTED_KEYS && TRUSTED_KEYS_TPM select CRYPTO_HMAC select CRYPTO_SHA1 select CRYPTO_HASH_INFO diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 64b81abd087e..9ec302962fe2 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 5b35f1b87644..8cab69e5d0da 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 };