From patchwork Thu Nov 3 18:01:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 13030776 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 3F914C4167D for ; Thu, 3 Nov 2022 18:04:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229485AbiKCSEv (ORCPT ); Thu, 3 Nov 2022 14:04:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229809AbiKCSEG (ORCPT ); Thu, 3 Nov 2022 14:04:06 -0400 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2543823BC2 for ; Thu, 3 Nov 2022 11:01:47 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id b11so2404125pjp.2 for ; Thu, 03 Nov 2022 11:01:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=izZdOIN6JWP3fwMuNlCfXVu66JA2QFEY9SoPm54SNBw=; b=MOY3PJGr2LIy205MrPpag/ClsGw4MP56tI7WpOwNj6gRfuTiQCVn98MtRZStlxteOr z/rYnBoJ3tFl3LO6m2/egnvL4bcl7xkZx16guu7qdEyEmyMdVtcyQ9dR/pPXZQo6EsME JCOc9PvVPmrBN7ZLPAp3bUoEUQZ3DsvlFd5so= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=izZdOIN6JWP3fwMuNlCfXVu66JA2QFEY9SoPm54SNBw=; b=d0+LhGCtie0uwnYDdZ8yQkX4Jly7mhfVEG26T3FrbcimuFylGakQtTFTLeBbtKOeaN JcD9nN8ikN5rJEnoAismL6dNWIA3I2h0Mr+X7uEA7N94Pzh5m8hwLiEywanY2ZI/gaHv NPSJoNbbSq5J8b6Ctkl4f3jRZ6vSMhkzLOMV5+y1B2lXtLJBhZW7CiHfBlQBfpUOAk9L rQk3Bj5xN53RPAAIE7tijxh3mIHIiZC97w6LYoMsMn6/6nvQS7LWf7PFW2GiuTixecMi OHdo/FvK9hUgeptSLUJNb7NBlMK0rHqgdljSfPoHBXp2GpeDug2imbNPwku4u8jDqL9i AqPQ== X-Gm-Message-State: ACrzQf29avluf8HS0WXJMog0UPkYC7pW7brtymcZsKE5vSYwDf1ZfMB1 8ABz9imzxi/4WahEAWnxjdteOA== X-Google-Smtp-Source: AMsMyM6RmbXOOHxWXmI1WbxbS7/D6I8ewM4LRqfQX2jVykTakTV/EqKIJaeg9+BsosfNX6F7K9BLXw== X-Received: by 2002:a17:90a:540e:b0:210:1e26:9422 with SMTP id z14-20020a17090a540e00b002101e269422mr31496427pjh.100.1667498506839; Thu, 03 Nov 2022 11:01:46 -0700 (PDT) Received: from evgreen-glaptop.lan ([98.45.28.95]) by smtp.gmail.com with ESMTPSA id t12-20020a1709027fcc00b00177fb862a87sm1000277plb.20.2022.11.03.11.01.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Nov 2022 11:01:46 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: corbet@lwn.net, linux-pm@vger.kernel.org, rjw@rjwysocki.net, gwendal@chromium.org, apronin@chromium.org, Pavel Machek , Kees Cook , Matthew Garrett , linux-integrity@vger.kernel.org, jejb@linux.ibm.com, zohar@linux.ibm.com, dlunev@google.com, Eric Biggers , Ben Boeckel , jarkko@kernel.org, Matthew Garrett , Matthew Garrett , Evan Green , Ben Boeckel , David Howells , James Morris , Paul Moore , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-doc@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v4 05/11] security: keys: trusted: Allow storage of PCR values in creation data Date: Thu, 3 Nov 2022 11:01:13 -0700 Message-Id: <20221103105558.v4.5.I32591db064b6cdc91850d777f363c9d05c985b39@changeid> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog In-Reply-To: <20221103180120.752659-1-evgreen@chromium.org> References: <20221103180120.752659-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: From: Matthew Garrett When TPMs generate keys, they can also generate some information describing the state of the PCRs at creation time. This data can then later be certified by the TPM, allowing verification of the PCR values. This allows us to determine the state of the system at the time a key was generated. Add an additional argument to the trusted key creation options, allowing the user to provide the set of PCRs that should have their values incorporated into the creation data. Link: https://lore.kernel.org/lkml/20210220013255.1083202-6-matthewgarrett@google.com/ Signed-off-by: Matthew Garrett Signed-off-by: Evan Green Reviewed-by: Ben Boeckel Reviewed-by: Kees Cook --- (no changes since v3) Changes in v3: - Clarified creationpcrs documentation (Ben) .../security/keys/trusted-encrypted.rst | 6 +++++ include/keys/trusted-type.h | 1 + security/keys/trusted-keys/trusted_tpm1.c | 9 +++++++ security/keys/trusted-keys/trusted_tpm2.c | 25 +++++++++++++++++-- 4 files changed, 39 insertions(+), 2 deletions(-) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 9bc9db8ec6517c..a1872964fe862f 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -199,6 +199,12 @@ Usage:: policyhandle= handle to an authorization policy session that defines the same policy and with the same hash algorithm as was used to seal the key. + creationpcrs= hex integer representing the set of PCRs to be + included in the creation data. For each bit set, the + corresponding PCR will be included in the key creation + data. Bit 0 corresponds to PCR0. Currently only the first + PC standard 24 PCRs are supported on the currently active + bank. Leading zeroes are optional. TPM2 only. "keyctl print" returns an ascii hex copy of the sealed key, which is in standard TPM_STORED_DATA format. The key length for new keys are always in bytes. diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index 209086fed240a5..8523d41507b2a4 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -54,6 +54,7 @@ struct trusted_key_options { uint32_t policydigest_len; unsigned char policydigest[MAX_DIGEST_SIZE]; uint32_t policyhandle; + uint32_t creation_pcrs; }; struct trusted_key_ops { diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index aa108bea6739b3..2975827c01bec0 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -713,6 +713,7 @@ enum { Opt_hash, Opt_policydigest, Opt_policyhandle, + Opt_creationpcrs, }; static const match_table_t key_tokens = { @@ -725,6 +726,7 @@ static const match_table_t key_tokens = { {Opt_hash, "hash=%s"}, {Opt_policydigest, "policydigest=%s"}, {Opt_policyhandle, "policyhandle=%s"}, + {Opt_creationpcrs, "creationpcrs=%s"}, {Opt_err, NULL} }; @@ -858,6 +860,13 @@ static int getoptions(char *c, struct trusted_key_payload *pay, return -EINVAL; opt->policyhandle = handle; break; + case Opt_creationpcrs: + if (!tpm2) + return -EINVAL; + res = kstrtoint(args[0].from, 16, &opt->creation_pcrs); + if (res < 0) + return -EINVAL; + break; default: return -EINVAL; } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index e1388d7d799a36..a7ad83bc0e5396 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -401,7 +401,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, struct tpm_buf buf; u32 hash; u32 flags; - int i; + int i, j; int rc; for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) { @@ -470,7 +470,28 @@ int tpm2_seal_trusted(struct tpm_chip *chip, tpm_buf_append_u16(&buf, 0); /* creation PCR */ - tpm_buf_append_u32(&buf, 0); + if (options->creation_pcrs) { + /* One bank */ + tpm_buf_append_u32(&buf, 1); + /* Which bank to use */ + tpm_buf_append_u16(&buf, hash); + /* Length of the PCR bitmask */ + tpm_buf_append_u8(&buf, 3); + /* PCR bitmask */ + for (i = 0; i < 3; i++) { + char tmp = 0; + + for (j = 0; j < 8; j++) { + char bit = (i * 8) + j; + + if (options->creation_pcrs & (1 << bit)) + tmp |= (1 << j); + } + tpm_buf_append_u8(&buf, tmp); + } + } else { + tpm_buf_append_u32(&buf, 0); + } if (buf.flags & TPM_BUF_OVERFLOW) { rc = -E2BIG;