From patchwork Fri Nov 11 23:16:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 13040914 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 C6A61C4332F for ; Fri, 11 Nov 2022 23:20:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234575AbiKKXUN (ORCPT ); Fri, 11 Nov 2022 18:20:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234320AbiKKXTy (ORCPT ); Fri, 11 Nov 2022 18:19:54 -0500 Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 570378292F for ; Fri, 11 Nov 2022 15:19:49 -0800 (PST) Received: by mail-pl1-x636.google.com with SMTP id io19so5366583plb.8 for ; Fri, 11 Nov 2022 15:19:49 -0800 (PST) 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=0i0QEQiN8N6kWJaFnnOPreeJ6mOVw1qdLR4E8EZb574=; b=j0sOuXL3t/5MxHh4ziRJcxsV6WuCyyRXKIUnXkmE9l2HHtMnM2zwez5AC0YhPLvPKr lfjYYzI0IOdaR0Tk+uk0AfLK/Rh1SvJxA29G2dXPRsKFpblpjDjAMSlYidKoY8TIM7vQ 9vu8va++By1TIkdKup+QjSA9y0T72AksG31ws= 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=0i0QEQiN8N6kWJaFnnOPreeJ6mOVw1qdLR4E8EZb574=; b=qDvv0ffYWCYTaCo5/CWfcz6wJMDBXxgXmebOWM2WDlqKrSthAIU2ARN3pPMcK/FPeO lHZ6RCm1YjmrIDnqqnnPtujGNrsLgIR5qK/fRYqZOkP4mEQTUAs9J3HVOwggzZLStIxL zLMxHL2Xg5N5wIR3fbi/kpEdJju+992RHndPgt4taAdiMpA3ygLCAhGM+PL1mM9A4B12 RTgv+P+56OyzI49vA0SEJOqLVsKI0XUYPja2GVdo3WxjBLf/2wmYERr3Aj6IQoq+taeF TjL/+fng5JrZ+PTioDg8oVXWtj/MMmnHaMd0FvPpd3VkT9/+hL5uL55tVoyhKH0e/+ic Mbgw== X-Gm-Message-State: ANoB5pml7bUlJNFr2nmL8Mdxu/XCmWI0hKq7XI8JDHzwgMcOQeAOPAba 6IFMffjRWRmMyiesK+4jT4EMvQ== X-Google-Smtp-Source: AA0mqf6KdQhIsONTKfxNTXU4F9A2vRgqSgfniE81X2SnNX8zVkszwxquPC+K1ejg5yLANg8SEckDyw== X-Received: by 2002:a17:90b:1891:b0:210:4438:2d40 with SMTP id mn17-20020a17090b189100b0021044382d40mr4125013pjb.196.1668208788735; Fri, 11 Nov 2022 15:19:48 -0800 (PST) Received: from evgreen-glaptop.lan ([98.45.28.95]) by smtp.gmail.com with ESMTPSA id x128-20020a623186000000b0056da2ad6503sm2106900pfx.39.2022.11.11.15.19.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Nov 2022 15:19:48 -0800 (PST) From: Evan Green To: linux-kernel@vger.kernel.org Cc: corbet@lwn.net, linux-integrity@vger.kernel.org, Eric Biggers , gwendal@chromium.org, dianders@chromium.org, apronin@chromium.org, Pavel Machek , Ben Boeckel , rjw@rjwysocki.net, jejb@linux.ibm.com, Kees Cook , dlunev@google.com, zohar@linux.ibm.com, Matthew Garrett , jarkko@kernel.org, linux-pm@vger.kernel.org, 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 v5 05/11] security: keys: trusted: Allow storage of PCR values in creation data Date: Fri, 11 Nov 2022 15:16:30 -0800 Message-Id: <20221111151451.v5.5.I32591db064b6cdc91850d777f363c9d05c985b39@changeid> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog In-Reply-To: <20221111231636.3748636-1-evgreen@chromium.org> References: <20221111231636.3748636-1-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 --- Changes in v5: - Make Matthew's tag match author 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 ff2aede8986236..3d84c3d41bdee1 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -428,7 +428,7 @@ 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++) { @@ -497,7 +497,28 @@ 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;