From patchwork Tue Sep 27 16:49:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12990939 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 F353FC6FA8E for ; Tue, 27 Sep 2022 16:50:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233218AbiI0Quu (ORCPT ); Tue, 27 Sep 2022 12:50:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233237AbiI0QuI (ORCPT ); Tue, 27 Sep 2022 12:50:08 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7586E56B98 for ; Tue, 27 Sep 2022 09:50:02 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id d10so9078528pfh.6 for ; Tue, 27 Sep 2022 09:50:02 -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; bh=5nBgpNKzsdj6MGnq+ieEANFB3+OBuHFrCAD/K8T14mQ=; b=FATo9vuZTut0+55sKRQoF7Q0d0XgoVnuny/cBjrOPP8uEExZK4+44eMjWOk9IZNbzY gR2j7K3dtcsdMBKoLxUHrSEUcBzPp2s95Kdja19042qfwcRSzKS0DxrnyEsxc2H/5Ag4 xKCPqjXswjD3BlK475kLKbfTcyG8uUdqIf4aM= 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; bh=5nBgpNKzsdj6MGnq+ieEANFB3+OBuHFrCAD/K8T14mQ=; b=StDMgbikL3lFM16BmquwnG9OtQrsA1UVJwc/+X9VLz0sDM//v+iak8IdcYPEvI52k5 yY5ASoCSEyLXDQVGxwFvzvDX3PmA5o76TmXhr5eN1vE7jCewdx35BVOmapOLWWhtsLnk jkPkR6S7jE+ZF25KT4xjgjKpNyLZJKHGmR2lCL4328UfvZkPXuFNEVMXFnJyvZJW5ThU IPV2wlapHN2PrDHolzyxyGJBWzNZOpc1z3uuJ3YmhhYf7YcyiBXrk/AsY6dUkGxMOuva 4Hr4fbM+X1N4LCgTu99dAi3yJwhYX6MPURmG1wDkOONR49U4Q5saAxm35KpW4QA3/CW0 dTaQ== X-Gm-Message-State: ACrzQf1kG3vyT5elCHmxoi9Smwb7gVjNZ1dsHIsnz/lnTXUETb7G3gpq AeHlFJZgJ20Ze6h8pSVK9GZIVA== X-Google-Smtp-Source: AMsMyM7xllXajWOzanmc0BzTHihO8Omb0iNFfYp8ARnak/8g6+fx2BcYco5pVM/5jk2u6CAog7Wkhw== X-Received: by 2002:a05:6a00:16c4:b0:535:890:d4a with SMTP id l4-20020a056a0016c400b0053508900d4amr30331740pfc.0.1664297401878; Tue, 27 Sep 2022 09:50:01 -0700 (PDT) Received: from evgreen-glaptop.lan ([73.231.74.141]) by smtp.gmail.com with ESMTPSA id p13-20020a63950d000000b00434272fe870sm1753509pgd.88.2022.09.27.09.49.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Sep 2022 09:50:01 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: linux-integrity@vger.kernel.org, apronin@chromium.org, dlunev@google.com, jarkko@kernel.org, Pavel Machek , Ben Boeckel , rjw@rjwysocki.net, corbet@lwn.net, linux-pm@vger.kernel.org, zohar@linux.ibm.com, Kees Cook , Eric Biggers , jejb@linux.ibm.com, gwendal@chromium.org, Matthew Garrett , Evan Green , David Howells , James Morris , Paul Moore , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v3 04/11] security: keys: trusted: Include TPM2 creation data Date: Tue, 27 Sep 2022 09:49:15 -0700 Message-Id: <20220927094559.v3.4.Ieb1215f598bc9df56b0e29e5977eae4fcca25e15@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220927164922.3383711-1-evgreen@chromium.org> References: <20220927164922.3383711-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: In addition to the private key and public key, the TPM2_Create command may also return creation data, a creation hash, and a creation ticket. These fields allow the TPM to attest to the contents of a specified set of PCRs at the time the trusted key was created. Encrypted hibernation will use this to ensure that PCRs settable only by the kernel were set properly at the time of creation, indicating this is an authentic hibernate key. Encode these additional parameters into the ASN.1 created to represent the key blob. The new fields are made optional so that they don't bloat key blobs which don't need them, and to ensure interoperability with old blobs. Signed-off-by: Evan Green --- Changes in v3: - Fix SoB and -- note ordering (Kees) - Add comments describing the TPM2 spec type names for the new fields in tpm2key.asn1 (Kees) - Add len buffer checks in tpm2_key_encode() (Kees) This is a replacement for Matthew's original patch here: https://patchwork.kernel.org/patch/12096489/ That patch was written before the exported key format was switched to ASN.1. This patch accomplishes the same thing (saving, loading, and getting pointers to the creation data) while utilizing the new ASN.1 format. --- include/keys/trusted-type.h | 8 + security/keys/trusted-keys/tpm2key.asn1 | 15 +- security/keys/trusted-keys/trusted_tpm2.c | 216 +++++++++++++++++++--- 3 files changed, 213 insertions(+), 26 deletions(-) diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index 4eb64548a74f1a..209086fed240a5 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -22,15 +22,23 @@ #define MAX_BLOB_SIZE 512 #define MAX_PCRINFO_SIZE 64 #define MAX_DIGEST_SIZE 64 +#define MAX_CREATION_DATA 412 +#define MAX_TK 76 struct trusted_key_payload { struct rcu_head rcu; unsigned int key_len; unsigned int blob_len; + unsigned int creation_len; + unsigned int creation_hash_len; + unsigned int tk_len; unsigned char migratable; unsigned char old_format; unsigned char key[MAX_KEY_SIZE + 1]; unsigned char blob[MAX_BLOB_SIZE]; + unsigned char *creation; + unsigned char *creation_hash; + unsigned char *tk; }; struct trusted_key_options { diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 index f57f869ad60068..608f8d9ca95fa8 100644 --- a/security/keys/trusted-keys/tpm2key.asn1 +++ b/security/keys/trusted-keys/tpm2key.asn1 @@ -7,5 +7,18 @@ TPMKey ::= SEQUENCE { emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, parent INTEGER ({tpm2_key_parent}), pubkey OCTET STRING ({tpm2_key_pub}), - privkey OCTET STRING ({tpm2_key_priv}) + privkey OCTET STRING ({tpm2_key_priv}), + --- + --- A TPM2B_CREATION_DATA struct as returned from the TPM2_Create command. + --- + creationData [1] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_creation_data}), + --- + --- A TPM2B_DIGEST of the creationHash as returned from the TPM2_Create + --- command. + --- + creationHash [2] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_creation_hash}), + --- + --- A TPMT_TK_CREATION ticket as returned from the TPM2_Create command. + --- + creationTk [3] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_creation_tk}) } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 2b2c8eb258d5bd..e1388d7d799a36 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -33,19 +33,54 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, u8 *src, u32 len) { const int SCRATCH_SIZE = PAGE_SIZE; + u8 *end = src + len; u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); u8 *work = scratch, *work1; u8 *end_work = scratch + SCRATCH_SIZE; u8 *priv, *pub; + u8 *creation_data = NULL, *creation_hash = NULL, *creation_tk = NULL; + u16 creation_data_len, creation_hash_len = 0, creation_tk_len = 0; u16 priv_len, pub_len; + int rc; + + if (src + 2 > end) + return -EINVAL; priv_len = get_unaligned_be16(src) + 2; priv = src; src += priv_len; - + if (src + 2 > end) + return -EINVAL; pub_len = get_unaligned_be16(src) + 2; pub = src; + src += pub_len; + if (src + 2 > end) + return -EINVAL; + creation_data_len = get_unaligned_be16(src); + if (creation_data_len) { + creation_data_len += 2; + creation_data = src; + src += creation_data_len; + if (src + 2 > end) + return -EINVAL; + + creation_hash_len = get_unaligned_be16(src) + 2; + creation_hash = src; + src += creation_hash_len; + if (src + 2 > end) + return -EINVAL; + + /* + * The creation ticket (TPMT_TK_CREATION) consists of a 2 byte + * tag, 4 byte handle, and then a TPM2B_DIGEST, which is a 2 + * byte length followed by data. + */ + creation_tk_len = get_unaligned_be16(src + 6) + 8; + creation_tk = src; + if (creation_tk + creation_tk_len > end) + return -EINVAL; + } if (!scratch) return -ENOMEM; @@ -63,26 +98,81 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, } /* - * Assume both octet strings will encode to a 2 byte definite length + * Assume each octet string will encode to a 2 byte definite length. + * Each optional octet string consumes one extra byte. * - * Note: For a well behaved TPM, this warning should never - * trigger, so if it does there's something nefarious going on + * Note: For a well behaved TPM, this warning should never trigger, so + * if it does there's something nefarious going on */ - if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, - "BUG: scratch buffer is too small")) - return -EINVAL; + if (WARN(work - scratch + pub_len + priv_len + creation_data_len + + creation_hash_len + creation_tk_len + (7 * 5) + 3 > + SCRATCH_SIZE, + "BUG: scratch buffer is too small")) { + rc = -EINVAL; + goto err; + } work = asn1_encode_integer(work, end_work, options->keyhandle); work = asn1_encode_octet_string(work, end_work, pub, pub_len); work = asn1_encode_octet_string(work, end_work, priv, priv_len); + if (creation_data_len) { + u8 *scratch2 = kmalloc(SCRATCH_SIZE, GFP_KERNEL); + u8 *work2; + u8 *end_work2 = scratch2 + SCRATCH_SIZE; + + if (!scratch2) { + rc = -ENOMEM; + goto err; + } + + work2 = asn1_encode_octet_string(scratch2, + end_work2, + creation_data, + creation_data_len); + + work = asn1_encode_tag(work, + end_work, + 1, + scratch2, + work2 - scratch2); + + work2 = asn1_encode_octet_string(scratch2, + end_work2, + creation_hash, + creation_hash_len); + + work = asn1_encode_tag(work, + end_work, + 2, + scratch2, + work2 - scratch2); + + work2 = asn1_encode_octet_string(scratch2, + end_work2, + creation_tk, + creation_tk_len); + + work = asn1_encode_tag(work, + end_work, + 3, + scratch2, + work2 - scratch2); + + kfree(scratch2); + } work1 = payload->blob; work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob), scratch, work - scratch); - if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) - return PTR_ERR(work1); + if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) { + rc = PTR_ERR(work1); + goto err; + } return work1 - payload->blob; +err: + kfree(scratch); + return rc; } struct tpm2_key_context { @@ -91,15 +181,21 @@ struct tpm2_key_context { u32 pub_len; const u8 *priv; u32 priv_len; + const u8 *creation_data; + u32 creation_data_len; + const u8 *creation_hash; + u32 creation_hash_len; + const u8 *creation_tk; + u32 creation_tk_len; }; static int tpm2_key_decode(struct trusted_key_payload *payload, - struct trusted_key_options *options, - u8 **buf) + struct trusted_key_options *options) { + u64 data_len; int ret; struct tpm2_key_context ctx; - u8 *blob; + u8 *blob, *buf; memset(&ctx, 0, sizeof(ctx)); @@ -108,21 +204,57 @@ static int tpm2_key_decode(struct trusted_key_payload *payload, if (ret < 0) return ret; - if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) + data_len = ctx.priv_len + ctx.pub_len + ctx.creation_data_len + + ctx.creation_hash_len + ctx.creation_tk_len; + + if (data_len > MAX_BLOB_SIZE) return -EINVAL; - blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); - if (!blob) + buf = kmalloc(data_len + 4, GFP_KERNEL); + if (!buf) return -ENOMEM; - *buf = blob; + blob = buf; options->keyhandle = ctx.parent; memcpy(blob, ctx.priv, ctx.priv_len); blob += ctx.priv_len; memcpy(blob, ctx.pub, ctx.pub_len); + blob += ctx.pub_len; + if (ctx.creation_data_len) { + memcpy(blob, ctx.creation_data, ctx.creation_data_len); + blob += ctx.creation_data_len; + } + + if (ctx.creation_hash_len) { + memcpy(blob, ctx.creation_hash, ctx.creation_hash_len); + blob += ctx.creation_hash_len; + } + + if (ctx.creation_tk_len) { + memcpy(blob, ctx.creation_tk, ctx.creation_tk_len); + blob += ctx.creation_tk_len; + } + + /* + * Copy the buffer back into the payload blob since the creation + * info will be used after loading. + */ + payload->blob_len = blob - buf; + memcpy(payload->blob, buf, payload->blob_len); + if (ctx.creation_data_len) { + payload->creation = payload->blob + ctx.priv_len + ctx.pub_len; + payload->creation_len = ctx.creation_data_len; + payload->creation_hash = payload->creation + ctx.creation_data_len; + payload->creation_hash_len = ctx.creation_hash_len; + payload->tk = payload->creation_hash + + payload->creation_hash_len; + + payload->tk_len = ctx.creation_tk_len; + } + kfree(buf); return 0; } @@ -185,6 +317,42 @@ int tpm2_key_priv(void *context, size_t hdrlen, return 0; } +int tpm2_key_creation_data(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_context *ctx = context; + + ctx->creation_data = value; + ctx->creation_data_len = vlen; + + return 0; +} + +int tpm2_key_creation_hash(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_context *ctx = context; + + ctx->creation_hash = value; + ctx->creation_hash_len = vlen; + + return 0; +} + +int tpm2_key_creation_tk(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_context *ctx = context; + + ctx->creation_tk = value; + ctx->creation_tk_len = vlen; + + return 0; +} + /** * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. * @@ -229,6 +397,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, struct trusted_key_options *options) { int blob_len = 0; + unsigned int offset; struct tpm_buf buf; u32 hash; u32 flags; @@ -317,13 +486,14 @@ int tpm2_seal_trusted(struct tpm_chip *chip, rc = -E2BIG; goto out; } - if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) { + offset = TPM_HEADER_SIZE + 4; + if (tpm_buf_length(&buf) < offset + blob_len) { rc = -EFAULT; goto out; } blob_len = tpm2_key_encode(payload, options, - &buf.data[TPM_HEADER_SIZE + 4], + &buf.data[offset], blob_len); out: @@ -370,13 +540,11 @@ static int tpm2_load_cmd(struct tpm_chip *chip, int rc; u32 attrs; - rc = tpm2_key_decode(payload, options, &blob); - if (rc) { - /* old form */ - blob = payload->blob; + rc = tpm2_key_decode(payload, options); + if (rc) payload->old_format = 1; - } + blob = payload->blob; /* new format carries keyhandle but old format doesn't */ if (!options->keyhandle) return -EINVAL; @@ -433,8 +601,6 @@ static int tpm2_load_cmd(struct tpm_chip *chip, (__be32 *) &buf.data[TPM_HEADER_SIZE]); out: - if (blob != payload->blob) - kfree(blob); tpm_buf_destroy(&buf); if (rc > 0) From patchwork Tue Sep 27 16:49:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12990940 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 58BBAC6FA92 for ; Tue, 27 Sep 2022 16:50:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233234AbiI0Qux (ORCPT ); Tue, 27 Sep 2022 12:50:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233253AbiI0QuK (ORCPT ); Tue, 27 Sep 2022 12:50:10 -0400 Received: from mail-pf1-x42e.google.com (mail-pf1-x42e.google.com [IPv6:2607:f8b0:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 061525851A for ; Tue, 27 Sep 2022 09:50:07 -0700 (PDT) Received: by mail-pf1-x42e.google.com with SMTP id 9so10164785pfz.12 for ; Tue, 27 Sep 2022 09:50:07 -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; bh=Osgivv1xZqrvAofoxgxtt3Fhv5buczncGhXN6IzEZgM=; b=MnrEQZGGGi7Zz5FsNy2Hp51B9vBhT3Qw6PnZqJ8R1qlLmr9ahYCagnw0WtklFIQ77J WB9FmgJGeez4cna1TcM4yZVBghJmmKK/4rqdTnorUHJKRzyIazqEyoYoDR0ScsJQaQgY Lb3shhu74tkzqegJoyfLluUZF7kePYYkzwBNc= 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; bh=Osgivv1xZqrvAofoxgxtt3Fhv5buczncGhXN6IzEZgM=; b=jeaZFB4y+Xy2y3G+32UbOY98u+Ze6kb4Y0F6wuASGqgIviIRGjPROi/q0gbsje0uS/ +n+JbXHxgrlpmDT+DJHf6dSww0JpIU/AwdDpuZyQUd/NzxceqSpA/om2W9WP278t3or9 jquqadX8FCQb4A2RNMTZYGs1qa8XpV7SavBtfGY5N3NrAicKyUaFoURBTFlwppxBpC5t Ps4rzsOVRvkZCjtQB+ODqJbsucoPbwM17Gr9iPlzxDbGza1pVgKUF/iGRasbiVKw1sWX 8Gjh3SLuwo067UL7pfFzCc5nHNnzDUddsi0fmsnNDO7dtk2tgoY6qeFPdu/hXKlgj03e ZAWw== X-Gm-Message-State: ACrzQf0J7t4gZsE9hDsAmNQwQB7FEURHQuM0oNViPbnBmQ9+Ui4YSmVI cIrw9vzLccUHl1vsUQoGIHgCoQ== X-Google-Smtp-Source: AMsMyM6zg6GU62faRZTKgXdQyh5+c6x1H6TPVhoa0Pj8IbzdKDRvUzr6V2vk1Pk1Ou1mPyi78I5E1w== X-Received: by 2002:a63:8643:0:b0:440:2914:c57 with SMTP id x64-20020a638643000000b0044029140c57mr921010pgd.604.1664297406379; Tue, 27 Sep 2022 09:50:06 -0700 (PDT) Received: from evgreen-glaptop.lan ([73.231.74.141]) by smtp.gmail.com with ESMTPSA id p13-20020a63950d000000b00434272fe870sm1753509pgd.88.2022.09.27.09.50.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Sep 2022 09:50:05 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: linux-integrity@vger.kernel.org, apronin@chromium.org, dlunev@google.com, jarkko@kernel.org, Pavel Machek , Ben Boeckel , rjw@rjwysocki.net, corbet@lwn.net, linux-pm@vger.kernel.org, zohar@linux.ibm.com, Kees Cook , Eric Biggers , jejb@linux.ibm.com, gwendal@chromium.org, Matthew Garrett , Matthew Garrett , Matthew Garrett , Evan Green , 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 v3 05/11] security: keys: trusted: Allow storage of PCR values in creation data Date: Tue, 27 Sep 2022 09:49:16 -0700 Message-Id: <20220927094559.v3.5.I32591db064b6cdc91850d777f363c9d05c985b39@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220927164922.3383711-1-evgreen@chromium.org> References: <20220927164922.3383711-1-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 --- 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 0bfb4c33974890..fd9c7cd72a6254 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; From patchwork Tue Sep 27 16:49:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12990941 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 12739C6FA82 for ; Tue, 27 Sep 2022 16:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232607AbiI0QvN (ORCPT ); Tue, 27 Sep 2022 12:51:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233265AbiI0QuO (ORCPT ); Tue, 27 Sep 2022 12:50:14 -0400 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 DAC1A5FDE6 for ; Tue, 27 Sep 2022 09:50:11 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id d24so9615639pls.4 for ; Tue, 27 Sep 2022 09:50:11 -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; bh=Y5IIjhYcp6pllpBstUKppAn5vOER8d/5NeFiMFC+AZ4=; b=KtOFCJo06CDDr+BAxpO/ygHq6cEPoZynIvZgbfM1UHBzDuHQUJ5CbEi4ZoiG9svTxR pKrL9ectGlvt8OIUq4guOEuCs5QSQsuOcd71aO/aHyyn3G+JRcxLp4QddwkV6WaeekXJ p/dLQjZ0L0skPBXMyfxZMM9L8/y7cz6FrOn3c= 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; bh=Y5IIjhYcp6pllpBstUKppAn5vOER8d/5NeFiMFC+AZ4=; b=hBuXVR0ox8L3VTdJvIAVBIMlZdaT7ySz+Xqvm7FBqCh+h2osxNfIpc/VhRkL0xO29T vFJuAqKXwXOto8tMJE2kSEaiE1Za71Wyzw6Ls5UJDssWONWrzEzv/ccBYaowldz7kRiA c2s1TcqI3CQ4cDheAUtfeDGZnXOuRCfnHy06Tiphv/rmdaCd01986t6752ye9w/N2vAN H354Dsxt0noBU9RjtndaQpv5HX5CwjKMm3ZagqFn6gieCFv28pZTfjrxhctbh0qY+fDh fv0Mxu+dOEVIOqwTj3sPgqazFU20WA0c4U6UztSq99LK1/ewPaVYLhlzQggFxaI9cf+s V/0g== X-Gm-Message-State: ACrzQf3pXAzZ+9jbiyVdTpcadbKHi7gFC53mBZnwiP3RORueTyAyGWV6 katFuez2jKl1h0WyXT6Id5YQxw== X-Google-Smtp-Source: AMsMyM4ctE5xgYsg5LsKG4IlQynNCZ/9CXt4peHvCFJnISdc8MiKkgtgmmifk2yFFB9mBJnY2OBKVA== X-Received: by 2002:a17:90a:1096:b0:202:c5a9:bf1e with SMTP id c22-20020a17090a109600b00202c5a9bf1emr5669884pja.3.1664297411430; Tue, 27 Sep 2022 09:50:11 -0700 (PDT) Received: from evgreen-glaptop.lan ([73.231.74.141]) by smtp.gmail.com with ESMTPSA id p13-20020a63950d000000b00434272fe870sm1753509pgd.88.2022.09.27.09.50.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Sep 2022 09:50:10 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: linux-integrity@vger.kernel.org, apronin@chromium.org, dlunev@google.com, jarkko@kernel.org, Pavel Machek , Ben Boeckel , rjw@rjwysocki.net, corbet@lwn.net, linux-pm@vger.kernel.org, zohar@linux.ibm.com, Kees Cook , Eric Biggers , jejb@linux.ibm.com, gwendal@chromium.org, Matthew Garrett , Evan Green , Matthew Garrett , David Howells , Hao Wu , James Morris , Matthew Garrett , Paul Moore , "Serge E. Hallyn" , axelj , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v3 06/11] security: keys: trusted: Verify creation data Date: Tue, 27 Sep 2022 09:49:17 -0700 Message-Id: <20220927094559.v3.6.I6cdb522cb5ea28fcd1e35b4cd92cbd067f99269a@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220927164922.3383711-1-evgreen@chromium.org> References: <20220927164922.3383711-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: If a loaded key contains creation data, ask the TPM to verify that creation data. This allows users like encrypted hibernate to know that the loaded and parsed creation data has not been tampered with. Suggested-by: Matthew Garrett Signed-off-by: Evan Green --- Source material for this change is at: https://patchwork.kernel.org/project/linux-pm/patch/20210220013255.1083202-9-matthewgarrett@google.com/ Changes in v3: - Changed funky tag to suggested-by (Kees). Matthew, holler if you want something different. Changes in v2: - Adjust hash len by 2 due to new ASN.1 storage, and add underflow check. include/linux/tpm.h | 1 + security/keys/trusted-keys/trusted_tpm2.c | 77 ++++++++++++++++++++++- 2 files changed, 77 insertions(+), 1 deletion(-) diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 8320cbac6f4009..438f8bc0a50582 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -224,6 +224,7 @@ enum tpm2_command_codes { TPM2_CC_SELF_TEST = 0x0143, TPM2_CC_STARTUP = 0x0144, TPM2_CC_SHUTDOWN = 0x0145, + TPM2_CC_CERTIFYCREATION = 0x014A, TPM2_CC_NV_READ = 0x014E, TPM2_CC_CREATE = 0x0153, TPM2_CC_LOAD = 0x0157, diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index a7ad83bc0e5396..c76a1b5a2e8471 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -703,6 +703,74 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, return rc; } +/** + * tpm2_certify_creation() - execute a TPM2_CertifyCreation command + * + * @chip: TPM chip to use + * @payload: the key data in clear and encrypted form + * @blob_handle: the loaded TPM handle of the key + * + * Return: 0 on success + * -EINVAL on tpm error status + * < 0 error from tpm_send or tpm_buf_init + */ +static int tpm2_certify_creation(struct tpm_chip *chip, + struct trusted_key_payload *payload, + u32 blob_handle) +{ + struct tpm_header *head; + struct tpm_buf buf; + int rc; + + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CERTIFYCREATION); + if (rc) + return rc; + + /* Use TPM_RH_NULL for signHandle */ + tpm_buf_append_u32(&buf, 0x40000007); + + /* Object handle */ + tpm_buf_append_u32(&buf, blob_handle); + + /* Auth */ + tpm_buf_append_u32(&buf, 9); + tpm_buf_append_u32(&buf, TPM2_RS_PW); + tpm_buf_append_u16(&buf, 0); + tpm_buf_append_u8(&buf, 0); + tpm_buf_append_u16(&buf, 0); + + /* Qualifying data */ + tpm_buf_append_u16(&buf, 0); + + /* Creation data hash */ + if (payload->creation_hash_len < 2) { + rc = -EINVAL; + goto out; + } + + tpm_buf_append_u16(&buf, payload->creation_hash_len - 2); + tpm_buf_append(&buf, payload->creation_hash + 2, + payload->creation_hash_len - 2); + + /* signature scheme */ + tpm_buf_append_u16(&buf, TPM_ALG_NULL); + + /* creation ticket */ + tpm_buf_append(&buf, payload->tk, payload->tk_len); + + rc = tpm_transmit_cmd(chip, &buf, 6, "certifying creation data"); + if (rc) + goto out; + + head = (struct tpm_header *)buf.data; + + if (be32_to_cpu(head->return_code) != TPM2_RC_SUCCESS) + rc = -EINVAL; +out: + tpm_buf_destroy(&buf); + return rc; +} + /** * tpm2_unseal_trusted() - unseal the payload of a trusted key * @@ -728,8 +796,15 @@ int tpm2_unseal_trusted(struct tpm_chip *chip, goto out; rc = tpm2_unseal_cmd(chip, payload, options, blob_handle); - tpm2_flush_context(chip, blob_handle); + if (rc) + goto flush; + + if (payload->creation_len) + rc = tpm2_certify_creation(chip, payload, blob_handle); + +flush: + tpm2_flush_context(chip, blob_handle); out: tpm_put_ops(chip);