From patchwork Tue Aug 23 22:25:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12952685 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 E8724C38142 for ; Tue, 23 Aug 2022 22:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234187AbiHWW0n (ORCPT ); Tue, 23 Aug 2022 18:26:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233952AbiHWW0P (ORCPT ); Tue, 23 Aug 2022 18:26:15 -0400 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4E9C87686 for ; Tue, 23 Aug 2022 15:26:05 -0700 (PDT) Received: by mail-pj1-x102e.google.com with SMTP id s3-20020a17090a2f0300b001facfc6fdbcso15428268pjd.1 for ; Tue, 23 Aug 2022 15:26:05 -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; bh=2ncyxa+e8puSkzyAo28dlynzalbwgiQJVy99ctIQYXQ=; b=Yafelakgwq5oLYYTlKWk4gtQoYKcyYn9otte8CgXghwEJlBijSWB4wKveUY3edwMIP Bjzf/CzbNPaR776m7/QUXarSah1IO5SxkIt5LbTPpceurSyoiEHAgxf5jaBm6R20S5Yo ZLpLG2SmcqRUQ1zz5x7rAqLOnJMbnFr2f9rYc= 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; bh=2ncyxa+e8puSkzyAo28dlynzalbwgiQJVy99ctIQYXQ=; b=4+RKPb5V5uLxdZ4ObG1MCL0BJVqb9msPAoWypkBj5DqkHyxLUd23wfAdvavTOUI+8j 7lb/eRrww4wOGa1Bb7Okp+syCsovLIXcEL8ZfQbsGsZAKGL5PQbHIlWgXGsrPxHQAz3p uu3nwEWdKbj7/unDjs4i0qIhHgrZL1k0KshkiWKeP7+y6hKG38HK1xf72ZKZVH+UwN9Q NvXGS9fqZy7lHT7YvPbjLpixnN9Eq7gT4gM1OQO96aYxtSR618jHjmvXVh2YtTs8/jaH FvEeBe1Vpm6ZMfb9b3ZBHoY4Yt6YpnSI93T/6Rhv38XwuULCVQQNUB0vwLInLmpHFx8A tEnQ== X-Gm-Message-State: ACgBeo26/G4mJMwGYH+zamRvn3XEMiHloUNeSzjY6indEye2Ht2wLVlw It+vha+7xpZxN9dcMhC1ZCxfuA== X-Google-Smtp-Source: AA6agR4ueU8fQBN/JYWXCi3IJqLo6KhUgY4cT5WpRS70mkceXPZWF2eDQDlqQTsxIuB8GlyzGukQ0g== X-Received: by 2002:a17:902:f550:b0:172:fe5d:aa0a with SMTP id h16-20020a170902f55000b00172fe5daa0amr5532628plf.170.1661293565132; Tue, 23 Aug 2022 15:26:05 -0700 (PDT) Received: from evgreen-glaptop.lan ([98.45.66.167]) by smtp.gmail.com with ESMTPSA id f76-20020a62384f000000b0052f20d70845sm11256292pfa.150.2022.08.23.15.26.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Aug 2022 15:26:04 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: gwendal@chromium.org, Eric Biggers , Matthew Garrett , jarkko@kernel.org, zohar@linux.ibm.com, linux-integrity@vger.kernel.org, Pavel Machek , apronin@chromium.org, dlunev@google.com, rjw@rjwysocki.net, linux-pm@vger.kernel.org, corbet@lwn.net, jejb@linux.ibm.com, Evan Green , David Howells , James Morris , Paul Moore , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 03/10] security: keys: trusted: Include TPM2 creation data Date: Tue, 23 Aug 2022 15:25:19 -0700 Message-Id: <20220823152108.v2.3.Ieb1215f598bc9df56b0e29e5977eae4fcca25e15@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220823222526.1524851-1-evgreen@chromium.org> References: <20220823222526.1524851-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org 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. --- (no changes since v1) 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. Signed-off-by: Evan Green --- include/keys/trusted-type.h | 8 + security/keys/trusted-keys/tpm2key.asn1 | 5 +- security/keys/trusted-keys/trusted_tpm2.c | 202 +++++++++++++++++++--- 3 files changed, 190 insertions(+), 25 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..1bfbf290e523a3 100644 --- a/security/keys/trusted-keys/tpm2key.asn1 +++ b/security/keys/trusted-keys/tpm2key.asn1 @@ -7,5 +7,8 @@ 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}), + creationData [1] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_creation_data}), + creationHash [2] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_creation_hash}), + 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..1f166d4fa307a9 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -37,7 +37,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, 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; priv_len = get_unaligned_be16(src) + 2; priv = src; @@ -46,6 +49,26 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, pub_len = get_unaligned_be16(src) + 2; pub = src; + src += pub_len; + + creation_data_len = get_unaligned_be16(src); + if (creation_data_len) { + creation_data_len += 2; + creation_data = src; + src += creation_data_len; + + creation_hash_len = get_unaligned_be16(src) + 2; + creation_hash = src; + src += creation_hash_len; + + /* + * 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 (!scratch) return -ENOMEM; @@ -63,26 +86,81 @@ 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 +169,21 @@ 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 +192,57 @@ 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 +305,42 @@ 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 +385,7 @@ 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 +474,14 @@ 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 +528,11 @@ 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 +589,6 @@ 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 Aug 23 22:25:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12952686 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 CBD7EC32789 for ; Tue, 23 Aug 2022 22:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234205AbiHWW0y (ORCPT ); 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Tue, 23 Aug 2022 15:26:08 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: gwendal@chromium.org, Eric Biggers , Matthew Garrett , jarkko@kernel.org, zohar@linux.ibm.com, linux-integrity@vger.kernel.org, Pavel Machek , apronin@chromium.org, dlunev@google.com, rjw@rjwysocki.net, linux-pm@vger.kernel.org, corbet@lwn.net, jejb@linux.ibm.com, 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 v2 04/10] security: keys: trusted: Allow storage of PCR values in creation data Date: Tue, 23 Aug 2022 15:25:20 -0700 Message-Id: <20220823152108.v2.4.I32591db064b6cdc91850d777f363c9d05c985b39@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220823222526.1524851-1-evgreen@chromium.org> References: <20220823222526.1524851-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org 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. From: Matthew Garrett Signed-off-by: Matthew Garrett Signed-off-by: Evan Green --- Matthew's original version of this patch is at: https://patchwork.kernel.org/patch/12096503/ (no changes since v1) .../security/keys/trusted-encrypted.rst | 4 +++ 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, 37 insertions(+), 2 deletions(-) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 0bfb4c33974890..dc9e11bb4824da 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -199,6 +199,10 @@ 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 PCR values to be + included in the PCR creation data. The bit corresponding + to each PCR should be 1 to be included, 0 to be ignored. + 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 1f166d4fa307a9..1d1470b880ca01 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -389,7 +389,7 @@ 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++) { @@ -458,7 +458,28 @@ 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 Aug 23 22:25:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 12952687 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 B1BBCC32789 for ; Tue, 23 Aug 2022 22:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234236AbiHWW05 (ORCPT ); Tue, 23 Aug 2022 18:26:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233719AbiHWW0U (ORCPT ); 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Hallyn" , axelj , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 05/10] security: keys: trusted: Verify creation data Date: Tue, 23 Aug 2022 15:25:21 -0700 Message-Id: <20220823152108.v2.5.I6cdb522cb5ea28fcd1e35b4cd92cbd067f99269a@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220823222526.1524851-1-evgreen@chromium.org> References: <20220823222526.1524851-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org 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. Partially-sourced-from: 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 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 1d1470b880ca01..f81c6578c7f783 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -691,6 +691,74 @@ 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 (head->return_code != 0) + rc = -EINVAL; +out: + tpm_buf_destroy(&buf); + return rc; +} + /** * tpm2_unseal_trusted() - unseal the payload of a trusted key * @@ -716,8 +784,15 @@ 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);