From patchwork Sun Dec 8 05:10:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 11278091 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0B7491575 for ; Sun, 8 Dec 2019 05:10:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C197D206D6 for ; Sun, 8 Dec 2019 05:10:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="v34Kn/Da"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="MyllRyI0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725268AbfLHFKc (ORCPT ); Sun, 8 Dec 2019 00:10:32 -0500 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:58006 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725263AbfLHFKc (ORCPT ); Sun, 8 Dec 2019 00:10:32 -0500 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 038978EE111; Sat, 7 Dec 2019 21:10:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1575781832; bh=/rTl1L/VN7aIxSXMhw1XCI6oGGa1VCCqGdKgokJbQTM=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=v34Kn/Daw0U0Yx1Qn4yrIKN6aT20pzBCwe6Hdo/DJCmR3GBsKeFQEXtueyAzac76T B3HwU3HbPhEugmS0YLbDuhG1kjxXHjzUwq6zZlqDR9BntwrLUjxGu70uJgOqMmZx5J hwLQk8nu+Yi9HX46OtpzP5Nao+DE0KC3Q580+A9U= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UTBSLjDzTCqB; Sat, 7 Dec 2019 21:10:31 -0800 (PST) Received: from jarvis.lan (unknown [50.35.76.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 9A7C98EE109; Sat, 7 Dec 2019 21:10:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1575781831; bh=/rTl1L/VN7aIxSXMhw1XCI6oGGa1VCCqGdKgokJbQTM=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=MyllRyI0iQ40eDeRVOU9O4mwFDk4YioAHwHiR18DJFXPAVkL+uCfY+ygC67nNY+Uv hxoKgGaesOcbODz56o92VsBgjUiM5TImAT2obmT+5XvUchThfBUwrs0/ly9R3fL65t YTc45aevEqjwC/Lo8eESJs5z/1sEpAEx+fmvbNig= Message-ID: <1575781831.14069.13.camel@HansenPartnership.com> Subject: [PATCH 4/8] security: keys: trusted: use ASN.1 tpm2 key format for the blobs From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Mimi Zohar , Jarkko Sakkinen Date: Sat, 07 Dec 2019 21:10:31 -0800 In-Reply-To: <1575781600.14069.8.camel@HansenPartnership.com> References: <1575781600.14069.8.camel@HansenPartnership.com> X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Modify the tpm2 key format blob output to export and import in the ASN.1 form for tpm2 sealed object keys. For compatibility with prior trusted keys, the importer will also accept two tpm2b quantities representing the public and private parts of the key. However, the export via keyctl pipe will only output the ASN.1 format. The benefit of the ASN.1 format is that it's a standard and thus the exported key can be used by userspace tools. The format includes policy specifications, thus it gets us out of having to construct policy handles in userspace and the format includes the parent meaning you don't have to keep passing it in each time. This patch only implements basic handling for the ASN.1 format, so keys with passwords but no policy. Signed-off-by: James Bottomley --- security/keys/trusted-keys/Makefile | 2 +- security/keys/trusted-keys/tpm2key.asn1 | 23 ++++ security/keys/trusted-keys/trusted_tpm1.c | 2 +- security/keys/trusted-keys/trusted_tpm2.c | 170 +++++++++++++++++++++++++++++- 4 files changed, 190 insertions(+), 7 deletions(-) create mode 100644 security/keys/trusted-keys/tpm2key.asn1 diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index 7b73cebbb378..e0198641eff2 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -5,4 +5,4 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_tpm1.o -trusted-y += trusted_tpm2.o +trusted-y += trusted_tpm2.o tpm2key.asn1.o diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 new file mode 100644 index 000000000000..1851b7c80f08 --- /dev/null +++ b/security/keys/trusted-keys/tpm2key.asn1 @@ -0,0 +1,23 @@ +--- +--- Note: This isn't quite the definition in the standard +--- However, the Linux asn.1 parser doesn't understand +--- [2] EXPLICIT SEQUENCE OF OPTIONAL +--- So there's an extra intermediate TPMPolicySequence +--- definition to work around this + +TPMKey ::= SEQUENCE { + type OBJECT IDENTIFIER ({tpmkey_type}), + emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, + policy [1] EXPLICIT TPMPolicySequence OPTIONAL, + secret [2] EXPLICIT OCTET STRING OPTIONAL, + parent INTEGER ({tpmkey_parent}), + pubkey OCTET STRING ({tpmkey_pub}), + privkey OCTET STRING ({tpmkey_priv}) + } + +TPMPolicySequence ::= SEQUENCE OF TPMPolicy + +TPMPolicy ::= SEQUENCE { + commandCode [0] EXPLICIT INTEGER, + commandPolicy [1] EXPLICIT OCTET STRING + } diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index d2c5ec1e040b..d744a0d1cb89 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -991,7 +991,7 @@ static int trusted_instantiate(struct key *key, goto out; } - if (!options->keyhandle) { + if (!options->keyhandle && !tpm2) { ret = -EINVAL; goto out; } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 08ec7f48f01d..4efc7b64d1cd 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -4,6 +4,8 @@ * Copyright (C) 2014 Intel Corporation */ +#include +#include #include #include #include @@ -12,6 +14,10 @@ #include #include +#include + +#include "tpm2key.asn1.h" + static struct tpm2_hash tpm2_hash_map[] = { {HASH_ALGO_SHA1, TPM_ALG_SHA1}, {HASH_ALGO_SHA256, TPM_ALG_SHA256}, @@ -20,6 +26,141 @@ static struct tpm2_hash tpm2_hash_map[] = { {HASH_ALGO_SM3_256, TPM_ALG_SM3_256}, }; +static u32 tpm2key_oid[] = { 2,23,133,10,1,5 }; + +static int tpm2_key_encode(struct trusted_key_payload *payload, + struct trusted_key_options *options, + u8 *src, u32 len) +{ + u8 *scratch = kmalloc(PAGE_SIZE, GFP_KERNEL); + u8 *work = scratch, *work1; + u8 *priv, *pub; + u16 priv_len, pub_len; + + priv_len = get_unaligned_be16(src); + src += 2; + priv = src; + src += priv_len; + pub_len = get_unaligned_be16(src); + src += 2; + pub = src; + + if (!scratch) + return -ENOMEM; + + asn1_encode_oid(&work, tpm2key_oid, asn1_oid_len(tpm2key_oid)); + if (options->blobauth[0] == 0) { + unsigned char bool[3], *w = bool; + /* tag 0 is emptyAuth */ + asn1_encode_boolean(&w, true); + asn1_encode_tag(&work, 0, bool, w - bool); + } + asn1_encode_integer(&work, options->keyhandle); + asn1_encode_octet_string(&work, pub, pub_len); + asn1_encode_octet_string(&work, priv, priv_len); + + work1 = payload->blob; + asn1_encode_sequence(&work1, scratch, work - scratch); + + return work1 - payload->blob; +} + +struct tpm2key_context { + u32 parent; + const u8 *pub; + u32 pub_len; + const u8 *priv; + u32 priv_len; +}; + +static int tpm2_key_decode(struct trusted_key_payload *payload, + struct trusted_key_options *options, + u8 **buf) +{ + int ret; + struct tpm2key_context ctx; + u8 *blob; + + ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, + payload->blob_len); + if (ret < 0) + return ret; + + if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) + return -EINVAL; + + blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); + if (!blob) + return -ENOMEM; + + *buf = blob; + options->keyhandle = ctx.parent; + put_unaligned_be16(ctx.priv_len, blob); + blob += 2; + memcpy(blob, ctx.priv, ctx.priv_len); + blob += ctx.priv_len; + put_unaligned_be16(ctx.pub_len, blob); + blob += 2; + memcpy(blob, ctx.pub, ctx.pub_len); + + return 0; +} + +int tpmkey_parent(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2key_context *ctx = context; + const u8 *v = value; + int i; + + ctx->parent = 0; + for (i = 0; i < vlen; i++) { + ctx->parent <<= 8; + ctx->parent |= v[i]; + } + return 0; +} + +int tpmkey_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + enum OID oid = look_up_OID(value, vlen); + + if (oid != OID_TPMSealedData) { + char buffer[50]; + + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_debug("OID is \"%s\" which is not TPMSealedData\n", + buffer); + return -EINVAL; + } + return 0; +} + +int tpmkey_pub(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2key_context *ctx = context; + + ctx->pub = value; + ctx->pub_len = vlen; + return 0; +} + +int tpmkey_priv(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2key_context *ctx = context; + + ctx->priv = value; + ctx->priv_len = vlen; + return 0; +} + /** * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. * @@ -79,6 +220,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip, if (i == ARRAY_SIZE(tpm2_hash_map)) return -EINVAL; + if (!options->keyhandle) + return -EINVAL; + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE); if (rc) return rc; @@ -144,8 +288,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip, goto out; } - memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len); - payload->blob_len = blob_len; + payload->blob_len = + tpm2_key_encode(payload, options, + &buf.data[TPM_HEADER_SIZE + 4], + blob_len); out: tpm_buf_destroy(&buf); @@ -156,6 +302,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip, else rc = -EPERM; } + if (payload->blob_len < 0) + return payload->blob_len; return rc; } @@ -182,13 +330,23 @@ static int tpm2_load_cmd(struct tpm_chip *chip, unsigned int private_len; unsigned int public_len; unsigned int blob_len; + u8 *blob; int rc; - private_len = be16_to_cpup((__be16 *) &payload->blob[0]); + rc = tpm2_key_decode(payload, options, &blob); + if (rc) + /* old form */ + blob = payload->blob; + + /* new format carries keyhandle but old format doesn't */ + if (!options->keyhandle) + return -EINVAL; + + private_len = be16_to_cpup((__be16 *) &blob[0]); if (private_len > (payload->blob_len - 2)) return -E2BIG; - public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]); + public_len = be16_to_cpup((__be16 *) &blob[2 + private_len]); blob_len = private_len + public_len + 4; if (blob_len > payload->blob_len) return -E2BIG; @@ -204,7 +362,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip, options->keyauth /* hmac */, TPM_DIGEST_SIZE); - tpm_buf_append(&buf, payload->blob, blob_len); + tpm_buf_append(&buf, blob, blob_len); if (buf.flags & TPM_BUF_OVERFLOW) { rc = -E2BIG; @@ -217,6 +375,8 @@ 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)