From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7160BC64EB8 for ; Tue, 9 Oct 2018 16:48:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38A572087D for ; Tue, 9 Oct 2018 16:48:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38A572087D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726415AbeJJAGL (ORCPT ); Tue, 9 Oct 2018 20:06:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40836 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726695AbeJJAGL (ORCPT ); Tue, 9 Oct 2018 20:06:11 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 29186811A9; Tue, 9 Oct 2018 16:48:20 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-149.rdu2.redhat.com [10.10.120.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8DF3D600D1; Tue, 9 Oct 2018 16:48:18 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 12/22] KEYS: Add parser for TPM-based keys [ver #2] From: David Howells To: jmorris@namei.org Cc: Denis Kenzior , Marcel Holtmann , Marcel Holtmann , dhowells@redhat.com, denkenz@gmail.com, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 09 Oct 2018 17:48:17 +0100 Message-ID: <153910369777.12141.14183321463564348797.stgit@warthog.procyon.org.uk> In-Reply-To: <153910360263.12141.6032694262361399627.stgit@warthog.procyon.org.uk> References: <153910360263.12141.6032694262361399627.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 09 Oct 2018 16:48:20 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: Denis Kenzior For TPM based keys, the only standard seems to be described here: http://david.woodhou.se/draft-woodhouse-cert-best-practice.html#rfc.section.4.4 Quote from the relevant section: "Rather, a common form of storage for "wrapped" keys is to encode the binary TCPA_KEY structure in a single ASN.1 OCTET-STRING, and store the result in PEM format with the tag "-----BEGIN TSS KEY BLOB-----". " This patch implements the above behavior. It is assumed that the PEM encoding is stripped out by userspace and only the raw DER/BER format is provided. This is similar to how PKCS7, PKCS8 and X.509 keys are handled. Signed-off-by: Denis Kenzior Signed-off-by: David Howells Tested-by: Marcel Holtmann Reviewed-by: Marcel Holtmann --- crypto/asymmetric_keys/Kconfig | 9 +++ crypto/asymmetric_keys/Makefile | 11 ++++ crypto/asymmetric_keys/tpm.asn1 | 5 ++ crypto/asymmetric_keys/tpm_parser.c | 102 +++++++++++++++++++++++++++++++++++ 4 files changed, 127 insertions(+) create mode 100644 crypto/asymmetric_keys/tpm.asn1 create mode 100644 crypto/asymmetric_keys/tpm_parser.c diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index b75555c7d8ae..88353a9ebc9b 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -52,6 +52,15 @@ config PKCS8_PRIVATE_KEY_PARSER private key data and provides the ability to instantiate a crypto key from that data. +config TPM_KEY_PARSER + tristate "TPM private key parser" + depends on ASYMMETRIC_TPM_KEY_SUBTYPE + select ASN1 + help + This option provides support for parsing TPM format blobs for + private key data and provides the ability to instantiate a crypto key + from that data. + config PKCS7_MESSAGE_PARSER tristate "PKCS#7 message parser" depends on X509_CERTIFICATE_PARSER diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile index 73fbe650ff1d..28b91adba2ae 100644 --- a/crypto/asymmetric_keys/Makefile +++ b/crypto/asymmetric_keys/Makefile @@ -75,3 +75,14 @@ verify_signed_pefile-y := \ $(obj)/mscode_parser.o: $(obj)/mscode.asn1.h $(obj)/mscode.asn1.h $(obj)/mscode.asn1.o: $(obj)/mscode.asn1.c $(obj)/mscode.asn1.h + +# +# TPM private key parsing +# +obj-$(CONFIG_TPM_KEY_PARSER) += tpm_key_parser.o +tpm_key_parser-y := \ + tpm.asn1.o \ + tpm_parser.o + +$(obj)/tpm_parser.o: $(obj)/tpm.asn1.h +$(obj)/tpm.asn1.o: $(obj)/tpm.asn1.c $(obj)/tpm.asn1.h diff --git a/crypto/asymmetric_keys/tpm.asn1 b/crypto/asymmetric_keys/tpm.asn1 new file mode 100644 index 000000000000..d7f194232f30 --- /dev/null +++ b/crypto/asymmetric_keys/tpm.asn1 @@ -0,0 +1,5 @@ +-- +-- Unencryted TPM Blob. For details of the format, see: +-- http://david.woodhou.se/draft-woodhouse-cert-best-practice.html#I-D.mavrogiannopoulos-tpmuri +-- +PrivateKeyInfo ::= OCTET STRING ({ tpm_note_key }) diff --git a/crypto/asymmetric_keys/tpm_parser.c b/crypto/asymmetric_keys/tpm_parser.c new file mode 100644 index 000000000000..96405d8dcd98 --- /dev/null +++ b/crypto/asymmetric_keys/tpm_parser.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) "TPM-PARSER: "fmt +#include +#include +#include +#include +#include +#include +#include +#include +#include "tpm.asn1.h" + +struct tpm_parse_context { + const void *blob; + u32 blob_len; +}; + +/* + * Note the key data of the ASN.1 blob. + */ +int tpm_note_key(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm_parse_context *ctx = context; + + ctx->blob = value; + ctx->blob_len = vlen; + + return 0; +} + +/* + * Parse a TPM-encrypted private key blob. + */ +static struct tpm_key *tpm_parse(const void *data, size_t datalen) +{ + struct tpm_parse_context ctx; + long ret; + + memset(&ctx, 0, sizeof(ctx)); + + /* Attempt to decode the private key */ + ret = asn1_ber_decoder(&tpm_decoder, &ctx, data, datalen); + if (ret < 0) + goto error; + + return tpm_key_create(ctx.blob, ctx.blob_len); + +error: + return ERR_PTR(ret); +} +/* + * Attempt to parse a data blob for a key as a TPM private key blob. + */ +static int tpm_key_preparse(struct key_preparsed_payload *prep) +{ + struct tpm_key *tk; + + /* + * TPM 1.2 keys are max 2048 bits long, so assume the blob is no + * more than 4x that + */ + if (prep->datalen > 256 * 4) + return -EMSGSIZE; + + tk = tpm_parse(prep->data, prep->datalen); + + if (IS_ERR(tk)) + return PTR_ERR(tk); + + /* We're pinning the module by being linked against it */ + __module_get(asym_tpm_subtype.owner); + prep->payload.data[asym_subtype] = &asym_tpm_subtype; + prep->payload.data[asym_key_ids] = NULL; + prep->payload.data[asym_crypto] = tk; + prep->payload.data[asym_auth] = NULL; + prep->quotalen = 100; + return 0; +} + +static struct asymmetric_key_parser tpm_key_parser = { + .owner = THIS_MODULE, + .name = "tpm_parser", + .parse = tpm_key_preparse, +}; + +static int __init tpm_key_init(void) +{ + return register_asymmetric_key_parser(&tpm_key_parser); +} + +static void __exit tpm_key_exit(void) +{ + unregister_asymmetric_key_parser(&tpm_key_parser); +} + +module_init(tpm_key_init); +module_exit(tpm_key_exit); + +MODULE_DESCRIPTION("TPM private key-blob parser"); +MODULE_LICENSE("GPL v2");