From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Date: Tue, 15 Sep 2020 09:09:50 +0000 Subject: Re: [PATCH v11 3/5] security: keys: trusted: fix TPM2 authorizations Message-Id: <20200915090950.GB3612@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable List-Id: References: <20200912172643.9063-1-James.Bottomley@HansenPartnership.com> <20200912172643.9063-4-James.Bottomley@HansenPartnership.com> In-Reply-To: <20200912172643.9063-4-James.Bottomley@HansenPartnership.com> To: James Bottomley Cc: linux-integrity@vger.kernel.org, Mimi Zohar , David Woodhouse , keyrings@vger.kernel.org, David Howells On Sat, Sep 12, 2020 at 10:26:41AM -0700, James Bottomley wrote: > In TPM 1.2 an authorization was a 20 byte number. The spec actually > recommended you to hash variable length passwords and use the sha1 > hash as the authorization. Because the spec doesn't require this > hashing, the current authorization for trusted keys is a 40 digit hex > number. For TPM 2.0 the spec allows the passing in of variable length > passwords and passphrases directly, so we should allow that in trusted > keys for ease of use. Update the 'blobauth' parameter to take this > into account, so we can now use plain text passwords for the keys. >=20 > so before >=20 > keyctl add trusted kmk "new 32 blobauth=F572d396fae9206628714fb2ce00f72e9= 4f2258f" >=20 > after we will accept both the old hex sha1 form as well as a new > directly supplied password: >=20 > keyctl add trusted kmk "new 32 blobauth=3Dhello keyhandle=81000001" >=20 > Since a sha1 hex code must be exactly 40 bytes long and a direct > password must be 20 or less, we use the length as the discriminator > for which form is input. >=20 > Note this is both and enhancement and a potential bug fix. The TPM > 2.0 spec requires us to strip leading zeros, meaning empyty > authorization is a zero length HMAC whereas we're currently passing in > 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the > Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch > makes the Microsoft TPM emulator work with trusted keys. >=20 > Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips") > Signed-off-by: James Bottomley > Reviewed-by: Jarkko Sakkinen I created a key: $ sudo ./tpm2-root-key 0x80000000 $ sudo ./tpm2-list-handles 0x80000000 $ keyctl add trusted kmk "new 32 blobauth=3Dhello keyhandle=3D0x80000000" $ lsmod Module Size Used by sha1_generic 16384 2 trusted 32768 0 asn1_encoder 16384 1 trusted x86_pkg_temp_thermal 20480 0 iwlmvm 356352 0 iwlwifi 315392 1 iwlmvm tpm_crb 16384 0 tpm_tis 16384 0 tpm_tis_core 24576 1 tpm_tis tpm 61440 4 tpm_tis,trusted,tpm_crb,tpm_tis_core efivarfs 16384 1 What could be wrong? Have the full seris applied on a test kernel. The root key creation is contained in create_root_key(): https://github.com/jsakkine-intel/tpm2-scripts/blob/master/tpm2.py /Jarkko 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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_HELO_NONE,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 BC2A4C43461 for ; Tue, 15 Sep 2020 09:10:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 852282078D for ; Tue, 15 Sep 2020 09:10:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726269AbgIOJJ7 (ORCPT ); Tue, 15 Sep 2020 05:09:59 -0400 Received: from mga18.intel.com ([134.134.136.126]:37789 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726119AbgIOJJ6 (ORCPT ); Tue, 15 Sep 2020 05:09:58 -0400 IronPort-SDR: 1HvWKyEPmSJ40zRoYeycI+Zj7SqsCt8sdQZskuizJhK9tP+rtf1SozpS2sw6iga3b2KtZ9f81q JBvwI7yA56Og== X-IronPort-AV: E=McAfee;i="6000,8403,9744"; a="146967076" X-IronPort-AV: E=Sophos;i="5.76,429,1592895600"; d="scan'208";a="146967076" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2020 02:09:56 -0700 IronPort-SDR: wppjluMxy0S5Wx5Ey4/7QgSn3ZnEEcFahxfF0jvcDA+rGIJaC5PWOQAvJz+wqU85rpiXBSkqR+ WPfndzIvt1eA== X-IronPort-AV: E=Sophos;i="5.76,429,1592895600"; d="scan'208";a="451228991" Received: from blank-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.62.208]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2020 02:09:52 -0700 Date: Tue, 15 Sep 2020 12:09:50 +0300 From: Jarkko Sakkinen To: James Bottomley Cc: linux-integrity@vger.kernel.org, Mimi Zohar , David Woodhouse , keyrings@vger.kernel.org, David Howells Subject: Re: [PATCH v11 3/5] security: keys: trusted: fix TPM2 authorizations Message-ID: <20200915090950.GB3612@linux.intel.com> References: <20200912172643.9063-1-James.Bottomley@HansenPartnership.com> <20200912172643.9063-4-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200912172643.9063-4-James.Bottomley@HansenPartnership.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Sat, Sep 12, 2020 at 10:26:41AM -0700, James Bottomley wrote: > In TPM 1.2 an authorization was a 20 byte number. The spec actually > recommended you to hash variable length passwords and use the sha1 > hash as the authorization. Because the spec doesn't require this > hashing, the current authorization for trusted keys is a 40 digit hex > number. For TPM 2.0 the spec allows the passing in of variable length > passwords and passphrases directly, so we should allow that in trusted > keys for ease of use. Update the 'blobauth' parameter to take this > into account, so we can now use plain text passwords for the keys. > > so before > > keyctl add trusted kmk "new 32 blobauth=f572d396fae9206628714fb2ce00f72e94f2258f" > > after we will accept both the old hex sha1 form as well as a new > directly supplied password: > > keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001" > > Since a sha1 hex code must be exactly 40 bytes long and a direct > password must be 20 or less, we use the length as the discriminator > for which form is input. > > Note this is both and enhancement and a potential bug fix. The TPM > 2.0 spec requires us to strip leading zeros, meaning empyty > authorization is a zero length HMAC whereas we're currently passing in > 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the > Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch > makes the Microsoft TPM emulator work with trusted keys. > > Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips") > Signed-off-by: James Bottomley > Reviewed-by: Jarkko Sakkinen I created a key: $ sudo ./tpm2-root-key 0x80000000 $ sudo ./tpm2-list-handles 0x80000000 $ keyctl add trusted kmk "new 32 blobauth=hello keyhandle=0x80000000" $ lsmod Module Size Used by sha1_generic 16384 2 trusted 32768 0 asn1_encoder 16384 1 trusted x86_pkg_temp_thermal 20480 0 iwlmvm 356352 0 iwlwifi 315392 1 iwlmvm tpm_crb 16384 0 tpm_tis 16384 0 tpm_tis_core 24576 1 tpm_tis tpm 61440 4 tpm_tis,trusted,tpm_crb,tpm_tis_core efivarfs 16384 1 What could be wrong? Have the full seris applied on a test kernel. The root key creation is contained in create_root_key(): https://github.com/jsakkine-intel/tpm2-scripts/blob/master/tpm2.py /Jarkko