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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 59821C10F25 for ; Fri, 6 Mar 2020 19:52:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28A1420675 for ; Fri, 6 Mar 2020 19:52:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726368AbgCFTwu (ORCPT ); Fri, 6 Mar 2020 14:52:50 -0500 Received: from mga17.intel.com ([192.55.52.151]:5212 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbgCFTwu (ORCPT ); Fri, 6 Mar 2020 14:52:50 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Mar 2020 11:52:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,523,1574150400"; d="scan'208";a="288059538" Received: from sineadfi-mobl.ger.corp.intel.com (HELO localhost) ([10.252.15.28]) by FMSMGA003.fm.intel.com with ESMTP; 06 Mar 2020 11:52:48 -0800 Date: Fri, 6 Mar 2020 21:52:47 +0200 From: Jarkko Sakkinen To: James Bottomley Cc: linux-integrity@vger.kernel.org, Mimi Zohar , David Woodhouse , keyrings@vger.kernel.org Subject: Re: [PATCH v7 3/6] security: keys: trusted: fix TPM2 authorizations Message-ID: <20200306195247.GA11362@linux.intel.com> References: <20200305022744.12492-1-James.Bottomley@HansenPartnership.com> <20200305022744.12492-4-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200305022744.12492-4-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 Wed, Mar 04, 2020 at 06:27:41PM -0800, 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 /Jarkko