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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 A57AAECDE4B for ; Thu, 8 Nov 2018 14:08:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7442A20827 for ; Thu, 8 Nov 2018 14:08:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7442A20827 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727489AbeKHXn5 (ORCPT ); Thu, 8 Nov 2018 18:43:57 -0500 Received: from mga01.intel.com ([192.55.52.88]:39216 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbeKHXn4 (ORCPT ); Thu, 8 Nov 2018 18:43:56 -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 fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Nov 2018 06:08:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,478,1534834800"; d="scan'208";a="94661856" Received: from ibanaga-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.75]) by FMSMGA003.fm.intel.com with ESMTP; 08 Nov 2018 06:08:15 -0800 Date: Thu, 8 Nov 2018 16:08:14 +0200 From: Jarkko Sakkinen To: Roberto Sassu Cc: zohar@linux.ibm.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, silviu.vlasceanu@huawei.com Subject: Re: [PATCH v4 6/6] tpm: ensure that the output of PCR read contains the correct digest size Message-ID: <20181108140814.GF8922@linux.intel.com> References: <20181106150159.1136-1-roberto.sassu@huawei.com> <20181106150159.1136-7-roberto.sassu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181106150159.1136-7-roberto.sassu@huawei.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 06, 2018 at 04:01:59PM +0100, Roberto Sassu wrote: > This patch protects against data corruption that could happen in the bus, > by checking that that the digest size returned by the TPM during a PCR read > matches the size of the algorithm passed as argument to tpm2_pcr_read(). > > This check is performed after information about the PCR banks has been > retrieved. > > Signed-off-by: Roberto Sassu > --- > drivers/char/tpm/tpm2-cmd.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c > index e2d5b84286a7..3b0b5b032901 100644 > --- a/drivers/char/tpm/tpm2-cmd.c > +++ b/drivers/char/tpm/tpm2-cmd.c > @@ -187,15 +187,28 @@ struct tpm2_pcr_read_out { > int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, > struct tpm_digest *digest_struct, u16 *digest_size_ptr) > { > + int i; > int rc; > struct tpm_buf buf; > struct tpm2_pcr_read_out *out; > u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0}; > u16 digest_size; > + u16 expected_digest_size = 0; > > if (pcr_idx >= TPM2_PLATFORM_PCR) > return -EINVAL; > > + if (!digest_size_ptr) { > + for (i = 0; i < chip->nr_active_banks && > + chip->active_banks[i].alg_id != digest_struct->alg_id; i++) > + ; Not sure if the semicolon should be in its own line. ` > + > + if (i == chip->nr_active_banks) > + return -EINVAL; > + > + expected_digest_size = chip->active_banks[i].digest_size; > + } > + > rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ); > if (rc) > return rc; > @@ -215,7 +228,8 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, > > out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE]; > digest_size = be16_to_cpu(out->digest_size); > - if (digest_size > sizeof(digest_struct->digest)) { > + if (digest_size > sizeof(digest_struct->digest) || > + (!digest_size_ptr && digest_size != expected_digest_size)) { > rc = -EINVAL; > goto out; > } > -- > 2.17.1 > Please add Cc: stable@vger.kernel.org. /Jarkko