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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 14EBFC43441 for ; Tue, 13 Nov 2018 13:08:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD2C322507 for ; Tue, 13 Nov 2018 13:08:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD2C322507 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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 S2387418AbeKMXGz (ORCPT ); Tue, 13 Nov 2018 18:06:55 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:32753 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732728AbeKMXGz (ORCPT ); Tue, 13 Nov 2018 18:06:55 -0500 Received: from LHREML714-CAH.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 851EF55C6FEAD; Tue, 13 Nov 2018 13:08:48 +0000 (GMT) Received: from [10.204.65.144] (10.204.65.144) by smtpsuk.huawei.com (10.201.108.37) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 13 Nov 2018 13:08:40 +0000 Subject: Re: [PATCH v4 6/6] tpm: ensure that the output of PCR read contains the correct digest size To: Jarkko Sakkinen CC: , , , , References: <20181106150159.1136-1-roberto.sassu@huawei.com> <20181106150159.1136-7-roberto.sassu@huawei.com> <20181108140814.GF8922@linux.intel.com> From: Roberto Sassu Message-ID: Date: Tue, 13 Nov 2018 14:08:39 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181108140814.GF8922@linux.intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.204.65.144] X-CFilter-Loop: Reflected Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 11/8/2018 3:08 PM, Jarkko Sakkinen wrote: > 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. Should I do the same for the previous patches? This patch cannot be applied alone. Roberto > /Jarkko > -- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Bo PENG, Jian LI, Yanli SHI