From patchwork Tue Oct 30 15:47:11 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 10661175 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5B15C13BF for ; Tue, 30 Oct 2018 15:51:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4CAA32A751 for ; Tue, 30 Oct 2018 15:51:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4AB9F2A81E; Tue, 30 Oct 2018 15:51:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 002412A751 for ; Tue, 30 Oct 2018 15:51:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726364AbeJaAp0 (ORCPT ); Tue, 30 Oct 2018 20:45:26 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:32708 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726792AbeJaAp0 (ORCPT ); Tue, 30 Oct 2018 20:45:26 -0400 Received: from lhreml703-cah.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id A0FA8A7E41F59; Tue, 30 Oct 2018 15:51:23 +0000 (GMT) Received: from roberto-HP-EliteDesk-800-G2-DM-65W.huawei.com (10.204.65.153) by smtpsuk.huawei.com (10.201.108.44) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 30 Oct 2018 15:51:15 +0000 From: Roberto Sassu To: , CC: , , , , Roberto Sassu Subject: [PATCH v3 5/5] tpm: ensure that output of PCR read contains the correct digest size Date: Tue, 30 Oct 2018 16:47:11 +0100 Message-ID: <20181030154711.2782-6-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181030154711.2782-1-roberto.sassu@huawei.com> References: <20181030154711.2782-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.65.153] X-CFilter-Loop: Reflected Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch ensures 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(). The 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 8e821e7b4674..477dcc30fc53 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 < ARRAY_SIZE(chip->active_banks) && + chip->active_banks[i].alg_id != digest_struct->alg_id; i++) + ; + + if (i == ARRAY_SIZE(chip->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_ptr && digest_size > sizeof(digest_struct->digest)) || + (!digest_size_ptr && digest_size != expected_digest_size)) { rc = -EINVAL; goto out; }