From patchwork Wed Mar 7 23:32:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 10265613 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A0DC060211 for ; Wed, 7 Mar 2018 23:32:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 90AC6289E2 for ; Wed, 7 Mar 2018 23:32:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8580229197; Wed, 7 Mar 2018 23:32:22 +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=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham 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 2A57D289E2 for ; Wed, 7 Mar 2018 23:32:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754757AbeCGXcU (ORCPT ); Wed, 7 Mar 2018 18:32:20 -0500 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:53054 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754745AbeCGXcU (ORCPT ); Wed, 7 Mar 2018 18:32:20 -0500 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id CE1A98EE180; Wed, 7 Mar 2018 15:32:19 -0800 (PST) Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UEKj7DTUBrXR; Wed, 7 Mar 2018 15:32:19 -0800 (PST) Received: from [153.66.254.194] (unknown [50.35.65.221]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 6B4FE8EE0D3; Wed, 7 Mar 2018 15:32:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1520465539; bh=xXbsnGYKJiO481vk6gQGdOmDPQsdpka6zNcVDo/RuHs=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Syw4NSP0iHmGhHGPAdHVW3qzcO/3hNneVmv4WmoukkHF/OT3R5AK4f4A9oFyPhIqu zu2nD6OHY6599XoT2HG0JhU9h3F6s+W+KCvuASUzpQ8m1CcJ6DK/mhrTvcI8QBs87+ aFAV8An1eQ6JemZn31BIs1z+Y0DPn6fMPupgnEtY= Message-ID: <1520465538.4894.15.camel@HansenPartnership.com> Subject: [RFC v2 3/5] tpm2: add hmac checks to tpm2_pcr_extend() From: James Bottomley To: linux-integrity@vger.kernel.org Cc: linux-crypto@vger.kernel.org, linux-security-module@vger.kernel.org, Jarkko Sakkinen Date: Wed, 07 Mar 2018 15:32:18 -0800 In-Reply-To: <1520465374.4894.12.camel@HansenPartnership.com> References: <1520465374.4894.12.camel@HansenPartnership.com> X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 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 We use tpm2_pcr_extend() in trusted keys to extend a PCR to prevent a key from being re-loaded until the next reboot. To use this functionality securely, that extend must be protected by a session hmac. Signed-off-by: James Bottomley --- drivers/char/tpm/tpm2-cmd.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 2042d4008b9c..a56cdd5d55ff 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -247,13 +247,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf) return rc; } -struct tpm2_null_auth_area { - __be32 handle; - __be16 nonce_size; - u8 attributes; - __be16 auth_size; -} __packed; - /** * tpm2_pcr_extend() - extend a PCR value * @@ -268,7 +261,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count, struct tpm2_digest *digests) { struct tpm_buf buf; - struct tpm2_null_auth_area auth_area; + struct tpm2_auth *auth; int rc; int i; int j; @@ -276,20 +269,17 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count, if (count > ARRAY_SIZE(chip->active_banks)) return -EINVAL; - rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND); + rc = tpm2_start_auth_session(chip, &auth); if (rc) return rc; - tpm_buf_append_u32(&buf, pcr_idx); + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND); + if (rc) + return rc; - auth_area.handle = cpu_to_be32(TPM2_RS_PW); - auth_area.nonce_size = 0; - auth_area.attributes = 0; - auth_area.auth_size = 0; + tpm_buf_append_name(&buf, auth, pcr_idx, NULL); + tpm_buf_append_hmac_session(&buf, auth, 0, NULL, 0); - tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area)); - tpm_buf_append(&buf, (const unsigned char *)&auth_area, - sizeof(auth_area)); tpm_buf_append_u32(&buf, count); for (i = 0; i < count; i++) { @@ -302,9 +292,10 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count, hash_digest_size[tpm2_hash_map[j].crypto_id]); } } - - rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0, - "attempting extend a PCR value"); + tpm_buf_fill_hmac_session(&buf, auth); + rc = tpm_transmit_cmd(chip, &chip->kernel_space, buf.data, PAGE_SIZE, + 0, 0, "attempting extend a PCR value"); + rc = tpm_buf_check_hmac_response(&buf, auth, rc); tpm_buf_destroy(&buf);