From patchwork Fri Dec 9 16:06:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 13069958 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5464BC4332F for ; Fri, 9 Dec 2022 16:10:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229634AbiLIQKE (ORCPT ); Fri, 9 Dec 2022 11:10:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbiLIQKD (ORCPT ); Fri, 9 Dec 2022 11:10:03 -0500 Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [IPv6:2607:fcd0:100:8a00::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8F3D38A1; Fri, 9 Dec 2022 08:10:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1670602202; bh=AYt4KHra+GFCWNnVuXL1fFkucm0Cnki8Vo+tlWH9FvQ=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References:From; b=ILTuTcpb6Cstq23HZsP7wWcfP+uAEuZS6JHNIpgpnVxLiRV9gYMGCgKGFBs2wDDg3 KhN+qwh5xvqYl4smdqz73txIWY27vcPKRe8lwVircOVi5t312GlBFomnv3fMLtSiNU WQWzt0tz89fihS4wn0CTf27qOyx8S9qaJmo+Upw8= Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id AD4B21281045; Fri, 9 Dec 2022 11:10:02 -0500 (EST) 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 rdFl-qBSb_CB; Fri, 9 Dec 2022 11:10:02 -0500 (EST) Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 0FB3912803C0; Fri, 9 Dec 2022 11:10:01 -0500 (EST) From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Ard Biesheuvel , Jarkko Sakkinen , keyrings@vger.kernel.org Subject: [PATCH 07/11] tpm: add hmac checks to tpm2_pcr_extend() Date: Fri, 9 Dec 2022 11:06:07 -0500 Message-Id: <20221209160611.30207-8-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20221209160611.30207-1-James.Bottomley@HansenPartnership.com> References: <20221209160611.30207-1-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org 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 | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 056dad3dd5c9..001360d5956d 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -216,13 +216,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, 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 * @@ -236,24 +229,23 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, struct tpm_digest *digests) { struct tpm_buf buf; - struct tpm2_null_auth_area auth_area; + struct tpm2_auth *auth; int rc; int i; - 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) { + tpm2_end_auth_session(auth); + 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, chip->nr_allocated_banks); for (i = 0; i < chip->nr_allocated_banks; i++) { @@ -262,7 +254,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, chip->allocated_banks[i].digest_size); } + tpm_buf_fill_hmac_session(&buf, auth); rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value"); + rc = tpm_buf_check_hmac_response(&buf, auth, rc); tpm_buf_destroy(&buf);