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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C367C433EF for ; Thu, 4 Nov 2021 14:05:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4EAF60ED7 for ; Thu, 4 Nov 2021 14:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231373AbhKDOIA (ORCPT ); Thu, 4 Nov 2021 10:08:00 -0400 Received: from 212.199.177.27.static.012.net.il ([212.199.177.27]:47755 "EHLO herzl.nuvoton.co.il" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S231325AbhKDOH7 (ORCPT ); Thu, 4 Nov 2021 10:07:59 -0400 Received: from taln60.nuvoton.co.il (ntil-fw [212.199.177.25]) by herzl.nuvoton.co.il (8.13.8/8.13.8) with ESMTP id 1A4E26M5029313; Thu, 4 Nov 2021 16:02:06 +0200 Received: by taln60.nuvoton.co.il (Postfix, from userid 10140) id 0DD2963A20; Thu, 4 Nov 2021 16:02:18 +0200 (IST) From: amirmizi6@gmail.com To: Eyal.Cohen@nuvoton.com, jarkko@kernel.org, oshrialkoby85@gmail.com, alexander.steffen@infineon.com, robh+dt@kernel.org, mark.rutland@arm.com, peterhuewe@gmx.de, jgg@ziepe.ca, arnd@arndb.de, gregkh@linuxfoundation.org, benoit.houyere@st.com, eajames@linux.ibm.com, joel@jms.id.au Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, oshri.alkoby@nuvoton.com, tmaimon77@gmail.com, gcwilson@us.ibm.com, kgoldman@us.ibm.com, Dan.Morav@nuvoton.com, oren.tanami@nuvoton.com, shmulik.hager@nuvoton.com, amir.mizinski@nuvoton.com, Amir Mizinski Subject: [PATCH v19 3/5] tpm: tpm_tis: Verify TPM_STS register is valid after locality request Date: Thu, 4 Nov 2021 16:02:09 +0200 Message-Id: <20211104140211.6258-4-amirmizi6@gmail.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20211104140211.6258-1-amirmizi6@gmail.com> References: <20211104140211.6258-1-amirmizi6@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Amir Mizinski An invalid TPM_STS value could be used when the following two events occur: TPM does not update TPM_STS register after a locality request (TPM_STS Initial value = 0xFF), and a TPM_STS register read occurs in the tpm_tis_status(chip) function call. In probe_itpm(), a call to tpm_tis_send_data() function is made after a request_locality() call, and the condition ("if ((status & TPM_STS_COMMAND_READY) == 0)") is checked. At this moment if the status value is 0xFF, then it is considered, wrongly, in “ready” state (by checking only one bit). However, at this moment the TPM is, in fact, in "Idle" state and remains in "Idle" state because "tpm_tis_ready(chip);" was not executed. Waiting for the condition TPM_STS.tpmGo == 0, will ensure that the TPM status register has the correct value. Suggested-by: Benoit Houyere Signed-off-by: Amir Mizinski --- drivers/char/tpm/tpm_tis_core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 6ff8b44..770685a 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -177,8 +177,12 @@ static int request_locality(struct tpm_chip *chip, int l) } else { /* wait for burstcount */ do { - if (check_locality(chip, l)) + if (check_locality(chip, l)) { + if (tpm_tis_wait_for_stat(chip, TPM_STS_GO, 0, chip->timeout_c, + &priv->int_queue, false) < 0) + return -ETIME; return l; + } tpm_msleep(TPM_TIMEOUT); } while (time_before(jiffies, stop)); } -- 2.7.4