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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 66267C282DC for ; Wed, 17 Apr 2019 14:59:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3ECBC217F4 for ; Wed, 17 Apr 2019 14:59:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732088AbfDQO7e (ORCPT ); Wed, 17 Apr 2019 10:59:34 -0400 Received: from mga01.intel.com ([192.55.52.88]:25777 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732299AbfDQO7d (ORCPT ); Wed, 17 Apr 2019 10:59:33 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Apr 2019 07:59:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,362,1549958400"; d="scan'208";a="162427036" Received: from asapir-mobl.ger.corp.intel.com (HELO localhost) ([10.252.18.154]) by fmsmga002.fm.intel.com with ESMTP; 17 Apr 2019 07:59:30 -0700 From: Jarkko Sakkinen To: stable@vger.kernel.org Cc: Jarkko Sakkinen , James Morris , Tomas Winkler , Jerry Snitselaar Subject: [PATCH] tpm/tpm_crb: Avoid unaligned reads in crb_recv() Date: Wed, 17 Apr 2019 17:59:15 +0300 Message-Id: <20190417145915.30956-1-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 3d7a850fdc1a2e4d2adbc95cc0fc962974725e88 upstream The current approach to read first 6 bytes from the response and then tail of the response, can cause the 2nd memcpy_fromio() to do an unaligned read (e.g. read 32-bit word from address aligned to a 16-bits), depending on how memcpy_fromio() is implemented. If this happens, the read will fail and the memory controller will fill the read with 1's. This was triggered by 170d13ca3a2f, which should be probably refined to check and react to the address alignment. Before that commit, on x86 memcpy_fromio() turned out to be memcpy(). By a luck GCC has done the right thing (from tpm_crb's perspective) for us so far, but we should not rely on that. Thus, it makes sense to fix this also in tpm_crb, not least because the fix can be then backported to stable kernels and make them more robust when compiled in differing environments. Cc: stable@vger.kernel.org Cc: James Morris Cc: Tomas Winkler Cc: Jerry Snitselaar Fixes: 30fc8d138e91 ("tpm: TPM 2.0 CRB Interface") Signed-off-by: Jarkko Sakkinen Reviewed-by: Jerry Snitselaar Acked-by: Tomas Winkler --- backport v4.9.99 drivers/char/tpm/tpm_crb.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index fa0f66809503..d29f78441cdb 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -102,19 +102,29 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count) struct crb_priv *priv = dev_get_drvdata(&chip->dev); unsigned int expected; - /* sanity check */ - if (count < 6) + /* A sanity check that the upper layer wants to get at least the header + * as that is the minimum size for any TPM response. + */ + if (count < TPM_HEADER_SIZE) return -EIO; + /* If this bit is set, according to the spec, the TPM is in + * unrecoverable condition. + */ if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR) return -EIO; - memcpy_fromio(buf, priv->rsp, 6); - expected = be32_to_cpup((__be32 *) &buf[2]); - if (expected > count || expected < 6) + /* Read the first 8 bytes in order to get the length of the response. + * We read exactly a quad word in order to make sure that the remaining + * reads will be aligned. + */ + memcpy_fromio(buf, priv->rsp, 8); + + expected = be32_to_cpup((__be32 *)&buf[2]); + if (expected > count || expected < TPM_HEADER_SIZE) return -EIO; - memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6); + memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8); return expected; } -- 2.19.1