From patchwork Fri Feb 1 11:19:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10792587 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 D9BFB13BF for ; Fri, 1 Feb 2019 11:34:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CCC3630DF9 for ; Fri, 1 Feb 2019 11:34:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BD8C4312D6; Fri, 1 Feb 2019 11:34:03 +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=-6.9 required=2.0 tests=BAYES_00,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 639E531502 for ; Fri, 1 Feb 2019 11:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730154AbfBALd5 (ORCPT ); Fri, 1 Feb 2019 06:33:57 -0500 Received: from mga12.intel.com ([192.55.52.136]:11876 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726849AbfBALd4 (ORCPT ); Fri, 1 Feb 2019 06:33:56 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Feb 2019 03:33:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,548,1539673200"; d="scan'208";a="139818063" Received: from jsakkine-mobl1.tm.intel.com (HELO localhost) ([10.237.50.172]) by fmsmga002.fm.intel.com with ESMTP; 01 Feb 2019 03:33:53 -0800 From: Jarkko Sakkinen To: linux-kernel@vger.kernel.org Cc: linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, Jarkko Sakkinen , stable@vger.kernel.org, Linus Torvalds , James Morris , Tomas Winkler , Jerry Snitselaar Subject: [PATCH] tpm/tpm_crb: Avoid unaligned reads in crb_recv(): Date: Fri, 1 Feb 2019 13:19:49 +0200 Message-Id: <20190201111949.14881-1-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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: Linus Torvalds 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 --- drivers/char/tpm/tpm_crb.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index 36952ef98f90..7f47e43aa9f1 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -288,18 +288,18 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count) unsigned int expected; /* sanity check */ - if (count < 6) + if (count < 8) return -EIO; if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR) return -EIO; - memcpy_fromio(buf, priv->rsp, 6); + memcpy_fromio(buf, priv->rsp, 8); expected = be32_to_cpup((__be32 *) &buf[2]); - if (expected > count || expected < 6) + if (expected > count || expected < 8) return -EIO; - memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6); + memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8); return expected; }