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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 3A6FAC282CB for ; Tue, 5 Feb 2019 14:35:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01B45217F9 for ; Tue, 5 Feb 2019 14:35:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729151AbfBEOfw (ORCPT ); Tue, 5 Feb 2019 09:35:52 -0500 Received: from mga17.intel.com ([192.55.52.151]:16654 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728644AbfBEOfw (ORCPT ); Tue, 5 Feb 2019 09:35:52 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2019 06:35:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,564,1539673200"; d="scan'208";a="122160687" Received: from jsakkine-mobl1.tm.intel.com (HELO localhost) ([10.237.50.172]) by fmsmga008.fm.intel.com with ESMTP; 05 Feb 2019 06:35:49 -0800 Date: Tue, 5 Feb 2019 16:35:41 +0200 From: Jarkko Sakkinen To: "Winkler, Tomas" Cc: "linux-integrity@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "stable@vger.kernel.org" , James Morris , Jerry Snitselaar Subject: Re: [PATCH v3] tpm/tpm_crb: Avoid unaligned reads in crb_recv() Message-ID: <20190205143541.GA18330@linux.intel.com> References: <20190205105136.3086-1-jarkko.sakkinen@linux.intel.com> <5B8DA87D05A7694D9FA63FD143655C1B9DA90A8B@hasmsx108.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5B8DA87D05A7694D9FA63FD143655C1B9DA90A8B@hasmsx108.ger.corp.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Tue, Feb 05, 2019 at 11:07:16AM +0000, Winkler, Tomas wrote: > > 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 > > --- > > v3: > > * Fix typo i.e. %s/reminding/remaining/g > > Why you haven't fixed all the typos I've pointed out? I think you missed that. I saw only comment about remaining. Was there something else? Can fix. /Jarkko