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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 662AAC43465 for ; Mon, 21 Sep 2020 16:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BE6C23976 for ; Mon, 21 Sep 2020 16:35:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706107; bh=/fpLA+rpqmMn/gnvH2S795sUxYoaCUo9g6VfqswwEto=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=c8+a25OSkmc+lhf5BrJE6xskmS8xZ+rsjZQ/OnGgUA0L2Kuc8SEAIo4diidgSZtuN Zwx4RfxXfWUA7O2OTLvhbJNoXRChxylbySCw02x1RgW9KsX0iFP+8VTN2Rjd0WhYW3 eGRYX84monOl3TUnb95WAMT+u+N0d4bC+SIOgmMg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728826AbgIUQfE (ORCPT ); Mon, 21 Sep 2020 12:35:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:60820 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728712AbgIUQeM (ORCPT ); Mon, 21 Sep 2020 12:34:12 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3706E239D1; Mon, 21 Sep 2020 16:34:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706051; bh=/fpLA+rpqmMn/gnvH2S795sUxYoaCUo9g6VfqswwEto=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2cFcBuvENqUsredSoqCLG+kVQb0EP7BevAZqJh9RMJyLTGAXREd0+z2VoU2PKE0Yu vd3cgdmYmgnzlXYYqRRPgsKPNh4yb3Mg+8vjwEv+MrGxMbblFdLeU3qBN/b2dBJ6Dm MCHqL3EZxv8SuRpcsq9/tXaSc0Q+xrcnqwer9E9k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , =?UTF-8?q?Stefan=20Br=C3=BCns?= , Marc Titinger , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.9 20/70] iio:adc:ina2xx Fix timestamp alignment issue. Date: Mon, 21 Sep 2020 18:27:20 +0200 Message-Id: <20200921162036.052173149@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.136047591@linuxfoundation.org> References: <20200921162035.136047591@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jonathan Cameron commit f8cd222feb82ecd82dcf610fcc15186f55f9c2b5 upstream. One of a class of bugs pointed out by Lars in a recent review. iio_push_to_buffers_with_timestamp assumes the buffer used is aligned to the size of the timestamp (8 bytes). This is not guaranteed in this driver which uses a 32 byte array of smaller elements on the stack. As Lars also noted this anti pattern can involve a leak of data to userspace and that indeed can happen here. We close both issues by moving to a suitable structure in the iio_priv() data with alignment explicitly requested. This data is allocated with kzalloc so no data can leak apart from previous readings. The explicit alignment isn't technically needed here, but it reduced fragility and avoids cut and paste into drivers where it will be needed. If we want this in older stables will need manual backport due to driver reworks. Fixes: c43a102e67db ("iio: ina2xx: add support for TI INA2xx Power Monitors") Reported-by: Lars-Peter Clausen Cc: Stefan Brüns Cc: Marc Titinger Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/ina2xx-adc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -117,6 +117,11 @@ struct ina2xx_chip_info { int int_time_vbus; /* Bus voltage integration time uS */ int int_time_vshunt; /* Shunt voltage integration time uS */ bool allow_async_readout; + /* data buffer needs space for channel data and timestamp */ + struct { + u16 chan[4]; + u64 ts __aligned(8); + } scan; }; static const struct ina2xx_config ina2xx_config[] = { @@ -459,7 +464,6 @@ static const struct iio_chan_spec ina2xx static int ina2xx_work_buffer(struct iio_dev *indio_dev) { struct ina2xx_chip_info *chip = iio_priv(indio_dev); - unsigned short data[8]; int bit, ret, i = 0; s64 time_a, time_b; unsigned int alert; @@ -500,13 +504,12 @@ static int ina2xx_work_buffer(struct iio if (ret < 0) return ret; - data[i++] = val; + chip->scan.chan[i++] = val; } time_b = iio_get_time_ns(indio_dev); - iio_push_to_buffers_with_timestamp(indio_dev, - (unsigned int *)data, time_a); + iio_push_to_buffers_with_timestamp(indio_dev, &chip->scan, time_a); return (unsigned long)(time_b - time_a) / 1000; };