From patchwork Tue Sep 15 14:13:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 309553 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=-12.7 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=unavailable 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 F219FC433E2 for ; Wed, 16 Sep 2020 00:24:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B21A3206A4 for ; Wed, 16 Sep 2020 00:24:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600215872; bh=/s9SdzqIqbDPpKski1siH9r8hrHl0bNr6w/EOFvhlVA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Nf778RmOmOgnSbhro3cKOGVR1h1BHShz+K5HnYnDUC+nV9PPpERFNvhaOUoiWopUE ClHIQUnm2CCQUK9CJ4mWDEUZr3K4Xzi0OFG1qY2KXb4999/9AiIbv50R8Ze7gtp4Bc 2lQoNk5jyPN46Rk6rMXr9GX8Ci/j3nk6lN5kMLd4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726148AbgIPAYa (ORCPT ); Tue, 15 Sep 2020 20:24:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:33662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726776AbgIOOUY (ORCPT ); Tue, 15 Sep 2020 10:20:24 -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 A082B2223C; Tue, 15 Sep 2020 14:16:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179400; bh=/s9SdzqIqbDPpKski1siH9r8hrHl0bNr6w/EOFvhlVA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nxjEbzdMk2SOY5MC10mpU+qg7WXyHMMHQ1MC/KNwvtrBt7VS1z2r8UwZawk3RP4L8 DdCZoxjFvuzuIoFxlXn9J8iVrvhLAVMNPzZjzsnCoLrqW2MvCEZfNtC3IyiDxt6vfh mKV/CxgWUMYLnsSdzbqNLAxMokKN1qUxo1f6ZYXE= 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_Br=C3=BCns?= , Marc Titinger , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.19 45/78] iio:adc:ina2xx Fix timestamp alignment issue. Date: Tue, 15 Sep 2020 16:13:10 +0200 Message-Id: <20200915140635.837721257@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140633.552502750@linuxfoundation.org> References: <20200915140633.552502750@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -146,6 +146,11 @@ struct ina2xx_chip_info { int range_vbus; /* Bus voltage maximum in V */ int pga_gain_vshunt; /* Shunt voltage PGA gain */ 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[] = { @@ -736,8 +741,6 @@ static int ina2xx_conversion_ready(struc static int ina2xx_work_buffer(struct iio_dev *indio_dev) { struct ina2xx_chip_info *chip = iio_priv(indio_dev); - /* data buffer needs space for channel data and timestap */ - unsigned short data[4 + sizeof(s64)/sizeof(short)]; int bit, ret, i = 0; s64 time; @@ -756,10 +759,10 @@ static int ina2xx_work_buffer(struct iio if (ret < 0) return ret; - data[i++] = val; + chip->scan.chan[i++] = val; } - iio_push_to_buffers_with_timestamp(indio_dev, data, time); + iio_push_to_buffers_with_timestamp(indio_dev, &chip->scan, time); return 0; };