From patchwork Mon Sep 21 16:27:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 263729 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 8DDF6C43466 for ; Mon, 21 Sep 2020 16:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5887C239D0 for ; Mon, 21 Sep 2020 16:37:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706271; bh=nLG5hz/X1zlrm0O9qtbq0AnEnLFtbPiptbdPee2Suyo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gG3eopfsfjRGa9GoY4NfkGgZ4cyDcO4U54rWnOMk3J1/sShABa/H3Tzi8TFUcWj9K lw+d1g7YHRiyLRvej2UKhD/i2IK9d0gokKAXWO6LfCD7B3mgLONZom9bY6eROkJixG JAdHQlX3k6QbRjSCE+ocaJa1m0/zI/b2v7eztoZ4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728601AbgIUQhu (ORCPT ); Mon, 21 Sep 2020 12:37:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:38304 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729098AbgIUQhl (ORCPT ); Mon, 21 Sep 2020 12:37:41 -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 4C8C3206DC; Mon, 21 Sep 2020 16:37:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706260; bh=nLG5hz/X1zlrm0O9qtbq0AnEnLFtbPiptbdPee2Suyo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mpzWo6Uz0x/3YvNAdbrdAV4ZJZGEhk0NkiDkXy2OriwQ0OmZKm29EtOXdXpqWrRbm Syi/kU33Dvit0jhRTXsT6d2JBKgRcTcZ//QLP9hK1rX32QkRB+x+qn/Tfz2FoqfQUD 3UYJEU3zcK9TtDzzSkir7GLk/kNhS7eM9yQakVLM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Akinobu Mita , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.14 30/94] iio:adc:max1118 Fix alignment of timestamp and data leak issues Date: Mon, 21 Sep 2020 18:27:17 +0200 Message-Id: <20200921162036.941209076@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit db8f06d97ec284dc018e2e4890d2e5035fde8630 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 an 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. This data is allocated with kzalloc so no data can leak apart from previous readings. The explicit alignment of ts is necessary to ensure correct padding on architectures where s64 is only 4 bytes aligned such as x86_32. Fixes: a9e9c7153e96 ("iio: adc: add max1117/max1118/max1119 ADC driver") Reported-by: Lars-Peter Clausen Cc: Akinobu Mita Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/max1118.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/iio/adc/max1118.c +++ b/drivers/iio/adc/max1118.c @@ -38,6 +38,11 @@ struct max1118 { struct spi_device *spi; struct mutex lock; struct regulator *reg; + /* Ensure natural alignment of buffer elements */ + struct { + u8 channels[2]; + s64 ts __aligned(8); + } scan; u8 data ____cacheline_aligned; }; @@ -163,7 +168,6 @@ static irqreturn_t max1118_trigger_handl struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct max1118 *adc = iio_priv(indio_dev); - u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ int scan_index; int i = 0; @@ -181,10 +185,10 @@ static irqreturn_t max1118_trigger_handl goto out; } - data[i] = ret; + adc->scan.channels[i] = ret; i++; } - iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, iio_get_time_ns(indio_dev)); out: mutex_unlock(&adc->lock);