From patchwork Mon Sep 21 16:27:21 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: 309493 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=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 1BBBEC4346B for ; Mon, 21 Sep 2020 16:34:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D494A239EE for ; Mon, 21 Sep 2020 16:34:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706068; bh=p7jydHRi2UcpgGqpxPC294TEpk0O700BEyFJFD72Stg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZZAxjiEglta4WZnhAsJl3tWmN1mLJG1LSzKWFjuDRERz+sX5+S9/LbjTnt0s17Lc7 BEzDeNmvRCOFrFNE2NwQsK/5qX66JcZxkK9G8DDs/0YX2dpLYqkiujCakQJZtvAlcI ycrzVRz7UCdVbbSG1F6/kqOFthiNTkgVxmXKh7lU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728739AbgIUQeY (ORCPT ); Mon, 21 Sep 2020 12:34:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:60894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728720AbgIUQeO (ORCPT ); Mon, 21 Sep 2020 12:34:14 -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 ADBB023976; Mon, 21 Sep 2020 16:34:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706054; bh=p7jydHRi2UcpgGqpxPC294TEpk0O700BEyFJFD72Stg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FnkTuMZrTAsKalrb3gpPd/dnFTJSHEOke7r7tVYlyAi+to8PIPDUvfUTDdg7P+0nN dX8yluJ1CxonVs6jCeVyll0S0rQm8PmxUx69f6uzO9wLbiH+mUrQ9BuQzhrj26ilyI /QsZWdgf31/fKFAjoYHcGtqm2I0kTkvhkqfAZoWI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.9 21/70] iio:adc:ti-adc081c Fix alignment and data leak issues Date: Mon, 21 Sep 2020 18:27:21 +0200 Message-Id: <20200921162036.086090915@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 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jonathan Cameron commit 54f82df2ba86e2a8e9cbf4036d192366e3905c89 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(). This data is allocated with kzalloc so no data can leak apart from previous readings. The eplicit alignment of ts is necessary to ensure correct padding on x86_32 where s64 is only aligned to 4 bytes. Fixes: 08e05d1fce5c ("ti-adc081c: Initial triggered buffer support") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/ti-adc081c.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/iio/adc/ti-adc081c.c +++ b/drivers/iio/adc/ti-adc081c.c @@ -36,6 +36,12 @@ struct adc081c { /* 8, 10 or 12 */ int bits; + + /* Ensure natural alignment of buffer elements */ + struct { + u16 channel; + s64 ts __aligned(8); + } scan; }; #define REG_CONV_RES 0x00 @@ -132,14 +138,13 @@ static irqreturn_t adc081c_trigger_handl struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct adc081c *data = iio_priv(indio_dev); - u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */ int ret; ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES); if (ret < 0) goto out; - buf[0] = ret; - iio_push_to_buffers_with_timestamp(indio_dev, buf, + data->scan.channel = ret; + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); out: iio_trigger_notify_done(indio_dev->trig);