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=-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=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 58217C433E2 for ; Wed, 16 Sep 2020 00:03:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B33520756 for ; Wed, 16 Sep 2020 00:03:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600214585; bh=55ZisWJVlxaSEZINh0YnfSesZVKgcXViiQZG7620QPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YJJTor90S+Tl0SbQGlDdP/pB7iSsXAfiA8VhFx7c6YAtQWhLgKVl22ZznBI/8919N lrsNngOyVwGAUyRDsUW2lAB7Ukb10xvmqRxB9aKe56RUTVGU7d6WWxY3/LYj0z3M4T zDkLLOL5BuwRCGFwRo3em0Et6j35H/UrapFVLxIM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727118AbgIPADE (ORCPT ); Tue, 15 Sep 2020 20:03:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:41427 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726391AbgIOO3w (ORCPT ); Tue, 15 Sep 2020 10:29:52 -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 D360922AAD; Tue, 15 Sep 2020 14:21:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179699; bh=55ZisWJVlxaSEZINh0YnfSesZVKgcXViiQZG7620QPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FG7oYXZq/Sdwm62tQ32tqsP6htZ8HTaCk7Uzjinu11LQPlecOobOdFXVUNCqOAerL j51IiR6RGBbFNjI/bh53byS2dGKObCrSCGPT2Mb9wfsgmrv/m60r+DI+dBUsI2IVJ8 a/NUEVuEitVWVuHbfQHUY3r87kPq2ZWqV/4+F1Sk= 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 5.4 083/132] iio:adc:ti-adc081c Fix alignment and data leak issues Date: Tue, 15 Sep 2020 16:13:05 +0200 Message-Id: <20200915140648.256705345@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org 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 @@ -33,6 +33,12 @@ 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 @@ -128,14 +134,13 @@ 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);