From patchwork Tue Sep 15 14:13:09 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: 263962 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 93D7FC43461 for ; Tue, 15 Sep 2020 23:16:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F388218AC for ; Tue, 15 Sep 2020 23:16:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600211761; bh=55ZisWJVlxaSEZINh0YnfSesZVKgcXViiQZG7620QPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uHKgfWosg3qWwgm8gQLfvVLprlEzyuVuXZFQ6ZICSAWXtRDe0AnrVlT9VQ/PdT2vY bB//QfMnUTpH82U/YHqbf2Ap2kK/4oaPdBbTyPs2FoxR0NxhAph407ck5j7OVmpX1P pW8deiQvO+N/hVqHcXxMXfpeIBPLYQO2SlbgzvRk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727289AbgIOXP5 (ORCPT ); Tue, 15 Sep 2020 19:15:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:48794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726921AbgIOOj2 (ORCPT ); Tue, 15 Sep 2020 10:39:28 -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 AC38421D1B; Tue, 15 Sep 2020 14:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180143; bh=55ZisWJVlxaSEZINh0YnfSesZVKgcXViiQZG7620QPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dLC8FJNWx0EOIG5OavCz1GOcpJDyZAx1EZTtKF38z++33QV8SG8Au0Bn7NQJGKv/T bRS1yVy+MRPPbOqyKC1jsIPM83qDemnZF36ING9UMp2wTC8Oq6NKsmAPiDDoTX7hF/ BGk/muFOfds2mCrQO5EKBeSgTlKGv6DdLIoNr5eE= 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 5.8 118/177] iio:adc:ti-adc081c Fix alignment and data leak issues Date: Tue, 15 Sep 2020 16:13:09 +0200 Message-Id: <20200915140659.298022721@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140653.610388773@linuxfoundation.org> References: <20200915140653.610388773@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 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);