From patchwork Tue Sep 15 14:13:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 263814 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 C5B08C433E2 for ; Wed, 16 Sep 2020 00:24:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A9FB206A4 for ; Wed, 16 Sep 2020 00:24:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600215844; bh=zlO04cuBhV3PjPDzXpp2mShiEaTudJ8etpwglLcOXLo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UCWqhrZdMH53PjAC8Hry+VksqBcC4BiKbXlXY0OknQaDacUtoQgNjkgIsGb+Skqo0 gTuqAN750k1dJNVgSKAzOel7Z10EBk/p8dgAe9uftLTMwVX2D2+/XkW/4jgjz7OdCS 4f/H0IgpMrnH3ruTM27mh+5sN3KSyIAG3XQT2vZQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727480AbgIPAXh (ORCPT ); Tue, 15 Sep 2020 20:23:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:60686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbgIOOU6 (ORCPT ); Tue, 15 Sep 2020 10:20:58 -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 BF27722242; Tue, 15 Sep 2020 14:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179405; bh=zlO04cuBhV3PjPDzXpp2mShiEaTudJ8etpwglLcOXLo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CLnqK2sGoXSidqXWbc+JF90wZLWokOyo1K7q7OhNf5mzSULrlAP8Hn79mlLZW/YBw SeHaF0xGQ/XGgRCTDAiZXifF81TC4ZtR4EXzQSOg80CG29pngsJzyWmo+aCRE7Smu8 lIvx0w5IEOZsNgEOjc1jn9wZduxQhUPVLqG0epuI= 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 4.19 47/78] iio:adc:ti-adc081c Fix alignment and data leak issues Date: Tue, 15 Sep 2020 16:13:12 +0200 Message-Id: <20200915140635.936272631@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 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 @@ -131,14 +137,13 @@ 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);