From patchwork Tue Sep 15 14:13:04 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: 263950 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 032F8C43461 for ; Tue, 15 Sep 2020 23:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B929020936 for ; Tue, 15 Sep 2020 23:21:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600212097; bh=U6sg0ulo525FLOXbhNDlLR1yH2QgYYDk6gs/A4oeoOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Zagh/w4h/LejX7t9f4D2BFVWHa1BxMRiWiYof6mFJtZwHoDbVA2xLu3ZA2T9yBTLW PunAmGlfxwXzvlePmos+S8IhwIFMeAq771foztVzxpjy217hd0F8nBRLaSND/rj57N D9H24bx47+qGJJCk4fN7cupP56JwNAi8ubwsboas= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727045AbgIOXVg (ORCPT ); Tue, 15 Sep 2020 19:21:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:48814 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727212AbgIOOiW (ORCPT ); Tue, 15 Sep 2020 10:38:22 -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 8DB6F23C8E; Tue, 15 Sep 2020 14:28:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180112; bh=U6sg0ulo525FLOXbhNDlLR1yH2QgYYDk6gs/A4oeoOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=omD564Wwur/ySsKhQI2WQRlyFLks0xTpo/ZiwRSeP1FglO7ZmK2wzGopxV5YeZxZ8 9c/Sb6EbgxRYzWBTOQDz661odA5BpiF+ldLgpxApUape+Sq3YI+kODc2qYfm2Q50xA dMC9CTZEwL107FgFUUzCbyF5QMHcO5B6YU3idPc4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Andreas Klinger , Jonathan Cameron , Stable@vger.kernel.org, Andy Shevchenko Subject: [PATCH 5.8 113/177] iio:proximity:mb1232: Fix timestamp alignment and prevent data leak. Date: Tue, 15 Sep 2020 16:13:04 +0200 Message-Id: <20200915140659.066420728@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 f60e8bb84282b8e633956cfe74b4f0d64ca73cec 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 a 16 byte s16 array 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 with alignment ensured by use of an explicit c structure. This data is allocated with kzalloc so no data can leak appart from previous readings. In this case the forced alignment of the ts is necessary to ensure correct padding on x86_32 where the s64 would only be 4 byte aligned. Fixes: 16b05261537e ("mb1232.c: add distance iio sensor with i2c") Reported-by: Lars-Peter Clausen Cc: Andreas Klinger Signed-off-by: Jonathan Cameron Cc: Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/iio/proximity/mb1232.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) --- a/drivers/iio/proximity/mb1232.c +++ b/drivers/iio/proximity/mb1232.c @@ -40,6 +40,11 @@ struct mb1232_data { */ struct completion ranging; int irqnr; + /* Ensure correct alignment of data to push to IIO buffer */ + struct { + s16 distance; + s64 ts __aligned(8); + } scan; }; static irqreturn_t mb1232_handle_irq(int irq, void *dev_id) @@ -113,17 +118,13 @@ static irqreturn_t mb1232_trigger_handle struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct mb1232_data *data = iio_priv(indio_dev); - /* - * triggered buffer - * 16-bit channel + 48-bit padding + 64-bit timestamp - */ - s16 buffer[8] = { 0 }; - buffer[0] = mb1232_read_distance(data); - if (buffer[0] < 0) + data->scan.distance = mb1232_read_distance(data); + if (data->scan.distance < 0) goto err; - iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp); + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, + pf->timestamp); err: iio_trigger_notify_done(indio_dev->trig);