From patchwork Sun May 17 17:29:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11554225 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8A9DA90 for ; Sun, 17 May 2020 17:32:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BF4220810 for ; Sun, 17 May 2020 17:32:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589736732; bh=ncSOtpH0DdCs1lxPhvgnk159v8K/cbijvzKLrvrbtP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QuBH4LoExUbs2Tzu1U+SB6BD6Yfmp5mEP82TaGNIkLj4Kc8KXT5QvS66f5xgbLphk Raz9o5MIX/pk6ox4wnYrPC9GfYghWvg0V+EFK99hHz+0tizx9KZMzqcfUUU4cyJK9B zTpHiuNdxzmudj3gDLcePdIrOwS6mcL7nXzPVbnM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726406AbgEQRcM (ORCPT ); Sun, 17 May 2020 13:32:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:51348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726362AbgEQRcL (ORCPT ); Sun, 17 May 2020 13:32:11 -0400 Received: from localhost.localdomain (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8480C20801; Sun, 17 May 2020 17:32:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589736731; bh=ncSOtpH0DdCs1lxPhvgnk159v8K/cbijvzKLrvrbtP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bPMW/RC/RTtQgiUcxtoccCKKSZWClPmDPkf1N2FHWw32cTOPwpqhynnj/d6fygxuI TfxCdvSr/ZYm1TU+EsVBR/a6xrZwZ/EAtsSSh6I6W2PDrkWfANq7aNblw+4Jy22rUk t8oswAgb80qLrHUeWy/klkBrN2o0uMRKlCfs8f0Y= From: jic23@kernel.org To: linux-iio@vger.kernel.org Cc: Jonathan Cameron , Lars-Peter Clausen Subject: [PATCH 05/11] iio:gyro:itg3200: Fix timestamp alignment and prevent data leak. Date: Sun, 17 May 2020 18:29:54 +0100 Message-Id: <20200517173000.220819-6-jic23@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200517173000.220819-1-jic23@kernel.org> References: <20200517173000.220819-1-jic23@kernel.org> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Jonathan Cameron 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 array of smaller elements on the stack. This is fixed by using an explicit c structure. As there are no holes in the structure, there is no possiblity of data leakage in this case. Fixes: 36e0371e7764 ("iio:itg3200: Use iio_push_to_buffers_with_timestamp()") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/gyro/itg3200_buffer.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/iio/gyro/itg3200_buffer.c b/drivers/iio/gyro/itg3200_buffer.c index d3fbe9d86467..cd405801e61e 100644 --- a/drivers/iio/gyro/itg3200_buffer.c +++ b/drivers/iio/gyro/itg3200_buffer.c @@ -46,13 +46,20 @@ static irqreturn_t itg3200_trigger_handler(int irq, void *p) struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct itg3200 *st = iio_priv(indio_dev); - __be16 buf[ITG3200_SCAN_ELEMENTS + sizeof(s64)/sizeof(u16)]; - - int ret = itg3200_read_all_channels(st->i2c, buf); + /* + * Ensure correct alignment and padding including for the + * timestamp that may be inserted. + */ + struct { + __be16 buf[ITG3200_SCAN_ELEMENTS]; + s64 ts; + } scan; + + int ret = itg3200_read_all_channels(st->i2c, scan.buf); if (ret < 0) goto error_ret; - iio_push_to_buffers_with_timestamp(indio_dev, buf, pf->timestamp); + iio_push_to_buffers_with_timestamp(indio_dev, &scan, pf->timestamp); iio_trigger_notify_done(indio_dev->trig);