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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT autolearn=unavailable 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 7ED38C433E0 for ; Mon, 28 Dec 2020 15:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44A3E206E5 for ; Mon, 28 Dec 2020 15:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408244AbgL1Pzw (ORCPT ); Mon, 28 Dec 2020 10:55:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:35674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389418AbgL1Nfo (ORCPT ); Mon, 28 Dec 2020 08:35:44 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 84BCF22A84; Mon, 28 Dec 2020 13:35:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162529; bh=fT2Ef8ACX3SqVzjESbjRL4wVWp/i1bWFda6mD95v0zM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1Fop+1lEGT/J5nsmihAuGPJ/tSUb+xgNnBUweCOlKCQxOSONE1ROx1LggLmx68EtR +3ecUgdQ9UM09qN4KcLPUCUwtGLDebPjjK03bZmfZfTtg+wPUqcJxrl96VJfANchBh MY48gO2n1GaosPhZM0bkX8BBMu6ypAsRD+23Yhgo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Alexandru Ardelean , Lorenzo Bianconi , Stable@vger.kernel.org Subject: [PATCH 4.19 331/346] iio:light:st_uvis25: Fix timestamp alignment and prevent data leak. Date: Mon, 28 Dec 2020 13:50:50 +0100 Message-Id: <20201228124935.776763822@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jonathan Cameron commit d837a996f57c29a985177bc03b0e599082047f27 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. A local unsigned int variable is used for the regmap call so it is clear there is no potential issue with writing into the padding of the structure. Fixes: 3025c8688c1e ("iio: light: add support for UVIS25 sensor") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Reviewed-by: Alexandru Ardelean Acked-by: Lorenzo Bianconi Cc: Link: https://lore.kernel.org/r/20200920112742.170751-3-jic23@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/iio/light/st_uvis25.h | 5 +++++ drivers/iio/light/st_uvis25_core.c | 8 +++++--- 2 files changed, 10 insertions(+), 3 deletions(-) --- a/drivers/iio/light/st_uvis25.h +++ b/drivers/iio/light/st_uvis25.h @@ -28,6 +28,11 @@ struct st_uvis25_hw { struct iio_trigger *trig; bool enabled; int irq; + /* Ensure timestamp is naturally aligned */ + struct { + u8 chan; + s64 ts __aligned(8); + } scan; }; extern const struct dev_pm_ops st_uvis25_pm_ops; --- a/drivers/iio/light/st_uvis25_core.c +++ b/drivers/iio/light/st_uvis25_core.c @@ -235,17 +235,19 @@ static const struct iio_buffer_setup_ops static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p) { - u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)]; struct iio_poll_func *pf = p; struct iio_dev *iio_dev = pf->indio_dev; struct st_uvis25_hw *hw = iio_priv(iio_dev); + unsigned int val; int err; - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, &val); if (err < 0) goto out; - iio_push_to_buffers_with_timestamp(iio_dev, buffer, + hw->scan.chan = val; + + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, iio_get_time_ns(iio_dev)); out: