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=-11.2 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=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 DDCDBC43466 for ; Mon, 21 Sep 2020 17:05:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA7582084C for ; Mon, 21 Sep 2020 17:05:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707928; bh=V+hMxe2Lwr/FAnvCw25sVauwGTJ4DqBLe1JJIdJzaaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Oh/cVLPDeAQaXOGdKGfpRK6tMohy+uGo8fqCzmwXQssScLclo/T1yWS9yfKnIqzqb MfeTzvXuaNod3fDslAu3w7aHSByWgTmegKHwP0qHYrtEWXWjUN56YWXliLo2Pz0ui9 paiBw2dqMwLdbkGIKBcWZ2ATBymuZBF28oluN/7E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730469AbgIURF1 (ORCPT ); Mon, 21 Sep 2020 13:05:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:60714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728705AbgIUQeH (ORCPT ); Mon, 21 Sep 2020 12:34:07 -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 12884239A1; Mon, 21 Sep 2020 16:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706046; bh=V+hMxe2Lwr/FAnvCw25sVauwGTJ4DqBLe1JJIdJzaaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zrITKK4M51DdGpIEcb5Cl448zstGXxBMyYLSgfhbiDnngmLA2N++4gcjsygP9Xdnw n2Z6RwvjJFldugOdi2vdercut+vqhjLtC8tGYkZ54kJ4XfLAcmuBpeH2fdAfNv8ECN rl1afqzkoYSLvkOn6RaCbN0ycDJr4hmzUZ8wdDNQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Jonathan Cameron , Srinivas Pandruvada , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.9 19/70] iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak. Date: Mon, 21 Sep 2020 18:27:19 +0200 Message-Id: <20200921162036.012927073@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.136047591@linuxfoundation.org> References: <20200921162035.136047591@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 a6f86f724394de3629da63fe5e1b7a4ab3396efe 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 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() 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. Fixes tag is beyond some major refactoring so likely manual backporting would be needed to get that far back. Whilst the force alignment of the ts is not strictly necessary, it does make the code less fragile. Fixes: 3bbec9773389 ("iio: bmc150_accel: add support for hardware fifo") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Acked-by: Srinivas Pandruvada Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/accel/bmc150-accel-core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/drivers/iio/accel/bmc150-accel-core.c +++ b/drivers/iio/accel/bmc150-accel-core.c @@ -197,6 +197,14 @@ struct bmc150_accel_data { struct mutex mutex; u8 fifo_mode, watermark; s16 buffer[8]; + /* + * Ensure there is sufficient space and correct alignment for + * the timestamp if enabled + */ + struct { + __le16 channels[3]; + s64 ts __aligned(8); + } scan; u8 bw_bits; u32 slope_dur; u32 slope_thres; @@ -933,15 +941,16 @@ static int __bmc150_accel_fifo_flush(str * now. */ for (i = 0; i < count; i++) { - u16 sample[8]; int j, bit; j = 0; for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) - memcpy(&sample[j++], &buffer[i * 3 + bit], 2); + memcpy(&data->scan.channels[j++], &buffer[i * 3 + bit], + sizeof(data->scan.channels[0])); - iio_push_to_buffers_with_timestamp(indio_dev, sample, tstamp); + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, + tstamp); tstamp += sample_period; }