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=-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 DB805C43461 for ; Tue, 15 Sep 2020 23:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F60220936 for ; Tue, 15 Sep 2020 23:21:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600212086; bh=X5TVl7ZiumJRI9j4Ydvor+UpyVUz5md9qjnynv0E7QA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gxETb0VEgkes7WQ0VPZzpsLeXgl4P1QPTxHlYYyGqvZcbAltDCKPJhHZ+WCxtzGvm /NnwTJ/3xH9OvIKO6yocwH4nBYT8plB8BwwjpgnVprLE0ikmWQ/XHBFYLHUqsFHtK+ RuEDd8FceurDP3GS61q66cfs9VW/rAqzfkEGpzW0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726900AbgIOXVV (ORCPT ); Tue, 15 Sep 2020 19:21:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:48812 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727213AbgIOOiW (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 126F723C8F; Tue, 15 Sep 2020 14:28:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180114; bh=X5TVl7ZiumJRI9j4Ydvor+UpyVUz5md9qjnynv0E7QA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0uCYff0RRhNPgO4Mi1FI/hIXBSyUBvUAUhYEfdawLPdFnZqb/v8JYsLRQaeeFMkhc 6Ga1wOCRyytICV6Q+HaKE13C/fcOus3em9cEFyLwBNOUu6l4P86cUhi+slkYVZr0W4 OwuyKl5f8qz6w9qUflJOhhb/8msYuMJu8yZlbQ8Y= 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 5.8 114/177] iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak. Date: Tue, 15 Sep 2020 16:13:05 +0200 Message-Id: <20200915140659.106405977@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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org 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 @@ -189,6 +189,14 @@ 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; @@ -922,15 +930,16 @@ 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; }