From patchwork Mon Sep 21 16:27:29 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: 309510 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=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 17A18C4346B for ; Mon, 21 Sep 2020 16:31:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D76BF239A1 for ; Mon, 21 Sep 2020 16:31:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705917; bh=Kikms6u3+toTfKNvKFXkU4+H6n1KmacY2wRUK+4odSU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y0fhXGzgwWHHjIMjZ9lOGkRlNaJZQS8IgbgjlaW93w4CwdeMJkLCcFWCE5b9DiQPi cEwCNX6i9II8uFxU4+ZjZO7QGFwpwUXLoTXYVtnNcmHlsvuXV/EcClPI2E7DK/X27C Xk4pxwb6Dd+CCqGFgPCjWTnuVOylE+DjckkRCXSo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728058AbgIUQb5 (ORCPT ); Mon, 21 Sep 2020 12:31:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:56994 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728286AbgIUQbx (ORCPT ); Mon, 21 Sep 2020 12:31:53 -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 E5A412399A; Mon, 21 Sep 2020 16:31:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705912; bh=Kikms6u3+toTfKNvKFXkU4+H6n1KmacY2wRUK+4odSU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LZDLNgVGzjG7DEts9X3o4/9q0V3Pth0wT7RbWjHl1ODi/QDerH7d2JBNJXgga0HlE bJdkUwZz7qnpnJI/wZjGF0suR4YvMd2N32SAAAO48BQXgk+kiAVvnoMG5537SIkkDm n95HeqJtlOB6CtM9tzI9dG2NKHbFhDkhPTh/EITY= 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 4.4 13/46] iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak. Date: Mon, 21 Sep 2020 18:27:29 +0200 Message-Id: <20200921162033.966266919@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162033.346434578@linuxfoundation.org> References: <20200921162033.346434578@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -198,6 +198,14 @@ 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; @@ -924,15 +932,16 @@ 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; }