From patchwork Tue Sep 15 14:13:01 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: 263861 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 3FBF3C43461 for ; Wed, 16 Sep 2020 00:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F353520739 for ; Wed, 16 Sep 2020 00:05:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600214713; bh=X5TVl7ZiumJRI9j4Ydvor+UpyVUz5md9qjnynv0E7QA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yb4P3UnP/T46Cae9fq2x3TPiPPwEkvMegcAegHak0cNK7cQsAgFeAIMypZSztauk8 Q7ykZRsQ787ESu1+Gj+IwPe6gRPPPZuzxU6jvaXlXsoe8lO7XQOBX8XksCm6VR2PpS G4xHX815mxBrkPQe8RorrSzYymD65lcl8A6Jx1xs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727184AbgIPAFJ (ORCPT ); Tue, 15 Sep 2020 20:05:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:42984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726976AbgIOO3B (ORCPT ); Tue, 15 Sep 2020 10:29:01 -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 BD19622A84; Tue, 15 Sep 2020 14:21:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179689; bh=X5TVl7ZiumJRI9j4Ydvor+UpyVUz5md9qjnynv0E7QA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gl4nJVn8R4U5GyGEpgMU9mWOGujZjcyyOiM1N4+024J4Y8k1q6K9R0juBlKvZmqtW C45GUxTut8fSEkmyzHmJOCORsQH/OzJK+epfHuIj3mMTvKANl2F0GVqa6WVaQLK6yW rxtzIFpHRjNjqOr5jPiOx8ohYDNQ1/ATaDWGFFE4= 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 5.4 079/132] iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak. Date: Tue, 15 Sep 2020 16:13:01 +0200 Message-Id: <20200915140648.055474786@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org 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 @@ -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; }