From patchwork Mon Sep 21 16:27:19 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: 309319 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 0AD4AC43469 for ; Mon, 21 Sep 2020 17:02:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE82D206BE for ; Mon, 21 Sep 2020 17:02:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600707771; bh=P7jqaOAApyzqqrUZrsopvtD81Sgcku1U3iZX28GTxMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CnbJFEdFPLLTIlvXUmb0gZAVMTtPkWb2iOPfzC49phHWBsbpDYffpuQEGVr6tfvwN 9EiVSYybwPAHczlL/agfVBFO/y8wc62Zf7BhtvJVK/TtCReTZvpzGisANVORCZzHdk WgNAtDrdwRXGAR4OAMvgVHTMfSFNFxpxekcRAIhU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729125AbgIURCu (ORCPT ); Mon, 21 Sep 2020 13:02:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:38516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729104AbgIUQhr (ORCPT ); Mon, 21 Sep 2020 12:37:47 -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 01E9D23998; Mon, 21 Sep 2020 16:37:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706266; bh=P7jqaOAApyzqqrUZrsopvtD81Sgcku1U3iZX28GTxMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fb6cotHyP/E4/pMs9yeLqzpiF/VzwnUSmx08LlYxsFklOl1JW7oV3+psgHQZgij6f kDCJdqPSLbYbGPQmX0GZJIjSkPcA+zHYVcE0dMDJmKRwzxDBJmvoyoTF0QAtFzzEUo LbXtnozzqeoYjKDMSLJBHai7EoLDJC3lWr16gMTQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Gregor Boirie , Linus Walleij , Jonathan Cameron , Andy Shevchenko , Stable@vger.kernel.org Subject: [PATCH 4.14 32/94] iio:magnetometer:ak8975 Fix alignment and data leak issues. Date: Mon, 21 Sep 2020 18:27:19 +0200 Message-Id: <20200921162037.022542525@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@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 02ad21cefbac4d89ac443866f25b90449527737b 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() data. This data is allocated with kzalloc so no data can leak apart from previous readings. The explicit alignment of ts is not necessary in this case as by coincidence the padding will end up the same, however I consider it to make the code less fragile and have included it. Fixes: bc11ca4a0b84 ("iio:magnetometer:ak8975: triggered buffer support") Reported-by: Lars-Peter Clausen Cc: Gregor Boirie Cc: Linus Walleij Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/magnetometer/ak8975.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) --- a/drivers/iio/magnetometer/ak8975.c +++ b/drivers/iio/magnetometer/ak8975.c @@ -381,6 +381,12 @@ struct ak8975_data { struct iio_mount_matrix orientation; struct regulator *vdd; struct regulator *vid; + + /* Ensure natural alignment of timestamp */ + struct { + s16 channels[3]; + s64 ts __aligned(8); + } scan; }; /* Enable attached power regulator if any. */ @@ -815,7 +821,6 @@ static void ak8975_fill_buffer(struct ii const struct i2c_client *client = data->client; const struct ak_def *def = data->def; int ret; - s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */ __le16 fval[3]; mutex_lock(&data->lock); @@ -838,12 +843,13 @@ static void ak8975_fill_buffer(struct ii mutex_unlock(&data->lock); /* Clamp to valid range. */ - buff[0] = clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range); - buff[1] = clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range); - buff[2] = clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range); + data->scan.channels[0] = clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range); + data->scan.channels[1] = clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range); + data->scan.channels[2] = clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range); - iio_push_to_buffers_with_timestamp(indio_dev, buff, + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, iio_get_time_ns(indio_dev)); + return; unlock: