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=-10.0 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 28B3CC433E6 for ; Mon, 20 Jul 2020 16:08:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0249E22CBB for ; Mon, 20 Jul 2020 16:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595261293; bh=1CVY6Ixyfc3N1iXZi/C5GQOuWmGjDONCEAmLWXAlKvI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jcpl5diNOU9JV3yodars7vFhXa876r+HySamibuGBZRCg49o8vQd3tZiM065WbUP+ +HmGquKE8WmYvSO/n1fy4KzfiEWFwOMX55CY9t7Qh83AleV2OGOru/dKmAJoMtRIUO cr8eyv5TuqlruMhLeFU8pGeGRlZXcUyXx1NfJFd8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732510AbgGTQIL (ORCPT ); Mon, 20 Jul 2020 12:08:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:45328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733242AbgGTQIE (ORCPT ); Mon, 20 Jul 2020 12:08:04 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 8891722CB1; Mon, 20 Jul 2020 16:08:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595261284; bh=1CVY6Ixyfc3N1iXZi/C5GQOuWmGjDONCEAmLWXAlKvI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hhZN90Z4bjdwKvB/q8Yy4QOSwQivumx4NIPzLwzn0xotRvWsr64V21vF2+E4iqj4Y zHw3ltHooKjuWA7bQeqKoUQpDpXlGd6/dYc6o049XEcJ1JbH1hCx14iz16Yo3NltXL ddSJEl5pVKKAqzapeBnoxLzxvuiCiotR3YIVhYzQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Linus Walleij , Jonathan Cameron , Stable@vger.kernel.org Subject: [PATCH 5.7 060/244] iio:magnetometer:ak8974: Fix alignment and data leak issues Date: Mon, 20 Jul 2020 17:35:31 +0200 Message-Id: <20200720152828.711414923@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720152825.863040590@linuxfoundation.org> References: <20200720152825.863040590@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 838e00b13bfd4cac8b24df25bfc58e2eb99bcc70 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 appart from previous readings. Fixes: 7c94a8b2ee8cf ("iio: magn: add a driver for AK8974") Reported-by: Lars-Peter Clausen Reviewed-by: Linus Walleij Signed-off-by: Jonathan Cameron Cc: Signed-off-by: Greg Kroah-Hartman --- drivers/iio/magnetometer/ak8974.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/iio/magnetometer/ak8974.c +++ b/drivers/iio/magnetometer/ak8974.c @@ -185,6 +185,11 @@ struct ak8974 { bool drdy_irq; struct completion drdy_complete; bool drdy_active_low; + /* Ensure timestamp is naturally aligned */ + struct { + __le16 channels[3]; + s64 ts __aligned(8); + } scan; }; static const char ak8974_reg_avdd[] = "avdd"; @@ -581,7 +586,6 @@ static void ak8974_fill_buffer(struct ii { struct ak8974 *ak8974 = iio_priv(indio_dev); int ret; - __le16 hw_values[8]; /* Three axes + 64bit padding */ pm_runtime_get_sync(&ak8974->i2c->dev); mutex_lock(&ak8974->lock); @@ -591,13 +595,13 @@ static void ak8974_fill_buffer(struct ii dev_err(&ak8974->i2c->dev, "error triggering measure\n"); goto out_unlock; } - ret = ak8974_getresult(ak8974, hw_values); + ret = ak8974_getresult(ak8974, ak8974->scan.channels); if (ret) { dev_err(&ak8974->i2c->dev, "error getting measures\n"); goto out_unlock; } - iio_push_to_buffers_with_timestamp(indio_dev, hw_values, + iio_push_to_buffers_with_timestamp(indio_dev, &ak8974->scan, iio_get_time_ns(indio_dev)); out_unlock: