From patchwork Sun Jun 7 15:53:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 11591681 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5910D913 for ; Sun, 7 Jun 2020 15:56:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38895207D8 for ; Sun, 7 Jun 2020 15:56:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545391; bh=ivuToFhcb/RIqOUjvSILL6KctK9DcKr+jnj1Swv7Im8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jGM/UDctOBjv5Ika57UnG1+Q/kPT0aMjx31ijZA7V4PeGsoONxezagOAH6/U7+Jta iYuPP/yUa3dKCTRDEmDOxv1UkqyH76ihMljRzo73fop+SofkTqnr+j/DGnWGvt63Tp akwqdyM6z7j+7TJvTfTEdBtY5+WwdcZOadhKTT3A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726699AbgFGP4a (ORCPT ); Sun, 7 Jun 2020 11:56:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:57360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726697AbgFGP43 (ORCPT ); Sun, 7 Jun 2020 11:56:29 -0400 Received: from localhost.localdomain (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6B740206F6; Sun, 7 Jun 2020 15:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591545389; bh=ivuToFhcb/RIqOUjvSILL6KctK9DcKr+jnj1Swv7Im8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ouv1fvEHVIFpP7QO5lcPe/OcrsfWY90ahPbp8gXJwvo1/32bPwM8M7SRBdqqrpvEg r/+OkiHNIRLH48dmJdQgaRR8F2mWs2Vu+CLf4U9nS+LJsERklgX3MKVzbjNLlxzjYW WJMINwnR53dzXQScjfvPV0vJl/MHjSahnczGlHTw= From: Jonathan Cameron To: linux-iio@vger.kernel.org Cc: Andy Shevchenko , Jonathan Cameron , Lars-Peter Clausen , Lorenzo Bianconi Subject: [PATCH 11/32] iio:light:st_uvis25 Fix timestamp alignment and prevent data leak. Date: Sun, 7 Jun 2020 16:53:47 +0100 Message-Id: <20200607155408.958437-12-jic23@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200607155408.958437-1-jic23@kernel.org> References: <20200607155408.958437-1-jic23@kernel.org> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Jonathan Cameron 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() This data is allocated with kzalloc so no data can leak apart from previous readings. Fixes: 3025c8688c1e ("iio: light: add support for UVIS25 sensor") Reported-by: Lars-Peter Clausen Acked-by: Lorenzo Bianconi Signed-off-by: Jonathan Cameron --- drivers/iio/light/st_uvis25.h | 5 +++++ drivers/iio/light/st_uvis25_core.c | 6 +++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/iio/light/st_uvis25.h b/drivers/iio/light/st_uvis25.h index 78bc56aad129..283086887caf 100644 --- a/drivers/iio/light/st_uvis25.h +++ b/drivers/iio/light/st_uvis25.h @@ -27,6 +27,11 @@ struct st_uvis25_hw { struct iio_trigger *trig; bool enabled; int irq; + /* Ensure timestamp is naturally aligned */ + struct { + u8 chan; + s64 ts __aligned(8); + } scan; }; extern const struct dev_pm_ops st_uvis25_pm_ops; diff --git a/drivers/iio/light/st_uvis25_core.c b/drivers/iio/light/st_uvis25_core.c index 4d001d50e775..818b8faea73c 100644 --- a/drivers/iio/light/st_uvis25_core.c +++ b/drivers/iio/light/st_uvis25_core.c @@ -234,17 +234,17 @@ static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = { static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p) { - u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)]; struct iio_poll_func *pf = p; struct iio_dev *iio_dev = pf->indio_dev; struct st_uvis25_hw *hw = iio_priv(iio_dev); int err; - err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, + (unsigned int *)&hw->scan.chan); if (err < 0) goto out; - iio_push_to_buffers_with_timestamp(iio_dev, buffer, + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, iio_get_time_ns(iio_dev)); out: