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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 50FCCC433DF for ; Thu, 2 Jul 2020 01:27:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26580214F1 for ; Thu, 2 Jul 2020 01:27:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653244; bh=EwCvbKD99LhUvvDLGR7ZX5EpZgYdVpsHJlAuL0pgn1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=c/BK5cE6lIq7YQ61FjSraGo1kM3vdRkyfnIgTAzZK8dzvsu6bHd1um0/9wTBy1+sc 80Vj8UJo61c/2TnypF3wg7Rh0QcuRo8iGZ7A8wO8TmeNPM7mM5juYbTEZZaSM1885F Cq8Ml+RzaiZUlsdvuVyg/c3Ga5vz0FqBYCiaiE9s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729452AbgGBB1U (ORCPT ); Wed, 1 Jul 2020 21:27:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:59134 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729105AbgGBB1T (ORCPT ); Wed, 1 Jul 2020 21:27:19 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 1DB0A214F1; Thu, 2 Jul 2020 01:27:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653238; bh=EwCvbKD99LhUvvDLGR7ZX5EpZgYdVpsHJlAuL0pgn1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BfwT+WfxiMvEawJuortA1iIMU8LeXEDiRDC25JtBDgtcp/j9N71Rf45EhOcwBQtgv PSuj+mcWhd5OktdpIPGNfJl6HWeYOUUPawNJLN4e/1xqO+N+n0X9K8ut8jQIk5j3Bp f2iHMF2/10arFEE0aAdoiVRbcMg94FJc31XfTSpE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhenzhong Duan , Mark Brown , Sasha Levin , linux-spi@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 05/13] spi: spidev: fix a potential use-after-free in spidev_release() Date: Wed, 1 Jul 2020 21:27:04 -0400 Message-Id: <20200702012712.2701986-5-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200702012712.2701986-1-sashal@kernel.org> References: <20200702012712.2701986-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org From: Zhenzhong Duan [ Upstream commit 06096cc6c5a84ced929634b0d79376b94c65a4bd ] If an spi device is unbounded from the driver before the release process, there will be an NULL pointer reference when it's referenced in spi_slave_abort(). Fix it by checking it's already freed before reference. Signed-off-by: Zhenzhong Duan Link: https://lore.kernel.org/r/20200618032125.4650-2-zhenzhong.duan@gmail.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spidev.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index 67ad7e46da42d..c364d9ce6d4b5 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -636,15 +636,20 @@ static int spidev_open(struct inode *inode, struct file *filp) static int spidev_release(struct inode *inode, struct file *filp) { struct spidev_data *spidev; + int dofree; mutex_lock(&device_list_lock); spidev = filp->private_data; filp->private_data = NULL; + spin_lock_irq(&spidev->spi_lock); + /* ... after we unbound from the underlying device? */ + dofree = (spidev->spi == NULL); + spin_unlock_irq(&spidev->spi_lock); + /* last close? */ spidev->users--; if (!spidev->users) { - int dofree; kfree(spidev->tx_buffer); spidev->tx_buffer = NULL; @@ -652,19 +657,14 @@ static int spidev_release(struct inode *inode, struct file *filp) kfree(spidev->rx_buffer); spidev->rx_buffer = NULL; - spin_lock_irq(&spidev->spi_lock); - if (spidev->spi) - spidev->speed_hz = spidev->spi->max_speed_hz; - - /* ... after we unbound from the underlying device? */ - dofree = (spidev->spi == NULL); - spin_unlock_irq(&spidev->spi_lock); - if (dofree) kfree(spidev); + else + spidev->speed_hz = spidev->spi->max_speed_hz; } #ifdef CONFIG_SPI_SLAVE - spi_slave_abort(spidev->spi); + if (!dofree) + spi_slave_abort(spidev->spi); #endif mutex_unlock(&device_list_lock); -- 2.25.1