From patchwork Mon Jul 19 14:53:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 480866 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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 7EB1AC12002 for ; Mon, 19 Jul 2021 15:51:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F0CA61279 for ; Mon, 19 Jul 2021 15:51:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344632AbhGSPKk (ORCPT ); Mon, 19 Jul 2021 11:10:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:39496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345483AbhGSPJY (ORCPT ); Mon, 19 Jul 2021 11:09:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 34A0361376; Mon, 19 Jul 2021 15:49:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626709741; bh=eWAWdoYUyGT4tcyRnagC6znYfXGQBgaN1dR66rV/snc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fyrNMXzmnvpxETHxoFduue1QfsZjmYuFcrS+w3JIZrFerfAS8BnPm2lB9AzlNn5Gl uQbm9dAugLrmuElB/TjIziHHF0Z+iacqFOA0e75EfPhE/mAJG3QM/0+fv7h5PlDbic 1x7/MPoLHcG20/RM4syXCB7+xUw4/qbsOem/TjnQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hulk Robot , Zou Wei , Guenter Roeck , Vladimir Zapolskiy , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 5.4 079/149] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Mon, 19 Jul 2021 16:53:07 +0200 Message-Id: <20210719144920.070037841@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144901.370365147@linuxfoundation.org> References: <20210719144901.370365147@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Zou Wei [ Upstream commit d0212f095ab56672f6f36aabc605bda205e1e0bf ] This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself. Reported-by: Hulk Robot Signed-off-by: Zou Wei Reviewed-by: Guenter Roeck Acked-by: Vladimir Zapolskiy Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin --- drivers/watchdog/lpc18xx_wdt.c | 2 +- drivers/watchdog/w83877f_wdt.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c index 78cf11c94941..60b6d74f267d 100644 --- a/drivers/watchdog/lpc18xx_wdt.c +++ b/drivers/watchdog/lpc18xx_wdt.c @@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); - del_timer(&lpc18xx_wdt->timer); + del_timer_sync(&lpc18xx_wdt->timer); return 0; } diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c index 6eb5185d6ea6..d9addf06b44d 100644 --- a/drivers/watchdog/w83877f_wdt.c +++ b/drivers/watchdog/w83877f_wdt.c @@ -166,7 +166,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); wdt_change(WDT_DISABLE);