From patchwork Thu Nov 17 04:59:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: V4bel X-Patchwork-Id: 13046123 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80C66C4321E for ; Thu, 17 Nov 2022 05:00:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234311AbiKQFAm (ORCPT ); Thu, 17 Nov 2022 00:00:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233466AbiKQFAj (ORCPT ); Thu, 17 Nov 2022 00:00:39 -0500 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92887391D2; Wed, 16 Nov 2022 21:00:38 -0800 (PST) Received: by mail-pj1-x1032.google.com with SMTP id q1-20020a17090a750100b002139ec1e999so914392pjk.1; Wed, 16 Nov 2022 21:00:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=8WPa8f4LFDKConeqlZDv2XsPvTsZR4ro7M3jEFaX4AY=; b=lg5y8VnsWwrjUOczSSKQLttrOGSqMH6EcN1COOOou/9v2VC2hZxLXapiAMkWvK4/Vs txQmcL3Pih4V2FtZfqYWloIT7TyQcDmP/T+0m/onlTPp803nqhbzEcG+UdZ9oFlMx2Fs fEgr/QvypvOAfqT2abkAwU/uMDKTTCYEbdpYpQVA4xJTDj5P3XVE/nYgNYHQDoDoUt5k nk/QVU2KqLjt3LdX4Whuv8eY4qF2t4pFu/UAl1VmvHHDYpJaEzWzMYP6cemK0dg7bODT l2XDqcXzEGXn0eL/Z4w0+KUhHzC+YHTGhLYDowGWmIaY5Xs0mY/6TVI4S/LYI/XiUNJ2 7SSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8WPa8f4LFDKConeqlZDv2XsPvTsZR4ro7M3jEFaX4AY=; b=u/ydiAY0R+1PtxQfr4zhHPoeNGVXFwCgIOxY9tSP4lhgVUp4HoNE5PUTOrPpoe+QuU Py0yVvcTfXun5LmrSej6tVQrSdk+WdutUezbSswRs1+TExCkJi3JFaXPDoCoADJdyolK X1l+oAasIWkw8CaKavJLGyysX2fNWMmh+Fs1jCg2jXq+q0rW4o8T0TuRpmFVAS5zVcAu bAgSbqpguP8zer10sKnP9Es8hV9Rtqn57bN8YkYlGiYeRxMDDCPv9JxHjLKeaGCK3AHL +eF9nTjcB0T47vyaWRsDMi6UO5NHx47gYE1D5s93f9py83kPAA7ZJxqSHxgzZma8h4fO YHMA== X-Gm-Message-State: ANoB5plJWNtPPoKtgSahgElCY8wmeVhw2HJF8u5G6kceZ6rU+LnhG8nx o7gXEbP+FxlOu8GGZvkjM3o= X-Google-Smtp-Source: AA0mqf5M7+DgwIWjWgoOO2siMiXYPM0bbmlmzAcBXHXlVUYid5apfqT2yMfNwCdlZQJtailigKM30Q== X-Received: by 2002:a17:902:f641:b0:187:19c4:373a with SMTP id m1-20020a170902f64100b0018719c4373amr1007171plg.163.1668661237983; Wed, 16 Nov 2022 21:00:37 -0800 (PST) Received: from localhost.localdomain ([175.124.254.119]) by smtp.gmail.com with ESMTPSA id y18-20020aa79af2000000b0053e468a78a8sm11911178pfp.158.2022.11.16.21.00.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 21:00:37 -0800 (PST) From: Hyunwoo Kim To: mchehab@kernel.org Cc: kernel@tuxforce.de, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, cai.huoqing@linux.dev, tiwai@suse.de, imv4bel@gmail.com Subject: [PATCH v3 1/4] media: dvb-core: Fix use-after-free due to race condition occurring in dvb_frontend Date: Wed, 16 Nov 2022 20:59:22 -0800 Message-Id: <20221117045925.14297-2-imv4bel@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221117045925.14297-1-imv4bel@gmail.com> References: <20221117045925.14297-1-imv4bel@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org If the device node of dvb_frontend is open() and the device is disconnected, many kinds of UAFs may occur when calling close() on the device node. The root cause of this is that wake_up() for dvbdev->wait_queue is implemented in the dvb_frontend_release() function, but wait_event() is not implemented in the dvb_frontend_stop() function. So, implement wait_event() function in dvb_frontend_stop() and add 'remove_mutex' which prevents race condition for 'fe->exit'. Signed-off-by: Hyunwoo Kim --- drivers/media/dvb-core/dvb_frontend.c | 39 +++++++++++++++++++++++---- include/media/dvb_frontend.h | 6 ++++- 2 files changed, 39 insertions(+), 6 deletions(-) diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index 48e735cdbe6b..b3556e3580c6 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -809,6 +809,8 @@ static void dvb_frontend_stop(struct dvb_frontend *fe) dev_dbg(fe->dvb->device, "%s:\n", __func__); + mutex_lock(&fe->remove_mutex); + if (fe->exit != DVB_FE_DEVICE_REMOVED) fe->exit = DVB_FE_NORMAL_EXIT; mb(); @@ -818,6 +820,13 @@ static void dvb_frontend_stop(struct dvb_frontend *fe) kthread_stop(fepriv->thread); + mutex_unlock(&fe->remove_mutex); + + if (fepriv->dvbdev->users < -1) { + wait_event(fepriv->dvbdev->wait_queue, + fepriv->dvbdev->users == -1); + } + sema_init(&fepriv->sem, 1); fepriv->state = FESTATE_IDLE; @@ -2750,9 +2759,13 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) struct dvb_adapter *adapter = fe->dvb; int ret; + mutex_lock(&fe->remove_mutex); + dev_dbg(fe->dvb->device, "%s:\n", __func__); - if (fe->exit == DVB_FE_DEVICE_REMOVED) + if (fe->exit == DVB_FE_DEVICE_REMOVED) { + mutex_unlock(&fe->remove_mutex); return -ENODEV; + } if (adapter->mfe_shared) { mutex_lock(&adapter->mfe_lock); @@ -2773,8 +2786,10 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) while (mferetry-- && (mfedev->users != -1 || mfepriv->thread)) { if (msleep_interruptible(500)) { - if (signal_pending(current)) + if (signal_pending(current)) { + mutex_unlock(&fe->remove_mutex); return -EINTR; + } } } @@ -2786,6 +2801,7 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (mfedev->users != -1 || mfepriv->thread) { mutex_unlock(&adapter->mfe_lock); + mutex_unlock(&fe->remove_mutex); return -EBUSY; } adapter->mfe_dvbdev = dvbdev; @@ -2845,6 +2861,8 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (adapter->mfe_shared) mutex_unlock(&adapter->mfe_lock); + + mutex_unlock(&fe->remove_mutex); return ret; err3: @@ -2866,6 +2884,8 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) err0: if (adapter->mfe_shared) mutex_unlock(&adapter->mfe_lock); + + mutex_unlock(&fe->remove_mutex); return ret; } @@ -2876,6 +2896,8 @@ static int dvb_frontend_release(struct inode *inode, struct file *file) struct dvb_frontend_private *fepriv = fe->frontend_priv; int ret; + mutex_lock(&fe->remove_mutex); + dev_dbg(fe->dvb->device, "%s:\n", __func__); if ((file->f_flags & O_ACCMODE) != O_RDONLY) { @@ -2897,11 +2919,17 @@ static int dvb_frontend_release(struct inode *inode, struct file *file) } mutex_unlock(&fe->dvb->mdev_lock); #endif - if (fe->exit != DVB_FE_NO_EXIT) - wake_up(&dvbdev->wait_queue); if (fe->ops.ts_bus_ctrl) fe->ops.ts_bus_ctrl(fe, 0); - } + + if (fe->exit != DVB_FE_NO_EXIT) { + mutex_unlock(&fe->remove_mutex); + wake_up(&dvbdev->wait_queue); + } else + mutex_unlock(&fe->remove_mutex); + + } else + mutex_unlock(&fe->remove_mutex); dvb_frontend_put(fe); @@ -3000,6 +3028,7 @@ int dvb_register_frontend(struct dvb_adapter *dvb, fepriv = fe->frontend_priv; kref_init(&fe->refcount); + mutex_init(&fe->remove_mutex); /* * After initialization, there need to be two references: one diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h index e7c44870f20d..411ec32cd8df 100644 --- a/include/media/dvb_frontend.h +++ b/include/media/dvb_frontend.h @@ -686,7 +686,10 @@ struct dtv_frontend_properties { * @id: Frontend ID * @exit: Used to inform the DVB core that the frontend * thread should exit (usually, means that the hardware - * got disconnected. + * got disconnected.) + * @remove_mutex: mutex that avoids a race condition between a callback + * called when the hardware is disconnected and the + * file_operations of dvb_frontend */ struct dvb_frontend { @@ -704,6 +707,7 @@ struct dvb_frontend { int (*callback)(void *adapter_priv, int component, int cmd, int arg); int id; unsigned int exit; + struct mutex remove_mutex; }; /**