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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F130BC433EF for ; Wed, 18 May 2022 12:32:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236784AbiERMcN (ORCPT ); Wed, 18 May 2022 08:32:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236553AbiERM3R (ORCPT ); Wed, 18 May 2022 08:29:17 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D34C170657; Wed, 18 May 2022 05:27:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id CFB9CB81F40; Wed, 18 May 2022 12:27:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 396B4C36AE2; Wed, 18 May 2022 12:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652876870; bh=0/NFO8cYx8eV49vuYrkyZNzByuqpxYe0Qj+VfRawypc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bCjqESaz4VEECBYwOXmzdci2iUXr3v3KcGBDcWFrdP15Hob4UnyxpOWzKKF4qkAA5 k7mB93r0A1lOxEN4C1zZCOmOD15mwztAABzRyej9Y+pxdJ/JtsxxfP1tZ3muHMS4ze 9LA1BcYnqR/4hPndVfCMidfamFMLIuEG+Iu6/DSNtV22CNg1Dj8KYyS6VZc6fIwpOu EEqPJ+s6qExQWHVoTtJVEMoN6r+SOmaKNcbCW7EP2bwgQkb+0yMjwJQrt/Z0AcgaNs A1Xr0AIFOXE8lM6lxqANFUMp6YKepdUTTFMyxcPWcTojplM0Q3KveumfTC9iJKruq3 KG58VGmDeVv3Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Schspa Shi , syzbot+dc7c3ca638e773db07f6@syzkaller.appspotmail.com, Andrey Konovalov , Greg Kroah-Hartman , Sasha Levin , balbi@kernel.org, jannh@google.com, Julia.Lawall@inria.fr, jj251510319013@gmail.com, linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 5.17 23/23] usb: gadget: fix race when gadget driver register via ioctl Date: Wed, 18 May 2022 08:26:36 -0400 Message-Id: <20220518122641.342120-23-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220518122641.342120-1-sashal@kernel.org> References: <20220518122641.342120-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Schspa Shi [ Upstream commit 5f0b5f4d50fa0faa8c76ef9d42a42e8d43f98b44 ] The usb_gadget_register_driver can be called multi time by to threads via USB_RAW_IOCTL_RUN ioctl syscall, which will lead to multiple registrations. Call trace: driver_register+0x220/0x3a0 drivers/base/driver.c:171 usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1546 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:513 [inline] raw_ioctl+0x1883/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1220 ioctl USB_RAW_IOCTL_RUN This routine allows two processes to register the same driver instance via ioctl syscall. which lead to a race condition. Please refer to the following scenarios. T1 T2 ------------------------------------------------------------------ usb_gadget_register_driver_owner driver_register driver_register driver_find driver_find bus_add_driver bus_add_driver priv alloced drv->p = priv; kobject_init_and_add // refcount = 1; //couldn't find an available UDC or it's busy priv alloced drv->priv = priv; kobject_init_and_add ---> refcount = 1 <------ // register success ===================== another ioctl/process ====================== driver_register driver_find k = kset_find_obj() ---> refcount = 2 <------ driver_unregister // drv->p become T2's priv ---> refcount = 1 <------ kobject_put(k) ---> refcount = 0 <------ return priv->driver; --------UAF here---------- There will be UAF in this scenario. We can fix it by adding a new STATE_DEV_REGISTERING device state to avoid double register. Reported-by: syzbot+dc7c3ca638e773db07f6@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/000000000000e66c2805de55b15a@google.com/ Reviewed-by: Andrey Konovalov Signed-off-by: Schspa Shi Link: https://lore.kernel.org/r/20220508150247.38204-1-schspa@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/legacy/raw_gadget.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c index d86c3a36441e..3427ce37a5c5 100644 --- a/drivers/usb/gadget/legacy/raw_gadget.c +++ b/drivers/usb/gadget/legacy/raw_gadget.c @@ -145,6 +145,7 @@ enum dev_state { STATE_DEV_INVALID = 0, STATE_DEV_OPENED, STATE_DEV_INITIALIZED, + STATE_DEV_REGISTERING, STATE_DEV_RUNNING, STATE_DEV_CLOSED, STATE_DEV_FAILED @@ -508,6 +509,7 @@ static int raw_ioctl_run(struct raw_dev *dev, unsigned long value) ret = -EINVAL; goto out_unlock; } + dev->state = STATE_DEV_REGISTERING; spin_unlock_irqrestore(&dev->lock, flags); ret = usb_gadget_probe_driver(&dev->driver); -- 2.35.1