From nobody Sat May 4 07:51:48 2024 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 C1557C4321E for ; Mon, 5 Dec 2022 03:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231398AbiLEDvW (ORCPT ); Sun, 4 Dec 2022 22:51:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231161AbiLEDvT (ORCPT ); Sun, 4 Dec 2022 22:51:19 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58114FCFA for ; Sun, 4 Dec 2022 19:51:17 -0800 (PST) Received: from dggpemm500007.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4NQV1x3F51z15N58; Mon, 5 Dec 2022 11:50:29 +0800 (CST) Received: from huawei.com (10.175.103.91) by dggpemm500007.china.huawei.com (7.185.36.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 5 Dec 2022 11:51:15 +0800 From: Yang Yingliang To: CC: , , Subject: [PATCH] driver core: fix potential null-ptr-deref in device_add() Date: Mon, 5 Dec 2022 11:49:04 +0800 Message-ID: <20221205034904.2077765-1-yangyingliang@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500007.china.huawei.com (7.185.36.183) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" I got the following null-ptr-deref report while doing fault injection test: BUG: kernel NULL pointer dereference, address: 0000000000000058 CPU: 2 PID: 278 Comm: 37-i2c-ds2482 Tainted: G B W N 6.1.0-rc3+ RIP: 0010:klist_put+0x2d/0xd0 Call Trace: klist_remove+0xf1/0x1c0 device_release_driver_internal+0x196/0x210 bus_remove_device+0x1bd/0x240 device_add+0xd3d/0x1100 w1_add_master_device+0x476/0x490 [wire] ds2482_probe+0x303/0x3e0 [ds2482] This is how it happened: w1_alloc_dev() // The dev->driver is set to w1_master_driver. memcpy(&dev->dev, device, sizeof(struct device)); device_add() bus_add_device() dpm_sysfs_add() // It fails, calls bus_remove_device. // error path bus_remove_device() // The dev->driver is not null, but driver is not bound. __device_release_driver() klist_remove(&dev->p->knode_driver) <-- It causes null-ptr-deref. // normal path bus_probe_device() // It's not called yet. device_bind_driver() If dev->driver is set, in the error path after calling bus_add_device() in device_add(), bus_remove_device() is called, then the device will be detached from driver. But device_bind_driver() is not called yet, so it causes null-ptr-deref while access the 'knode_driver'. To fix this, set dev->driver to null in the error path before calling bus_remove_device(). Fixes: 57eee3d23e88 ("Driver core: Call device_pm_add() after bus_add_devic= e() in device_add()") Signed-off-by: Yang Yingliang --- drivers/base/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index d02501933467..e5c15061070b 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3551,6 +3551,7 @@ int device_add(struct device *dev) device_pm_remove(dev); dpm_sysfs_remove(dev); DPMError: + dev->driver =3D NULL; bus_remove_device(dev); BusError: device_remove_attrs(dev); --=20 2.25.1