From nobody Mon Apr 13 18:46:00 2026 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 CE0E5C433FE for ; Wed, 16 Nov 2022 03:38:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231886AbiKPDis (ORCPT ); Tue, 15 Nov 2022 22:38:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbiKPDip (ORCPT ); Tue, 15 Nov 2022 22:38:45 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA64626AC9 for ; Tue, 15 Nov 2022 19:38:43 -0800 (PST) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NBpZk2yJJzqSLW; Wed, 16 Nov 2022 11:34:54 +0800 (CST) Received: from dggpemm500007.china.huawei.com (7.185.36.183) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 16 Nov 2022 11:38:42 +0800 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; Wed, 16 Nov 2022 11:38:41 +0800 From: Yang Yingliang To: CC: , Subject: [PATCH] regulator: core: fix UAF in destroy_regulator() Date: Wed, 16 Nov 2022 11:37:06 +0800 Message-ID: <20221116033706.3595812-1-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: dggems704-chm.china.huawei.com (10.3.19.181) 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 a UAF report as following: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: use-after-free in __lock_acquire+0x935/0x2060 Read of size 8 at addr ffff88810e838220 by task python3/268 Call Trace: dump_stack_lvl+0x67/0x83 print_report+0x178/0x4b0 kasan_report+0x90/0x190 __lock_acquire+0x935/0x2060 lock_acquire+0x156/0x400 _raw_spin_lock+0x2a/0x40 lockref_get+0x11/0x30 simple_recursive_removal+0x41/0x440 debugfs_remove.part.12+0x32/0x50 debugfs_remove+0x29/0x30 _regulator_put.cold.54+0x3e/0x27f regulator_put+0x1f/0x30 release_nodes+0x6a/0xa0 devres_release_all+0xf8/0x150 Allocated by task 37: kasan_save_stack+0x1c/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x5d/0x70 slab_post_alloc_hook+0x62/0x510 kmem_cache_alloc_lru+0x222/0x5a0 __d_alloc+0x31/0x440 d_alloc+0x30/0xf0 d_alloc_parallel+0xc4/0xd20 __lookup_slow+0x15e/0x2f0 lookup_one_len+0x13a/0x150 start_creating+0xea/0x190 debugfs_create_dir+0x1e/0x210 create_regulator+0x254/0x4e0 _regulator_get+0x2a1/0x467 _devm_regulator_get+0x5a/0xb0 regulator_virtual_probe+0xb9/0x1a0 Freed by task 30: kasan_save_stack+0x1c/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x50 __kasan_slab_free+0x102/0x190 kmem_cache_free+0xf6/0x600 rcu_core+0x54c/0x12b0 __do_softirq+0xf2/0x5e3 Last potentially related work creation: kasan_save_stack+0x1c/0x40 __kasan_record_aux_stack+0x98/0xb0 call_rcu+0x42/0x700 dentry_free+0x6c/0xd0 __dentry_kill+0x23b/0x2d0 dput.part.31+0x431/0x780 simple_recursive_removal+0xa9/0x440 debugfs_remove.part.12+0x32/0x50 debugfs_remove+0x29/0x30 regulator_unregister+0xe3/0x230 release_nodes+0x6a/0xa0 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Here is how happened: processor A processor B regulator_register() rdev_init_debugfs() rdev->debugfs =3D debugfs_create_dir() devm_regulator_get() rdev =3D regulator_dev_lookup() create_regulator(rdev) // using rdev->debugfs as parent debugfs_create_dir(rdev->debugfs) mfd_remove_devices_fn() release_nodes() regulator_unregister() // free rdev->debugfs debugfs_remove_recursive(rdev->debugfs) release_nodes() destroy_regulator() debugfs_remove_recursive() <- causes UAF In devm_regulator_get(), after getting rdev, the refcount is get, so fix this by moving debugfs_remove_recursive() to regulator_dev_release(), then it can be proctected by the refcount, the 'rdev->debugfs' can not be freed until the refcount is 0. Fixes: 5de705194e98 ("regulator: Add basic per consumer debugfs") Signed-off-by: Yang Yingliang --- drivers/regulator/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index d63e6a8f569b..ce5d80b345ad 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5155,6 +5155,7 @@ static void regulator_dev_release(struct device *dev) { struct regulator_dev *rdev =3D dev_get_drvdata(dev); =20 + debugfs_remove_recursive(rdev->debugfs); kfree(rdev->constraints); of_node_put(rdev->dev.of_node); kfree(rdev); @@ -5678,7 +5679,6 @@ void regulator_unregister(struct regulator_dev *rdev) =20 mutex_lock(®ulator_list_mutex); =20 - debugfs_remove_recursive(rdev->debugfs); WARN_ON(rdev->open_count); regulator_remove_coupling(rdev); unset_regulator_supplies(rdev); --=20 2.25.1