From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E303F79C0 for ; Wed, 30 Nov 2022 18:45:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66202C433D6; Wed, 30 Nov 2022 18:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669833924; bh=KmkX2VovcmCMsJH2eGNzk3Wu9eMHG3Rq1VpV1QlWbwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rTwGQhkCuVXHFHE4ew5FIKoHLJHI+xiHaa7D70gi2UbN5ZMl/9s5LE5Jdh5Mz3ms6 rcSI7rLJ+d0xCey4vGXgQ+acgdGv6SmgiBySzkccoIU1/rCXnrP0YTBM4ZwvsEeu+M mYyVKJzI9Aj9NuCayQ9BQ1EKuMFkaJTVbkchy+2s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yang Yingliang , Mark Brown , Sasha Levin Subject: [PATCH 6.0 065/289] regulator: core: fix UAF in destroy_regulator() Date: Wed, 30 Nov 2022 19:20:50 +0100 Message-Id: <20221130180545.603091744@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221130180544.105550592@linuxfoundation.org> References: <20221130180544.105550592@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yang Yingliang [ Upstream commit 1f386d6894d0f1b7de8ef640c41622ddd698e7ab ] I got a UAF report as following: ================================================================== 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 ================================================================== Here is how happened: processor A processor B regulator_register() rdev_init_debugfs() rdev->debugfs = debugfs_create_dir() devm_regulator_get() rdev = 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 Link: https://lore.kernel.org/r/20221116033706.3595812-1-yangyingliang@huawei.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- 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 5f82a996dbea..c0f368f1b49f 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5138,6 +5138,7 @@ static void regulator_dev_release(struct device *dev) { struct regulator_dev *rdev = dev_get_drvdata(dev); + debugfs_remove_recursive(rdev->debugfs); kfree(rdev->constraints); of_node_put(rdev->dev.of_node); kfree(rdev); @@ -5653,7 +5654,6 @@ void regulator_unregister(struct regulator_dev *rdev) mutex_lock(®ulator_list_mutex); - debugfs_remove_recursive(rdev->debugfs); WARN_ON(rdev->open_count); regulator_remove_coupling(rdev); unset_regulator_supplies(rdev); -- 2.35.1