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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Lizhi Xu <lizhi.xu@windriver.com>
Cc: dakr@kernel.org, djrscally@gmail.com, dvyukov@google.com,
	gregkh@linuxfoundation.org, heikki.krogerus@linux.intel.com,
	jgg@nvidia.com, kevin.tian@intel.com, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, nicolinc@nvidia.com,
	rafael@kernel.org, sakari.ailus@linux.intel.com,
	syzbot+2ff22910687ee0dfd48e@syzkaller.appspotmail.com,
	syzkaller-bugs@googlegroups.com, yi.l.liu@intel.com
Subject: Re: [PATCH V2] software node: Prevent link creation failure from causing kobj reference count imbalance
Date: Mon, 14 Apr 2025 10:22:41 +0300	[thread overview]
Message-ID: <Z_y3wd7zur1_xUjM@smile.fi.intel.com> (raw)
In-Reply-To: <20250414071123.1228331-1-lizhi.xu@windriver.com>

On Mon, Apr 14, 2025 at 03:11:23PM +0800, Lizhi Xu wrote:
> syzbot reported a uaf in software_node_notify_remove. [1]
> 
> When any of the two sysfs_create_link() in software_node_notify() fails,
> the swnode->kobj reference count will not increase normally, which will
> cause swnode to be released incorrectly due to the imbalance of kobj reference
> count when executing software_node_notify_remove().
> 
> Increase the reference count of kobj before creating the link to avoid uaf.
> 
> [1]
> BUG: KASAN: slab-use-after-free in software_node_notify_remove+0x1bc/0x1c0 drivers/base/swnode.c:1108
> Read of size 1 at addr ffff888033c08908 by task syz-executor105/5844
> Freed by task 5844:
>  software_node_notify_remove+0x159/0x1c0 drivers/base/swnode.c:1106
>  device_platform_notify_remove drivers/base/core.c:2387 [inline]

The fix looks correct to me,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2025-04-14  7:22 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-06 11:37 [syzbot] [acpi?] KASAN: slab-use-after-free Read in software_node_notify_remove syzbot
2025-04-06 13:13 ` Andy Shevchenko
2025-04-06 13:31   ` syzbot
2025-04-06 13:24 ` Andy Shevchenko
2025-04-06 14:09   ` syzbot
2025-04-08 14:54 ` Andy Shevchenko
2025-04-11  0:42 ` [PATCH] software node: Prevent link creation failure from causing kobj reference count imbalance Lizhi Xu
2025-04-14  6:20   ` Andy Shevchenko
2025-04-14  6:27     ` Andy Shevchenko
2025-04-14  7:08     ` Lizhi Xu
2025-04-14  7:16       ` Andy Shevchenko
2025-04-14  7:11     ` [PATCH V2] " Lizhi Xu
2025-04-14  7:22       ` Andy Shevchenko [this message]
2025-04-14  8:41       ` Sakari Ailus

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