linux-kernel - Re: [BUG] possible race between md_free_disk and md_notify

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z7alWBZfQLlP-EO7@bender.morinfr.org>
Date: Thu, 20 Feb 2025 04:45:28 +0100
From: Guillaume Morin <guillaume@...infr.org>
To: Yu Kuai <yukuai3@...wei.com>
Cc: Guillaume Morin <guillaume@...infr.org>,
	Yu Kuai <yukuai1@...weicloud.com>, linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org, song@...nel.org
Subject: Re: [BUG] possible race between md_free_disk and md_notify_reboot

On 20 Feb 11:19, Yu Kuai wrote:
>
> Hi,
> 
> 在 2025/02/20 11:05, Guillaume Morin 写道:
> > how it was guaranteed that mddev_get() would fail as mddev_free() does not check or synchronize with the active atomic
> 
> Please check how mddev is freed, start from mddev_put(). There might be
> something wrong, but it's not what you said.

I will take a look. Though if you're confident that this logic protects
any uaf, that makes sense to me.

However as I mentioned this is not what the crash was about (I mentioned
the UAF in passing). The GPF seems to be about deleting the _next_
pointer while iterating over all mddevs. The mddev_get on the
current item is not going to help with this.

-- 
Guillaume Morin <guillaume@...infr.org>