From: Zheng Hacker <hackerzheng666@gmail.com>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: Zheng Wang <zyytlz.wz@163.com>,
valentina.manea.m@gmail.com, gregkh@linuxfoundation.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
1395428693sheep@gmail.com, alex000young@gmail.com
Subject: Re: [PATCH v3] usbip: vudc: Fix use after free bug in vudc_remove due to race condition
Date: Sat, 18 Mar 2023 15:39:22 +0800 [thread overview]
Message-ID: <CAJedcCwK8Z_nuBM4NnM1PwbTqTnfX2n6UEy9dd5LKf_GScq=xA@mail.gmail.com> (raw)
In-Reply-To: <d05ae776-ee19-2ce0-c06b-9825e5cbea82@linuxfoundation.org>
Shuah Khan <skhan@linuxfoundation.org> 于2023年3月18日周六 06:53写道:
>
> On 3/17/23 04:09, Zheng Wang wrote:
> > In vudc_probe, it calls init_vudc_hw, which bound &udc->timer with v_timer.
> >
> > When it calls usbip_sockfd_store, it will call v_start_timer to start the
> > timer work.
> >
> > When we call vudc_remove to remove the driver, theremay be a sequence as
> > follows:
> >
> > Fix it by shutdown the timer work before cleanup in vudc_remove.
> >
> > Note that removing a driver is a root-only operation, and should never
> > happen. But the attacker can directly unplug the usb to trigger the remove
> > function.
> >
> > CPU0 CPU1
> >
> > |v_timer
> > vudc_remove |
> > kfree(udc); |
> > //free shost |
> > |udc->gadget
> > |//use
> >
> > The udc might be removed before v_timer finished, and UAF happens.
> >
> > This bug was found by Codeql static analysis and might by false positive.
>
> This statement that this could be a false positive makes me hesitate
> taking this patch.
>
> What kind of testing have you done with this fix? Were you able to test
> the scenario of unplugging usb?
>
Sorry I did't make a full test for I did't have the device. The
attacking scenario if based on other cases.
Best regads,
Zheng
> thanks,
> -- Shuah
next prev parent reply other threads:[~2023-03-18 7:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-17 10:09 [PATCH v3] usbip: vudc: Fix use after free bug in vudc_remove due to race condition Zheng Wang
2023-03-17 22:53 ` Shuah Khan
2023-03-18 7:39 ` Zheng Hacker [this message]
2023-04-13 8:09 ` Zheng Hacker
2023-04-13 18:01 ` Shuah Khan
2023-04-14 2:33 ` Zheng Hacker
-- strict thread matches above, loose matches on Subject: below --
2023-03-16 17:44 Zheng Wang
2023-03-16 17:47 ` Zheng Hacker
2023-03-16 17:57 ` Shuah Khan
2023-03-16 18:02 ` Zheng Hacker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAJedcCwK8Z_nuBM4NnM1PwbTqTnfX2n6UEy9dd5LKf_GScq=xA@mail.gmail.com' \
--to=hackerzheng666@gmail.com \
--cc=1395428693sheep@gmail.com \
--cc=alex000young@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=skhan@linuxfoundation.org \
--cc=valentina.manea.m@gmail.com \
--cc=zyytlz.wz@163.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).