From: Shuah Khan <skhan@linuxfoundation.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Hillf Danton <hdanton@sina.com>,
syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>,
Valentina Manea <valentina.manea.m@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
syzkaller-bugs@googlegroups.com,
Shuah Khan <skhan@linuxfoundation.org>
Subject: Re: general protection fault in tomoyo_socket_sendmsg_permission
Date: Wed, 10 Feb 2021 12:29:15 -0700 [thread overview]
Message-ID: <92a4c6ae-172d-91cb-b89e-8eb857fdfb3a@linuxfoundation.org> (raw)
In-Reply-To: <4368349b-fc0c-6da3-a502-2733f953d271@i-love.sakura.ne.jp>
On 2/10/21 12:07 PM, Tetsuo Handa wrote:
> On 2021/02/11 3:17, Shuah Khan wrote:
>> I am looking to understand the syzbot configuration and a reproducer
>> to be able to debug and fix the problem. How is syzbot triggering the
>> vhci_hcd attach and detach sequence?
>
> I don't know. I'm waiting for syzbot to reproduce the problem on linux-next
> with https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/usb/usbip?id=f1bdf414e7dd0cbc26460425719fc3ea479947a2 .
>
>>
>> This helps me determine all these fix suggestions that are coming in
>> are fixes or papering over a real problem.
>
> What are these fix suggestions?
>
> "general protection fault in tomoyo_socket_sendmsg_permission" is a NULL pointer
> dereference which can happen if vhci_device_reset() and/or vhci_device_init()
> (which does vdev->ud.tcp_socket = NULL;) were unexpectedly called. There is no
> reproducer, and (as far as I know) no fix suggestion.
>
Right. I would like to get a clear understanding of how this condition
is triggered. I am not saying this isn't a problem. Understanding how
it is triggered helps find the best fix.
> "KASAN: null-ptr-deref Write in vhci_shutdown_connection" is an ERR_PTR(-EINTR)
> pointer dereference which can happen if kthread_create() was SIGKILLed. There is
> a reproducer, and https://lkml.kernel.org/r/20210205135707.4574-1-penguin-kernel@I-love.SAKURA.ne.jp
> is a fix suggestion.
>
This is a good find. I already replied to the thread to send a complete
fix.
thanks,
-- Shuah
next prev parent reply other threads:[~2021-02-10 19:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 7:21 general protection fault in tomoyo_socket_sendmsg_permission syzbot
[not found] ` <20201113120055.11748-1-hdanton@sina.com>
2020-11-13 17:14 ` Shuah Khan
2021-01-28 6:09 ` Tetsuo Handa
[not found] ` <2b70d360-a293-4acb-ea6c-2badda5e8b8b@linuxfoundation.org>
2021-01-29 5:48 ` Tetsuo Handa
[not found] ` <6b8da36f-a994-7604-77f4-52e29434605f@linuxfoundation.org>
2021-01-29 17:08 ` Tetsuo Handa
2021-01-29 21:18 ` Shuah Khan
2021-01-30 2:25 ` Tetsuo Handa
2021-02-10 18:17 ` Shuah Khan
2021-02-10 19:07 ` Tetsuo Handa
2021-02-10 19:29 ` Shuah Khan [this message]
2021-02-11 1:14 ` Tetsuo Handa
2021-02-12 1:34 ` Shuah Khan
2021-02-12 2:22 ` Tetsuo Handa
2021-02-12 4:58 ` Tetsuo Handa
2021-02-12 20:02 ` Shuah Khan
2021-02-13 10:02 ` Tetsuo Handa
2021-02-13 10:10 ` Greg Kroah-Hartman
2021-02-13 10:10 ` Greg Kroah-Hartman
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