From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: stefanha@redhat.com, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
sergei.shtylyov@cogentembedded.com
Subject: Re: [PATCH net V2] vhost-vsock: fix use after free
Date: Fri, 28 Sep 2018 07:37:37 +0800 [thread overview]
Message-ID: <588ed28b-7e4b-9dc8-92ce-d75692836c9e@redhat.com> (raw)
In-Reply-To: <20180927123539-mutt-send-email-mst@kernel.org>
On 2018年09月28日 01:04, Michael S. Tsirkin wrote:
> On Thu, Sep 27, 2018 at 08:22:04PM +0800, Jason Wang wrote:
>> The access of vsock is not protected by vhost_vsock_lock. This may
>> lead to use after free since vhost_vsock_dev_release() may free the
>> pointer at the same time.
>>
>> Fix this by holding the lock during the access.
>>
>> Reported-by:syzbot+e3e074963495f92a89ed@syzkaller.appspotmail.com
>> Fixes: 16320f363ae1 ("vhost-vsock: add pkt cancel capability")
>> Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
>> Cc: Stefan Hajnoczi<stefanha@redhat.com>
>> Signed-off-by: Jason Wang<jasowang@redhat.com>
> Wow is that really the best we can do?
For net/stable, probably yes.
> A global lock on a data path
> operation?
It's already there, and the patch only increase the critical section.
> Granted use after free is nasty but Stefan said he sees
> a way to fix it using a per socket refcount. He's on vacation
> until Oct 4 though ...
>
Stefan has acked the pacth, so I think it's ok? We can do optimization
for -next on top.
Thanks
next prev parent reply other threads:[~2018-09-27 23:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 12:22 [PATCH net V2] vhost-vsock: fix use after free Jason Wang
2018-09-27 15:33 ` Stefan Hajnoczi
2018-09-27 17:04 ` Michael S. Tsirkin
2018-09-27 23:37 ` Jason Wang [this message]
2018-09-27 23:50 ` Michael S. Tsirkin
2018-10-08 2:20 ` Jason Wang
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