From: Sasha Levin <levinsasha928@gmail.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH v2 2/2] virtio-net: Prevent NULL dereference
Date: Sat, 08 Oct 2011 10:40:11 +0200 [thread overview]
Message-ID: <1318063211.7385.1.camel@lappy> (raw)
In-Reply-To: <20111003190516.GD22427@redhat.com>
On Mon, 2011-10-03 at 21:05 +0200, Michael S. Tsirkin wrote:
> I thought about this some more. If length was too large host is
> right now writing into pages that we have freed.
> That is very bad, and I don't know what do do with it,
> really not worth prettifying that IMO, NULL pointer is the least of our
> worries.
>
> But, with mergeable buffers at least, and that is the main mode anyway,
> there is always a single page per buf, right?
> So I think we should change the code,
> and for mergeable buffers we shall only verify that
> length <= PAGE_SIZE.
In receive_mergeable() we already verify both 'page' being non-null and
length:
if (len > PAGE_SIZE)
len = PAGE_SIZE;
>
> IOW copy a bit of code from page_to_skb(vi, page, len)
> to receive_mergeable, maybe add a common function
> if we need to avoid duplication.
--
Sasha.
next prev parent reply other threads:[~2011-10-08 8:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-28 14:40 [PATCH v2 1/2] virtio-net: Verify page list size before fitting into skb Sasha Levin
2011-09-28 14:40 ` [PATCH v2 2/2] virtio-net: Prevent NULL dereference Sasha Levin
2011-10-03 18:40 ` Michael S. Tsirkin
2011-10-05 13:50 ` Sasha Levin
2011-10-05 18:59 ` Michael S. Tsirkin
2011-10-03 19:05 ` Michael S. Tsirkin
2011-10-08 8:40 ` Sasha Levin [this message]
2011-10-06 19:41 ` David Miller
2011-10-03 18:19 ` [PATCH v2 1/2] virtio-net: Verify page list size before fitting into skb David Miller
2011-10-03 18:42 ` Michael S. Tsirkin
2011-10-03 19:04 ` Michael S. Tsirkin
2011-10-05 13:50 ` Sasha Levin
2011-10-05 18:59 ` Michael S. Tsirkin
2011-10-06 19:41 ` David Miller
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