Re: [PATCH 3/6] macvtap: zerocopy: validate vector length beforepinning user pages

From: Michael S. Tsirkin
Date: Tue Apr 17 2012 - 01:44:17 EST


On Tue, Apr 17, 2012 at 07:33:28AM +0200, Eric Dumazet wrote:
> On Mon, 2012-04-16 at 16:21 +0800, Jason Wang wrote:
> > Hi:
> > On 04/16/2012 02:53 PM, Eric Dumazet wrote:
> > if ((num_pages != size) ||
> > >> (num_pages> MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))
> > >>
> > > Hi Jason
> > >
> > > Why is -EFAULT the right error code ?
> >
> > E2BIG or is there any error code you prefer?
>
> Might be good yes.
>
> However it sounds strange user cant write any size he wants (and kernel
> needs to build several skbs to fulfill user request)

We never supported arbitrary length writes:
macvtap is exactly like packet sockets in this regard.

--
MST

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/