On Fri, 14 Apr 2023 13:40:32 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> On Thu, Apr 13, 2023 at 8:19 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > Here we copy the data from the original buf to the new page. But we
> > not check that it may be overflow.
> >
> > As long as the size received(including vnethdr) is greater than 3840
> > (PAGE_SIZE -VIRTIO_XDP_HEADROOM). Then the memcpy will overflow.
> >
> > And this is completely possible, as long as the MTU is large, such
> > as 4096. In our test environment, this will cause crash. Since crash is
> > caused by the written memory, it is meaningless, so I do not include it.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
>
> Missing fixes tag?
>
> Other than this,
>
> Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Sorry, miss this.
Thanks.
>
> Thanks
>
> > ---
> > drivers/net/virtio_net.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 2396c28c0122..ea1bd4bb326d 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -814,8 +814,13 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
> > int page_off,
> > unsigned int *len)
> > {
> > - struct page *page = alloc_page(GFP_ATOMIC);
> > + int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> > + struct page *page;
> > +
> > + if (page_off + *len + tailroom > PAGE_SIZE)
> > + return NULL;
> >
> > + page = alloc_page(GFP_ATOMIC);
> > if (!page)
> > return NULL;
> >
> > @@ -823,7 +828,6 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
> > page_off += *len;
> >
> > while (--*num_buf) {
> > - int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> > unsigned int buflen;
> > void *buf;
> > int off;
> > --
> > 2.32.0.3.g01195cf9f
> >
>
