| Message ID | 20230413121937.46135-1-xuanzhuo@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] virtio_net: bugfix overflow inside xdp_linearize_page() | expand |
On Thu, Apr 13, 2023 at 8:19 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> 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@linux.alibaba.com> Missing fixes tag? Other than this, Acked-by: Jason Wang <jasowang@redhat.com> 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 >
On Fri, 14 Apr 2023 13:40:32 +0800, Jason Wang <jasowang@redhat.com> wrote: > On Thu, Apr 13, 2023 at 8:19 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> 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@linux.alibaba.com> > > Missing fixes tag? > > Other than this, > > Acked-by: Jason Wang <jasowang@redhat.com> 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 > > >
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;
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@linux.alibaba.com> --- drivers/net/virtio_net.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)