[PATCH v2] virtio-net: Add validation for used length
From: Xie Yongji <hidden>
Date: 2021-05-27 07:37:10
Also in:
lkml
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
This adds validation for used length (might come from an untrusted device) to avoid data corruption or loss. Signed-off-by: Xie Yongji <redacted> --- drivers/net/virtio_net.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c4711e23af88..01f10049f686 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -661,6 +661,17 @@ static struct sk_buff *receive_small(struct net_device *dev, rcu_read_lock(); xdp_prog = rcu_dereference(rq->xdp_prog); + if (unlikely(len > GOOD_PACKET_LEN)) { + pr_debug("%s: rx error: len %u exceeds max size %d\n", + dev->name, len, GOOD_PACKET_LEN); + dev->stats.rx_length_errors++; + if (xdp_prog) + goto err_xdp; + + rcu_read_unlock(); + put_page(page); + return NULL; + } if (xdp_prog) { struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset; struct xdp_frame *xdpf;
@@ -815,6 +826,16 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, rcu_read_lock(); xdp_prog = rcu_dereference(rq->xdp_prog); + if (unlikely(len > truesize)) { + pr_debug("%s: rx error: len %u exceeds truesize %lu\n", + dev->name, len, (unsigned long)ctx); + dev->stats.rx_length_errors++; + if (xdp_prog) + goto err_xdp; + + rcu_read_unlock(); + goto err_skb; + } if (xdp_prog) { struct xdp_frame *xdpf; struct page *xdp_page;
@@ -937,13 +958,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, } rcu_read_unlock(); - if (unlikely(len > truesize)) { - pr_debug("%s: rx error: len %u exceeds truesize %lu\n", - dev->name, len, (unsigned long)ctx); - dev->stats.rx_length_errors++; - goto err_skb; - } - head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog, metasize); curr_skb = head_skb;
--
2.11.0