[PATCH v2] virtio-net: Add validation for used length
From: Xie Yongji <hidden>
Date: 2021-05-27 07:37:10
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