From: Xie Yongji <xieyongji@xxxxxxxxxxxxx> [ Upstream commit ad993a95c508417acdeb15244109e009e50d8758 ] This adds validation for used length (might come from an untrusted device) to avoid data corruption or loss. Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx> Acked-by: Jason Wang <jasowang@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210531135852.113-1-xieyongji@xxxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/virtio_net.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 78a01c71a17c..252f6718d730 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -721,6 +721,12 @@ static struct sk_buff *receive_small(struct net_device *dev, len -= vi->hdr_len; stats->bytes += len; + 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++; + goto err_len; + } rcu_read_lock(); xdp_prog = rcu_dereference(rq->xdp_prog); if (xdp_prog) { @@ -824,6 +830,7 @@ static struct sk_buff *receive_small(struct net_device *dev, err_xdp: rcu_read_unlock(); stats->xdp_drops++; +err_len: stats->drops++; put_page(page); xdp_xmit: @@ -877,6 +884,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, head_skb = NULL; stats->bytes += len - vi->hdr_len; + 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; + } rcu_read_lock(); xdp_prog = rcu_dereference(rq->xdp_prog); if (xdp_prog) { @@ -1004,13 +1017,6 @@ 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, headroom); curr_skb = head_skb; -- 2.30.2
