virtio-net: Add validation for used length

This adds validation for used length (might come
from an untrusted device) to avoid data corruption
or loss.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210531135852.113-1-xieyongji@bytedance.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Xie Yongji 2021-05-31 21:58:52 +08:00 committed by Jakub Kicinski
parent e099f3e8b7
commit ad993a95c5

View File

@ -730,6 +730,12 @@ 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) {
@ -833,6 +839,7 @@ err:
err_xdp:
rcu_read_unlock();
stats->xdp_drops++;
err_len:
stats->drops++;
put_page(page);
xdp_xmit:
@ -886,6 +893,12 @@ 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) {
@ -1012,13 +1025,6 @@ 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;