From: Xie Yongji xieyongji@bytedance.com
commit ad993a95c508 ("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 (cherry picked from commit ad993a95c508417acdeb15244109e009e50d8758) [Larry: backport to 5.4.y. Minor conflict resolved due to missing commit 9ce6146ec7b50 virtio_net: Add XDP frame size in two code paths] Signed-off-by: Larry Bassel larry.bassel@oracle.com --- drivers/net/virtio_net.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 182b67270044..215c546bf50a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -717,6 +717,12 @@ 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) { @@ -819,6 +825,7 @@ 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: @@ -871,6 +878,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, head_skb = NULL; stats->bytes += len - vi->hdr_len;
+ truesize = mergeable_ctx_to_truesize(ctx); + 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) { @@ -990,14 +1004,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, } rcu_read_unlock();
- truesize = mergeable_ctx_to_truesize(ctx); - 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;