From b55e5a0159c8f53edefcb7848d95eb93db37bce1 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 28 Oct 2026 13:27:02 +0100 Subject: [PATCH] openvswitch: use eth_type_trans_careful() in internal_dev_recv() OVS actions like pop_eth followed by pop_mpls(ETH_P_TEB) or pop_nsh can expose an inner Ethernet header which is not in the linear part of the skb. Output to an internal port then crashes in eth_type_trans(): flow: in_port(0),eth(),eth_type(0x8847),mpls(lse=0x00010140) actions: pop_eth,pop_mpls(0x6558),0 # AF_PACKET SOCK_RAW on dp0: eth / mpls / eth / 4096 bytes of payload kernel BUG at include/linux/skbuff.h:2839! RIP: 0010:eth_type_trans (include/linux/etherdevice.h:635 net/ethernet/eth.c:163) Call Trace: internal_dev_recv (net/openvswitch/vport-internal_dev.c:202) openvswitch do_execute_actions (net/openvswitch/actions.c:1296) openvswitch ovs_execute_actions (net/openvswitch/actions.c:1606) openvswitch ovs_dp_process_packet (net/openvswitch/datapath.c:310) openvswitch ovs_vport_receive (net/openvswitch/vport.c:448) openvswitch internal_dev_xmit (net/openvswitch/vport-internal_dev.c:42) openvswitch dev_hard_start_xmit (include/linux/netdevice.h:5455 include/linux/netdevice.h:5464 net/core/dev.c:4057 net/core/dev.c:4073) __dev_queue_xmit (net/core/dev.c:5066) packet_sendmsg (net/packet/af_packet.c:3157 net/packet/af_packet.c:3189) Use eth_type_trans_careful(), and drop the packet if the Ethernet header can not be pulled. This covers all OVS actions at the consumer, instead of fixing each producer. Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support") Fixes: f66b53fdbb22 ("openvswitch: New MPLS actions for layer 2 tunnelling") Signed-off-by: Eric Dumazet Reviewed-by: Aaron Conole Reviewed-by: Jamal Hadi Salim Tested-by: Jamal Hadi Salim Acked-by: Alexei Starovoitov Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20261028122703.2093730-5-edumazet@kernel.org Signed-off-by: Jakub Kicinski --- net/openvswitch/vport-internal_dev.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c index 77a16d5ebd54..8f035087f0ee 100644 --- a/net/openvswitch/vport-internal_dev.c +++ b/net/openvswitch/vport-internal_dev.c @@ -188,6 +188,7 @@ static void internal_dev_destroy(struct vport *vport) static int internal_dev_recv(struct sk_buff *skb) { struct net_device *netdev = skb->dev; + enum skb_drop_reason reason; if (unlikely(!(netdev->flags & IFF_UP))) { kfree_skb(skb); @@ -199,7 +200,12 @@ static int internal_dev_recv(struct sk_buff *skb) nf_reset_ct(skb); skb->pkt_type = PACKET_HOST; - skb->protocol = eth_type_trans(skb, netdev); + reason = eth_type_trans_careful(skb, netdev); + if (unlikely(reason)) { + dev_core_stats_rx_dropped_inc(netdev); + kfree_skb_reason(skb, reason); + return NETDEV_TX_OK; + } skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); dev_sw_netstats_rx_add(netdev, skb->len);