From 45fa29c85117170b0508790f878b13ec6593c888 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Wed, 11 Sep 2024 11:20:58 +0200 Subject: [PATCH] bareudp: Pull inner IP header in bareudp_udp_encap_recv(). Bareudp reads the inner IP header to get the ECN value. Therefore, it needs to ensure that it's part of the skb's linear data. This is similar to the vxlan and geneve fixes for that same problem: * commit f7789419137b ("vxlan: Pull inner IP header in vxlan_rcv().") * commit 1ca1ba465e55 ("geneve: make sure to pull inner header in geneve_rx()") Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.") Signed-off-by: Guillaume Nault Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/5205940067c40218a70fbb888080466b2fc288db.1726046181.git.gnault@redhat.com Signed-off-by: Jakub Kicinski --- drivers/net/bareudp.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c index 7aca0544fb29..b4e820a123ca 100644 --- a/drivers/net/bareudp.c +++ b/drivers/net/bareudp.c @@ -68,6 +68,7 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) __be16 proto; void *oiph; int err; + int nh; bareudp = rcu_dereference_sk_user_data(sk); if (!bareudp) @@ -148,10 +149,25 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) } skb_dst_set(skb, &tun_dst->dst); skb->dev = bareudp->dev; - oiph = skb_network_header(skb); - skb_reset_network_header(skb); skb_reset_mac_header(skb); + /* Save offset of outer header relative to skb->head, + * because we are going to reset the network header to the inner header + * and might change skb->head. + */ + nh = skb_network_header(skb) - skb->head; + + skb_reset_network_header(skb); + + if (!pskb_inet_may_pull(skb)) { + DEV_STATS_INC(bareudp->dev, rx_length_errors); + DEV_STATS_INC(bareudp->dev, rx_errors); + goto drop; + } + + /* Get the outer header. */ + oiph = skb->head + nh; + if (!ipv6_mod_enabled() || family == AF_INET) err = IP_ECN_decapsulate(oiph, skb); else