Merge tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

Steffen Klassert says:

====================
pull request (net): ipsec 2026-01-14

1) Fix inner mode lookup in tunnel mode GSO segmentation.
   The protocol was taken from the wrong field.

2) Set ipv4 no_pmtu_disc flag only on output SAs. The
   insertation of input SAs can fail if no_pmtu_disc
   is set.

Please pull or let me know if there are problems.

ipsec-2026-01-14

* tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
  xfrm: set ipv4 no_pmtu_disc flag only on output sa when direction is set
  xfrm: Fix inner mode lookup in tunnel mode GSO segmentation
====================

Link: https://patch.msgid.link/20260114121817.1106134-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

net/ipv4/esp4_offload.c

@@ -122,8 +122,8 @@ static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
 						struct sk_buff *skb,
 						netdev_features_t features)
 {
-	const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x,
-					XFRM_MODE_SKB_CB(skb)->protocol);
+	struct xfrm_offload *xo = xfrm_offload(skb);
+	const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x, xo->proto);
 	__be16 type = inner_mode->family == AF_INET6 ? htons(ETH_P_IPV6)
 						     : htons(ETH_P_IP);
 

net/ipv6/esp6_offload.c

@@ -158,8 +158,8 @@ static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
 						struct sk_buff *skb,
 						netdev_features_t features)
 {
-	const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x,
-					XFRM_MODE_SKB_CB(skb)->protocol);
+	struct xfrm_offload *xo = xfrm_offload(skb);
+	const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x, xo->proto);
 	__be16 type = inner_mode->family == AF_INET ? htons(ETH_P_IP)
 						    : htons(ETH_P_IPV6);
 

net/xfrm/xfrm_state.c

@@ -3151,6 +3151,7 @@ int __xfrm_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 	int err;
 
 	if (family == AF_INET &&
+	    (!x->dir || x->dir == XFRM_SA_DIR_OUT) &&
 	    READ_ONCE(xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc))
 		x->props.flags |= XFRM_STATE_NOPMTUDISC;