[PATCH ipsec-next v6 03/14] xfrm: allow migration from UDP encapsulated to non-encapsulated ESP

Antony Antony
2026-03-09T18:45:55Z

The current code prevents migrating an SA from UDP encapsulation to
plain ESP. This is needed when moving from a NATed path to a non-NATed
one, for example when switching from IPv4+NAT to IPv6.

Only copy the existing encapsulation during migration if the encap
attribute is explicitly provided.

Note: PF_KEY's SADB_X_MIGRATE always passes encap=NULL and never
supported encapsulation in migration. PF_KEY is deprecated and was
in feature freeze when UDP encapsulation was added to xfrm.

Signed-off-by: Antony Antony <antony.antony@secunet.com>
---
net/xfrm/xfrm_state.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 86f21a19a0eed04325b2ea26b5fe4fbb3527b2e4..20ebd10dbee5cf0ee29c81c9cc3839fb031597c2 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2008,14 +2008,8 @@ static struct xfrm_state *xfrm_state_clone_and_setup(struct xfrm_state *orig,
}
x->props.calgo = orig->props.calgo;

- if (encap || orig->encap) {
- if (encap)
- x->encap = kmemdup(encap, sizeof(*x->encap),
- GFP_KERNEL);
- else
- x->encap = kmemdup(orig->encap, sizeof(*x->encap),
- GFP_KERNEL);
-
+ if (encap) {
+ x->encap = kmemdup(encap, sizeof(*x->encap), GFP_KERNEL);
if (!x->encap)
goto error;
}

--
2.47.3