From b7f9587f317d9faaafb1593b4e9d6b65214f8a5e Mon Sep 17 00:00:00 2001 From: Antony Antony Date: Thu, 11 Dec 2025 11:30:27 +0100 Subject: [PATCH] xfrm: set ipv4 no_pmtu_disc flag only on output sa when direction is set [ Upstream commit c196def07bbc6e8306d7a274433913444b0db20a ] The XFRM_STATE_NOPMTUDISC flag is only meaningful for output SAs, but it was being applied regardless of the SA direction when the sysctl ip_no_pmtu_disc is enabled. This can unintentionally affect input SAs. Limit setting XFRM_STATE_NOPMTUDISC to output SAs when the SA direction is configured. Closes: https://github.com/strongswan/strongswan/issues/2946 Fixes: a4a87fa4e96c ("xfrm: Add Direction to the SA in or out") Signed-off-by: Antony Antony Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/xfrm/xfrm_state.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 9e14e453b55cc..98b362d518363 100644 --- a/net/xfrm/xfrm_state.c +++ b/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; -- 2.47.3