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 <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index b9bac683645279c4f2b111a743c9696ec36c8f39..c927560a773166cde5faa8ffec1abcafc2b5c623 100644 (file)
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -3058,6 +3058,7 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload,
        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;