From 92da495cb65719583aa06bc946aeb18a10e1e6e2 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 12 Sep 2025 14:52:23 +0200 Subject: [PATCH] mptcp: tfo: record 'deny join id0' info When TFO is used, the check to see if the 'C' flag (deny join id0) was set was bypassed. This flag can be set when TFO is used, so the check should also be done when TFO is used. Note that the set_fully_established label is also used when a 4th ACK is received. In this case, deny_join_id0 will not be set. Fixes: dfc8d0603033 ("mptcp: implement delayed seq generation for passive fastopen") Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-4-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/options.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 2a8ea28442b27..1103b3341a705 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -985,13 +985,13 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, return false; } - if (mp_opt->deny_join_id0) - WRITE_ONCE(msk->pm.remote_deny_join_id0, true); - if (unlikely(!READ_ONCE(msk->pm.server_side))) pr_warn_once("bogus mpc option on established client sk"); set_fully_established: + if (mp_opt->deny_join_id0) + WRITE_ONCE(msk->pm.remote_deny_join_id0, true); + mptcp_data_lock((struct sock *)msk); __mptcp_subflow_fully_established(msk, subflow, mp_opt); mptcp_data_unlock((struct sock *)msk); -- 2.47.3