6.12-stable review patch. If anyone has any objections, please let me know.
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From: Matthieu Baerts (NGI0) matttbe@kernel.org
[ Upstream commit 96939cec994070aa5df852c10fad5fc303a97ea3 ]
When a SYN containing the 'C' flag (deny join id0) was received, this piece of information was not propagated to the path-manager.
Even if this flag is mainly set on the server side, a client can also tell the server it cannot try to establish new subflows to the client's initial IP address and port. The server's PM should then record such info when received, and before sending events about the new connection.
Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-1-401... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/subflow.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index a05f201d194c5..17d1a9d8b0e98 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -888,6 +888,10 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
ctx->subflow_id = 1; owner = mptcp_sk(ctx->conn); + + if (mp_opt.deny_join_id0) + WRITE_ONCE(owner->pm.remote_deny_join_id0, true); + mptcp_pm_new_connection(owner, child, 1);
/* with OoO packets we can reach here without ingress