5.15-stable review patch. If anyone has any objections, please let me know.
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From: "Matthieu Baerts (NGI0)" matttbe@kernel.org
commit 96939cec994070aa5df852c10fad5fc303a97ea3 upstream.
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 [ Conflicts in subflow.c, because of differences in the context, e.g. introduced by commit 3a236aef280e ("mptcp: refactor passive socket initialization"), which is not in this version. The same lines -- using 'mptcp_sk(new_msk)' instead of 'owner' -- can still be added approximately at the same place, before calling mptcp_pm_new_connection(). ] Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/subflow.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -758,6 +758,9 @@ create_child: */ WRITE_ONCE(mptcp_sk(new_msk)->first, child);
+ if (mp_opt.deny_join_id0) + WRITE_ONCE(mptcp_sk(new_msk)->pm.remote_deny_join_id0, true); + /* new mpc subflow takes ownership of the newly * created mptcp socket */