From: Paolo Abeni pabeni@redhat.com
commit 55b47ca7d80814ceb63d64e032e96cd6777811e5 upstream.
Active subflow are inserted into the connection list at creation time. When the MPJ handshake completes successfully, a new subflow creation netlink event is generated correctly, but the current code wrongly avoid initializing a couple of subflow data.
The above will cause misbehavior on a few exceptional events: unneeded mptcp-level retransmission on msk-level sequence wrap-around and infinite mapping fallback even when a MPJ socket is present.
Address the issue factoring out the needed initialization in a new helper and invoking the latter from __mptcp_finish_join() time for passive subflow and from mptcp_finish_join() for active ones.
Fixes: 0530020a7c8f ("mptcp: track and update contiguous data status") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau martineau@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -821,6 +821,13 @@ void mptcp_data_ready(struct sock *sk, s mptcp_data_unlock(sk); }
+static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk) +{ + mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq); + WRITE_ONCE(msk->allow_infinite_fallback, false); + mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); +} + static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) { struct sock *sk = (struct sock *)msk; @@ -835,6 +842,7 @@ static bool __mptcp_finish_join(struct m mptcp_sock_graft(ssk, sk->sk_socket);
mptcp_sockopt_sync_locked(msk, ssk); + mptcp_subflow_joined(msk, ssk); return true; }
@@ -3485,14 +3493,16 @@ bool mptcp_finish_join(struct sock *ssk) return false; }
- if (!list_empty(&subflow->node)) - goto out; + /* active subflow, already present inside the conn_list */ + if (!list_empty(&subflow->node)) { + mptcp_subflow_joined(msk, ssk); + return true; + }
if (!mptcp_pm_allow_new_subflow(msk)) goto err_prohibited;
- /* active connections are already on conn_list. - * If we can't acquire msk socket lock here, let the release callback + /* If we can't acquire msk socket lock here, let the release callback * handle it */ mptcp_data_lock(parent); @@ -3515,11 +3525,6 @@ err_prohibited: return false; }
- subflow->map_seq = READ_ONCE(msk->ack_seq); - WRITE_ONCE(msk->allow_infinite_fallback, false); - -out: - mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); return true; }