6.6-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
commit 1bba3f219c5e8c29e63afa3c1fc24f875ebec119 upstream.
In case of DSS corruption, the MPTCP protocol tries to avoid the subflow reset if fallback is possible. Such corruptions happen in the receive path; to ensure fallback is possible the stack additionally needs to check for OoO data, otherwise the fallback will break the data stream.
Fixes: e32d262c89e2 ("mptcp: handle consistently DSS corruption") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/598 Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-4-806d378... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -904,6 +904,13 @@ static bool __mptcp_finish_join(struct m if (sk->sk_state != TCP_ESTABLISHED) return false;
+ /* The caller possibly is not holding the msk socket lock, but + * in the fallback case only the current subflow is touching + * the OoO queue. + */ + if (!RB_EMPTY_ROOT(&msk->out_of_order_queue)) + return false; + spin_lock_bh(&msk->fallback_lock); if (!msk->allow_subflows) { spin_unlock_bh(&msk->fallback_lock);