From ce63fca13e9b500e9f687d80a457175ac967a371 Mon Sep 17 00:00:00 2001 From: dergoegge Date: Mon, 28 Nov 2022 16:37:24 +0000 Subject: [PATCH] [net processing] Assume that TxRelay::m_tx_inventory_to_send is empty pre-verack This commit documents our assumption about TxRelay::m_tx_inventory_to_send being empty prior to version handshake completion. The added Assume acts as testing oracle for our fuzzing tests to potentially detect if the assumption is violated. --- src/net_processing.cpp | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/src/net_processing.cpp b/src/net_processing.cpp index 70e7eb85d8a..6d5eb3a449d 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -3435,6 +3435,20 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type, } } + if (auto tx_relay = peer->GetTxRelay()) { + // `TxRelay::m_tx_inventory_to_send` must be empty before the + // version handshake is completed as + // `TxRelay::m_next_inv_send_time` is first initialised in + // `SendMessages` after the verack is received. Any transactions + // received during the version handshake would otherwise + // immediately be advertised without random delay, potentially + // leaking the time of arrival to a spy. + Assume(WITH_LOCK( + tx_relay->m_tx_inventory_mutex, + return tx_relay->m_tx_inventory_to_send.empty() && + tx_relay->m_next_inv_send_time == 0s)); + } + pfrom.fSuccessfullyConnected = true; return; }