From d3ead9bcb6d9c8dd59c299db914006d26382816d Mon Sep 17 00:00:00 2001 From: R E Broadley Date: Fri, 26 Jun 2015 22:38:07 +0300 Subject: [PATCH] Avoid "Unknown command" messages when receiving getaddr on outbound connections. Github-Pull: #7642 Rebased-From: d84ea1a59ce3704457a162f1fd8a7353047156de --- src/main.cpp | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/src/main.cpp b/src/main.cpp index 24d292454..8a9dae03a 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -5247,13 +5247,18 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, } - // This asymmetric behavior for inbound and outbound connections was introduced - // to prevent a fingerprinting attack: an attacker can send specific fake addresses - // to users' AddrMan and later request them by sending getaddr messages. - // Making nodes which are behind NAT and can only make outgoing connections ignore - // the getaddr message mitigates the attack. - else if ((strCommand == NetMsgType::GETADDR) && (pfrom->fInbound)) + else if (strCommand == NetMsgType::GETADDR) { + // This asymmetric behavior for inbound and outbound connections was introduced + // to prevent a fingerprinting attack: an attacker can send specific fake addresses + // to users' AddrMan and later request them by sending getaddr messages. + // Making nodes which are behind NAT and can only make outgoing connections ignore + // the getaddr message mitigates the attack. + if (!pfrom->fInbound) { + LogPrint("net", "Ignoring \"getaddr\" from outbound connection. peer=%d\n", pfrom->id); + return true; + } + pfrom->vAddrToSend.clear(); vector vAddr = addrman.GetAddr(); BOOST_FOREACH(const CAddress &addr, vAddr)