From e959ea976839041c0d287b7f3e865754596fc1e9 Mon Sep 17 00:00:00 2001 From: Duke Leto Date: Thu, 9 Jul 2020 08:35:04 -0400 Subject: [PATCH] Timedata changes from KMD 0.6 --- src/timedata.cpp | 149 +++++++++++++++-------------------------------- src/timedata.h | 78 +++++++------------------ 2 files changed, 66 insertions(+), 161 deletions(-) diff --git a/src/timedata.cpp b/src/timedata.cpp index 64a3955ff..246159a50 100644 --- a/src/timedata.cpp +++ b/src/timedata.cpp @@ -1,10 +1,11 @@ // Copyright (c) 2014 The Bitcoin Core developers // Copyright (c) 2019-2020 The Hush developers +// Copyright (c) 2020 The Zcash developers // Distributed under the MIT software license, see the accompanying -// file COPYING or http://www.opensource.org/licenses/mit-license.php. +// file COPYING or https://www.opensource.org/licenses/mit-license.php /****************************************************************************** - * Copyright © 2014-2019 The SuperNET Developers. * + * Copyright © 2014-2020 The SuperNET Developers. * * * * See the AUTHORS, DEVELOPER-AGREEMENT and LICENSE files at * * the top-level directory of this distribution for the individual copyright * @@ -26,114 +27,56 @@ #include "util.h" #include "utilstrencodings.h" -#include - -using namespace std; - -static CCriticalSection cs_nTimeOffset; -static int64_t nTimeOffset = 0; -#define KOMODO_ASSETCHAIN_MAXLEN 65 -extern char ASSETCHAINS_SYMBOL[KOMODO_ASSETCHAIN_MAXLEN]; +CTimeWarning timeWarning; /** - * "Never go to sea with two chronometers; take one or three." - * Our three time sources are: - * - System clock - * - Median of other nodes clocks - * - The user (asking the user to fix the system clock if the first two disagree) + * Warn if we have seen TIMEDATA_WARNING_SAMPLES peer times, in the version messages of the + * first TIMEDATA_MAX_SAMPLES unique (by IP address) peers that connect, that are more than + * TIMEDATA_WARNING_THRESHOLD seconds but less than TIMEDATA_IGNORE_THRESHOLD seconds away + * from local time. */ -int64_t GetTimeOffset() + +int64_t CTimeWarning::AddTimeData(const CNetAddr& ip, int64_t nTime, int64_t now) { - LOCK(cs_nTimeOffset); + assert(now >= 0 && now <= INT64_MAX - TIMEDATA_IGNORE_THRESHOLD); + + if (nTime <= now - TIMEDATA_IGNORE_THRESHOLD || nTime >= now + TIMEDATA_IGNORE_THRESHOLD) { + return 0; + } + + int64_t nTimeOffset = nTime - now; + + LOCK(cs); + // Ignore duplicate IPs. + if (setKnown.size() == TIMEDATA_MAX_SAMPLES || !setKnown.insert(ip).second) { + return nTimeOffset; + } + + LogPrintf("Added time data, samples %d, offset %+d (%+d minutes)\n", setKnown.size(), nTimeOffset, nTimeOffset/60); + + if (nPeersBehind + nPeersAhead < TIMEDATA_WARNING_SAMPLES) { + if (nTimeOffset < -TIMEDATA_WARNING_THRESHOLD) { + nPeersBehind++; + } else if (nTimeOffset > TIMEDATA_WARNING_THRESHOLD) { + nPeersAhead++; + } + if (nPeersBehind + nPeersAhead == TIMEDATA_WARNING_SAMPLES) { + Warn(nPeersAhead, nPeersBehind); + } + } return nTimeOffset; } -int64_t GetAdjustedTime() +void CTimeWarning::Warn(size_t peersAhead, size_t peersBehind) { - return GetTime() + GetTimeOffset(); -} - -static int64_t abs64(int64_t n) -{ - return (n >= 0 ? n : -n); -} - -#define BITCOIN_TIMEDATA_MAX_SAMPLES 200 - -void AddTimeData(const CNetAddr& ip, int64_t nOffsetSample) -{ - LOCK(cs_nTimeOffset); - // Ignore duplicates - static set setKnown; - if (setKnown.size() == BITCOIN_TIMEDATA_MAX_SAMPLES) - return; - if (!setKnown.insert(ip).second) - return; - - // Add data - static CMedianFilter vTimeOffsets(BITCOIN_TIMEDATA_MAX_SAMPLES, 0); - vTimeOffsets.input(nOffsetSample); - LogPrintf("Added time data, samples %d, offset %+d (%+d minutes)\n", vTimeOffsets.size(), nOffsetSample, nOffsetSample/60); - - // There is a known issue here (see issue #4521): - // - // - The structure vTimeOffsets contains up to 200 elements, after which - // any new element added to it will not increase its size, replacing the - // oldest element. - // - // - The condition to update nTimeOffset includes checking whether the - // number of elements in vTimeOffsets is odd, which will never happen after - // there are 200 elements. - // - // But in this case the 'bug' is protective against some attacks, and may - // actually explain why we've never seen attacks which manipulate the - // clock offset. - // - // So we should hold off on fixing this and clean it up as part of - // a timing cleanup that strengthens it in a number of other ways. - // - if (vTimeOffsets.size() >= 5 && vTimeOffsets.size() % 2 == 1) - { - int64_t nMedian = vTimeOffsets.median(); - std::vector vSorted = vTimeOffsets.sorted(); - // Only let other nodes change our time by so much - if (abs64(nMedian) < 30) // thanks to zawy for pointing this out!! zcash issues 4021 //70 * 60) - { - nTimeOffset = nMedian; - } - else - { - nTimeOffset = 0; - - static bool fDone; - if (!fDone) - { - // If nobody has a time different than ours but within 5 minutes of ours, give a warning - bool fMatch = false; - BOOST_FOREACH(int64_t nOffset, vSorted) - if (nOffset != 0 && abs64(nOffset) < 5 * 60) - fMatch = true; - - if (!fMatch) - { - fDone = true; - string strMessage; - if( strncmp(ASSETCHAINS_SYMBOL, "HUSH3",5) == 0 ) { - strMessage = _("Warning: Please check that your computer's date and time are correct! If your clock is wrong Hush will not work properly."); - } else { - strMessage = _("Warning: Please check that your computer's date and time are correct! If your clock is wrong Komodo will not work properly."); - } - strMiscWarning = strMessage; - LogPrintf("*** %s\n", strMessage); - uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_WARNING); - } - } - } - if (fDebug) { - BOOST_FOREACH(int64_t n, vSorted) - LogPrintf("%+d ", n); - LogPrintf("| "); - } - LogPrintf("nTimeOffset = %+d (%+d minutes)\n", nTimeOffset, nTimeOffset/60); + std::string strMessage; + if (peersBehind >= TIMEDATA_WARNING_MAJORITY) { + strMessage = _("Warning: Your computer's date and time may be ahead of the rest of the network! If your clock is wrong Hush will not work properly."); + } else if (peersAhead >= TIMEDATA_WARNING_MAJORITY) { + strMessage = _("Warning: Your computer's date and time may be behind the rest of the network! If your clock is wrong Hush will not work properly."); + } else { + strMessage = _("Warning: Please check that your computer's date and time are correct! If your clock is wrong Hush will not work properly."); } + LogPrintf("*** %s\n", strMessage); + uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_WARNING); } diff --git a/src/timedata.h b/src/timedata.h index 13cff12b3..4ced093b6 100644 --- a/src/timedata.h +++ b/src/timedata.h @@ -1,77 +1,39 @@ // Copyright (c) 2014 The Bitcoin Core developers // Copyright (c) 2019-2020 The Hush developers +// Copyright (c) 2020 The Zcash developers // Distributed under the MIT software license, see the accompanying -// file COPYING or http://www.opensource.org/licenses/mit-license.php. +// file COPYING or https://www.opensource.org/licenses/mit-license.php #ifndef BITCOIN_TIMEDATA_H #define BITCOIN_TIMEDATA_H -#include -#include +#include #include -#include +#include "netbase.h" +#include "sync.h" -class CNetAddr; - -/** - * Median filter over a stream of values. - * Returns the median of the last N numbers - */ -template -class CMedianFilter +class CTimeWarning { private: - std::vector vValues; - std::vector vSorted; - unsigned int nSize; + CCriticalSection cs; + std::set setKnown; + size_t nPeersAhead; + size_t nPeersBehind; public: - CMedianFilter(unsigned int size, T initial_value) : nSize(size) - { - vValues.reserve(size); - vValues.push_back(initial_value); - vSorted = vValues; - } + static const size_t TIMEDATA_WARNING_SAMPLES = 8; + static const size_t TIMEDATA_WARNING_MAJORITY = 6; + static const size_t TIMEDATA_MAX_SAMPLES = 20; + static const int64_t TIMEDATA_WARNING_THRESHOLD = 10 * 60; + static const int64_t TIMEDATA_IGNORE_THRESHOLD = 10 * 24 * 60 * 60; - void input(T value) - { - if (vValues.size() == nSize) { - vValues.erase(vValues.begin()); - } - vValues.push_back(value); + CTimeWarning() : nPeersBehind(0), nPeersAhead(0) {} + virtual ~CTimeWarning() {} - vSorted.resize(vValues.size()); - std::copy(vValues.begin(), vValues.end(), vSorted.begin()); - std::sort(vSorted.begin(), vSorted.end()); - } - - T median() const - { - int size = vSorted.size(); - assert(size > 0); - if (size & 1) // Odd number of elements - { - return vSorted[size / 2]; - } else // Even number of elements - { - return (vSorted[size / 2 - 1] + vSorted[size / 2]) / 2; - } - } - - int size() const - { - return vValues.size(); - } - - std::vector sorted() const - { - return vSorted; - } + int64_t AddTimeData(const CNetAddr& ip, int64_t nTime, int64_t now); + virtual void Warn(size_t peersAhead, size_t peersBehind); }; -/** Functions to keep track of adjusted P2P time */ -int64_t GetTimeOffset(); -int64_t GetAdjustedTime(); -void AddTimeData(const CNetAddr& ip, int64_t nTime); +extern CTimeWarning timeWarning; #endif // BITCOIN_TIMEDATA_H