diff options
Diffstat (limited to 'src/net.cpp')
| -rw-r--r-- | src/net.cpp | 162 |
1 files changed, 105 insertions, 57 deletions
diff --git a/src/net.cpp b/src/net.cpp index 6f9f17ed4e..70ba875c4b 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -42,6 +42,7 @@ #endif #include <algorithm> +#include <array> #include <cstdint> #include <functional> #include <optional> @@ -401,7 +402,8 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo pszDest ? 0.0 : (double)(GetAdjustedTime() - addrConnect.nTime)/3600.0); // Resolve - const uint16_t default_port{Params().GetDefaultPort()}; + const uint16_t default_port{pszDest != nullptr ? Params().GetDefaultPort(pszDest) : + Params().GetDefaultPort()}; if (pszDest) { std::vector<CService> resolved; if (Lookup(pszDest, resolved, default_port, fNameLookup && !HaveNameProxy(), 256) && !resolved.empty()) { @@ -841,18 +843,6 @@ static bool ReverseCompareNodeTimeConnected(const NodeEvictionCandidate &a, cons return a.nTimeConnected > b.nTimeConnected; } -static bool CompareLocalHostTimeConnected(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) -{ - if (a.m_is_local != b.m_is_local) return b.m_is_local; - return a.nTimeConnected > b.nTimeConnected; -} - -static bool CompareOnionTimeConnected(const NodeEvictionCandidate& a, const NodeEvictionCandidate& b) -{ - if (a.m_is_onion != b.m_is_onion) return b.m_is_onion; - return a.nTimeConnected > b.nTimeConnected; -} - static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) { return a.nKeyedNetGroup < b.nKeyedNetGroup; } @@ -883,6 +873,26 @@ static bool CompareNodeBlockRelayOnlyTime(const NodeEvictionCandidate &a, const return a.nTimeConnected > b.nTimeConnected; } +/** + * Sort eviction candidates by network/localhost and connection uptime. + * Candidates near the beginning are more likely to be evicted, and those + * near the end are more likely to be protected, e.g. less likely to be evicted. + * - First, nodes that are not `is_local` and that do not belong to `network`, + * sorted by increasing uptime (from most recently connected to connected longer). + * - Then, nodes that are `is_local` or belong to `network`, sorted by increasing uptime. + */ +struct CompareNodeNetworkTime { + const bool m_is_local; + const Network m_network; + CompareNodeNetworkTime(bool is_local, Network network) : m_is_local(is_local), m_network(network) {} + bool operator()(const NodeEvictionCandidate& a, const NodeEvictionCandidate& b) const + { + if (m_is_local && a.m_is_local != b.m_is_local) return b.m_is_local; + if ((a.m_network == m_network) != (b.m_network == m_network)) return b.m_network == m_network; + return a.nTimeConnected > b.nTimeConnected; + }; +}; + //! Sort an array by the specified comparator, then erase the last K elements where predicate is true. template <typename T, typename Comparator> static void EraseLastKElements( @@ -894,40 +904,77 @@ static void EraseLastKElements( elements.erase(std::remove_if(elements.end() - eraseSize, elements.end(), predicate), elements.end()); } -void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& vEvictionCandidates) +void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& eviction_candidates) { // Protect the half of the remaining nodes which have been connected the longest. // This replicates the non-eviction implicit behavior, and precludes attacks that start later. - // To favorise the diversity of our peer connections, reserve up to (half + 2) of - // these protected spots for onion and localhost peers, if any, even if they're not - // longest uptime overall. This helps protect tor peers, which tend to be otherwise + // To favorise the diversity of our peer connections, reserve up to half of these protected + // spots for Tor/onion, localhost and I2P peers, even if they're not longest uptime overall. + // This helps protect these higher-latency peers that tend to be otherwise // disadvantaged under our eviction criteria. - const size_t initial_size = vEvictionCandidates.size(); - size_t total_protect_size = initial_size / 2; - const size_t onion_protect_size = total_protect_size / 2; - - if (onion_protect_size) { - // Pick out up to 1/4 peers connected via our onion service, sorted by longest uptime. - EraseLastKElements(vEvictionCandidates, CompareOnionTimeConnected, onion_protect_size, - [](const NodeEvictionCandidate& n) { return n.m_is_onion; }); - } - - const size_t localhost_min_protect_size{2}; - if (onion_protect_size >= localhost_min_protect_size) { - // Allocate any remaining slots of the 1/4, or minimum 2 additional slots, - // to localhost peers, sorted by longest uptime, as manually configured - // hidden services not using `-bind=addr[:port]=onion` will not be detected - // as inbound onion connections. - const size_t remaining_tor_slots{onion_protect_size - (initial_size - vEvictionCandidates.size())}; - const size_t localhost_protect_size{std::max(remaining_tor_slots, localhost_min_protect_size)}; - EraseLastKElements(vEvictionCandidates, CompareLocalHostTimeConnected, localhost_protect_size, - [](const NodeEvictionCandidate& n) { return n.m_is_local; }); + const size_t initial_size = eviction_candidates.size(); + const size_t total_protect_size{initial_size / 2}; + + // Disadvantaged networks to protect: I2P, localhost, Tor/onion. In case of equal counts, earlier + // array members have first opportunity to recover unused slots from the previous iteration. + struct Net { bool is_local; Network id; size_t count; }; + std::array<Net, 3> networks{ + {{false, NET_I2P, 0}, {/* localhost */ true, NET_MAX, 0}, {false, NET_ONION, 0}}}; + + // Count and store the number of eviction candidates per network. + for (Net& n : networks) { + n.count = std::count_if(eviction_candidates.cbegin(), eviction_candidates.cend(), + [&n](const NodeEvictionCandidate& c) { + return n.is_local ? c.m_is_local : c.m_network == n.id; + }); + } + // Sort `networks` by ascending candidate count, to give networks having fewer candidates + // the first opportunity to recover unused protected slots from the previous iteration. + std::stable_sort(networks.begin(), networks.end(), [](Net a, Net b) { return a.count < b.count; }); + + // Protect up to 25% of the eviction candidates by disadvantaged network. + const size_t max_protect_by_network{total_protect_size / 2}; + size_t num_protected{0}; + + while (num_protected < max_protect_by_network) { + // Count the number of disadvantaged networks from which we have peers to protect. + auto num_networks = std::count_if(networks.begin(), networks.end(), [](const Net& n) { return n.count; }); + if (num_networks == 0) { + break; + } + const size_t disadvantaged_to_protect{max_protect_by_network - num_protected}; + const size_t protect_per_network{std::max(disadvantaged_to_protect / num_networks, static_cast<size_t>(1))}; + // Early exit flag if there are no remaining candidates by disadvantaged network. + bool protected_at_least_one{false}; + + for (Net& n : networks) { + if (n.count == 0) continue; + const size_t before = eviction_candidates.size(); + EraseLastKElements(eviction_candidates, CompareNodeNetworkTime(n.is_local, n.id), + protect_per_network, [&n](const NodeEvictionCandidate& c) { + return n.is_local ? c.m_is_local : c.m_network == n.id; + }); + const size_t after = eviction_candidates.size(); + if (before > after) { + protected_at_least_one = true; + const size_t delta{before - after}; + num_protected += delta; + if (num_protected >= max_protect_by_network) { + break; + } + n.count -= delta; + } + } + if (!protected_at_least_one) { + break; + } } // Calculate how many we removed, and update our total number of peers that // we want to protect based on uptime accordingly. - total_protect_size -= initial_size - vEvictionCandidates.size(); - EraseLastKElements(vEvictionCandidates, ReverseCompareNodeTimeConnected, total_protect_size); + assert(num_protected == initial_size - eviction_candidates.size()); + const size_t remaining_to_protect{total_protect_size - num_protected}; + EraseLastKElements(eviction_candidates, ReverseCompareNodeTimeConnected, remaining_to_protect); } [[nodiscard]] std::optional<NodeId> SelectNodeToEvict(std::vector<NodeEvictionCandidate>&& vEvictionCandidates) @@ -944,8 +991,7 @@ void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& vEvict // An attacker cannot manipulate this metric without performing useful work. EraseLastKElements(vEvictionCandidates, CompareNodeTXTime, 4); // Protect up to 8 non-tx-relay peers that have sent us novel blocks. - const size_t erase_size = std::min(size_t(8), vEvictionCandidates.size()); - EraseLastKElements(vEvictionCandidates, CompareNodeBlockRelayOnlyTime, erase_size, + EraseLastKElements(vEvictionCandidates, CompareNodeBlockRelayOnlyTime, 8, [](const NodeEvictionCandidate& n) { return !n.fRelayTxes && n.fRelevantServices; }); // Protect 4 nodes that most recently sent us novel blocks. @@ -1024,7 +1070,7 @@ bool CConnman::AttemptToEvictConnection() HasAllDesirableServiceFlags(node->nServices), peer_relay_txes, peer_filter_not_null, node->nKeyedNetGroup, node->m_prefer_evict, node->addr.IsLocal(), - node->m_inbound_onion}; + node->ConnectedThroughNetwork()}; vEvictionCandidates.push_back(candidate); } } @@ -2019,8 +2065,9 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect) // from advertising themselves as a service on another host and // port, causing a DoS attack as nodes around the network attempt // to connect to it fruitlessly. - if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50) + if (addr.GetPort() != Params().GetDefaultPort(addr.GetNetwork()) && nTries < 50) { continue; + } addrConnect = addr; break; @@ -2083,7 +2130,7 @@ std::vector<AddedNodeInfo> CConnman::GetAddedNodeInfo() const } for (const std::string& strAddNode : lAddresses) { - CService service(LookupNumeric(strAddNode, Params().GetDefaultPort())); + CService service(LookupNumeric(strAddNode, Params().GetDefaultPort(strAddNode))); AddedNodeInfo addedNode{strAddNode, CService(), false, false}; if (service.IsValid()) { // strAddNode is an IP:port @@ -2173,6 +2220,7 @@ void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai void CConnman::ThreadMessageHandler() { + FastRandomContext rng; while (!flagInterruptMsgProc) { std::vector<CNode*> vNodesCopy; @@ -2186,6 +2234,11 @@ void CConnman::ThreadMessageHandler() bool fMoreWork = false; + // Randomize the order in which we process messages from/to our peers. + // This prevents attacks in which an attacker exploits having multiple + // consecutive connections in the vNodes list. + Shuffle(vNodesCopy.begin(), vNodesCopy.end(), rng); + for (CNode* pnode : vNodesCopy) { if (pnode->fDisconnect) @@ -2419,30 +2472,25 @@ bool CConnman::Bind(const CService &addr, unsigned int flags, NetPermissionFlags return true; } -bool CConnman::InitBinds( - const std::vector<CService>& binds, - const std::vector<NetWhitebindPermissions>& whiteBinds, - const std::vector<CService>& onion_binds) +bool CConnman::InitBinds(const Options& options) { bool fBound = false; - for (const auto& addrBind : binds) { + for (const auto& addrBind : options.vBinds) { fBound |= Bind(addrBind, (BF_EXPLICIT | BF_REPORT_ERROR), NetPermissionFlags::None); } - for (const auto& addrBind : whiteBinds) { + for (const auto& addrBind : options.vWhiteBinds) { fBound |= Bind(addrBind.m_service, (BF_EXPLICIT | BF_REPORT_ERROR), addrBind.m_flags); } - if (binds.empty() && whiteBinds.empty()) { + for (const auto& addr_bind : options.onion_binds) { + fBound |= Bind(addr_bind, BF_EXPLICIT | BF_DONT_ADVERTISE, NetPermissionFlags::None); + } + if (options.bind_on_any) { struct in_addr inaddr_any; inaddr_any.s_addr = htonl(INADDR_ANY); struct in6_addr inaddr6_any = IN6ADDR_ANY_INIT; fBound |= Bind(CService(inaddr6_any, GetListenPort()), BF_NONE, NetPermissionFlags::None); fBound |= Bind(CService(inaddr_any, GetListenPort()), !fBound ? BF_REPORT_ERROR : BF_NONE, NetPermissionFlags::None); } - - for (const auto& addr_bind : onion_binds) { - fBound |= Bind(addr_bind, BF_EXPLICIT | BF_DONT_ADVERTISE, NetPermissionFlags::None); - } - return fBound; } @@ -2450,7 +2498,7 @@ bool CConnman::Start(CScheduler& scheduler, const Options& connOptions) { Init(connOptions); - if (fListen && !InitBinds(connOptions.vBinds, connOptions.vWhiteBinds, connOptions.onion_binds)) { + if (fListen && !InitBinds(connOptions)) { if (clientInterface) { clientInterface->ThreadSafeMessageBox( _("Failed to listen on any port. Use -listen=0 if you want this."), |