diff options
Diffstat (limited to 'src/net.h')
| -rw-r--r-- | src/net.h | 34 |
1 files changed, 34 insertions, 0 deletions
@@ -27,6 +27,7 @@ #include <atomic> #include <cstdint> #include <deque> +#include <map> #include <thread> #include <memory> #include <condition_variable> @@ -52,6 +53,9 @@ static const int TIMEOUT_INTERVAL = 20 * 60; static const int FEELER_INTERVAL = 120; /** The maximum number of new addresses to accumulate before announcing. */ static const unsigned int MAX_ADDR_TO_SEND = 1000; +// TODO: remove ADDRMAN_GETADDR_MAX and let the caller specify this limit with MAX_ADDR_TO_SEND. +static_assert(MAX_ADDR_TO_SEND == ADDRMAN_GETADDR_MAX, + "Max allowed ADDR message size should be equal to the max number of records returned from AddrMan."); /** Maximum length of incoming protocol messages (no message over 4 MB is currently acceptable). */ static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 4 * 1000 * 1000; /** Maximum length of the user agent string in `version` message */ @@ -251,6 +255,13 @@ public: void MarkAddressGood(const CAddress& addr); void AddNewAddresses(const std::vector<CAddress>& vAddr, const CAddress& addrFrom, int64_t nTimePenalty = 0); std::vector<CAddress> GetAddresses(); + /** + * Cache is used to minimize topology leaks, so it should + * be used for all non-trusted calls, for example, p2p. + * A non-malicious call (from RPC or a peer with addr permission) should + * call the function without a parameter to avoid using the cache. + */ + std::vector<CAddress> GetAddresses(Network requestor_network); // This allows temporarily exceeding m_max_outbound_full_relay, with the goal of finding // a peer that is better than all our current peers. @@ -416,6 +427,29 @@ private: unsigned int nPrevNodeCount{0}; /** + * Cache responses to addr requests to minimize privacy leak. + * Attack example: scraping addrs in real-time may allow an attacker + * to infer new connections of the victim by detecting new records + * with fresh timestamps (per self-announcement). + */ + struct CachedAddrResponse { + std::vector<CAddress> m_addrs_response_cache; + std::chrono::microseconds m_update_addr_response{0}; + }; + + /** + * Addr responses stored in different caches + * per network prevent cross-network node identification. + * If a node for example is multi-homed under Tor and IPv6, + * a single cache (or no cache at all) would let an attacker + * to easily detect that it is the same node by comparing responses. + * The used memory equals to 1000 CAddress records (or around 32 bytes) per + * distinct Network (up to 5) we have/had an inbound peer from, + * resulting in at most ~160 KB. + */ + std::map<Network, CachedAddrResponse> m_addr_response_caches; + + /** * Services this instance offers. * * This data is replicated in each CNode instance we create during peer |