diff options
Diffstat (limited to 'src/torcontrol.cpp')
| -rw-r--r-- | src/torcontrol.cpp | 776 |
1 files changed, 776 insertions, 0 deletions
diff --git a/src/torcontrol.cpp b/src/torcontrol.cpp new file mode 100644 index 0000000000..717d1cf7e5 --- /dev/null +++ b/src/torcontrol.cpp @@ -0,0 +1,776 @@ +// Copyright (c) 2015-2017 The Bitcoin Core developers +// Copyright (c) 2017 The Zcash developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#include <torcontrol.h> +#include <utilstrencodings.h> +#include <netbase.h> +#include <net.h> +#include <util.h> +#include <crypto/hmac_sha256.h> + +#include <vector> +#include <deque> +#include <set> +#include <stdlib.h> + +#include <boost/bind.hpp> +#include <boost/signals2/signal.hpp> +#include <boost/algorithm/string/split.hpp> +#include <boost/algorithm/string/classification.hpp> +#include <boost/algorithm/string/replace.hpp> + +#include <event2/bufferevent.h> +#include <event2/buffer.h> +#include <event2/util.h> +#include <event2/event.h> +#include <event2/thread.h> + +/** Default control port */ +const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051"; +/** Tor cookie size (from control-spec.txt) */ +static const int TOR_COOKIE_SIZE = 32; +/** Size of client/server nonce for SAFECOOKIE */ +static const int TOR_NONCE_SIZE = 32; +/** For computing serverHash in SAFECOOKIE */ +static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash"; +/** For computing clientHash in SAFECOOKIE */ +static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash"; +/** Exponential backoff configuration - initial timeout in seconds */ +static const float RECONNECT_TIMEOUT_START = 1.0; +/** Exponential backoff configuration - growth factor */ +static const float RECONNECT_TIMEOUT_EXP = 1.5; +/** Maximum length for lines received on TorControlConnection. + * tor-control-spec.txt mentions that there is explicitly no limit defined to line length, + * this is belt-and-suspenders sanity limit to prevent memory exhaustion. + */ +static const int MAX_LINE_LENGTH = 100000; + +/****** Low-level TorControlConnection ********/ + +/** Reply from Tor, can be single or multi-line */ +class TorControlReply +{ +public: + TorControlReply() { Clear(); } + + int code; + std::vector<std::string> lines; + + void Clear() + { + code = 0; + lines.clear(); + } +}; + +/** Low-level handling for Tor control connection. + * Speaks the SMTP-like protocol as defined in torspec/control-spec.txt + */ +class TorControlConnection +{ +public: + typedef std::function<void(TorControlConnection&)> ConnectionCB; + typedef std::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB; + + /** Create a new TorControlConnection. + */ + explicit TorControlConnection(struct event_base *base); + ~TorControlConnection(); + + /** + * Connect to a Tor control port. + * target is address of the form host:port. + * connected is the handler that is called when connection is successfully established. + * disconnected is a handler that is called when the connection is broken. + * Return true on success. + */ + bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected); + + /** + * Disconnect from Tor control port. + */ + bool Disconnect(); + + /** Send a command, register a handler for the reply. + * A trailing CRLF is automatically added. + * Return true on success. + */ + bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler); + + /** Response handlers for async replies */ + boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler; +private: + /** Callback when ready for use */ + std::function<void(TorControlConnection&)> connected; + /** Callback when connection lost */ + std::function<void(TorControlConnection&)> disconnected; + /** Libevent event base */ + struct event_base *base; + /** Connection to control socket */ + struct bufferevent *b_conn; + /** Message being received */ + TorControlReply message; + /** Response handlers */ + std::deque<ReplyHandlerCB> reply_handlers; + + /** Libevent handlers: internal */ + static void readcb(struct bufferevent *bev, void *ctx); + static void eventcb(struct bufferevent *bev, short what, void *ctx); +}; + +TorControlConnection::TorControlConnection(struct event_base *_base): + base(_base), b_conn(nullptr) +{ +} + +TorControlConnection::~TorControlConnection() +{ + if (b_conn) + bufferevent_free(b_conn); +} + +void TorControlConnection::readcb(struct bufferevent *bev, void *ctx) +{ + TorControlConnection *self = static_cast<TorControlConnection*>(ctx); + struct evbuffer *input = bufferevent_get_input(bev); + size_t n_read_out = 0; + char *line; + assert(input); + // If there is not a whole line to read, evbuffer_readln returns nullptr + while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != nullptr) + { + std::string s(line, n_read_out); + free(line); + if (s.size() < 4) // Short line + continue; + // <status>(-|+| )<data><CRLF> + self->message.code = atoi(s.substr(0,3)); + self->message.lines.push_back(s.substr(4)); + char ch = s[3]; // '-','+' or ' ' + if (ch == ' ') { + // Final line, dispatch reply and clean up + if (self->message.code >= 600) { + // Dispatch async notifications to async handler + // Synchronous and asynchronous messages are never interleaved + self->async_handler(*self, self->message); + } else { + if (!self->reply_handlers.empty()) { + // Invoke reply handler with message + self->reply_handlers.front()(*self, self->message); + self->reply_handlers.pop_front(); + } else { + LogPrint(BCLog::TOR, "tor: Received unexpected sync reply %i\n", self->message.code); + } + } + self->message.Clear(); + } + } + // Check for size of buffer - protect against memory exhaustion with very long lines + // Do this after evbuffer_readln to make sure all full lines have been + // removed from the buffer. Everything left is an incomplete line. + if (evbuffer_get_length(input) > MAX_LINE_LENGTH) { + LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n"); + self->Disconnect(); + } +} + +void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx) +{ + TorControlConnection *self = static_cast<TorControlConnection*>(ctx); + if (what & BEV_EVENT_CONNECTED) { + LogPrint(BCLog::TOR, "tor: Successfully connected!\n"); + self->connected(*self); + } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) { + if (what & BEV_EVENT_ERROR) { + LogPrint(BCLog::TOR, "tor: Error connecting to Tor control socket\n"); + } else { + LogPrint(BCLog::TOR, "tor: End of stream\n"); + } + self->Disconnect(); + self->disconnected(*self); + } +} + +bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& _connected, const ConnectionCB& _disconnected) +{ + if (b_conn) + Disconnect(); + // Parse target address:port + struct sockaddr_storage connect_to_addr; + int connect_to_addrlen = sizeof(connect_to_addr); + if (evutil_parse_sockaddr_port(target.c_str(), + (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) { + LogPrintf("tor: Error parsing socket address %s\n", target); + return false; + } + + // Create a new socket, set up callbacks and enable notification bits + b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE); + if (!b_conn) + return false; + bufferevent_setcb(b_conn, TorControlConnection::readcb, nullptr, TorControlConnection::eventcb, this); + bufferevent_enable(b_conn, EV_READ|EV_WRITE); + this->connected = _connected; + this->disconnected = _disconnected; + + // Finally, connect to target + if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) { + LogPrintf("tor: Error connecting to address %s\n", target); + return false; + } + return true; +} + +bool TorControlConnection::Disconnect() +{ + if (b_conn) + bufferevent_free(b_conn); + b_conn = nullptr; + return true; +} + +bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler) +{ + if (!b_conn) + return false; + struct evbuffer *buf = bufferevent_get_output(b_conn); + if (!buf) + return false; + evbuffer_add(buf, cmd.data(), cmd.size()); + evbuffer_add(buf, "\r\n", 2); + reply_handlers.push_back(reply_handler); + return true; +} + +/****** General parsing utilities ********/ + +/* Split reply line in the form 'AUTH METHODS=...' into a type + * 'AUTH' and arguments 'METHODS=...'. + * Grammar is implicitly defined in https://spec.torproject.org/control-spec by + * the server reply formats for PROTOCOLINFO (S3.21) and AUTHCHALLENGE (S3.24). + */ +static std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s) +{ + size_t ptr=0; + std::string type; + while (ptr < s.size() && s[ptr] != ' ') { + type.push_back(s[ptr]); + ++ptr; + } + if (ptr < s.size()) + ++ptr; // skip ' ' + return make_pair(type, s.substr(ptr)); +} + +/** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'. + * Returns a map of keys to values, or an empty map if there was an error. + * Grammar is implicitly defined in https://spec.torproject.org/control-spec by + * the server reply formats for PROTOCOLINFO (S3.21), AUTHCHALLENGE (S3.24), + * and ADD_ONION (S3.27). See also sections 2.1 and 2.3. + */ +static std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s) +{ + std::map<std::string,std::string> mapping; + size_t ptr=0; + while (ptr < s.size()) { + std::string key, value; + while (ptr < s.size() && s[ptr] != '=' && s[ptr] != ' ') { + key.push_back(s[ptr]); + ++ptr; + } + if (ptr == s.size()) // unexpected end of line + return std::map<std::string,std::string>(); + if (s[ptr] == ' ') // The remaining string is an OptArguments + break; + ++ptr; // skip '=' + if (ptr < s.size() && s[ptr] == '"') { // Quoted string + ++ptr; // skip opening '"' + bool escape_next = false; + while (ptr < s.size() && (escape_next || s[ptr] != '"')) { + // Repeated backslashes must be interpreted as pairs + escape_next = (s[ptr] == '\\' && !escape_next); + value.push_back(s[ptr]); + ++ptr; + } + if (ptr == s.size()) // unexpected end of line + return std::map<std::string,std::string>(); + ++ptr; // skip closing '"' + /** + * Unescape value. Per https://spec.torproject.org/control-spec section 2.1.1: + * + * For future-proofing, controller implementors MAY use the following + * rules to be compatible with buggy Tor implementations and with + * future ones that implement the spec as intended: + * + * Read \n \t \r and \0 ... \377 as C escapes. + * Treat a backslash followed by any other character as that character. + */ + std::string escaped_value; + for (size_t i = 0; i < value.size(); ++i) { + if (value[i] == '\\') { + // This will always be valid, because if the QuotedString + // ended in an odd number of backslashes, then the parser + // would already have returned above, due to a missing + // terminating double-quote. + ++i; + if (value[i] == 'n') { + escaped_value.push_back('\n'); + } else if (value[i] == 't') { + escaped_value.push_back('\t'); + } else if (value[i] == 'r') { + escaped_value.push_back('\r'); + } else if ('0' <= value[i] && value[i] <= '7') { + size_t j; + // Octal escape sequences have a limit of three octal digits, + // but terminate at the first character that is not a valid + // octal digit if encountered sooner. + for (j = 1; j < 3 && (i+j) < value.size() && '0' <= value[i+j] && value[i+j] <= '7'; ++j) {} + // Tor restricts first digit to 0-3 for three-digit octals. + // A leading digit of 4-7 would therefore be interpreted as + // a two-digit octal. + if (j == 3 && value[i] > '3') { + j--; + } + escaped_value.push_back(strtol(value.substr(i, j).c_str(), nullptr, 8)); + // Account for automatic incrementing at loop end + i += j - 1; + } else { + escaped_value.push_back(value[i]); + } + } else { + escaped_value.push_back(value[i]); + } + } + value = escaped_value; + } else { // Unquoted value. Note that values can contain '=' at will, just no spaces + while (ptr < s.size() && s[ptr] != ' ') { + value.push_back(s[ptr]); + ++ptr; + } + } + if (ptr < s.size() && s[ptr] == ' ') + ++ptr; // skip ' ' after key=value + mapping[key] = value; + } + return mapping; +} + +/** Read full contents of a file and return them in a std::string. + * Returns a pair <status, string>. + * If an error occurred, status will be false, otherwise status will be true and the data will be returned in string. + * + * @param maxsize Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data + * (with len > maxsize) will be returned. + */ +static std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize=std::numeric_limits<size_t>::max()) +{ + FILE *f = fsbridge::fopen(filename, "rb"); + if (f == nullptr) + return std::make_pair(false,""); + std::string retval; + char buffer[128]; + size_t n; + while ((n=fread(buffer, 1, sizeof(buffer), f)) > 0) { + // Check for reading errors so we don't return any data if we couldn't + // read the entire file (or up to maxsize) + if (ferror(f)) { + fclose(f); + return std::make_pair(false,""); + } + retval.append(buffer, buffer+n); + if (retval.size() > maxsize) + break; + } + fclose(f); + return std::make_pair(true,retval); +} + +/** Write contents of std::string to a file. + * @return true on success. + */ +static bool WriteBinaryFile(const fs::path &filename, const std::string &data) +{ + FILE *f = fsbridge::fopen(filename, "wb"); + if (f == nullptr) + return false; + if (fwrite(data.data(), 1, data.size(), f) != data.size()) { + fclose(f); + return false; + } + fclose(f); + return true; +} + +/****** Bitcoin specific TorController implementation ********/ + +/** Controller that connects to Tor control socket, authenticate, then create + * and maintain an ephemeral hidden service. + */ +class TorController +{ +public: + TorController(struct event_base* base, const std::string& target); + ~TorController(); + + /** Get name fo file to store private key in */ + fs::path GetPrivateKeyFile(); + + /** Reconnect, after getting disconnected */ + void Reconnect(); +private: + struct event_base* base; + std::string target; + TorControlConnection conn; + std::string private_key; + std::string service_id; + bool reconnect; + struct event *reconnect_ev; + float reconnect_timeout; + CService service; + /** Cookie for SAFECOOKIE auth */ + std::vector<uint8_t> cookie; + /** ClientNonce for SAFECOOKIE auth */ + std::vector<uint8_t> clientNonce; + + /** Callback for ADD_ONION result */ + void add_onion_cb(TorControlConnection& conn, const TorControlReply& reply); + /** Callback for AUTHENTICATE result */ + void auth_cb(TorControlConnection& conn, const TorControlReply& reply); + /** Callback for AUTHCHALLENGE result */ + void authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply); + /** Callback for PROTOCOLINFO result */ + void protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply); + /** Callback after successful connection */ + void connected_cb(TorControlConnection& conn); + /** Callback after connection lost or failed connection attempt */ + void disconnected_cb(TorControlConnection& conn); + + /** Callback for reconnect timer */ + static void reconnect_cb(evutil_socket_t fd, short what, void *arg); +}; + +TorController::TorController(struct event_base* _base, const std::string& _target): + base(_base), + target(_target), conn(base), reconnect(true), reconnect_ev(0), + reconnect_timeout(RECONNECT_TIMEOUT_START) +{ + reconnect_ev = event_new(base, -1, 0, reconnect_cb, this); + if (!reconnect_ev) + LogPrintf("tor: Failed to create event for reconnection: out of memory?\n"); + // Start connection attempts immediately + if (!conn.Connect(_target, boost::bind(&TorController::connected_cb, this, _1), + boost::bind(&TorController::disconnected_cb, this, _1) )) { + LogPrintf("tor: Initiating connection to Tor control port %s failed\n", _target); + } + // Read service private key if cached + std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile()); + if (pkf.first) { + LogPrint(BCLog::TOR, "tor: Reading cached private key from %s\n", GetPrivateKeyFile().string()); + private_key = pkf.second; + } +} + +TorController::~TorController() +{ + if (reconnect_ev) { + event_free(reconnect_ev); + reconnect_ev = nullptr; + } + if (service.IsValid()) { + RemoveLocal(service); + } +} + +void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply) +{ + if (reply.code == 250) { + LogPrint(BCLog::TOR, "tor: ADD_ONION successful\n"); + for (const std::string &s : reply.lines) { + std::map<std::string,std::string> m = ParseTorReplyMapping(s); + std::map<std::string,std::string>::iterator i; + if ((i = m.find("ServiceID")) != m.end()) + service_id = i->second; + if ((i = m.find("PrivateKey")) != m.end()) + private_key = i->second; + } + if (service_id.empty()) { + LogPrintf("tor: Error parsing ADD_ONION parameters:\n"); + for (const std::string &s : reply.lines) { + LogPrintf(" %s\n", SanitizeString(s)); + } + return; + } + service = LookupNumeric(std::string(service_id+".onion").c_str(), GetListenPort()); + LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString()); + if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) { + LogPrint(BCLog::TOR, "tor: Cached service private key to %s\n", GetPrivateKeyFile().string()); + } else { + LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile().string()); + } + AddLocal(service, LOCAL_MANUAL); + // ... onion requested - keep connection open + } else if (reply.code == 510) { // 510 Unrecognized command + LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n"); + } else { + LogPrintf("tor: Add onion failed; error code %d\n", reply.code); + } +} + +void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply) +{ + if (reply.code == 250) { + LogPrint(BCLog::TOR, "tor: Authentication successful\n"); + + // Now that we know Tor is running setup the proxy for onion addresses + // if -onion isn't set to something else. + if (gArgs.GetArg("-onion", "") == "") { + CService resolved(LookupNumeric("127.0.0.1", 9050)); + proxyType addrOnion = proxyType(resolved, true); + SetProxy(NET_TOR, addrOnion); + SetLimited(NET_TOR, false); + } + + // Finally - now create the service + if (private_key.empty()) // No private key, generate one + private_key = "NEW:RSA1024"; // Explicitly request RSA1024 - see issue #9214 + // Request hidden service, redirect port. + // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient + // choice. TODO; refactor the shutdown sequence some day. + _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()), + boost::bind(&TorController::add_onion_cb, this, _1, _2)); + } else { + LogPrintf("tor: Authentication failed\n"); + } +} + +/** Compute Tor SAFECOOKIE response. + * + * ServerHash is computed as: + * HMAC-SHA256("Tor safe cookie authentication server-to-controller hash", + * CookieString | ClientNonce | ServerNonce) + * (with the HMAC key as its first argument) + * + * After a controller sends a successful AUTHCHALLENGE command, the + * next command sent on the connection must be an AUTHENTICATE command, + * and the only authentication string which that AUTHENTICATE command + * will accept is: + * + * HMAC-SHA256("Tor safe cookie authentication controller-to-server hash", + * CookieString | ClientNonce | ServerNonce) + * + */ +static std::vector<uint8_t> ComputeResponse(const std::string &key, const std::vector<uint8_t> &cookie, const std::vector<uint8_t> &clientNonce, const std::vector<uint8_t> &serverNonce) +{ + CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size()); + std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0); + computeHash.Write(cookie.data(), cookie.size()); + computeHash.Write(clientNonce.data(), clientNonce.size()); + computeHash.Write(serverNonce.data(), serverNonce.size()); + computeHash.Finalize(computedHash.data()); + return computedHash; +} + +void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply) +{ + if (reply.code == 250) { + LogPrint(BCLog::TOR, "tor: SAFECOOKIE authentication challenge successful\n"); + std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]); + if (l.first == "AUTHCHALLENGE") { + std::map<std::string,std::string> m = ParseTorReplyMapping(l.second); + if (m.empty()) { + LogPrintf("tor: Error parsing AUTHCHALLENGE parameters: %s\n", SanitizeString(l.second)); + return; + } + std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]); + std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]); + LogPrint(BCLog::TOR, "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce)); + if (serverNonce.size() != 32) { + LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n"); + return; + } + + std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce); + if (computedServerHash != serverHash) { + LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash)); + return; + } + + std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce); + _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), boost::bind(&TorController::auth_cb, this, _1, _2)); + } else { + LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n"); + } + } else { + LogPrintf("tor: SAFECOOKIE authentication challenge failed\n"); + } +} + +void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply) +{ + if (reply.code == 250) { + std::set<std::string> methods; + std::string cookiefile; + /* + * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie" + * 250-AUTH METHODS=NULL + * 250-AUTH METHODS=HASHEDPASSWORD + */ + for (const std::string &s : reply.lines) { + std::pair<std::string,std::string> l = SplitTorReplyLine(s); + if (l.first == "AUTH") { + std::map<std::string,std::string> m = ParseTorReplyMapping(l.second); + std::map<std::string,std::string>::iterator i; + if ((i = m.find("METHODS")) != m.end()) + boost::split(methods, i->second, boost::is_any_of(",")); + if ((i = m.find("COOKIEFILE")) != m.end()) + cookiefile = i->second; + } else if (l.first == "VERSION") { + std::map<std::string,std::string> m = ParseTorReplyMapping(l.second); + std::map<std::string,std::string>::iterator i; + if ((i = m.find("Tor")) != m.end()) { + LogPrint(BCLog::TOR, "tor: Connected to Tor version %s\n", i->second); + } + } + } + for (const std::string &s : methods) { + LogPrint(BCLog::TOR, "tor: Supported authentication method: %s\n", s); + } + // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD + /* Authentication: + * cookie: hex-encoded ~/.tor/control_auth_cookie + * password: "password" + */ + std::string torpassword = gArgs.GetArg("-torpassword", ""); + if (!torpassword.empty()) { + if (methods.count("HASHEDPASSWORD")) { + LogPrint(BCLog::TOR, "tor: Using HASHEDPASSWORD authentication\n"); + boost::replace_all(torpassword, "\"", "\\\""); + _conn.Command("AUTHENTICATE \"" + torpassword + "\"", boost::bind(&TorController::auth_cb, this, _1, _2)); + } else { + LogPrintf("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available\n"); + } + } else if (methods.count("NULL")) { + LogPrint(BCLog::TOR, "tor: Using NULL authentication\n"); + _conn.Command("AUTHENTICATE", boost::bind(&TorController::auth_cb, this, _1, _2)); + } else if (methods.count("SAFECOOKIE")) { + // Cookie: hexdump -e '32/1 "%02x""\n"' ~/.tor/control_auth_cookie + LogPrint(BCLog::TOR, "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile); + std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE); + if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) { + // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), boost::bind(&TorController::auth_cb, this, _1, _2)); + cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end()); + clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0); + GetRandBytes(clientNonce.data(), TOR_NONCE_SIZE); + _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), boost::bind(&TorController::authchallenge_cb, this, _1, _2)); + } else { + if (status_cookie.first) { + LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE); + } else { + LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile); + } + } + } else if (methods.count("HASHEDPASSWORD")) { + LogPrintf("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword\n"); + } else { + LogPrintf("tor: No supported authentication method\n"); + } + } else { + LogPrintf("tor: Requesting protocol info failed\n"); + } +} + +void TorController::connected_cb(TorControlConnection& _conn) +{ + reconnect_timeout = RECONNECT_TIMEOUT_START; + // First send a PROTOCOLINFO command to figure out what authentication is expected + if (!_conn.Command("PROTOCOLINFO 1", boost::bind(&TorController::protocolinfo_cb, this, _1, _2))) + LogPrintf("tor: Error sending initial protocolinfo command\n"); +} + +void TorController::disconnected_cb(TorControlConnection& _conn) +{ + // Stop advertising service when disconnected + if (service.IsValid()) + RemoveLocal(service); + service = CService(); + if (!reconnect) + return; + + LogPrint(BCLog::TOR, "tor: Not connected to Tor control port %s, trying to reconnect\n", target); + + // Single-shot timer for reconnect. Use exponential backoff. + struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0)); + if (reconnect_ev) + event_add(reconnect_ev, &time); + reconnect_timeout *= RECONNECT_TIMEOUT_EXP; +} + +void TorController::Reconnect() +{ + /* Try to reconnect and reestablish if we get booted - for example, Tor + * may be restarting. + */ + if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1), + boost::bind(&TorController::disconnected_cb, this, _1) )) { + LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target); + } +} + +fs::path TorController::GetPrivateKeyFile() +{ + return GetDataDir() / "onion_private_key"; +} + +void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg) +{ + TorController *self = static_cast<TorController*>(arg); + self->Reconnect(); +} + +/****** Thread ********/ +static struct event_base *gBase; +static std::thread torControlThread; + +static void TorControlThread() +{ + TorController ctrl(gBase, gArgs.GetArg("-torcontrol", DEFAULT_TOR_CONTROL)); + + event_base_dispatch(gBase); +} + +void StartTorControl() +{ + assert(!gBase); +#ifdef WIN32 + evthread_use_windows_threads(); +#else + evthread_use_pthreads(); +#endif + gBase = event_base_new(); + if (!gBase) { + LogPrintf("tor: Unable to create event_base\n"); + return; + } + + torControlThread = std::thread(std::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread)); +} + +void InterruptTorControl() +{ + if (gBase) { + LogPrintf("tor: Thread interrupt\n"); + event_base_loopbreak(gBase); + } +} + +void StopTorControl() +{ + if (gBase) { + torControlThread.join(); + event_base_free(gBase); + gBase = nullptr; + } +} + |