src/torcontrol.cpp

   1 // Copyright (c) 2015-2017 The Bitcoin Core developers
   2 // Copyright (c) 2017 The Zcash developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include <torcontrol.h>
   7 #include <utilstrencodings.h>
   8 #include <netbase.h>
   9 #include <net.h>
  10 #include <util.h>
  11 #include <crypto/hmac_sha256.h>
  12
  13 #include <vector>
  14 #include <deque>
  15 #include <set>
  16 #include <stdlib.h>
  17
  18 #include <boost/bind.hpp>
  19 #include <boost/signals2/signal.hpp>
  20 #include <boost/algorithm/string/split.hpp>
  21 #include <boost/algorithm/string/classification.hpp>
  22 #include <boost/algorithm/string/replace.hpp>
  23
  24 #include <event2/bufferevent.h>
  25 #include <event2/buffer.h>
  26 #include <event2/util.h>
  27 #include <event2/event.h>
  28 #include <event2/thread.h>
  29
  30 /** Default control port */
  31 const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051";
  32 /** Tor cookie size (from control-spec.txt) */
  33 static const int TOR_COOKIE_SIZE = 32;
  34 /** Size of client/server nonce for SAFECOOKIE */
  35 static const int TOR_NONCE_SIZE = 32;
  36 /** For computing serverHash in SAFECOOKIE */
  37 static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
  38 /** For computing clientHash in SAFECOOKIE */
  39 static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
  40 /** Exponential backoff configuration - initial timeout in seconds */
  41 static const float RECONNECT_TIMEOUT_START = 1.0;
  42 /** Exponential backoff configuration - growth factor */
  43 static const float RECONNECT_TIMEOUT_EXP = 1.5;
  44 /** Maximum length for lines received on TorControlConnection.
  45  * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
  46  * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
  47  */
  48 static const int MAX_LINE_LENGTH = 100000;
  49
  50 /****** Low-level TorControlConnection ********/
  51
  52 /** Reply from Tor, can be single or multi-line */
  53 class TorControlReply
  54 {
  55 public:
  56     TorControlReply() { Clear(); }
  57
  58     int code;
  59     std::vector<std::string> lines;
  60
  61     void Clear()
  62     {
  63         code = 0;
  64         lines.clear();
  65     }
  66 };
  67
  68 /** Low-level handling for Tor control connection.
  69  * Speaks the SMTP-like protocol as defined in torspec/control-spec.txt
  70  */
  71 class TorControlConnection
  72 {
  73 public:
  74     typedef std::function<void(TorControlConnection&)> ConnectionCB;
  75     typedef std::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
  76
  77     /** Create a new TorControlConnection.
  78      */
  79     explicit TorControlConnection(struct event_base *base);
  80     ~TorControlConnection();
  81
  82     /**
  83      * Connect to a Tor control port.
  84      * target is address of the form host:port.
  85      * connected is the handler that is called when connection is successfully established.
  86      * disconnected is a handler that is called when the connection is broken.
  87      * Return true on success.
  88      */
  89     bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected);
  90
  91     /**
  92      * Disconnect from Tor control port.
  93      */
  94     bool Disconnect();
  95
  96     /** Send a command, register a handler for the reply.
  97      * A trailing CRLF is automatically added.
  98      * Return true on success.
  99      */
 100     bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler);
 101
 102     /** Response handlers for async replies */
 103     boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler;
 104 private:
 105     /** Callback when ready for use */
 106     std::function<void(TorControlConnection&)> connected;
 107     /** Callback when connection lost */
 108     std::function<void(TorControlConnection&)> disconnected;
 109     /** Libevent event base */
 110     struct event_base *base;
 111     /** Connection to control socket */
 112     struct bufferevent *b_conn;
 113     /** Message being received */
 114     TorControlReply message;
 115     /** Response handlers */
 116     std::deque<ReplyHandlerCB> reply_handlers;
 117
 118     /** Libevent handlers: internal */
 119     static void readcb(struct bufferevent *bev, void *ctx);
 120     static void eventcb(struct bufferevent *bev, short what, void *ctx);
 121 };
 122
 123 TorControlConnection::TorControlConnection(struct event_base *_base):
 124     base(_base), b_conn(nullptr)
 125 {
 126 }
 127
 128 TorControlConnection::~TorControlConnection()
 129 {
 130     if (b_conn)
 131         bufferevent_free(b_conn);
 132 }
 133
 134 void TorControlConnection::readcb(struct bufferevent *bev, void *ctx)
 135 {
 136     TorControlConnection *self = (TorControlConnection*)ctx;
 137     struct evbuffer *input = bufferevent_get_input(bev);
 138     size_t n_read_out = 0;
 139     char *line;
 140     assert(input);
 141     //  If there is not a whole line to read, evbuffer_readln returns nullptr
 142     while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != nullptr)
 143     {
 144         std::string s(line, n_read_out);
 145         free(line);
 146         if (s.size() < 4) // Short line
 147             continue;
 148         // <status>(-|+| )<data><CRLF>
 149         self->message.code = atoi(s.substr(0,3));
 150         self->message.lines.push_back(s.substr(4));
 151         char ch = s[3]; // '-','+' or ' '
 152         if (ch == ' ') {
 153             // Final line, dispatch reply and clean up
 154             if (self->message.code >= 600) {
 155                 // Dispatch async notifications to async handler
 156                 // Synchronous and asynchronous messages are never interleaved
 157                 self->async_handler(*self, self->message);
 158             } else {
 159                 if (!self->reply_handlers.empty()) {
 160                     // Invoke reply handler with message
 161                     self->reply_handlers.front()(*self, self->message);
 162                     self->reply_handlers.pop_front();
 163                 } else {
 164                     LogPrint(BCLog::TOR, "tor: Received unexpected sync reply %i\n", self->message.code);
 165                 }
 166             }
 167             self->message.Clear();
 168         }
 169     }
 170     //  Check for size of buffer - protect against memory exhaustion with very long lines
 171     //  Do this after evbuffer_readln to make sure all full lines have been
 172     //  removed from the buffer. Everything left is an incomplete line.
 173     if (evbuffer_get_length(input) > MAX_LINE_LENGTH) {
 174         LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n");
 175         self->Disconnect();
 176     }
 177 }
 178
 179 void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx)
 180 {
 181     TorControlConnection *self = (TorControlConnection*)ctx;
 182     if (what & BEV_EVENT_CONNECTED) {
 183         LogPrint(BCLog::TOR, "tor: Successfully connected!\n");
 184         self->connected(*self);
 185     } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
 186         if (what & BEV_EVENT_ERROR) {
 187             LogPrint(BCLog::TOR, "tor: Error connecting to Tor control socket\n");
 188         } else {
 189             LogPrint(BCLog::TOR, "tor: End of stream\n");
 190         }
 191         self->Disconnect();
 192         self->disconnected(*self);
 193     }
 194 }
 195
 196 bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& _connected, const ConnectionCB&  _disconnected)
 197 {
 198     if (b_conn)
 199         Disconnect();
 200     // Parse target address:port
 201     struct sockaddr_storage connect_to_addr;
 202     int connect_to_addrlen = sizeof(connect_to_addr);
 203     if (evutil_parse_sockaddr_port(target.c_str(),
 204         (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) {
 205         LogPrintf("tor: Error parsing socket address %s\n", target);
 206         return false;
 207     }
 208
 209     // Create a new socket, set up callbacks and enable notification bits
 210     b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
 211     if (!b_conn)
 212         return false;
 213     bufferevent_setcb(b_conn, TorControlConnection::readcb, nullptr, TorControlConnection::eventcb, this);
 214     bufferevent_enable(b_conn, EV_READ|EV_WRITE);
 215     this->connected = _connected;
 216     this->disconnected = _disconnected;
 217
 218     // Finally, connect to target
 219     if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) {
 220         LogPrintf("tor: Error connecting to address %s\n", target);
 221         return false;
 222     }
 223     return true;
 224 }
 225
 226 bool TorControlConnection::Disconnect()
 227 {
 228     if (b_conn)
 229         bufferevent_free(b_conn);
 230     b_conn = nullptr;
 231     return true;
 232 }
 233
 234 bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
 235 {
 236     if (!b_conn)
 237         return false;
 238     struct evbuffer *buf = bufferevent_get_output(b_conn);
 239     if (!buf)
 240         return false;
 241     evbuffer_add(buf, cmd.data(), cmd.size());
 242     evbuffer_add(buf, "\r\n", 2);
 243     reply_handlers.push_back(reply_handler);
 244     return true;
 245 }
 246
 247 /****** General parsing utilities ********/
 248
 249 /* Split reply line in the form 'AUTH METHODS=...' into a type
 250  * 'AUTH' and arguments 'METHODS=...'.
 251  * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
 252  * the server reply formats for PROTOCOLINFO (S3.21) and AUTHCHALLENGE (S3.24).
 253  */
 254 static std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
 255 {
 256     size_t ptr=0;
 257     std::string type;
 258     while (ptr < s.size() && s[ptr] != ' ') {
 259         type.push_back(s[ptr]);
 260         ++ptr;
 261     }
 262     if (ptr < s.size())
 263         ++ptr; // skip ' '
 264     return make_pair(type, s.substr(ptr));
 265 }
 266
 267 /** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'.
 268  * Returns a map of keys to values, or an empty map if there was an error.
 269  * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
 270  * the server reply formats for PROTOCOLINFO (S3.21), AUTHCHALLENGE (S3.24),
 271  * and ADD_ONION (S3.27). See also sections 2.1 and 2.3.
 272  */
 273 static std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
 274 {
 275     std::map<std::string,std::string> mapping;
 276     size_t ptr=0;
 277     while (ptr < s.size()) {
 278         std::string key, value;
 279         while (ptr < s.size() && s[ptr] != '=' && s[ptr] != ' ') {
 280             key.push_back(s[ptr]);
 281             ++ptr;
 282         }
 283         if (ptr == s.size()) // unexpected end of line
 284             return std::map<std::string,std::string>();
 285         if (s[ptr] == ' ') // The remaining string is an OptArguments
 286             break;
 287         ++ptr; // skip '='
 288         if (ptr < s.size() && s[ptr] == '"') { // Quoted string
 289             ++ptr; // skip opening '"'
 290             bool escape_next = false;
 291             while (ptr < s.size() && (escape_next || s[ptr] != '"')) {
 292                 // Repeated backslashes must be interpreted as pairs
 293                 escape_next = (s[ptr] == '\\' && !escape_next);
 294                 value.push_back(s[ptr]);
 295                 ++ptr;
 296             }
 297             if (ptr == s.size()) // unexpected end of line
 298                 return std::map<std::string,std::string>();
 299             ++ptr; // skip closing '"'
 300             /**
 301              * Unescape value. Per https://spec.torproject.org/control-spec section 2.1.1:
 302              *
 303              *   For future-proofing, controller implementors MAY use the following
 304              *   rules to be compatible with buggy Tor implementations and with
 305              *   future ones that implement the spec as intended:
 306              *
 307              *     Read \n \t \r and \0 ... \377 as C escapes.
 308              *     Treat a backslash followed by any other character as that character.
 309              */
 310             std::string escaped_value;
 311             for (size_t i = 0; i < value.size(); ++i) {
 312                 if (value[i] == '\\') {
 313                     // This will always be valid, because if the QuotedString
 314                     // ended in an odd number of backslashes, then the parser
 315                     // would already have returned above, due to a missing
 316                     // terminating double-quote.
 317                     ++i;
 318                     if (value[i] == 'n') {
 319                         escaped_value.push_back('\n');
 320                     } else if (value[i] == 't') {
 321                         escaped_value.push_back('\t');
 322                     } else if (value[i] == 'r') {
 323                         escaped_value.push_back('\r');
 324                     } else if ('0' <= value[i] && value[i] <= '7') {
 325                         size_t j;
 326                         // Octal escape sequences have a limit of three octal digits,
 327                         // but terminate at the first character that is not a valid
 328                         // octal digit if encountered sooner.
 329                         for (j = 1; j < 3 && (i+j) < value.size() && '0' <= value[i+j] && value[i+j] <= '7'; ++j) {}
 330                         // Tor restricts first digit to 0-3 for three-digit octals.
 331                         // A leading digit of 4-7 would therefore be interpreted as
 332                         // a two-digit octal.
 333                         if (j == 3 && value[i] > '3') {
 334                             j--;
 335                         }
 336                         escaped_value.push_back(strtol(value.substr(i, j).c_str(), nullptr, 8));
 337                         // Account for automatic incrementing at loop end
 338                         i += j - 1;
 339                     } else {
 340                         escaped_value.push_back(value[i]);
 341                     }
 342                 } else {
 343                     escaped_value.push_back(value[i]);
 344                 }
 345             }
 346             value = escaped_value;
 347         } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
 348             while (ptr < s.size() && s[ptr] != ' ') {
 349                 value.push_back(s[ptr]);
 350                 ++ptr;
 351             }
 352         }
 353         if (ptr < s.size() && s[ptr] == ' ')
 354             ++ptr; // skip ' ' after key=value
 355         mapping[key] = value;
 356     }
 357     return mapping;
 358 }
 359
 360 /** Read full contents of a file and return them in a std::string.
 361  * Returns a pair <status, string>.
 362  * If an error occurred, status will be false, otherwise status will be true and the data will be returned in string.
 363  *
 364  * @param maxsize Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data
 365  *         (with len > maxsize) will be returned.
 366  */
 367 static std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize=std::numeric_limits<size_t>::max())
 368 {
 369     FILE *f = fsbridge::fopen(filename, "rb");
 370     if (f == nullptr)
 371         return std::make_pair(false,"");
 372     std::string retval;
 373     char buffer[128];
 374     size_t n;
 375     while ((n=fread(buffer, 1, sizeof(buffer), f)) > 0) {
 376         // Check for reading errors so we don't return any data if we couldn't
 377         // read the entire file (or up to maxsize)
 378         if (ferror(f)) {
 379             fclose(f);
 380             return std::make_pair(false,"");
 381         }
 382         retval.append(buffer, buffer+n);
 383         if (retval.size() > maxsize)
 384             break;
 385     }
 386     fclose(f);
 387     return std::make_pair(true,retval);
 388 }
 389
 390 /** Write contents of std::string to a file.
 391  * @return true on success.
 392  */
 393 static bool WriteBinaryFile(const fs::path &filename, const std::string &data)
 394 {
 395     FILE *f = fsbridge::fopen(filename, "wb");
 396     if (f == nullptr)
 397         return false;
 398     if (fwrite(data.data(), 1, data.size(), f) != data.size()) {
 399         fclose(f);
 400         return false;
 401     }
 402     fclose(f);
 403     return true;
 404 }
 405
 406 /****** Bitcoin specific TorController implementation ********/
 407
 408 /** Controller that connects to Tor control socket, authenticate, then create
 409  * and maintain an ephemeral hidden service.
 410  */
 411 class TorController
 412 {
 413 public:
 414     TorController(struct event_base* base, const std::string& target);
 415     ~TorController();
 416
 417     /** Get name fo file to store private key in */
 418     fs::path GetPrivateKeyFile();
 419
 420     /** Reconnect, after getting disconnected */
 421     void Reconnect();
 422 private:
 423     struct event_base* base;
 424     std::string target;
 425     TorControlConnection conn;
 426     std::string private_key;
 427     std::string service_id;
 428     bool reconnect;
 429     struct event *reconnect_ev;
 430     float reconnect_timeout;
 431     CService service;
 432     /** Cookie for SAFECOOKIE auth */
 433     std::vector<uint8_t> cookie;
 434     /** ClientNonce for SAFECOOKIE auth */
 435     std::vector<uint8_t> clientNonce;
 436
 437     /** Callback for ADD_ONION result */
 438     void add_onion_cb(TorControlConnection& conn, const TorControlReply& reply);
 439     /** Callback for AUTHENTICATE result */
 440     void auth_cb(TorControlConnection& conn, const TorControlReply& reply);
 441     /** Callback for AUTHCHALLENGE result */
 442     void authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply);
 443     /** Callback for PROTOCOLINFO result */
 444     void protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply);
 445     /** Callback after successful connection */
 446     void connected_cb(TorControlConnection& conn);
 447     /** Callback after connection lost or failed connection attempt */
 448     void disconnected_cb(TorControlConnection& conn);
 449
 450     /** Callback for reconnect timer */
 451     static void reconnect_cb(evutil_socket_t fd, short what, void *arg);
 452 };
 453
 454 TorController::TorController(struct event_base* _base, const std::string& _target):
 455     base(_base),
 456     target(_target), conn(base), reconnect(true), reconnect_ev(0),
 457     reconnect_timeout(RECONNECT_TIMEOUT_START)
 458 {
 459     reconnect_ev = event_new(base, -1, 0, reconnect_cb, this);
 460     if (!reconnect_ev)
 461         LogPrintf("tor: Failed to create event for reconnection: out of memory?\n");
 462     // Start connection attempts immediately
 463     if (!conn.Connect(_target, boost::bind(&TorController::connected_cb, this, _1),
 464          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 465         LogPrintf("tor: Initiating connection to Tor control port %s failed\n", _target);
 466     }
 467     // Read service private key if cached
 468     std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
 469     if (pkf.first) {
 470         LogPrint(BCLog::TOR, "tor: Reading cached private key from %s\n", GetPrivateKeyFile().string());
 471         private_key = pkf.second;
 472     }
 473 }
 474
 475 TorController::~TorController()
 476 {
 477     if (reconnect_ev) {
 478         event_free(reconnect_ev);
 479         reconnect_ev = nullptr;
 480     }
 481     if (service.IsValid()) {
 482         RemoveLocal(service);
 483     }
 484 }
 485
 486 void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply)
 487 {
 488     if (reply.code == 250) {
 489         LogPrint(BCLog::TOR, "tor: ADD_ONION successful\n");
 490         for (const std::string &s : reply.lines) {
 491             std::map<std::string,std::string> m = ParseTorReplyMapping(s);
 492             std::map<std::string,std::string>::iterator i;
 493             if ((i = m.find("ServiceID")) != m.end())
 494                 service_id = i->second;
 495             if ((i = m.find("PrivateKey")) != m.end())
 496                 private_key = i->second;
 497         }
 498         if (service_id.empty()) {
 499             LogPrintf("tor: Error parsing ADD_ONION parameters:\n");
 500             for (const std::string &s : reply.lines) {
 501                 LogPrintf("    %s\n", SanitizeString(s));
 502             }
 503             return;
 504         }
 505         service = LookupNumeric(std::string(service_id+".onion").c_str(), GetListenPort());
 506         LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString());
 507         if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
 508             LogPrint(BCLog::TOR, "tor: Cached service private key to %s\n", GetPrivateKeyFile().string());
 509         } else {
 510             LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile().string());
 511         }
 512         AddLocal(service, LOCAL_MANUAL);
 513         // ... onion requested - keep connection open
 514     } else if (reply.code == 510) { // 510 Unrecognized command
 515         LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n");
 516     } else {
 517         LogPrintf("tor: Add onion failed; error code %d\n", reply.code);
 518     }
 519 }
 520
 521 void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply)
 522 {
 523     if (reply.code == 250) {
 524         LogPrint(BCLog::TOR, "tor: Authentication successful\n");
 525
 526         // Now that we know Tor is running setup the proxy for onion addresses
 527         // if -onion isn't set to something else.
 528         if (gArgs.GetArg("-onion", "") == "") {
 529             CService resolved(LookupNumeric("127.0.0.1", 9050));
 530             proxyType addrOnion = proxyType(resolved, true);
 531             SetProxy(NET_TOR, addrOnion);
 532             SetLimited(NET_TOR, false);
 533         }
 534
 535         // Finally - now create the service
 536         if (private_key.empty()) // No private key, generate one
 537             private_key = "NEW:RSA1024"; // Explicitly request RSA1024 - see issue #9214
 538         // Request hidden service, redirect port.
 539         // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient
 540         // choice.  TODO; refactor the shutdown sequence some day.
 541         _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()),
 542             boost::bind(&TorController::add_onion_cb, this, _1, _2));
 543     } else {
 544         LogPrintf("tor: Authentication failed\n");
 545     }
 546 }
 547
 548 /** Compute Tor SAFECOOKIE response.
 549  *
 550  *    ServerHash is computed as:
 551  *      HMAC-SHA256("Tor safe cookie authentication server-to-controller hash",
 552  *                  CookieString | ClientNonce | ServerNonce)
 553  *    (with the HMAC key as its first argument)
 554  *
 555  *    After a controller sends a successful AUTHCHALLENGE command, the
 556  *    next command sent on the connection must be an AUTHENTICATE command,
 557  *    and the only authentication string which that AUTHENTICATE command
 558  *    will accept is:
 559  *
 560  *      HMAC-SHA256("Tor safe cookie authentication controller-to-server hash",
 561  *                  CookieString | ClientNonce | ServerNonce)
 562  *
 563  */
 564 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)
 565 {
 566     CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
 567     std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
 568     computeHash.Write(cookie.data(), cookie.size());
 569     computeHash.Write(clientNonce.data(), clientNonce.size());
 570     computeHash.Write(serverNonce.data(), serverNonce.size());
 571     computeHash.Finalize(computedHash.data());
 572     return computedHash;
 573 }
 574
 575 void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply)
 576 {
 577     if (reply.code == 250) {
 578         LogPrint(BCLog::TOR, "tor: SAFECOOKIE authentication challenge successful\n");
 579         std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
 580         if (l.first == "AUTHCHALLENGE") {
 581             std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 582             if (m.empty()) {
 583                 LogPrintf("tor: Error parsing AUTHCHALLENGE parameters: %s\n", SanitizeString(l.second));
 584                 return;
 585             }
 586             std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]);
 587             std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]);
 588             LogPrint(BCLog::TOR, "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce));
 589             if (serverNonce.size() != 32) {
 590                 LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n");
 591                 return;
 592             }
 593
 594             std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce);
 595             if (computedServerHash != serverHash) {
 596                 LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash));
 597                 return;
 598             }
 599
 600             std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce);
 601             _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), boost::bind(&TorController::auth_cb, this, _1, _2));
 602         } else {
 603             LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n");
 604         }
 605     } else {
 606         LogPrintf("tor: SAFECOOKIE authentication challenge failed\n");
 607     }
 608 }
 609
 610 void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply)
 611 {
 612     if (reply.code == 250) {
 613         std::set<std::string> methods;
 614         std::string cookiefile;
 615         /*
 616          * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie"
 617          * 250-AUTH METHODS=NULL
 618          * 250-AUTH METHODS=HASHEDPASSWORD
 619          */
 620         for (const std::string &s : reply.lines) {
 621             std::pair<std::string,std::string> l = SplitTorReplyLine(s);
 622             if (l.first == "AUTH") {
 623                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 624                 std::map<std::string,std::string>::iterator i;
 625                 if ((i = m.find("METHODS")) != m.end())
 626                     boost::split(methods, i->second, boost::is_any_of(","));
 627                 if ((i = m.find("COOKIEFILE")) != m.end())
 628                     cookiefile = i->second;
 629             } else if (l.first == "VERSION") {
 630                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 631                 std::map<std::string,std::string>::iterator i;
 632                 if ((i = m.find("Tor")) != m.end()) {
 633                     LogPrint(BCLog::TOR, "tor: Connected to Tor version %s\n", i->second);
 634                 }
 635             }
 636         }
 637         for (const std::string &s : methods) {
 638             LogPrint(BCLog::TOR, "tor: Supported authentication method: %s\n", s);
 639         }
 640         // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD
 641         /* Authentication:
 642          *   cookie:   hex-encoded ~/.tor/control_auth_cookie
 643          *   password: "password"
 644          */
 645         std::string torpassword = gArgs.GetArg("-torpassword", "");
 646         if (!torpassword.empty()) {
 647             if (methods.count("HASHEDPASSWORD")) {
 648                 LogPrint(BCLog::TOR, "tor: Using HASHEDPASSWORD authentication\n");
 649                 boost::replace_all(torpassword, "\"", "\\\"");
 650                 _conn.Command("AUTHENTICATE \"" + torpassword + "\"", boost::bind(&TorController::auth_cb, this, _1, _2));
 651             } else {
 652                 LogPrintf("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available\n");
 653             }
 654         } else if (methods.count("NULL")) {
 655             LogPrint(BCLog::TOR, "tor: Using NULL authentication\n");
 656             _conn.Command("AUTHENTICATE", boost::bind(&TorController::auth_cb, this, _1, _2));
 657         } else if (methods.count("SAFECOOKIE")) {
 658             // Cookie: hexdump -e '32/1 "%02x""\n"'  ~/.tor/control_auth_cookie
 659             LogPrint(BCLog::TOR, "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile);
 660             std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE);
 661             if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
 662                 // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), boost::bind(&TorController::auth_cb, this, _1, _2));
 663                 cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
 664                 clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
 665                 GetRandBytes(clientNonce.data(), TOR_NONCE_SIZE);
 666                 _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), boost::bind(&TorController::authchallenge_cb, this, _1, _2));
 667             } else {
 668                 if (status_cookie.first) {
 669                     LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE);
 670                 } else {
 671                     LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile);
 672                 }
 673             }
 674         } else if (methods.count("HASHEDPASSWORD")) {
 675             LogPrintf("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword\n");
 676         } else {
 677             LogPrintf("tor: No supported authentication method\n");
 678         }
 679     } else {
 680         LogPrintf("tor: Requesting protocol info failed\n");
 681     }
 682 }
 683
 684 void TorController::connected_cb(TorControlConnection& _conn)
 685 {
 686     reconnect_timeout = RECONNECT_TIMEOUT_START;
 687     // First send a PROTOCOLINFO command to figure out what authentication is expected
 688     if (!_conn.Command("PROTOCOLINFO 1", boost::bind(&TorController::protocolinfo_cb, this, _1, _2)))
 689         LogPrintf("tor: Error sending initial protocolinfo command\n");
 690 }
 691
 692 void TorController::disconnected_cb(TorControlConnection& _conn)
 693 {
 694     // Stop advertising service when disconnected
 695     if (service.IsValid())
 696         RemoveLocal(service);
 697     service = CService();
 698     if (!reconnect)
 699         return;
 700
 701     LogPrint(BCLog::TOR, "tor: Not connected to Tor control port %s, trying to reconnect\n", target);
 702
 703     // Single-shot timer for reconnect. Use exponential backoff.
 704     struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0));
 705     if (reconnect_ev)
 706         event_add(reconnect_ev, &time);
 707     reconnect_timeout *= RECONNECT_TIMEOUT_EXP;
 708 }
 709
 710 void TorController::Reconnect()
 711 {
 712     /* Try to reconnect and reestablish if we get booted - for example, Tor
 713      * may be restarting.
 714      */
 715     if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1),
 716          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 717         LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target);
 718     }
 719 }
 720
 721 fs::path TorController::GetPrivateKeyFile()
 722 {
 723     return GetDataDir() / "onion_private_key";
 724 }
 725
 726 void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg)
 727 {
 728     TorController *self = (TorController*)arg;
 729     self->Reconnect();
 730 }
 731
 732 /****** Thread ********/
 733 static struct event_base *gBase;
 734 static boost::thread torControlThread;
 735
 736 static void TorControlThread()
 737 {
 738     TorController ctrl(gBase, gArgs.GetArg("-torcontrol", DEFAULT_TOR_CONTROL));
 739
 740     event_base_dispatch(gBase);
 741 }
 742
 743 void StartTorControl(boost::thread_group& threadGroup, CScheduler& scheduler)
 744 {
 745     assert(!gBase);
 746 #ifdef WIN32
 747     evthread_use_windows_threads();
 748 #else
 749     evthread_use_pthreads();
 750 #endif
 751     gBase = event_base_new();
 752     if (!gBase) {
 753         LogPrintf("tor: Unable to create event_base\n");
 754         return;
 755     }
 756
 757     torControlThread = boost::thread(boost::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread));
 758 }
 759
 760 void InterruptTorControl()
 761 {
 762     if (gBase) {
 763         LogPrintf("tor: Thread interrupt\n");
 764         event_base_loopbreak(gBase);
 765     }
 766 }
 767
 768 void StopTorControl()
 769 {
 770     if (gBase) {
 771         torControlThread.join();
 772         event_base_free(gBase);
 773         gBase = nullptr;
 774     }
 775 }
 776