src/torcontrol.cpp

   1 // Copyright (c) 2015-2016 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/foreach.hpp>
  21 #include <boost/algorithm/string/split.hpp>
  22 #include <boost/algorithm/string/classification.hpp>
  23 #include <boost/algorithm/string/replace.hpp>
  24
  25 #include <event2/bufferevent.h>
  26 #include <event2/buffer.h>
  27 #include <event2/util.h>
  28 #include <event2/event.h>
  29 #include <event2/thread.h>
  30
  31 /** Default control port */
  32 const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051";
  33 /** Tor cookie size (from control-spec.txt) */
  34 static const int TOR_COOKIE_SIZE = 32;
  35 /** Size of client/server nonce for SAFECOOKIE */
  36 static const int TOR_NONCE_SIZE = 32;
  37 /** For computing serverHash in SAFECOOKIE */
  38 static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
  39 /** For computing clientHash in SAFECOOKIE */
  40 static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
  41 /** Exponential backoff configuration - initial timeout in seconds */
  42 static const float RECONNECT_TIMEOUT_START = 1.0;
  43 /** Exponential backoff configuration - growth factor */
  44 static const float RECONNECT_TIMEOUT_EXP = 1.5;
  45 /** Maximum length for lines received on TorControlConnection.
  46  * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
  47  * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
  48  */
  49 static const int MAX_LINE_LENGTH = 100000;
  50
  51 /****** Low-level TorControlConnection ********/
  52
  53 /** Reply from Tor, can be single or multi-line */
  54 class TorControlReply
  55 {
  56 public:
  57     TorControlReply() { Clear(); }
  58
  59     int code;
  60     std::vector<std::string> lines;
  61
  62     void Clear()
  63     {
  64         code = 0;
  65         lines.clear();
  66     }
  67 };
  68
  69 /** Low-level handling for Tor control connection.
  70  * Speaks the SMTP-like protocol as defined in torspec/control-spec.txt
  71  */
  72 class TorControlConnection
  73 {
  74 public:
  75     typedef std::function<void(TorControlConnection&)> ConnectionCB;
  76     typedef std::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
  77
  78     /** Create a new TorControlConnection.
  79      */
  80     TorControlConnection(struct event_base *base);
  81     ~TorControlConnection();
  82
  83     /**
  84      * Connect to a Tor control port.
  85      * target is address of the form host:port.
  86      * connected is the handler that is called when connection is successfully established.
  87      * disconnected is a handler that is called when the connection is broken.
  88      * Return true on success.
  89      */
  90     bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected);
  91
  92     /**
  93      * Disconnect from Tor control port.
  94      */
  95     bool Disconnect();
  96
  97     /** Send a command, register a handler for the reply.
  98      * A trailing CRLF is automatically added.
  99      * Return true on success.
 100      */
 101     bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler);
 102
 103     /** Response handlers for async replies */
 104     boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler;
 105 private:
 106     /** Callback when ready for use */
 107     std::function<void(TorControlConnection&)> connected;
 108     /** Callback when connection lost */
 109     std::function<void(TorControlConnection&)> disconnected;
 110     /** Libevent event base */
 111     struct event_base *base;
 112     /** Connection to control socket */
 113     struct bufferevent *b_conn;
 114     /** Message being received */
 115     TorControlReply message;
 116     /** Response handlers */
 117     std::deque<ReplyHandlerCB> reply_handlers;
 118
 119     /** Libevent handlers: internal */
 120     static void readcb(struct bufferevent *bev, void *ctx);
 121     static void eventcb(struct bufferevent *bev, short what, void *ctx);
 122 };
 123
 124 TorControlConnection::TorControlConnection(struct event_base *_base):
 125     base(_base), b_conn(0)
 126 {
 127 }
 128
 129 TorControlConnection::~TorControlConnection()
 130 {
 131     if (b_conn)
 132         bufferevent_free(b_conn);
 133 }
 134
 135 void TorControlConnection::readcb(struct bufferevent *bev, void *ctx)
 136 {
 137     TorControlConnection *self = (TorControlConnection*)ctx;
 138     struct evbuffer *input = bufferevent_get_input(bev);
 139     size_t n_read_out = 0;
 140     char *line;
 141     assert(input);
 142     //  If there is not a whole line to read, evbuffer_readln returns NULL
 143     while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != NULL)
 144     {
 145         std::string s(line, n_read_out);
 146         free(line);
 147         if (s.size() < 4) // Short line
 148             continue;
 149         // <status>(-|+| )<data><CRLF>
 150         self->message.code = atoi(s.substr(0,3));
 151         self->message.lines.push_back(s.substr(4));
 152         char ch = s[3]; // '-','+' or ' '
 153         if (ch == ' ') {
 154             // Final line, dispatch reply and clean up
 155             if (self->message.code >= 600) {
 156                 // Dispatch async notifications to async handler
 157                 // Synchronous and asynchronous messages are never interleaved
 158                 self->async_handler(*self, self->message);
 159             } else {
 160                 if (!self->reply_handlers.empty()) {
 161                     // Invoke reply handler with message
 162                     self->reply_handlers.front()(*self, self->message);
 163                     self->reply_handlers.pop_front();
 164                 } else {
 165                     LogPrint(BCLog::TOR, "tor: Received unexpected sync reply %i\n", self->message.code);
 166                 }
 167             }
 168             self->message.Clear();
 169         }
 170     }
 171     //  Check for size of buffer - protect against memory exhaustion with very long lines
 172     //  Do this after evbuffer_readln to make sure all full lines have been
 173     //  removed from the buffer. Everything left is an incomplete line.
 174     if (evbuffer_get_length(input) > MAX_LINE_LENGTH) {
 175         LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n");
 176         self->Disconnect();
 177     }
 178 }
 179
 180 void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx)
 181 {
 182     TorControlConnection *self = (TorControlConnection*)ctx;
 183     if (what & BEV_EVENT_CONNECTED) {
 184         LogPrint(BCLog::TOR, "tor: Successfully connected!\n");
 185         self->connected(*self);
 186     } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
 187         if (what & BEV_EVENT_ERROR) {
 188             LogPrint(BCLog::TOR, "tor: Error connecting to Tor control socket\n");
 189         } else {
 190             LogPrint(BCLog::TOR, "tor: End of stream\n");
 191         }
 192         self->Disconnect();
 193         self->disconnected(*self);
 194     }
 195 }
 196
 197 bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& _connected, const ConnectionCB&  _disconnected)
 198 {
 199     if (b_conn)
 200         Disconnect();
 201     // Parse target address:port
 202     struct sockaddr_storage connect_to_addr;
 203     int connect_to_addrlen = sizeof(connect_to_addr);
 204     if (evutil_parse_sockaddr_port(target.c_str(),
 205         (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) {
 206         LogPrintf("tor: Error parsing socket address %s\n", target);
 207         return false;
 208     }
 209
 210     // Create a new socket, set up callbacks and enable notification bits
 211     b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
 212     if (!b_conn)
 213         return false;
 214     bufferevent_setcb(b_conn, TorControlConnection::readcb, NULL, TorControlConnection::eventcb, this);
 215     bufferevent_enable(b_conn, EV_READ|EV_WRITE);
 216     this->connected = _connected;
 217     this->disconnected = _disconnected;
 218
 219     // Finally, connect to target
 220     if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) {
 221         LogPrintf("tor: Error connecting to address %s\n", target);
 222         return false;
 223     }
 224     return true;
 225 }
 226
 227 bool TorControlConnection::Disconnect()
 228 {
 229     if (b_conn)
 230         bufferevent_free(b_conn);
 231     b_conn = 0;
 232     return true;
 233 }
 234
 235 bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
 236 {
 237     if (!b_conn)
 238         return false;
 239     struct evbuffer *buf = bufferevent_get_output(b_conn);
 240     if (!buf)
 241         return false;
 242     evbuffer_add(buf, cmd.data(), cmd.size());
 243     evbuffer_add(buf, "\r\n", 2);
 244     reply_handlers.push_back(reply_handler);
 245     return true;
 246 }
 247
 248 /****** General parsing utilities ********/
 249
 250 /* Split reply line in the form 'AUTH METHODS=...' into a type
 251  * 'AUTH' and arguments 'METHODS=...'.
 252  * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
 253  * the server reply formats for PROTOCOLINFO (S3.21) and AUTHCHALLENGE (S3.24).
 254  */
 255 static std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
 256 {
 257     size_t ptr=0;
 258     std::string type;
 259     while (ptr < s.size() && s[ptr] != ' ') {
 260         type.push_back(s[ptr]);
 261         ++ptr;
 262     }
 263     if (ptr < s.size())
 264         ++ptr; // skip ' '
 265     return make_pair(type, s.substr(ptr));
 266 }
 267
 268 /** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'.
 269  * Returns a map of keys to values, or an empty map if there was an error.
 270  * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
 271  * the server reply formats for PROTOCOLINFO (S3.21), AUTHCHALLENGE (S3.24),
 272  * and ADD_ONION (S3.27). See also sections 2.1 and 2.3.
 273  */
 274 static std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
 275 {
 276     std::map<std::string,std::string> mapping;
 277     size_t ptr=0;
 278     while (ptr < s.size()) {
 279         std::string key, value;
 280         while (ptr < s.size() && s[ptr] != '=' && s[ptr] != ' ') {
 281             key.push_back(s[ptr]);
 282             ++ptr;
 283         }
 284         if (ptr == s.size()) // unexpected end of line
 285             return std::map<std::string,std::string>();
 286         if (s[ptr] == ' ') // The remaining string is an OptArguments
 287             break;
 288         ++ptr; // skip '='
 289         if (ptr < s.size() && s[ptr] == '"') { // Quoted string
 290             ++ptr; // skip opening '"'
 291             bool escape_next = false;
 292             while (ptr < s.size() && (escape_next || s[ptr] != '"')) {
 293                 // Repeated backslashes must be interpreted as pairs
 294                 escape_next = (s[ptr] == '\\' && !escape_next);
 295                 value.push_back(s[ptr]);
 296                 ++ptr;
 297             }
 298             if (ptr == s.size()) // unexpected end of line
 299                 return std::map<std::string,std::string>();
 300             ++ptr; // skip closing '"'
 301             /**
 302              * Unescape value. Per https://spec.torproject.org/control-spec section 2.1.1:
 303              *
 304              *   For future-proofing, controller implementors MAY use the following
 305              *   rules to be compatible with buggy Tor implementations and with
 306              *   future ones that implement the spec as intended:
 307              *
 308              *     Read \n \t \r and \0 ... \377 as C escapes.
 309              *     Treat a backslash followed by any other character as that character.
 310              */
 311             std::string escaped_value;
 312             for (size_t i = 0; i < value.size(); ++i) {
 313                 if (value[i] == '\\') {
 314                     // This will always be valid, because if the QuotedString
 315                     // ended in an odd number of backslashes, then the parser
 316                     // would already have returned above, due to a missing
 317                     // terminating double-quote.
 318                     ++i;
 319                     if (value[i] == 'n') {
 320                         escaped_value.push_back('\n');
 321                     } else if (value[i] == 't') {
 322                         escaped_value.push_back('\t');
 323                     } else if (value[i] == 'r') {
 324                         escaped_value.push_back('\r');
 325                     } else if ('0' <= value[i] && value[i] <= '7') {
 326                         size_t j;
 327                         // Octal escape sequences have a limit of three octal digits,
 328                         // but terminate at the first character that is not a valid
 329                         // octal digit if encountered sooner.
 330                         for (j = 1; j < 3 && (i+j) < value.size() && '0' <= value[i+j] && value[i+j] <= '7'; ++j) {}
 331                         // Tor restricts first digit to 0-3 for three-digit octals.
 332                         // A leading digit of 4-7 would therefore be interpreted as
 333                         // a two-digit octal.
 334                         if (j == 3 && value[i] > '3') {
 335                             j--;
 336                         }
 337                         escaped_value.push_back(strtol(value.substr(i, j).c_str(), NULL, 8));
 338                         // Account for automatic incrementing at loop end
 339                         i += j - 1;
 340                     } else {
 341                         escaped_value.push_back(value[i]);
 342                     }
 343                 } else {
 344                     escaped_value.push_back(value[i]);
 345                 }
 346             }
 347             value = escaped_value;
 348         } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
 349             while (ptr < s.size() && s[ptr] != ' ') {
 350                 value.push_back(s[ptr]);
 351                 ++ptr;
 352             }
 353         }
 354         if (ptr < s.size() && s[ptr] == ' ')
 355             ++ptr; // skip ' ' after key=value
 356         mapping[key] = value;
 357     }
 358     return mapping;
 359 }
 360
 361 /** Read full contents of a file and return them in a std::string.
 362  * Returns a pair <status, string>.
 363  * If an error occurred, status will be false, otherwise status will be true and the data will be returned in string.
 364  *
 365  * @param maxsize Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data
 366  *         (with len > maxsize) will be returned.
 367  */
 368 static std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize=std::numeric_limits<size_t>::max())
 369 {
 370     FILE *f = fsbridge::fopen(filename, "rb");
 371     if (f == NULL)
 372         return std::make_pair(false,"");
 373     std::string retval;
 374     char buffer[128];
 375     size_t n;
 376     while ((n=fread(buffer, 1, sizeof(buffer), f)) > 0) {
 377         // Check for reading errors so we don't return any data if we couldn't
 378         // read the entire file (or up to maxsize)
 379         if (ferror(f)) {
 380             fclose(f);
 381             return std::make_pair(false,"");
 382         }
 383         retval.append(buffer, buffer+n);
 384         if (retval.size() > maxsize)
 385             break;
 386     }
 387     fclose(f);
 388     return std::make_pair(true,retval);
 389 }
 390
 391 /** Write contents of std::string to a file.
 392  * @return true on success.
 393  */
 394 static bool WriteBinaryFile(const fs::path &filename, const std::string &data)
 395 {
 396     FILE *f = fsbridge::fopen(filename, "wb");
 397     if (f == NULL)
 398         return false;
 399     if (fwrite(data.data(), 1, data.size(), f) != data.size()) {
 400         fclose(f);
 401         return false;
 402     }
 403     fclose(f);
 404     return true;
 405 }
 406
 407 /****** Bitcoin specific TorController implementation ********/
 408
 409 /** Controller that connects to Tor control socket, authenticate, then create
 410  * and maintain a ephemeral hidden service.
 411  */
 412 class TorController
 413 {
 414 public:
 415     TorController(struct event_base* base, const std::string& target);
 416     ~TorController();
 417
 418     /** Get name fo file to store private key in */
 419     fs::path GetPrivateKeyFile();
 420
 421     /** Reconnect, after getting disconnected */
 422     void Reconnect();
 423 private:
 424     struct event_base* base;
 425     std::string target;
 426     TorControlConnection conn;
 427     std::string private_key;
 428     std::string service_id;
 429     bool reconnect;
 430     struct event *reconnect_ev;
 431     float reconnect_timeout;
 432     CService service;
 433     /** Cookie for SAFECOOKIE auth */
 434     std::vector<uint8_t> cookie;
 435     /** ClientNonce for SAFECOOKIE auth */
 436     std::vector<uint8_t> clientNonce;
 437
 438     /** Callback for ADD_ONION result */
 439     void add_onion_cb(TorControlConnection& conn, const TorControlReply& reply);
 440     /** Callback for AUTHENTICATE result */
 441     void auth_cb(TorControlConnection& conn, const TorControlReply& reply);
 442     /** Callback for AUTHCHALLENGE result */
 443     void authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply);
 444     /** Callback for PROTOCOLINFO result */
 445     void protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply);
 446     /** Callback after successful connection */
 447     void connected_cb(TorControlConnection& conn);
 448     /** Callback after connection lost or failed connection attempt */
 449     void disconnected_cb(TorControlConnection& conn);
 450
 451     /** Callback for reconnect timer */
 452     static void reconnect_cb(evutil_socket_t fd, short what, void *arg);
 453 };
 454
 455 TorController::TorController(struct event_base* _base, const std::string& _target):
 456     base(_base),
 457     target(_target), conn(base), reconnect(true), reconnect_ev(0),
 458     reconnect_timeout(RECONNECT_TIMEOUT_START)
 459 {
 460     reconnect_ev = event_new(base, -1, 0, reconnect_cb, this);
 461     if (!reconnect_ev)
 462         LogPrintf("tor: Failed to create event for reconnection: out of memory?\n");
 463     // Start connection attempts immediately
 464     if (!conn.Connect(_target, boost::bind(&TorController::connected_cb, this, _1),
 465          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 466         LogPrintf("tor: Initiating connection to Tor control port %s failed\n", _target);
 467     }
 468     // Read service private key if cached
 469     std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
 470     if (pkf.first) {
 471         LogPrint(BCLog::TOR, "tor: Reading cached private key from %s\n", GetPrivateKeyFile().string());
 472         private_key = pkf.second;
 473     }
 474 }
 475
 476 TorController::~TorController()
 477 {
 478     if (reconnect_ev) {
 479         event_free(reconnect_ev);
 480         reconnect_ev = 0;
 481     }
 482     if (service.IsValid()) {
 483         RemoveLocal(service);
 484     }
 485 }
 486
 487 void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply)
 488 {
 489     if (reply.code == 250) {
 490         LogPrint(BCLog::TOR, "tor: ADD_ONION successful\n");
 491         for (const std::string &s : reply.lines) {
 492             std::map<std::string,std::string> m = ParseTorReplyMapping(s);
 493             std::map<std::string,std::string>::iterator i;
 494             if ((i = m.find("ServiceID")) != m.end())
 495                 service_id = i->second;
 496             if ((i = m.find("PrivateKey")) != m.end())
 497                 private_key = i->second;
 498         }
 499         if (service_id.empty()) {
 500             LogPrintf("tor: Error parsing ADD_ONION parameters:\n");
 501             for (const std::string &s : reply.lines) {
 502                 LogPrintf("    %s\n", SanitizeString(s));
 503             }
 504             return;
 505         }
 506         service = LookupNumeric(std::string(service_id+".onion").c_str(), GetListenPort());
 507         LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString());
 508         if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
 509             LogPrint(BCLog::TOR, "tor: Cached service private key to %s\n", GetPrivateKeyFile().string());
 510         } else {
 511             LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile().string());
 512         }
 513         AddLocal(service, LOCAL_MANUAL);
 514         // ... onion requested - keep connection open
 515     } else if (reply.code == 510) { // 510 Unrecognized command
 516         LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n");
 517     } else {
 518         LogPrintf("tor: Add onion failed; error code %d\n", reply.code);
 519     }
 520 }
 521
 522 void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply)
 523 {
 524     if (reply.code == 250) {
 525         LogPrint(BCLog::TOR, "tor: Authentication successful\n");
 526
 527         // Now that we know Tor is running setup the proxy for onion addresses
 528         // if -onion isn't set to something else.
 529         if (GetArg("-onion", "") == "") {
 530             CService resolved(LookupNumeric("127.0.0.1", 9050));
 531             proxyType addrOnion = proxyType(resolved, true);
 532             SetProxy(NET_TOR, addrOnion);
 533             SetLimited(NET_TOR, false);
 534         }
 535
 536         // Finally - now create the service
 537         if (private_key.empty()) // No private key, generate one
 538             private_key = "NEW:RSA1024"; // Explicitly request RSA1024 - see issue #9214
 539         // Request hidden service, redirect port.
 540         // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient
 541         // choice.  TODO; refactor the shutdown sequence some day.
 542         _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()),
 543             boost::bind(&TorController::add_onion_cb, this, _1, _2));
 544     } else {
 545         LogPrintf("tor: Authentication failed\n");
 546     }
 547 }
 548
 549 /** Compute Tor SAFECOOKIE response.
 550  *
 551  *    ServerHash is computed as:
 552  *      HMAC-SHA256("Tor safe cookie authentication server-to-controller hash",
 553  *                  CookieString | ClientNonce | ServerNonce)
 554  *    (with the HMAC key as its first argument)
 555  *
 556  *    After a controller sends a successful AUTHCHALLENGE command, the
 557  *    next command sent on the connection must be an AUTHENTICATE command,
 558  *    and the only authentication string which that AUTHENTICATE command
 559  *    will accept is:
 560  *
 561  *      HMAC-SHA256("Tor safe cookie authentication controller-to-server hash",
 562  *                  CookieString | ClientNonce | ServerNonce)
 563  *
 564  */
 565 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)
 566 {
 567     CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
 568     std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
 569     computeHash.Write(cookie.data(), cookie.size());
 570     computeHash.Write(clientNonce.data(), clientNonce.size());
 571     computeHash.Write(serverNonce.data(), serverNonce.size());
 572     computeHash.Finalize(computedHash.data());
 573     return computedHash;
 574 }
 575
 576 void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply)
 577 {
 578     if (reply.code == 250) {
 579         LogPrint(BCLog::TOR, "tor: SAFECOOKIE authentication challenge successful\n");
 580         std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
 581         if (l.first == "AUTHCHALLENGE") {
 582             std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 583             if (m.empty()) {
 584                 LogPrintf("tor: Error parsing AUTHCHALLENGE parameters: %s\n", SanitizeString(l.second));
 585                 return;
 586             }
 587             std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]);
 588             std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]);
 589             LogPrint(BCLog::TOR, "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce));
 590             if (serverNonce.size() != 32) {
 591                 LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n");
 592                 return;
 593             }
 594
 595             std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce);
 596             if (computedServerHash != serverHash) {
 597                 LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash));
 598                 return;
 599             }
 600
 601             std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce);
 602             _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), boost::bind(&TorController::auth_cb, this, _1, _2));
 603         } else {
 604             LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n");
 605         }
 606     } else {
 607         LogPrintf("tor: SAFECOOKIE authentication challenge failed\n");
 608     }
 609 }
 610
 611 void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply)
 612 {
 613     if (reply.code == 250) {
 614         std::set<std::string> methods;
 615         std::string cookiefile;
 616         /*
 617          * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie"
 618          * 250-AUTH METHODS=NULL
 619          * 250-AUTH METHODS=HASHEDPASSWORD
 620          */
 621         for (const std::string &s : reply.lines) {
 622             std::pair<std::string,std::string> l = SplitTorReplyLine(s);
 623             if (l.first == "AUTH") {
 624                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 625                 std::map<std::string,std::string>::iterator i;
 626                 if ((i = m.find("METHODS")) != m.end())
 627                     boost::split(methods, i->second, boost::is_any_of(","));
 628                 if ((i = m.find("COOKIEFILE")) != m.end())
 629                     cookiefile = i->second;
 630             } else if (l.first == "VERSION") {
 631                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 632                 std::map<std::string,std::string>::iterator i;
 633                 if ((i = m.find("Tor")) != m.end()) {
 634                     LogPrint(BCLog::TOR, "tor: Connected to Tor version %s\n", i->second);
 635                 }
 636             }
 637         }
 638         for (const std::string &s : methods) {
 639             LogPrint(BCLog::TOR, "tor: Supported authentication method: %s\n", s);
 640         }
 641         // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD
 642         /* Authentication:
 643          *   cookie:   hex-encoded ~/.tor/control_auth_cookie
 644          *   password: "password"
 645          */
 646         std::string torpassword = GetArg("-torpassword", "");
 647         if (!torpassword.empty()) {
 648             if (methods.count("HASHEDPASSWORD")) {
 649                 LogPrint(BCLog::TOR, "tor: Using HASHEDPASSWORD authentication\n");
 650                 boost::replace_all(torpassword, "\"", "\\\"");
 651                 _conn.Command("AUTHENTICATE \"" + torpassword + "\"", boost::bind(&TorController::auth_cb, this, _1, _2));
 652             } else {
 653                 LogPrintf("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available\n");
 654             }
 655         } else if (methods.count("NULL")) {
 656             LogPrint(BCLog::TOR, "tor: Using NULL authentication\n");
 657             _conn.Command("AUTHENTICATE", boost::bind(&TorController::auth_cb, this, _1, _2));
 658         } else if (methods.count("SAFECOOKIE")) {
 659             // Cookie: hexdump -e '32/1 "%02x""\n"'  ~/.tor/control_auth_cookie
 660             LogPrint(BCLog::TOR, "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile);
 661             std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE);
 662             if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
 663                 // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), boost::bind(&TorController::auth_cb, this, _1, _2));
 664                 cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
 665                 clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
 666                 GetRandBytes(&clientNonce[0], TOR_NONCE_SIZE);
 667                 _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), boost::bind(&TorController::authchallenge_cb, this, _1, _2));
 668             } else {
 669                 if (status_cookie.first) {
 670                     LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE);
 671                 } else {
 672                     LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile);
 673                 }
 674             }
 675         } else if (methods.count("HASHEDPASSWORD")) {
 676             LogPrintf("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword\n");
 677         } else {
 678             LogPrintf("tor: No supported authentication method\n");
 679         }
 680     } else {
 681         LogPrintf("tor: Requesting protocol info failed\n");
 682     }
 683 }
 684
 685 void TorController::connected_cb(TorControlConnection& _conn)
 686 {
 687     reconnect_timeout = RECONNECT_TIMEOUT_START;
 688     // First send a PROTOCOLINFO command to figure out what authentication is expected
 689     if (!_conn.Command("PROTOCOLINFO 1", boost::bind(&TorController::protocolinfo_cb, this, _1, _2)))
 690         LogPrintf("tor: Error sending initial protocolinfo command\n");
 691 }
 692
 693 void TorController::disconnected_cb(TorControlConnection& _conn)
 694 {
 695     // Stop advertising service when disconnected
 696     if (service.IsValid())
 697         RemoveLocal(service);
 698     service = CService();
 699     if (!reconnect)
 700         return;
 701
 702     LogPrint(BCLog::TOR, "tor: Not connected to Tor control port %s, trying to reconnect\n", target);
 703
 704     // Single-shot timer for reconnect. Use exponential backoff.
 705     struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0));
 706     if (reconnect_ev)
 707         event_add(reconnect_ev, &time);
 708     reconnect_timeout *= RECONNECT_TIMEOUT_EXP;
 709 }
 710
 711 void TorController::Reconnect()
 712 {
 713     /* Try to reconnect and reestablish if we get booted - for example, Tor
 714      * may be restarting.
 715      */
 716     if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1),
 717          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 718         LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target);
 719     }
 720 }
 721
 722 fs::path TorController::GetPrivateKeyFile()
 723 {
 724     return GetDataDir() / "onion_private_key";
 725 }
 726
 727 void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg)
 728 {
 729     TorController *self = (TorController*)arg;
 730     self->Reconnect();
 731 }
 732
 733 /****** Thread ********/
 734 static struct event_base *gBase;
 735 static boost::thread torControlThread;
 736
 737 static void TorControlThread()
 738 {
 739     TorController ctrl(gBase, GetArg("-torcontrol", DEFAULT_TOR_CONTROL));
 740
 741     event_base_dispatch(gBase);
 742 }
 743
 744 void StartTorControl(boost::thread_group& threadGroup, CScheduler& scheduler)
 745 {
 746     assert(!gBase);
 747 #ifdef WIN32
 748     evthread_use_windows_threads();
 749 #else
 750     evthread_use_pthreads();
 751 #endif
 752     gBase = event_base_new();
 753     if (!gBase) {
 754         LogPrintf("tor: Unable to create event_base\n");
 755         return;
 756     }
 757
 758     torControlThread = boost::thread(boost::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread));
 759 }
 760
 761 void InterruptTorControl()
 762 {
 763     if (gBase) {
 764         LogPrintf("tor: Thread interrupt\n");
 765         event_base_loopbreak(gBase);
 766     }
 767 }
 768
 769 void StopTorControl()
 770 {
 771     if (gBase) {
 772         torControlThread.join();
 773         event_base_free(gBase);
 774         gBase = 0;
 775     }
 776 }
 777