torcontrol.cpp raw
1 // Copyright (c) 2015-present 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
8 #include <chainparams.h>
9 #include <chainparamsbase.h>
10 #include <common/args.h>
11 #include <compat/compat.h>
12 #include <crypto/hmac_sha256.h>
13 #include <net.h>
14 #include <netaddress.h>
15 #include <netbase.h>
16 #include <random.h>
17 #include <tinyformat.h>
18 #include <util/check.h>
19 #include <util/fs.h>
20 #include <util/log.h>
21 #include <util/readwritefile.h>
22 #include <util/strencodings.h>
23 #include <util/string.h>
24 #include <util/thread.h>
25 #include <util/time.h>
26
27 #include <algorithm>
28 #include <cassert>
29 #include <chrono>
30 #include <cstdint>
31 #include <cstdlib>
32 #include <deque>
33 #include <functional>
34 #include <map>
35 #include <optional>
36 #include <set>
37 #include <thread>
38 #include <utility>
39 #include <vector>
40
41 using util::ReplaceAll;
42 using util::SplitString;
43 using util::ToString;
44
45 /** Default control ip and port */
46 const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:" + ToString(DEFAULT_TOR_CONTROL_PORT);
47 /** Tor cookie size (from control-spec.txt) */
48 constexpr int TOR_COOKIE_SIZE = 32;
49 /** Size of client/server nonce for SAFECOOKIE */
50 constexpr int TOR_NONCE_SIZE = 32;
51 /** For computing server_hash in SAFECOOKIE */
52 static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
53 /** For computing clientHash in SAFECOOKIE */
54 static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
55 /** Exponential backoff configuration - initial timeout in seconds */
56 constexpr std::chrono::duration<double> RECONNECT_TIMEOUT_START{1.0};
57 /** Exponential backoff configuration - growth factor */
58 constexpr double RECONNECT_TIMEOUT_EXP = 1.5;
59 /** Maximum reconnect timeout in seconds to prevent excessive delays */
60 constexpr std::chrono::duration<double> RECONNECT_TIMEOUT_MAX{600.0};
61 /** Maximum length for lines received on TorControlConnection.
62 * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
63 * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
64 */
65 constexpr int MAX_LINE_LENGTH = 100000;
66 /** Maximum number of lines received on TorControlConnection per reply to avoid
67 * memory exhaustion. The largest expected now is 5 (PROTOCOLINFO), but future
68 * changes to this file might need to re-evaluate MAX_LINE_COUNT.
69 */
70 constexpr int MAX_LINE_COUNT = 1000;
71 /** Timeout for socket operations */
72 constexpr auto SOCKET_SEND_TIMEOUT = 10s;
73
74 /****** Low-level TorControlConnection ********/
75
76 TorControlConnection::TorControlConnection(CThreadInterrupt& interrupt)
77 : m_interrupt(interrupt)
78 {
79 }
80
81 TorControlConnection::~TorControlConnection()
82 {
83 Disconnect();
84 }
85
86 bool TorControlConnection::Connect(const std::string& tor_control_center)
87 {
88 if (m_sock) {
89 Disconnect();
90 }
91
92 std::optional<CService> control_service = Lookup(tor_control_center, DEFAULT_TOR_CONTROL_PORT, fNameLookup);
93 if (!control_service.has_value()) {
94 LogWarning("tor: Failed to look up control center %s", tor_control_center);
95 return false;
96 }
97
98 m_sock = ConnectDirectly(control_service.value(), /*manual_connection=*/true);
99 if (!m_sock) {
100 LogWarning("tor: Error connecting to address %s", tor_control_center);
101 return false;
102 }
103
104 m_recv_buffer.clear();
105 m_message.Clear();
106 m_reply_handlers.clear();
107
108 LogDebug(BCLog::TOR, "Successfully connected to Tor control port");
109 return true;
110 }
111
112 void TorControlConnection::Disconnect()
113 {
114 m_sock.reset();
115 m_recv_buffer.clear();
116 m_message.Clear();
117 m_reply_handlers.clear();
118 }
119
120 bool TorControlConnection::IsConnected() const
121 {
122 if (!m_sock) return false;
123 std::string errmsg;
124 const bool connected{m_sock->IsConnected(errmsg)};
125 if (!connected && !errmsg.empty()) {
126 LogDebug(BCLog::TOR, "Connection check failed: %s", errmsg);
127 }
128 return connected;
129 }
130
131 bool TorControlConnection::WaitForData(std::chrono::milliseconds timeout)
132 {
133 if (!m_sock) return false;
134
135 Sock::Event event{0};
136 if (!m_sock->Wait(timeout, Sock::RecvEvent, &event)) {
137 return false;
138 }
139 if (event & Sock::ErrorEvent) {
140 LogDebug(BCLog::TOR, "Socket error detected");
141 Disconnect();
142 return false;
143 }
144
145 return (event & Sock::RecvEvent);
146 }
147
148 bool TorControlConnection::ReceiveAndProcess()
149 {
150 if (!m_sock) return false;
151
152 std::byte buf[4096];
153 ssize_t nread = m_sock->Recv(buf, sizeof(buf), MSG_DONTWAIT);
154
155 if (nread < 0) {
156 int err = WSAGetLastError();
157 if (err == WSAEWOULDBLOCK || err == WSAEINTR || err == WSAEINPROGRESS) {
158 // No data available currently
159 return true;
160 }
161 LogWarning("tor: Error reading from socket: %s", NetworkErrorString(err));
162 return false;
163 }
164
165 if (nread == 0) {
166 LogDebug(BCLog::TOR, "End of stream");
167 return false;
168 }
169
170 m_recv_buffer.insert(m_recv_buffer.end(), buf, buf + nread);
171 try {
172 return ProcessBuffer();
173 } catch (const std::runtime_error& e) {
174 LogWarning("tor: Error processing receive buffer: %s", e.what());
175 return false;
176 }
177 }
178
179 bool TorControlConnection::ProcessBuffer()
180 {
181 util::LineReader reader(m_recv_buffer, MAX_LINE_LENGTH);
182 auto start = reader.it;
183
184 while (auto line = reader.ReadLine()) {
185 if (m_message.lines.size() == MAX_LINE_COUNT) {
186 throw std::runtime_error(strprintf("Control port reply exceeded %d lines, disconnecting", MAX_LINE_COUNT));
187 }
188 // Skip short lines
189 if (line->size() < 4) continue;
190
191 // Parse: <code><separator><data>
192 // <status>(-|+| )<data>
193 m_message.code = ToIntegral<int>(line->substr(0, 3)).value_or(0);
194 m_message.lines.emplace_back(line->substr(4));
195 char separator = (*line)[3]; // '-', '+', or ' '
196
197 if (separator == ' ') {
198 if (m_message.code >= 600) {
199 // Async notifications are currently unused
200 // Synchronous and asynchronous messages are never interleaved
201 LogDebug(BCLog::TOR, "Received async notification %i", m_message.code);
202 } else if (!m_reply_handlers.empty()) {
203 // Invoke reply handler with message
204 m_reply_handlers.front()(*this, m_message);
205 m_reply_handlers.pop_front();
206 } else {
207 LogDebug(BCLog::TOR, "Received unexpected sync reply %i", m_message.code);
208 }
209 m_message.Clear();
210 }
211 }
212
213 m_recv_buffer.erase(m_recv_buffer.begin(), m_recv_buffer.begin() + std::distance(start, reader.it));
214 return true;
215 }
216
217 bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
218 {
219 if (!m_sock) return false;
220
221 std::string command = cmd + "\r\n";
222 try {
223 m_sock->SendComplete(std::span<const char>{command}, SOCKET_SEND_TIMEOUT, m_interrupt);
224 } catch (const std::runtime_error& e) {
225 LogWarning("tor: Error sending command: %s", e.what());
226 return false;
227 }
228
229 m_reply_handlers.push_back(reply_handler);
230 return true;
231 }
232
233 /****** General parsing utilities ********/
234
235 /* Split reply line in the form 'AUTH METHODS=...' into a type
236 * 'AUTH' and arguments 'METHODS=...'.
237 * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
238 * the server reply formats for PROTOCOLINFO (S3.21) and AUTHCHALLENGE (S3.24).
239 */
240 std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
241 {
242 size_t ptr=0;
243 std::string type;
244 while (ptr < s.size() && s[ptr] != ' ') {
245 type.push_back(s[ptr]);
246 ++ptr;
247 }
248 if (ptr < s.size())
249 ++ptr; // skip ' '
250 return make_pair(type, s.substr(ptr));
251 }
252
253 /** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'.
254 * Returns a map of keys to values, or an empty map if there was an error.
255 * Grammar is implicitly defined in https://spec.torproject.org/control-spec by
256 * the server reply formats for PROTOCOLINFO (S3.21), AUTHCHALLENGE (S3.24),
257 * and ADD_ONION (S3.27). See also sections 2.1 and 2.3.
258 */
259 std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
260 {
261 std::map<std::string,std::string> mapping;
262 size_t ptr=0;
263 while (ptr < s.size()) {
264 std::string key, value;
265 while (ptr < s.size() && s[ptr] != '=' && s[ptr] != ' ') {
266 key.push_back(s[ptr]);
267 ++ptr;
268 }
269 if (ptr == s.size()) // unexpected end of line
270 return std::map<std::string,std::string>();
271 if (s[ptr] == ' ') // The remaining string is an OptArguments
272 break;
273 ++ptr; // skip '='
274 if (ptr < s.size() && s[ptr] == '"') { // Quoted string
275 ++ptr; // skip opening '"'
276 bool escape_next = false;
277 while (ptr < s.size() && (escape_next || s[ptr] != '"')) {
278 // Repeated backslashes must be interpreted as pairs
279 escape_next = (s[ptr] == '\\' && !escape_next);
280 value.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 ++ptr; // skip closing '"'
286 /**
287 * Unescape value. Per https://spec.torproject.org/control-spec section 2.1.1:
288 *
289 * For future-proofing, controller implementers MAY use the following
290 * rules to be compatible with buggy Tor implementations and with
291 * future ones that implement the spec as intended:
292 *
293 * Read \n \t \r and \0 ... \377 as C escapes.
294 * Treat a backslash followed by any other character as that character.
295 */
296 std::string escaped_value;
297 for (size_t i = 0; i < value.size(); ++i) {
298 if (value[i] == '\\') {
299 // This will always be valid, because if the QuotedString
300 // ended in an odd number of backslashes, then the parser
301 // would already have returned above, due to a missing
302 // terminating double-quote.
303 ++i;
304 if (value[i] == 'n') {
305 escaped_value.push_back('\n');
306 } else if (value[i] == 't') {
307 escaped_value.push_back('\t');
308 } else if (value[i] == 'r') {
309 escaped_value.push_back('\r');
310 } else if ('0' <= value[i] && value[i] <= '7') {
311 size_t j;
312 // Octal escape sequences have a limit of three octal digits,
313 // but terminate at the first character that is not a valid
314 // octal digit if encountered sooner.
315 for (j = 1; j < 3 && (i+j) < value.size() && '0' <= value[i+j] && value[i+j] <= '7'; ++j) {}
316 // Tor restricts first digit to 0-3 for three-digit octals.
317 // A leading digit of 4-7 would therefore be interpreted as
318 // a two-digit octal.
319 if (j == 3 && value[i] > '3') {
320 j--;
321 }
322 const auto end{i + j};
323 uint8_t val{0};
324 while (i < end) {
325 val *= 8;
326 val += value[i++] - '0';
327 }
328 escaped_value.push_back(char(val));
329 // Account for automatic incrementing at loop end
330 --i;
331 } else {
332 escaped_value.push_back(value[i]);
333 }
334 } else {
335 escaped_value.push_back(value[i]);
336 }
337 }
338 value = escaped_value;
339 } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
340 while (ptr < s.size() && s[ptr] != ' ') {
341 value.push_back(s[ptr]);
342 ++ptr;
343 }
344 }
345 if (ptr < s.size() && s[ptr] == ' ')
346 ++ptr; // skip ' ' after key=value
347 mapping[key] = value;
348 }
349 return mapping;
350 }
351
352 TorController::TorController(const std::string& tor_control_center, const CService& target)
353 : m_tor_control_center(tor_control_center),
354 m_conn(m_interrupt),
355 m_reconnect(true),
356 m_reconnect_timeout(RECONNECT_TIMEOUT_START),
357 m_target(target)
358 {
359 // Read service private key if cached
360 std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
361 if (pkf.first) {
362 LogDebug(BCLog::TOR, "Reading cached private key from %s", fs::PathToString(GetPrivateKeyFile()));
363 m_private_key = pkf.second;
364 }
365 m_thread = std::thread(&util::TraceThread, "torcontrol", [this] { ThreadControl(); });
366 }
367
368 TorController::~TorController()
369 {
370 Interrupt();
371 Join();
372 if (m_service.IsValid()) {
373 RemoveLocal(m_service);
374 }
375 }
376
377 void TorController::Interrupt()
378 {
379 m_reconnect = false;
380 m_interrupt();
381 }
382
383 void TorController::Join()
384 {
385 if (m_thread.joinable()) {
386 m_thread.join();
387 }
388 }
389
390 void TorController::ThreadControl()
391 {
392 LogDebug(BCLog::TOR, "Entering Tor control thread");
393
394 while (!m_interrupt) {
395 // Try to connect if not connected already
396 if (!m_conn.IsConnected()) {
397 LogDebug(BCLog::TOR, "Attempting to connect to Tor control port %s", m_tor_control_center);
398
399 if (!m_conn.Connect(m_tor_control_center)) {
400 LogWarning("tor: Initiating connection to Tor control port %s failed", m_tor_control_center);
401 if (!m_reconnect) {
402 break;
403 }
404 // Wait before retrying with exponential backoff
405 LogDebug(BCLog::TOR, "Retrying in %.1f seconds", m_reconnect_timeout.count());
406 if (!m_interrupt.sleep_for(std::chrono::duration_cast<std::chrono::milliseconds>(m_reconnect_timeout))) {
407 break;
408 }
409 m_reconnect_timeout = std::min(m_reconnect_timeout * RECONNECT_TIMEOUT_EXP, RECONNECT_TIMEOUT_MAX);
410 continue;
411 }
412 // Successfully connected, reset timeout and trigger connected callback
413 m_reconnect_timeout = RECONNECT_TIMEOUT_START;
414 connected_cb(m_conn);
415 }
416 // Wait for data with a timeout
417 if (!m_conn.WaitForData(std::chrono::seconds(1))) {
418 // Check if still connected
419 if (!m_conn.IsConnected()) {
420 LogDebug(BCLog::TOR, "Lost connection to Tor control port");
421 disconnected_cb(m_conn);
422 continue;
423 }
424 // Just a timeout, continue waiting
425 continue;
426 }
427 // Process incoming data
428 if (!m_conn.ReceiveAndProcess()) {
429 disconnected_cb(m_conn);
430 }
431 }
432 LogDebug(BCLog::TOR, "Exited Tor control thread");
433 }
434
435 void TorController::get_socks_cb(TorControlConnection& _conn, const TorControlReply& reply)
436 {
437 // NOTE: We can only get here if -onion is unset
438 std::string socks_location;
439 if (reply.code == TOR_REPLY_OK) {
440 for (const auto& line : reply.lines) {
441 if (line.starts_with("net/listeners/socks=")) {
442 const std::string port_list_str = line.substr(20);
443 std::vector<std::string> port_list = SplitString(port_list_str, ' ');
444
445 for (auto& portstr : port_list) {
446 if (portstr.empty()) continue;
447 if ((portstr[0] == '"' || portstr[0] == '\'') && portstr.size() >= 2 && (*portstr.rbegin() == portstr[0])) {
448 portstr = portstr.substr(1, portstr.size() - 2);
449 if (portstr.empty()) continue;
450 }
451 socks_location = portstr;
452 if (portstr.starts_with("127.0.0.1:")) {
453 // Prefer localhost - ignore other ports
454 break;
455 }
456 }
457 }
458 }
459 if (!socks_location.empty()) {
460 LogDebug(BCLog::TOR, "Get SOCKS port command yielded %s", socks_location);
461 } else {
462 LogWarning("tor: Get SOCKS port command returned nothing");
463 }
464 } else if (reply.code == TOR_REPLY_UNRECOGNIZED) {
465 LogWarning("tor: Get SOCKS port command failed with unrecognized command (You probably should upgrade Tor)");
466 } else {
467 LogWarning("tor: Get SOCKS port command failed; error code %d", reply.code);
468 }
469
470 CService resolved;
471 Assume(!resolved.IsValid());
472 if (!socks_location.empty()) {
473 resolved = LookupNumeric(socks_location, DEFAULT_TOR_SOCKS_PORT);
474 }
475 if (!resolved.IsValid()) {
476 // Fallback to old behaviour
477 resolved = LookupNumeric("127.0.0.1", DEFAULT_TOR_SOCKS_PORT);
478 }
479
480 Assume(resolved.IsValid());
481 LogDebug(BCLog::TOR, "Configuring onion proxy for %s", resolved.ToStringAddrPort());
482
483 // Add Tor as proxy for .onion addresses.
484 // Enable stream isolation to prevent connection correlation and enhance privacy, by forcing a different Tor circuit for every connection.
485 // For this to work, the IsolateSOCKSAuth flag must be enabled on SOCKSPort (which is the default, see the IsolateSOCKSAuth section of Tor's manual page).
486 Proxy addrOnion = Proxy(resolved, /*tor_stream_isolation=*/ true);
487 SetProxy(NET_ONION, addrOnion);
488
489 const auto onlynets = gArgs.GetArgs("-onlynet");
490
491 const bool onion_allowed_by_onlynet{
492 onlynets.empty() ||
493 std::any_of(onlynets.begin(), onlynets.end(), [](const auto& n) {
494 return ParseNetwork(n) == NET_ONION;
495 })};
496
497 if (onion_allowed_by_onlynet) {
498 // If NET_ONION is reachable, then the below is a noop.
499 //
500 // If NET_ONION is not reachable, then none of -proxy or -onion was given.
501 // Since we are here, then -torcontrol and -torpassword were given.
502 g_reachable_nets.Add(NET_ONION);
503 }
504 }
505
506 static std::string MakeAddOnionCmd(const std::string& private_key, const std::string& target, bool enable_pow)
507 {
508 // Note that the 'virtual' port is always the default port to avoid decloaking nodes using other ports.
509 return strprintf("ADD_ONION %s%s Port=%i,%s",
510 private_key,
511 enable_pow ? " PoWDefensesEnabled=1" : "",
512 Params().GetDefaultPort(),
513 target);
514 }
515
516 void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply, bool pow_was_enabled)
517 {
518 if (reply.code == TOR_REPLY_OK) {
519 LogDebug(BCLog::TOR, "ADD_ONION successful (PoW defenses %s)", pow_was_enabled ? "enabled" : "disabled");
520 for (const std::string &s : reply.lines) {
521 std::map<std::string,std::string> m = ParseTorReplyMapping(s);
522 std::map<std::string,std::string>::iterator i;
523 if ((i = m.find("ServiceID")) != m.end())
524 m_service_id = i->second;
525 if ((i = m.find("PrivateKey")) != m.end())
526 m_private_key = i->second;
527 }
528 if (m_service_id.empty()) {
529 LogWarning("tor: Error parsing ADD_ONION parameters:");
530 for (const std::string &s : reply.lines) {
531 LogWarning(" %s", SanitizeString(s));
532 }
533 return;
534 }
535 m_service = LookupNumeric(std::string(m_service_id+".onion"), Params().GetDefaultPort());
536 LogInfo("Got tor service ID %s, advertising service %s", m_service_id, m_service.ToStringAddrPort());
537 if (WriteBinaryFile(GetPrivateKeyFile(), m_private_key)) {
538 LogDebug(BCLog::TOR, "Cached service private key to %s", fs::PathToString(GetPrivateKeyFile()));
539 } else {
540 LogWarning("tor: Error writing service private key to %s", fs::PathToString(GetPrivateKeyFile()));
541 }
542 AddLocal(m_service, LOCAL_MANUAL);
543 // ... onion requested - keep connection open
544 } else if (reply.code == TOR_REPLY_UNRECOGNIZED) {
545 LogWarning("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)");
546 } else if (pow_was_enabled && reply.code == TOR_REPLY_SYNTAX_ERROR) {
547 LogDebug(BCLog::TOR, "ADD_ONION failed with PoW defenses, retrying without");
548 _conn.Command(MakeAddOnionCmd(m_private_key, m_target.ToStringAddrPort(), /*enable_pow=*/false),
549 [this](TorControlConnection& conn, const TorControlReply& reply) {
550 add_onion_cb(conn, reply, /*pow_was_enabled=*/false);
551 });
552 } else {
553 LogWarning("tor: Add onion failed; error code %d", reply.code);
554 }
555 }
556
557 void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply)
558 {
559 if (reply.code == TOR_REPLY_OK) {
560 LogDebug(BCLog::TOR, "Authentication successful");
561
562 // Now that we know Tor is running setup the proxy for onion addresses
563 // if -onion isn't set to something else.
564 if (gArgs.GetArg("-onion", "") == "") {
565 _conn.Command("GETINFO net/listeners/socks", std::bind_front(&TorController::get_socks_cb, this));
566 }
567
568 // Finally - now create the service
569 if (m_private_key.empty()) { // No private key, generate one
570 m_private_key = "NEW:ED25519-V3"; // Explicitly request key type - see issue #9214
571 }
572 // Request onion service, redirect port.
573 _conn.Command(MakeAddOnionCmd(m_private_key, m_target.ToStringAddrPort(), /*enable_pow=*/true),
574 [this](TorControlConnection& conn, const TorControlReply& reply) {
575 add_onion_cb(conn, reply, /*pow_was_enabled=*/true);
576 });
577 } else {
578 LogWarning("tor: Authentication failed");
579 }
580 }
581
582 /** Compute Tor SAFECOOKIE response.
583 *
584 * ServerHash is computed as:
585 * HMAC-SHA256("Tor safe cookie authentication server-to-controller hash",
586 * CookieString | ClientNonce | ServerNonce)
587 * (with the HMAC key as its first argument)
588 *
589 * After a controller sends a successful AUTHCHALLENGE command, the
590 * next command sent on the connection must be an AUTHENTICATE command,
591 * and the only authentication string which that AUTHENTICATE command
592 * will accept is:
593 *
594 * HMAC-SHA256("Tor safe cookie authentication controller-to-server hash",
595 * CookieString | ClientNonce | ServerNonce)
596 *
597 */
598 static std::vector<uint8_t> ComputeResponse(std::string_view key, std::span<const uint8_t> cookie, std::span<const uint8_t> client_nonce, std::span<const uint8_t> server_nonce)
599 {
600 CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
601 std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
602 computeHash.Write(cookie.data(), cookie.size());
603 computeHash.Write(client_nonce.data(), client_nonce.size());
604 computeHash.Write(server_nonce.data(), server_nonce.size());
605 computeHash.Finalize(computedHash.data());
606 return computedHash;
607 }
608
609 void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply)
610 {
611 if (reply.code == TOR_REPLY_OK) {
612 LogDebug(BCLog::TOR, "SAFECOOKIE authentication challenge successful");
613 if (reply.lines.empty()) {
614 LogWarning("tor: AUTHCHALLENGE reply was empty");
615 return;
616 }
617 std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
618 if (l.first == "AUTHCHALLENGE") {
619 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
620 if (m.empty()) {
621 LogWarning("tor: Error parsing AUTHCHALLENGE parameters: %s", SanitizeString(l.second));
622 return;
623 }
624 std::vector<uint8_t> server_hash = ParseHex(m["SERVERHASH"]);
625 std::vector<uint8_t> server_nonce = ParseHex(m["SERVERNONCE"]);
626 LogDebug(BCLog::TOR, "AUTHCHALLENGE ServerHash %s ServerNonce %s", HexStr(server_hash), HexStr(server_nonce));
627 if (server_nonce.size() != 32) {
628 LogWarning("tor: ServerNonce is not 32 bytes, as required by spec");
629 return;
630 }
631
632 std::vector<uint8_t> computed_server_hash = ComputeResponse(TOR_SAFE_SERVERKEY, m_cookie, m_client_nonce, server_nonce);
633 if (computed_server_hash != server_hash) {
634 LogWarning("tor: ServerHash %s does not match expected ServerHash %s", HexStr(server_hash), HexStr(computed_server_hash));
635 return;
636 }
637
638 std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, m_cookie, m_client_nonce, server_nonce);
639 _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), std::bind_front(&TorController::auth_cb, this));
640 } else {
641 LogWarning("tor: Invalid reply to AUTHCHALLENGE");
642 }
643 } else {
644 LogWarning("tor: SAFECOOKIE authentication challenge failed");
645 }
646 }
647
648 void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply)
649 {
650 if (reply.code == TOR_REPLY_OK) {
651 std::set<std::string> methods;
652 std::string cookiefile;
653 /*
654 * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie"
655 * 250-AUTH METHODS=NULL
656 * 250-AUTH METHODS=HASHEDPASSWORD
657 */
658 for (const std::string &s : reply.lines) {
659 std::pair<std::string,std::string> l = SplitTorReplyLine(s);
660 if (l.first == "AUTH") {
661 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
662 std::map<std::string,std::string>::iterator i;
663 if ((i = m.find("METHODS")) != m.end()) {
664 std::vector<std::string> m_vec = SplitString(i->second, ',');
665 methods = std::set<std::string>(m_vec.begin(), m_vec.end());
666 }
667 if ((i = m.find("COOKIEFILE")) != m.end())
668 cookiefile = i->second;
669 } else if (l.first == "VERSION") {
670 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
671 std::map<std::string,std::string>::iterator i;
672 if ((i = m.find("Tor")) != m.end()) {
673 LogDebug(BCLog::TOR, "Connected to Tor version %s", i->second);
674 }
675 }
676 }
677 for (const std::string &s : methods) {
678 LogDebug(BCLog::TOR, "Supported authentication method: %s", s);
679 }
680 // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD
681 /* Authentication:
682 * cookie: hex-encoded ~/.tor/control_auth_cookie
683 * password: "password"
684 */
685 std::string torpassword = gArgs.GetArg("-torpassword", "");
686 if (!torpassword.empty()) {
687 if (methods.contains("HASHEDPASSWORD")) {
688 LogDebug(BCLog::TOR, "Using HASHEDPASSWORD authentication");
689 ReplaceAll(torpassword, "\"", "\\\"");
690 _conn.Command("AUTHENTICATE \"" + torpassword + "\"", std::bind_front(&TorController::auth_cb, this));
691 } else {
692 LogWarning("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available");
693 }
694 } else if (methods.contains("NULL")) {
695 LogDebug(BCLog::TOR, "Using NULL authentication");
696 _conn.Command("AUTHENTICATE", std::bind_front(&TorController::auth_cb, this));
697 } else if (methods.contains("SAFECOOKIE")) {
698 // Cookie: hexdump -e '32/1 "%02x""\n"' ~/.tor/control_auth_cookie
699 LogDebug(BCLog::TOR, "Using SAFECOOKIE authentication, reading cookie authentication from %s", cookiefile);
700 std::pair<bool,std::string> status_cookie = ReadBinaryFile(fs::PathFromString(cookiefile), TOR_COOKIE_SIZE);
701 if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
702 // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), std::bind_front(&TorController::auth_cb, this));
703 m_cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
704 m_client_nonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
705 GetRandBytes(m_client_nonce);
706 _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(m_client_nonce), std::bind_front(&TorController::authchallenge_cb, this));
707 } else {
708 if (status_cookie.first) {
709 LogWarning("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec", cookiefile, TOR_COOKIE_SIZE);
710 } else {
711 LogWarning("tor: Authentication cookie %s could not be opened (check permissions)", cookiefile);
712 }
713 }
714 } else if (methods.contains("HASHEDPASSWORD")) {
715 LogWarning("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword");
716 } else {
717 LogWarning("tor: No supported authentication method");
718 }
719 } else {
720 LogWarning("tor: Requesting protocol info failed");
721 }
722 }
723
724 void TorController::connected_cb(TorControlConnection& _conn)
725 {
726 m_reconnect_timeout = RECONNECT_TIMEOUT_START;
727 // First send a PROTOCOLINFO command to figure out what authentication is expected
728 if (!_conn.Command("PROTOCOLINFO 1", std::bind_front(&TorController::protocolinfo_cb, this)))
729 LogWarning("tor: Error sending initial protocolinfo command");
730 }
731
732 void TorController::disconnected_cb(TorControlConnection& _conn)
733 {
734 // Stop advertising service when disconnected
735 if (m_service.IsValid())
736 RemoveLocal(m_service);
737 m_service = CService();
738 if (!m_reconnect)
739 return;
740
741 LogDebug(BCLog::TOR, "Not connected to Tor control port %s, will retry", m_tor_control_center);
742 _conn.Disconnect();
743 }
744
745 fs::path TorController::GetPrivateKeyFile()
746 {
747 return gArgs.GetDataDirNet() / "onion_v3_private_key";
748 }
749
750 CService DefaultOnionServiceTarget(uint16_t port)
751 {
752 struct in_addr onion_service_target;
753 onion_service_target.s_addr = htonl(INADDR_LOOPBACK);
754 return {onion_service_target, port};
755 }
756