Line data Source code
1 : // Copyright (c) 2015-2016 The Bitcoin Core developers
2 : // Copyright (c) 2017 The Zcash developers
3 : // Copyright (c) 2017-2022 The PIVX Core developers
4 : // Distributed under the MIT software license, see the accompanying
5 : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
6 :
7 : #include "torcontrol.h"
8 :
9 : #include "chainparams.h"
10 : #include "utilstrencodings.h"
11 : #include "netbase.h"
12 : #include "net.h"
13 : #include "util/system.h"
14 : #include "crypto/hmac_sha256.h"
15 :
16 : #include <vector>
17 : #include <deque>
18 : #include <set>
19 : #include <stdlib.h>
20 :
21 : #include <boost/signals2/signal.hpp>
22 : #include <boost/algorithm/string/split.hpp>
23 : #include <boost/algorithm/string/classification.hpp>
24 : #include <boost/algorithm/string/replace.hpp>
25 :
26 : #include <event2/bufferevent.h>
27 : #include <event2/buffer.h>
28 : #include <event2/util.h>
29 : #include <event2/event.h>
30 : #include <event2/thread.h>
31 :
32 : /** Default control port */
33 : const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051";
34 : /** Tor cookie size (from control-spec.txt) */
35 : static const int TOR_COOKIE_SIZE = 32;
36 : /** Size of client/server nonce for SAFECOOKIE */
37 : static const int TOR_NONCE_SIZE = 32;
38 : /** For computing serverHash in SAFECOOKIE */
39 : static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
40 : /** For computing clientHash in SAFECOOKIE */
41 : static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
42 : /** Exponential backoff configuration - initial timeout in seconds */
43 : static const float RECONNECT_TIMEOUT_START = 1.0;
44 : /** Exponential backoff configuration - growth factor */
45 : static const float RECONNECT_TIMEOUT_EXP = 1.5;
46 : /** Maximum length for lines received on TorControlConnection.
47 : * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
48 : * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
49 : */
50 : static const int MAX_LINE_LENGTH = 100000;
51 :
52 : /****** Low-level TorControlConnection ********/
53 :
54 : /** Reply from Tor, can be single or multi-line */
55 0 : class TorControlReply
56 : {
57 : public:
58 0 : TorControlReply() { Clear(); }
59 :
60 : int code;
61 : std::vector<std::string> lines;
62 :
63 0 : void Clear()
64 : {
65 0 : code = 0;
66 0 : lines.clear();
67 0 : }
68 : };
69 :
70 : /** Low-level handling for Tor control connection.
71 : * Speaks the SMTP-like protocol as defined in torspec/control-spec.txt
72 : */
73 : class TorControlConnection
74 : {
75 : public:
76 : typedef std::function<void(TorControlConnection&)> ConnectionCB;
77 : typedef std::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
78 :
79 : /** Create a new TorControlConnection.
80 : */
81 : explicit TorControlConnection(struct event_base *base);
82 : ~TorControlConnection();
83 :
84 : /**
85 : * Connect to a Tor control port.
86 : * target is address of the form host:port.
87 : * connected is the handler that is called when connection is successfully established.
88 : * disconnected is a handler that is called when the connection is broken.
89 : * Return true on success.
90 : */
91 : bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected);
92 :
93 : /**
94 : * Disconnect from Tor control port.
95 : */
96 : void Disconnect();
97 :
98 : /** Send a command, register a handler for the reply.
99 : * A trailing CRLF is automatically added.
100 : * Return true on success.
101 : */
102 : bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler);
103 :
104 : /** Response handlers for async replies */
105 : boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler;
106 : private:
107 : /** Callback when ready for use */
108 : std::function<void(TorControlConnection&)> connected;
109 : /** Callback when connection lost */
110 : std::function<void(TorControlConnection&)> disconnected;
111 : /** Libevent event base */
112 : struct event_base *base;
113 : /** Connection to control socket */
114 : struct bufferevent *b_conn;
115 : /** Message being received */
116 : TorControlReply message;
117 : /** Response handlers */
118 : std::deque<ReplyHandlerCB> reply_handlers;
119 :
120 : /** Libevent handlers: internal */
121 : static void readcb(struct bufferevent *bev, void *ctx);
122 : static void eventcb(struct bufferevent *bev, short what, void *ctx);
123 : };
124 :
125 0 : TorControlConnection::TorControlConnection(struct event_base *_base):
126 0 : base(_base), b_conn(nullptr)
127 : {
128 0 : }
129 :
130 0 : TorControlConnection::~TorControlConnection()
131 : {
132 0 : if (b_conn)
133 0 : bufferevent_free(b_conn);
134 0 : }
135 :
136 0 : void TorControlConnection::readcb(struct bufferevent *bev, void *ctx)
137 : {
138 0 : TorControlConnection *self = static_cast<TorControlConnection*>(ctx);
139 0 : struct evbuffer *input = bufferevent_get_input(bev);
140 0 : size_t n_read_out = 0;
141 0 : char *line;
142 0 : assert(input);
143 : // If there is not a whole line to read, evbuffer_readln returns nullptr
144 0 : while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != nullptr)
145 : {
146 0 : std::string s(line, n_read_out);
147 0 : free(line);
148 0 : if (s.size() < 4) // Short line
149 0 : continue;
150 : // <status>(-|+| )<data><CRLF>
151 0 : self->message.code = atoi(s.substr(0,3));
152 0 : self->message.lines.push_back(s.substr(4));
153 0 : char ch = s[3]; // '-','+' or ' '
154 0 : if (ch == ' ') {
155 : // Final line, dispatch reply and clean up
156 0 : if (self->message.code >= 600) {
157 : // Dispatch async notifications to async handler
158 : // Synchronous and asynchronous messages are never interleaved
159 0 : self->async_handler(*self, self->message);
160 : } else {
161 0 : if (!self->reply_handlers.empty()) {
162 : // Invoke reply handler with message
163 0 : self->reply_handlers.front()(*self, self->message);
164 0 : self->reply_handlers.pop_front();
165 : } else {
166 0 : LogPrint(BCLog::TOR, "tor: Received unexpected sync reply %i\n", self->message.code);
167 : }
168 : }
169 0 : self->message.Clear();
170 : }
171 : }
172 : // Check for size of buffer - protect against memory exhaustion with very long lines
173 : // Do this after evbuffer_readln to make sure all full lines have been
174 : // removed from the buffer. Everything left is an incomplete line.
175 0 : if (evbuffer_get_length(input) > MAX_LINE_LENGTH) {
176 0 : LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n");
177 0 : self->Disconnect();
178 : }
179 0 : }
180 :
181 0 : void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx)
182 : {
183 0 : TorControlConnection *self = static_cast<TorControlConnection*>(ctx);
184 0 : if (what & BEV_EVENT_CONNECTED) {
185 0 : LogPrint(BCLog::TOR, "tor: Successfully connected!\n");
186 0 : self->connected(*self);
187 0 : } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
188 0 : if (what & BEV_EVENT_ERROR) {
189 0 : LogPrint(BCLog::TOR, "tor: Error connecting to Tor control socket\n");
190 : } else {
191 0 : LogPrint(BCLog::TOR, "tor: End of stream\n");
192 : }
193 0 : self->Disconnect();
194 0 : self->disconnected(*self);
195 : }
196 0 : }
197 :
198 0 : bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& _connected, const ConnectionCB& _disconnected)
199 : {
200 0 : if (b_conn)
201 0 : Disconnect();
202 : // Parse target address:port
203 0 : struct sockaddr_storage connect_to_addr;
204 0 : int connect_to_addrlen = sizeof(connect_to_addr);
205 0 : if (evutil_parse_sockaddr_port(target.c_str(),
206 : (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) {
207 0 : LogPrintf("tor: Error parsing socket address %s\n", target);
208 0 : return false;
209 : }
210 :
211 : // Create a new socket, set up callbacks and enable notification bits
212 0 : b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
213 0 : if (!b_conn)
214 : return false;
215 0 : bufferevent_setcb(b_conn, TorControlConnection::readcb, nullptr, TorControlConnection::eventcb, this);
216 0 : bufferevent_enable(b_conn, EV_READ|EV_WRITE);
217 0 : this->connected = _connected;
218 0 : this->disconnected = _disconnected;
219 :
220 : // Finally, connect to target
221 0 : if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) {
222 0 : LogPrintf("tor: Error connecting to address %s\n", target);
223 0 : return false;
224 : }
225 : return true;
226 : }
227 :
228 0 : void TorControlConnection::Disconnect()
229 : {
230 0 : if (b_conn)
231 0 : bufferevent_free(b_conn);
232 0 : b_conn = nullptr;
233 0 : }
234 :
235 0 : bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
236 : {
237 0 : if (!b_conn)
238 : return false;
239 0 : struct evbuffer *buf = bufferevent_get_output(b_conn);
240 0 : if (!buf)
241 : return false;
242 0 : evbuffer_add(buf, cmd.data(), cmd.size());
243 0 : evbuffer_add(buf, "\r\n", 2);
244 0 : reply_handlers.push_back(reply_handler);
245 0 : 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 10 : std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
256 : {
257 10 : size_t ptr=0;
258 10 : std::string type;
259 82 : while (ptr < s.size() && s[ptr] != ' ') {
260 72 : type.push_back(s[ptr]);
261 72 : ++ptr;
262 : }
263 10 : if (ptr < s.size())
264 9 : ++ptr; // skip ' '
265 20 : 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 27 : std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
275 : {
276 54 : std::map<std::string,std::string> mapping;
277 27 : size_t ptr=0;
278 58 : while (ptr < s.size()) {
279 69 : std::string key, value;
280 246 : while (ptr < s.size() && s[ptr] != '=' && s[ptr] != ' ') {
281 208 : key.push_back(s[ptr]);
282 208 : ++ptr;
283 : }
284 38 : if (ptr == s.size()) // unexpected end of line
285 2 : return std::map<std::string,std::string>();
286 37 : if (s[ptr] == ' ') // The remaining string is an OptArguments
287 : break;
288 32 : ++ptr; // skip '='
289 32 : if (ptr < s.size() && s[ptr] == '"') { // Quoted string
290 18 : ++ptr; // skip opening '"'
291 18 : bool escape_next = false;
292 224 : while (ptr < s.size() && (escape_next || s[ptr] != '"')) {
293 : // Repeated backslashes must be interpreted as pairs
294 206 : escape_next = (s[ptr] == '\\' && !escape_next);
295 206 : value.push_back(s[ptr]);
296 206 : ++ptr;
297 : }
298 18 : if (ptr == s.size()) // unexpected end of line
299 1 : return std::map<std::string,std::string>();
300 17 : ++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 34 : std::string escaped_value;
312 183 : for (size_t i = 0; i < value.size(); ++i) {
313 166 : 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 23 : ++i;
319 23 : if (value[i] == 'n') {
320 1 : escaped_value.push_back('\n');
321 22 : } else if (value[i] == 't') {
322 1 : escaped_value.push_back('\t');
323 21 : } else if (value[i] == 'r') {
324 1 : escaped_value.push_back('\r');
325 20 : } 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 21 : 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 11 : if (j == 3 && value[i] > '3') {
335 1 : j--;
336 : }
337 11 : escaped_value.push_back(strtol(value.substr(i, j).c_str(), nullptr, 8));
338 : // Account for automatic incrementing at loop end
339 11 : i += j - 1;
340 : } else {
341 9 : escaped_value.push_back(value[i]);
342 : }
343 : } else {
344 143 : escaped_value.push_back(value[i]);
345 : }
346 : }
347 17 : value = escaped_value;
348 : } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
349 132 : while (ptr < s.size() && s[ptr] != ' ') {
350 118 : value.push_back(s[ptr]);
351 118 : ++ptr;
352 : }
353 : }
354 31 : if (ptr < s.size() && s[ptr] == ' ')
355 11 : ++ptr; // skip ' ' after key=value
356 31 : mapping[key] = value;
357 : }
358 52 : return mapping;
359 : }
360 :
361 : /** Read full contents of a file and return them in a std::string.
362 : * Returns a pair <status, std::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 0 : static std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize=std::numeric_limits<size_t>::max())
369 : {
370 0 : FILE *f = fsbridge::fopen(filename, "rb");
371 0 : if (f == nullptr)
372 0 : return std::make_pair(false,"");
373 0 : std::string retval;
374 0 : char buffer[128];
375 0 : size_t n;
376 0 : 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 0 : if (ferror(f)) {
380 0 : fclose(f);
381 0 : return std::make_pair(false,"");
382 : }
383 0 : retval.append(buffer, buffer+n);
384 0 : if (retval.size() > maxsize)
385 : break;
386 : }
387 0 : fclose(f);
388 0 : return std::make_pair(true,retval);
389 : }
390 :
391 : /** Write contents of std::string to a file.
392 : * @return true on success.
393 : */
394 0 : static bool WriteBinaryFile(const fs::path &filename, const std::string &data)
395 : {
396 0 : FILE *f = fsbridge::fopen(filename, "wb");
397 0 : if (f == nullptr)
398 : return false;
399 0 : if (fwrite(data.data(), 1, data.size(), f) != data.size()) {
400 0 : fclose(f);
401 0 : return false;
402 : }
403 0 : fclose(f);
404 0 : return true;
405 : }
406 :
407 : /****** Bitcoin specific TorController implementation ********/
408 :
409 : /** Controller that connects to Tor control socket, authenticate, then create
410 : * and maintain an ephemeral onion service.
411 : */
412 : class TorController
413 : {
414 : public:
415 : TorController(struct event_base* base, const std::string& target);
416 : ~TorController();
417 :
418 : /** Get name of 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 0 : TorController::TorController(struct event_base* _base, const std::string& _target):
456 : base(_base),
457 : target(_target), conn(base), reconnect(true), reconnect_ev(0),
458 0 : reconnect_timeout(RECONNECT_TIMEOUT_START)
459 : {
460 0 : reconnect_ev = event_new(base, -1, 0, reconnect_cb, this);
461 0 : if (!reconnect_ev)
462 0 : LogPrintf("tor: Failed to create event for reconnection: out of memory?\n");
463 : // Start connection attempts immediately
464 0 : if (!conn.Connect(_target, std::bind(&TorController::connected_cb, this, std::placeholders::_1),
465 0 : std::bind(&TorController::disconnected_cb, this, std::placeholders::_1) )) {
466 0 : LogPrintf("tor: Initiating connection to Tor control port %s failed\n", _target);
467 : }
468 : // Read service private key if cached
469 0 : std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
470 0 : if (pkf.first) {
471 0 : LogPrint(BCLog::TOR, "tor: Reading cached private key from %s\n", GetPrivateKeyFile().string());
472 0 : private_key = pkf.second;
473 : }
474 0 : }
475 :
476 0 : TorController::~TorController()
477 : {
478 0 : if (reconnect_ev) {
479 0 : event_free(reconnect_ev);
480 0 : reconnect_ev = nullptr;
481 : }
482 0 : if (service.IsValid()) {
483 0 : RemoveLocal(service);
484 : }
485 0 : }
486 :
487 0 : void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply)
488 : {
489 0 : if (reply.code == 250) {
490 0 : LogPrint(BCLog::TOR, "tor: ADD_ONION successful\n");
491 0 : for (const std::string &s : reply.lines) {
492 0 : std::map<std::string,std::string> m = ParseTorReplyMapping(s);
493 0 : std::map<std::string,std::string>::iterator i;
494 0 : if ((i = m.find("ServiceID")) != m.end())
495 0 : service_id = i->second;
496 0 : if ((i = m.find("PrivateKey")) != m.end())
497 0 : private_key = i->second;
498 : }
499 0 : if (service_id.empty()) {
500 0 : LogPrintf("tor: Error parsing ADD_ONION parameters:\n");
501 0 : for (const std::string &s : reply.lines) {
502 0 : LogPrintf(" %s\n", SanitizeString(s));
503 : }
504 0 : return;
505 : }
506 0 : service = LookupNumeric(std::string(service_id + ".onion").c_str(), Params().GetDefaultPort());
507 0 : LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString());
508 0 : if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
509 0 : LogPrint(BCLog::TOR, "tor: Cached service private key to %s\n", GetPrivateKeyFile().string());
510 : } else {
511 0 : LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile().string());
512 : }
513 0 : AddLocal(service, LOCAL_MANUAL);
514 : // ... onion requested - keep connection open
515 0 : } else if (reply.code == 510) { // 510 Unrecognized command
516 0 : LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n");
517 : } else {
518 0 : LogPrintf("tor: Add onion failed; error code %d\n", reply.code);
519 : }
520 : }
521 :
522 0 : void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply)
523 : {
524 0 : if (reply.code == 250) {
525 0 : 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 0 : if (gArgs.GetArg("-onion", "") == "") {
530 0 : CService resolved(LookupNumeric("127.0.0.1", 9050));
531 0 : proxyType addrOnion = proxyType(resolved, true);
532 0 : SetProxy(NET_ONION, addrOnion);
533 0 : SetReachable(NET_ONION, true);
534 : }
535 :
536 : // Finally - now create the service
537 0 : if (private_key.empty()) { // No private key, generate one
538 0 : private_key = "NEW:ED25519-V3"; // Explicitly request key type - see issue #9214
539 : }
540 : // Request onion service, redirect port.
541 : // Note that the 'virtual' port is always the default port to avoid decloaking nodes using other ports.
542 0 : _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, Params().GetDefaultPort(), GetListenPort()),
543 0 : std::bind(&TorController::add_onion_cb, this, std::placeholders::_1, std::placeholders::_2));
544 : } else {
545 0 : LogPrintf("tor: Authentication failed\n");
546 : }
547 0 : }
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 0 : 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 0 : CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
568 0 : std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
569 0 : computeHash.Write(cookie.data(), cookie.size());
570 0 : computeHash.Write(clientNonce.data(), clientNonce.size());
571 0 : computeHash.Write(serverNonce.data(), serverNonce.size());
572 0 : computeHash.Finalize(computedHash.data());
573 0 : return computedHash;
574 : }
575 :
576 0 : void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply)
577 : {
578 0 : if (reply.code == 250) {
579 0 : LogPrint(BCLog::TOR, "tor: SAFECOOKIE authentication challenge successful\n");
580 0 : std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
581 0 : if (l.first == "AUTHCHALLENGE") {
582 0 : std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
583 0 : if (m.empty()) {
584 0 : LogPrintf("tor: Error parsing AUTHCHALLENGE parameters: %s\n", SanitizeString(l.second));
585 0 : return;
586 : }
587 0 : std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]);
588 0 : std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]);
589 0 : LogPrint(BCLog::TOR, "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce));
590 0 : if (serverNonce.size() != 32) {
591 0 : LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n");
592 0 : return;
593 : }
594 :
595 0 : std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce);
596 0 : if (computedServerHash != serverHash) {
597 0 : LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash));
598 0 : return;
599 : }
600 :
601 0 : std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce);
602 0 : _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), std::bind(&TorController::auth_cb, this, std::placeholders::_1, std::placeholders::_2));
603 : } else {
604 0 : LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n");
605 : }
606 : } else {
607 0 : LogPrintf("tor: SAFECOOKIE authentication challenge failed\n");
608 : }
609 : }
610 :
611 0 : void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply)
612 : {
613 0 : if (reply.code == 250) {
614 0 : std::set<std::string> methods;
615 0 : 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 0 : for (const std::string &s : reply.lines) {
622 0 : std::pair<std::string,std::string> l = SplitTorReplyLine(s);
623 0 : if (l.first == "AUTH") {
624 0 : std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
625 0 : std::map<std::string,std::string>::iterator i;
626 0 : if ((i = m.find("METHODS")) != m.end())
627 0 : boost::split(methods, i->second, boost::is_any_of(","));
628 0 : if ((i = m.find("COOKIEFILE")) != m.end())
629 0 : cookiefile = i->second;
630 0 : } else if (l.first == "VERSION") {
631 0 : std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
632 0 : std::map<std::string,std::string>::iterator i;
633 0 : if ((i = m.find("Tor")) != m.end()) {
634 0 : LogPrint(BCLog::TOR, "tor: Connected to Tor version %s\n", i->second);
635 : }
636 : }
637 : }
638 0 : for (const std::string &s : methods) {
639 0 : 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 0 : std::string torpassword = gArgs.GetArg("-torpassword", "");
647 0 : if (!torpassword.empty()) {
648 0 : if (methods.count("HASHEDPASSWORD")) {
649 0 : LogPrint(BCLog::TOR, "tor: Using HASHEDPASSWORD authentication\n");
650 0 : boost::replace_all(torpassword, "\"", "\\\"");
651 0 : _conn.Command("AUTHENTICATE \"" + torpassword + "\"", std::bind(&TorController::auth_cb, this, std::placeholders::_1, std::placeholders::_2));
652 : } else {
653 0 : LogPrintf("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available\n");
654 : }
655 0 : } else if (methods.count("NULL")) {
656 0 : LogPrint(BCLog::TOR, "tor: Using NULL authentication\n");
657 0 : _conn.Command("AUTHENTICATE", std::bind(&TorController::auth_cb, this, std::placeholders::_1, std::placeholders::_2));
658 0 : } else if (methods.count("SAFECOOKIE")) {
659 : // Cookie: hexdump -e '32/1 "%02x""\n"' ~/.tor/control_auth_cookie
660 0 : LogPrint(BCLog::TOR, "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile);
661 0 : std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE);
662 0 : if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
663 : // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), std::bind(&TorController::auth_cb, this, std::placeholders::_1, std::placeholders::_2));
664 0 : cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
665 0 : clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
666 0 : GetRandBytes(clientNonce.data(), TOR_NONCE_SIZE);
667 0 : _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), std::bind(&TorController::authchallenge_cb, this, std::placeholders::_1, std::placeholders::_2));
668 : } else {
669 0 : if (status_cookie.first) {
670 0 : LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE);
671 : } else {
672 0 : LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile);
673 : }
674 : }
675 0 : } else if (methods.count("HASHEDPASSWORD")) {
676 0 : LogPrintf("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword\n");
677 : } else {
678 0 : LogPrintf("tor: No supported authentication method\n");
679 : }
680 : } else {
681 0 : LogPrintf("tor: Requesting protocol info failed\n");
682 : }
683 0 : }
684 :
685 0 : void TorController::connected_cb(TorControlConnection& _conn)
686 : {
687 0 : reconnect_timeout = RECONNECT_TIMEOUT_START;
688 : // First send a PROTOCOLINFO command to figure out what authentication is expected
689 0 : if (!_conn.Command("PROTOCOLINFO 1", std::bind(&TorController::protocolinfo_cb, this, std::placeholders::_1, std::placeholders::_2)))
690 0 : LogPrintf("tor: Error sending initial protocolinfo command\n");
691 0 : }
692 :
693 0 : void TorController::disconnected_cb(TorControlConnection& _conn)
694 : {
695 : // Stop advertising service when disconnected
696 0 : if (service.IsValid())
697 0 : RemoveLocal(service);
698 0 : service = CService();
699 0 : if (!reconnect)
700 0 : return;
701 :
702 0 : 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 0 : struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0));
706 0 : if (reconnect_ev)
707 0 : event_add(reconnect_ev, &time);
708 0 : reconnect_timeout *= RECONNECT_TIMEOUT_EXP;
709 : }
710 :
711 0 : void TorController::Reconnect()
712 : {
713 : /* Try to reconnect and reestablish if we get booted - for example, Tor
714 : * may be restarting.
715 : */
716 0 : if (!conn.Connect(target, std::bind(&TorController::connected_cb, this, std::placeholders::_1),
717 0 : std::bind(&TorController::disconnected_cb, this, std::placeholders::_1) )) {
718 0 : LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target);
719 : }
720 0 : }
721 :
722 0 : fs::path TorController::GetPrivateKeyFile()
723 : {
724 0 : return GetDataDir() / "onion_v3_private_key";
725 : }
726 :
727 0 : void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg)
728 : {
729 0 : TorController *self = static_cast<TorController*>(arg);
730 0 : self->Reconnect();
731 0 : }
732 :
733 : /****** Thread ********/
734 : static struct event_base *gBase;
735 : static std::thread torControlThread;
736 :
737 0 : static void TorControlThread()
738 : {
739 0 : TorController ctrl(gBase, gArgs.GetArg("-torcontrol", DEFAULT_TOR_CONTROL));
740 :
741 0 : event_base_dispatch(gBase);
742 0 : }
743 :
744 0 : void StartTorControl()
745 : {
746 0 : assert(!gBase);
747 : #ifdef WIN32
748 : evthread_use_windows_threads();
749 : #else
750 0 : evthread_use_pthreads();
751 : #endif
752 0 : gBase = event_base_new();
753 0 : if (!gBase) {
754 0 : LogPrintf("tor: Unable to create event_base\n");
755 0 : return;
756 : }
757 :
758 0 : torControlThread = std::thread(std::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread));
759 : }
760 :
761 378 : void InterruptTorControl()
762 : {
763 378 : if (gBase) {
764 0 : LogPrintf("tor: Thread interrupt\n");
765 0 : event_base_once(gBase, -1, EV_TIMEOUT, [](evutil_socket_t, short, void*) {
766 : event_base_loopbreak(gBase);
767 : }, nullptr, nullptr);
768 : }
769 378 : }
770 :
771 378 : void StopTorControl()
772 : {
773 378 : if (gBase) {
774 0 : torControlThread.join();
775 0 : event_base_free(gBase);
776 0 : gBase = nullptr;
777 : }
778 378 : }
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