summaryrefslogtreecommitdiff
path: root/src/modules/m_ident.cpp
blob: 516287668c9fd7f45426fe127a1dabb05cf23e25 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2007, 2009 John Brooks <john.brooks@dereferenced.net>
 *   Copyright (C) 2006-2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2005-2008 Craig Edwards <craigedwards@brainbox.cc>
 *   Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "inspircd.h"

/* --------------------------------------------------------------
 * Note that this is the third incarnation of m_ident. The first
 * two attempts were pretty crashy, mainly due to the fact we tried
 * to use InspSocket/BufferedSocket to make them work. This class
 * is ok for more heavyweight tasks, it does a lot of things behind
 * the scenes that are not good for ident sockets and it has a huge
 * memory footprint!
 *
 * To fix all the issues that we had in the old ident modules (many
 * nasty race conditions that would cause segfaults etc) we have
 * rewritten this module to use a simplified socket object based
 * directly off EventHandler. As EventHandler only has low level
 * readability, writeability and error events tied directly to the
 * socket engine, this makes our lives easier as nothing happens to
 * our ident lookup class that is outside of this module, or out-
 * side of the control of the class. There are no timers, internal
 * events, or such, which will cause the socket to be deleted,
 * queued for deletion, etc. In fact, theres not even any queueing!
 *
 * Using this framework we have a much more stable module.
 *
 * A few things to note:
 *
 *   O  The only place that may *delete* an active or inactive
 *      ident socket is OnUserDisconnect in the module class.
 *      Because this is out of scope of the socket class there is
 *      no possibility that the socket may ever try to delete
 *      itself.
 *
 *   O  Closure of the ident socket with the Close() method will
 *      not cause removal of the socket from memory or detatchment
 *      from its 'parent' User class. It will only flag it as an
 *      inactive socket in the socket engine.
 *
 *   O  Timeouts are handled in OnCheckReaady at the same time as
 *      checking if the ident socket has a result. This is done
 *      by checking if the age the of the class (its instantiation
 *      time) plus the timeout value is greater than the current time.
 *
 *  O   The ident socket is able to but should not modify its
 *      'parent' user directly. Instead the ident socket class sets
 *      a completion flag and during the next call to OnCheckReady,
 *      the completion flag will be checked and any result copied to
 *      that user's class. This again ensures a single point of socket
 *      deletion for safer, neater code.
 *
 *  O   The code in the constructor of the ident socket is taken from
 *      BufferedSocket but majorly thinned down. It works for both
 *      IPv4 and IPv6.
 *
 *  O   In the event that the ident socket throws a ModuleException,
 *      nothing is done. This is counted as total and complete
 *      failure to create a connection.
 * --------------------------------------------------------------
 */

class IdentRequestSocket : public EventHandler
{
 public:
	LocalUser *user;			/* User we are attached to */
	std::string result;		/* Holds the ident string if done */
	time_t age;
	bool done;			/* True if lookup is finished */

	IdentRequestSocket(LocalUser* u) : user(u)
	{
		age = ServerInstance->Time();

		SetFd(socket(user->server_sa.sa.sa_family, SOCK_STREAM, 0));

		if (GetFd() == -1)
			throw ModuleException("Could not create socket");

		done = false;

		irc::sockets::sockaddrs bindaddr;
		irc::sockets::sockaddrs connaddr;

		memcpy(&bindaddr, &user->server_sa, sizeof(bindaddr));
		memcpy(&connaddr, &user->client_sa, sizeof(connaddr));

		if (connaddr.sa.sa_family == AF_INET6)
		{
			bindaddr.in6.sin6_port = 0;
			connaddr.in6.sin6_port = htons(113);
		}
		else
		{
			bindaddr.in4.sin_port = 0;
			connaddr.in4.sin_port = htons(113);
		}

		/* Attempt to bind (ident requests must come from the ip the query is referring to */
		if (ServerInstance->SE->Bind(GetFd(), bindaddr) < 0)
		{
			this->Close();
			throw ModuleException("failed to bind()");
		}

		ServerInstance->SE->NonBlocking(GetFd());

		/* Attempt connection (nonblocking) */
		if (ServerInstance->SE->Connect(this, &connaddr.sa, connaddr.sa_size()) == -1 && errno != EINPROGRESS)
		{
			this->Close();
			throw ModuleException("connect() failed");
		}

		/* Add fd to socket engine */
		if (!ServerInstance->SE->AddFd(this, FD_WANT_NO_READ | FD_WANT_POLL_WRITE))
		{
			this->Close();
			throw ModuleException("out of fds");
		}
	}

	void OnConnected()
	{
		ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "OnConnected()");
		ServerInstance->SE->ChangeEventMask(this, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);

		char req[32];

		/* Build request in the form 'localport,remoteport\r\n' */
		int req_size;
		if (user->client_sa.sa.sa_family == AF_INET6)
			req_size = snprintf(req, sizeof(req), "%d,%d\r\n",
				ntohs(user->client_sa.in6.sin6_port), ntohs(user->server_sa.in6.sin6_port));
		else
			req_size = snprintf(req, sizeof(req), "%d,%d\r\n",
				ntohs(user->client_sa.in4.sin_port), ntohs(user->server_sa.in4.sin_port));

		/* Send failed if we didnt write the whole ident request --
		 * might as well give up if this happens!
		 */
		if (ServerInstance->SE->Send(this, req, req_size, 0) < req_size)
			done = true;
	}

	void HandleEvent(EventType et, int errornum = 0)
	{
		switch (et)
		{
			case EVENT_READ:
				/* fd readable event, received ident response */
				ReadResponse();
			break;
			case EVENT_WRITE:
				/* fd writeable event, successfully connected! */
				OnConnected();
			break;
			case EVENT_ERROR:
				/* fd error event, ohshi- */
				ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "EVENT_ERROR");
				/* We *must* Close() here immediately or we get a
				 * huge storm of EVENT_ERROR events!
				 */
				Close();
				done = true;
			break;
		}
	}

	void Close()
	{
		/* Remove ident socket from engine, and close it, but dont detatch it
		 * from its parent user class, or attempt to delete its memory.
		 */
		if (GetFd() > -1)
		{
			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Close ident socket %d", GetFd());
			ServerInstance->SE->DelFd(this);
			ServerInstance->SE->Close(GetFd());
			this->SetFd(-1);
		}
	}

	bool HasResult()
	{
		return done;
	}

	void ReadResponse()
	{
		/* We don't really need to buffer for incomplete replies here, since IDENT replies are
		 * extremely short - there is *no* sane reason it'd be in more than one packet
		 */
		char ibuf[256];
		int recvresult = ServerInstance->SE->Recv(this, ibuf, sizeof(ibuf)-1, 0);

		/* Close (but don't delete from memory) our socket
		 * and flag as done since the ident lookup has finished
		 */
		Close();
		done = true;

		/* Cant possibly be a valid response shorter than 3 chars,
		 * because the shortest possible response would look like: '1,1'
		 */
		if (recvresult < 3)
			return;

		ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "ReadResponse()");

		/* Truncate at the first null character, but first make sure
		 * there is at least one null char (at the end of the buffer).
		 */
		ibuf[recvresult] = '\0';
		std::string buf(ibuf);

		/* <2 colons: invalid
		 *  2 colons: reply is an error
		 * >3 colons: there is a colon in the ident
		 */
		if (std::count(buf.begin(), buf.end(), ':') != 3)
			return;

		std::string::size_type lastcolon = buf.rfind(':');

		/* Truncate the ident at any characters we don't like, skip leading spaces */
		for (std::string::const_iterator i = buf.begin()+lastcolon+1; i != buf.end(); ++i)
		{
			if (result.size() == ServerInstance->Config->Limits.IdentMax)
				/* Ident is getting too long */
				break;

			if (*i == ' ')
				continue;

			/* Add the next char to the result and see if it's still a valid ident,
			 * according to IsIdent(). If it isn't, then erase what we just added and
			 * we're done.
			 */
			result += *i;
			if (!ServerInstance->IsIdent(result))
			{
				result.erase(result.end()-1);
				break;
			}
		}
	}
};

class ModuleIdent : public Module
{
	int RequestTimeout;
	SimpleExtItem<IdentRequestSocket> ext;
 public:
	ModuleIdent() : ext("ident_socket", this)
	{
	}

	Version GetVersion() CXX11_OVERRIDE
	{
		return Version("Provides support for RFC1413 ident lookups", VF_VENDOR);
	}

	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
	{
		RequestTimeout = ServerInstance->Config->ConfValue("ident")->getInt("timeout", 5);
		if (!RequestTimeout)
			RequestTimeout = 5;
	}

	void OnUserInit(LocalUser *user) CXX11_OVERRIDE
	{
		ConfigTag* tag = user->MyClass->config;
		if (!tag->getBool("useident", true))
			return;

		user->WriteNotice("*** Looking up your ident...");

		try
		{
			IdentRequestSocket *isock = new IdentRequestSocket(IS_LOCAL(user));
			ext.set(user, isock);
		}
		catch (ModuleException &e)
		{
			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Ident exception: %s", e.GetReason());
		}
	}

	/* This triggers pretty regularly, we can use it in preference to
	 * creating a Timer object and especially better than creating a
	 * Timer per ident lookup!
	 */
	ModResult OnCheckReady(LocalUser *user) CXX11_OVERRIDE
	{
		/* Does user have an ident socket attached at all? */
		IdentRequestSocket *isock = ext.get(user);
		if (!isock)
			return MOD_RES_PASSTHRU;

		time_t compare = isock->age;
		compare += RequestTimeout;

		/* Check for timeout of the socket */
		if (ServerInstance->Time() >= compare)
		{
			/* Ident timeout */
			user->WriteNotice("*** Ident request timed out.");
		}
		else if (!isock->HasResult())
		{
			// time still good, no result yet... hold the registration
			return MOD_RES_DENY;
		}

		/* wooo, got a result (it will be good, or bad) */
		if (isock->result.empty())
		{
			user->ident.insert(0, 1, '~');
			user->WriteNotice("*** Could not find your ident, using " + user->ident + " instead.");
		}
		else
		{
			user->ident = isock->result;
			user->WriteNotice("*** Found your ident, '" + user->ident + "'");
		}

		user->InvalidateCache();
		isock->Close();
		ext.unset(user);
		return MOD_RES_PASSTHRU;
	}

	ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass) CXX11_OVERRIDE
	{
		if (myclass->config->getBool("requireident") && user->ident[0] == '~')
			return MOD_RES_DENY;
		return MOD_RES_PASSTHRU;
	}

	void OnCleanup(int target_type, void *item) CXX11_OVERRIDE
	{
		/* Module unloading, tidy up users */
		if (target_type == TYPE_USER)
		{
			LocalUser* user = IS_LOCAL((User*) item);
			if (user)
				OnUserDisconnect(user);
		}
	}

	void OnUserDisconnect(LocalUser *user) CXX11_OVERRIDE
	{
		/* User disconnect (generic socket detatch event) */
		IdentRequestSocket *isock = ext.get(user);
		if (isock)
		{
			isock->Close();
			ext.unset(user);
		}
	}
};

MODULE_INIT(ModuleIdent)