1 /*
2  * ngIRCd -- The Next Generation IRC Daemon
3  * Copyright (c)2001,2002 by Alexander Barton (alex@barton.de)
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  * Please read the file COPYING, README and AUTHORS for more information.
10  */
11 
12 
13 #include "portab.h"
14 
15 static char UNUSED id[] = "$Id: parse.c,v 1.62 2005/06/01 21:52:18 alex Exp $";
16 
17 /**
18  * @file
19  * IRC command parser and validator.
20  */
21 
22 #include "imp.h"
23 #include <assert.h>
24 #include <stdlib.h>
25 #include <stdio.h>
26 #include <string.h>
27 #include <strings.h>
28 
29 #include "ngircd.h"
30 #include "defines.h"
31 #include "conn-func.h"
32 #include "client.h"
33 #include "channel.h"
34 #include "log.h"
35 #include "messages.h"
36 #include "tool.h"
37 
38 #include "exp.h"
39 #include "parse.h"
40 
41 #include "imp.h"
42 #include "irc.h"
43 #include "irc-channel.h"
44 #include "irc-info.h"
45 #include "irc-login.h"
46 #include "irc-mode.h"
47 #include "irc-op.h"
48 #include "irc-oper.h"
49 #include "irc-server.h"
50 #include "irc-write.h"
51 
52 #include "exp.h"
53 
54 
55 COMMAND My_Commands[] =
56 {
57 	{ "ADMIN", IRC_ADMIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
58 	{ "AWAY", IRC_AWAY, CLIENT_USER, 0, 0, 0 },
59 	{ "CONNECT", IRC_CONNECT, CLIENT_USER, 0, 0, 0 },
60 	{ "DIE", IRC_DIE, CLIENT_USER, 0, 0, 0 },
61 	{ "DISCONNECT", IRC_DISCONNECT, CLIENT_USER, 0, 0, 0 },
62 	{ "ERROR", IRC_ERROR, 0xFFFF, 0, 0, 0 },
63 	{ "HELP", IRC_HELP, CLIENT_USER, 0, 0, 0 },
64 	{ "INVITE", IRC_INVITE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
65 	{ "ISON", IRC_ISON, CLIENT_USER, 0, 0, 0 },
66 	{ "JOIN", IRC_JOIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
67 	{ "KICK", IRC_KICK, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
68 	{ "KILL", IRC_KILL, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
69 	{ "LINKS", IRC_LINKS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
70 	{ "LIST", IRC_LIST, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
71 	{ "LUSERS", IRC_LUSERS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
72 	{ "MODE", IRC_MODE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
73 	{ "MOTD", IRC_MOTD, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
74 	{ "NAMES", IRC_NAMES, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
75 	{ "NICK", IRC_NICK, 0xFFFF, 0, 0, 0 },
76 	{ "NJOIN", IRC_NJOIN, CLIENT_SERVER, 0, 0, 0 },
77 	{ "NOTICE", IRC_NOTICE, 0xFFFF, 0, 0, 0 },
78 	{ "OPER", IRC_OPER, CLIENT_USER, 0, 0, 0 },
79 	{ "PART", IRC_PART, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
80 	{ "PASS", IRC_PASS, 0xFFFF, 0, 0, 0 },
81 	{ "PING", IRC_PING, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
82 	{ "PONG", IRC_PONG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
83 	{ "PRIVMSG", IRC_PRIVMSG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
84 	{ "QUIT", IRC_QUIT, 0xFFFF, 0, 0, 0 },
85 	{ "REHASH", IRC_REHASH, CLIENT_USER, 0, 0, 0 },
86 	{ "RESTART", IRC_RESTART, CLIENT_USER, 0, 0, 0 },
87 	{ "SERVER", IRC_SERVER, 0xFFFF, 0, 0, 0 },
88 	{ "SQUIT", IRC_SQUIT, CLIENT_SERVER, 0, 0, 0 },
89 	{ "STATS", IRC_STATS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
90 	{ "TIME", IRC_TIME, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
91 	{ "TOPIC", IRC_TOPIC, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
92 	{ "TRACE", IRC_TRACE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
93 	{ "USER", IRC_USER, 0xFFFF, 0, 0, 0 },
94 	{ "USERHOST", IRC_USERHOST, CLIENT_USER, 0, 0, 0 },
95 	{ "VERSION", IRC_VERSION, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
96 	{ "WHO", IRC_WHO, CLIENT_USER, 0, 0, 0 },
97 	{ "WHOIS", IRC_WHOIS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
98 	{ "WHOWAS", IRC_WHOWAS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
99 #ifdef IRCPLUS
100 	{ "CHANINFO", IRC_CHANINFO, CLIENT_SERVER, 0, 0, 0 },
101 #endif
102 	{ NULL, NULL, 0x0, 0, 0, 0 } /* Ende-Marke */
103 };
104 
105 
106 LOCAL void Init_Request PARAMS(( REQUEST *Req ));
107 
108 LOCAL bool Validate_Prefix PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
109 LOCAL bool Validate_Command PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
110 LOCAL bool Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
111 
112 LOCAL bool Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
113 
114 
115 /**
116  * Return the pointer to the global "IRC command structure".
117  * This structure, an array of type "COMMAND" describes all the IRC commands
118  * implemented by ngIRCd and how to handle them.
119  * @return Pointer to the global command structure.
120  */
121 GLOBAL COMMAND *
122 Parse_GetCommandStruct( void )
123 {
124 	return My_Commands;
125 } /* Parse_GetCommandStruct */
126 
127 
128 /**
129  * Parse a command ("request") received from a client.
130  * 
131  * This function is called after the connection layer received a valid CR+LF
132  * terminated line of text: we asume that this is a valid IRC command and
133  * try to do something useful with it :-)
134  *
135  * All errors are reported to the client from which the command has been
136  * received, and if the error is fatal this connection is closed down.
137  *
138  * This function is able to parse the syntax as described in RFC 2812,
139  * section 2.3.
140  *
141  * @param Idx Index of the connection from which the command has been received.
142  * @param Request NULL terminated line of text (the "command").
143  * @return true on success (valid command or "regular" error), false if a
144  * 	fatal error occured and the connection has been shut down.
145  */
146 GLOBAL bool
147 Parse_Request( CONN_ID Idx, char *Request )
148 {
149 	REQUEST req;
150 	char *start, *ptr;
151 	bool closed;
152 
153 	assert( Idx >= 0 );
154 	assert( Request != NULL );
155 
156 #ifdef SNIFFER
157 	if( NGIRCd_Sniffer ) Log( LOG_DEBUG, " <- connection %d: '%s'.", Idx, Request );
158 #endif
159 
160 	Init_Request( &req );
161 
162 	/* Fuehrendes und folgendes "Geraffel" verwerfen */
163 	ngt_TrimStr( Request );
164 
165 	/* gibt es ein Prefix? */
166 	if( Request[0] == ':' )
167 	{
168 		/* Prefix vorhanden */
169 		req.prefix = Request + 1;
170 		ptr = strchr( Request, ' ' );
171 		if( ! ptr )
172 		{
173 			Log( LOG_DEBUG, "Connection %d: Parse error: prefix without command!?", Idx );
174 			return Conn_WriteStr( Idx, "ERROR :Prefix without command!?" );
175 		}
176 		*ptr = '\0';
177 #ifndef STRICT_RFC
178 		/* multiple Leerzeichen als Trenner zwischen
179 		 * Prefix und Befehl ignorieren */
180 		while( *(ptr + 1) == ' ' ) ptr++;
181 #endif
182 		start = ptr + 1;
183 	}
184 	else start = Request;
185 
186 	/* Befehl */
187 	ptr = strchr( start, ' ' );
188 	if( ptr )
189 	{
190 		*ptr = '\0';
191 #ifndef STRICT_RFC
192 		/* multiple Leerzeichen als Trenner vor
193 		 * Parametern ignorieren */
194 		while( *(ptr + 1) == ' ' ) ptr++;
195 #endif
196 	}
197 	req.command = start;
198 
199 	/* Argumente, Parameter */
200 	if( ptr )
201 	{
202 		/* Prinzipiell gibt es welche :-) */
203 		start = ptr + 1;
204 		while( start )
205 		{
206 			/* Parameter-String "zerlegen" */
207 			if( start[0] == ':' )
208 			{
209 				req.argv[req.argc] = start + 1;
210 				ptr = NULL;
211 			}
212 			else
213 			{
214 				req.argv[req.argc] = start;
215 				ptr = strchr( start, ' ' );
216 				if( ptr )
217 				{
218 					*ptr = '\0';
219 #ifndef STRICT_RFC
220 					/* multiple Leerzeichen als
221 					 * Parametertrenner ignorieren */
222 					while( *(ptr + 1) == ' ' ) ptr++;
223 #endif
224 				}
225 			}
226 
227 			req.argc++;
228 
229 			if( start[0] == ':' ) break;
230 			if( req.argc > 14 ) break;
231 
232 			if( ptr ) start = ptr + 1;
233 			else start = NULL;
234 		}
235 	}
236 
237 	/* Daten validieren */
238 	if( ! Validate_Prefix( Idx, &req, &closed )) return ! closed;
239 	if( ! Validate_Command( Idx, &req, &closed )) return ! closed;
240 	if( ! Validate_Args( Idx, &req, &closed )) return ! closed;
241 
242 	return Handle_Request( Idx, &req );
243 } /* Parse_Request */
244 
245 
246 /**
247  * Initialize request structure.
248  * @param Req Request structure to be initialized.
249  */
250 LOCAL void
251 Init_Request( REQUEST *Req )
252 {
253 	/* Neue Request-Struktur initialisieren */
254 
255 	int i;
256 
257 	assert( Req != NULL );
258 
259 	Req->prefix = NULL;
260 	Req->command = NULL;
261 	for( i = 0; i < 15; Req->argv[i++] = NULL );
262 	Req->argc = 0;
263 } /* Init_Request */
264 
265 
266 LOCAL bool
267 Validate_Prefix( CONN_ID Idx, REQUEST *Req, bool *Closed )
268 {
269 	CLIENT *client, *c;
270 
271 	assert( Idx >= 0 );
272 	assert( Req != NULL );
273 
274 	*Closed = false;
275 
276 	/* ist ueberhaupt ein Prefix vorhanden? */
277 	if( ! Req->prefix ) return true;
278 
279 	/* Client-Struktur der Connection ermitteln */
280 	client = Client_GetFromConn( Idx );
281 	assert( client != NULL );
282 
283 	/* nur validieren, wenn bereits registrierte Verbindung */
284 	if(( Client_Type( client ) != CLIENT_USER ) && ( Client_Type( client ) != CLIENT_SERVER ) && ( Client_Type( client ) != CLIENT_SERVICE ))
285 	{
286 		/* noch nicht registrierte Verbindung.
287 		 * Das Prefix wird ignoriert. */
288 		Req->prefix = NULL;
289 		return true;
290 	}
291 
292 	/* pruefen, ob der im Prefix angegebene Client bekannt ist */
293 	c = Client_Search( Req->prefix );
294 	if( ! c )
295 	{
296 		/* im Prefix angegebener Client ist nicht bekannt */
297 		Log( LOG_ERR, "Invalid prefix \"%s\", client not known (connection %d, command %s)!?", Req->prefix, Idx, Req->command );
298 		if( ! Conn_WriteStr( Idx, "ERROR :Invalid prefix \"%s\", client not known!?", Req->prefix )) *Closed = true;
299 		return false;
300 	}
301 
302 	/* pruefen, ob der Client mit dem angegebenen Prefix in Richtung
303 	 * des Senders liegt, d.h. sicherstellen, dass das Prefix nicht
304 	 * gefaelscht ist */
305 	if( Client_NextHop( c ) != client )
306 	{
307 		/* das angegebene Prefix ist aus dieser Richtung, also
308 		 * aus der gegebenen Connection, ungueltig! */
309 		Log( LOG_ERR, "Spoofed prefix \"%s\" from \"%s\" (connection %d, command %s)!", Req->prefix, Client_Mask( Client_GetFromConn( Idx )), Idx, Req->command );
310 		Conn_Close( Idx, NULL, "Spoofed prefix", true);
311 		*Closed = true;
312 		return false;
313 	}
314 
315 	return true;
316 } /* Validate_Prefix */
317 
318 
319 LOCAL bool
320 Validate_Command( CONN_ID Idx, REQUEST *Req, bool *Closed )
321 {
322 	assert( Idx >= 0 );
323 	assert( Req != NULL );
324 	*Closed = false;
325 
326 	return true;
327 } /* Validate_Comman */
328 
329 
330 LOCAL bool
331 Validate_Args( CONN_ID Idx, REQUEST *Req, bool *Closed )
332 {
333 	assert( Idx >= 0 );
334 	assert( Req != NULL );
335 	*Closed = false;
336 
337 	return true;
338 } /* Validate_Args */
339 
340 
341 LOCAL bool
342 Handle_Request( CONN_ID Idx, REQUEST *Req )
343 {
344 	/* Client-Request verarbeiten. Bei einem schwerwiegenden Fehler
345 	 * wird die Verbindung geschlossen und false geliefert. */
346 
347 	CLIENT *client, *target, *prefix;
348 	char str[LINE_LEN];
349 	bool result;
350 	COMMAND *cmd;
351 	int i;
352 
353 	assert( Idx >= 0 );
354 	assert( Req != NULL );
355 	assert( Req->command != NULL );
356 
357 	client = Client_GetFromConn( Idx );
358 	assert( client != NULL );
359 
360 	/* Statuscode? */
361 	if(( Client_Type( client ) == CLIENT_SERVER ) && ( strlen( Req->command ) == 3 ) && ( atoi( Req->command ) > 100 ))
362 	{
363 		/* Command is a status code from an other server */
364 
365 		/* Determine target */
366 		if( Req->argc > 0 ) target = Client_Search( Req->argv[0] );
367 		else target = NULL;
368 		if( ! target )
369 		{
370 			/* Status code without target!? */
371 			if( Req->argc > 0 ) Log( LOG_WARNING, "Unknown target for status code %s: \"%s\"", Req->command, Req->argv[0] );
372 			else Log( LOG_WARNING, "Unknown target for status code %s!", Req->command );
373 			return true;
374 		}
375 		if( target == Client_ThisServer( ))
376 		{
377 			/* This server is the target, ignore it */
378 			Log( LOG_DEBUG, "Ignored status code %s from \"%s\".", Req->command, Client_ID( client ));
379 			return true;
380 		}
381 
382 		/* Determine source */
383 		if( ! Req->prefix[0] )
384 		{
385 			/* Oops, no prefix!? */
386 			Log( LOG_WARNING, "Got status code %s from \"%s\" without prefix!?", Req->command, Client_ID( client ));
387 			return true;
388 		}
389 		else prefix = Client_Search( Req->prefix );
390 		if( ! prefix )
391 		{
392 			/* Oops, unknown prefix!? */
393 			Log( LOG_WARNING, "Got status code %s from unknown source: \"%s\"", Req->command, Req->prefix );
394 			return true;
395 		}
396 
397 		/* Forward status code */
398 		strlcpy( str, Req->command, sizeof( str ));
399 		for( i = 0; i < Req->argc; i++ )
400 		{
401 			if( i < Req->argc - 1 ) strlcat( str, " ", sizeof( str ));
402 			else strlcat( str, " :", sizeof( str ));
403 			strlcat( str, Req->argv[i], sizeof( str ));
404 		}
405 		return IRC_WriteStrClientPrefix( target, prefix, "%s", str );
406 	}
407 
408 	cmd = My_Commands;
409 	while( cmd->name )
410 	{
411 		/* Befehl suchen */
412 		if( strcasecmp( Req->command, cmd->name ) != 0 )
413 		{
414 			cmd++; continue;
415 		}
416 
417 		if( Client_Type( client ) & cmd->type )
418 		{
419 			/* Command is allowed for this client: call it and count produced bytes */
420 			Conn_ResetWCounter( );
421 			result = (cmd->function)( client, Req );
422 			cmd->bytes += Conn_WCounter( );
423 
424 			/* Adjust counters */
425 			if( Client_Type( client ) != CLIENT_SERVER ) cmd->lcount++;
426 			else cmd->rcount++;
427 
428 			return result;
429 		}
430 		else
431 		{
432 			/* Befehl ist fuer diesen Client-Typ nicht erlaubt! */
433 			return IRC_WriteStrClient( client, ERR_NOTREGISTERED_MSG, Client_ID( client ));
434 		}
435 	}
436 	
437 	/* Unbekannter Befehl */
438 	Log( LOG_DEBUG, "Connection %d: Unknown command \"%s\", %d %s,%s prefix.", Client_Conn( client ), Req->command, Req->argc, Req->argc == 1 ? "parameter" : "parameters", Req->prefix ? "" : " no" );
439 	if( Client_Type( client ) != CLIENT_SERVER ) return IRC_WriteStrClient( client, ERR_UNKNOWNCOMMAND_MSG, Client_ID( client ), Req->command );
440 	else return true;
441 } /* Handle_Request */
442 
443 
444 /* -eof- */