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  * IRC command parser and validator
12  */
13 
14 
15 #include "portab.h"
16 
17 static char UNUSED id[] = "$Id: parse.c,v 1.60 2004/01/17 03:17:49 alex Exp $";
18 
19 #include "imp.h"
20 #include <assert.h>
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <strings.h>
25 
26 #include "ngircd.h"
27 #include "defines.h"
28 #include "conn-func.h"
29 #include "client.h"
30 #include "channel.h"
31 #include "log.h"
32 #include "messages.h"
33 #include "tool.h"
34 
35 #include "exp.h"
36 #include "parse.h"
37 
38 #include "imp.h"
39 #include "irc.h"
40 #include "irc-channel.h"
41 #include "irc-info.h"
42 #include "irc-login.h"
43 #include "irc-mode.h"
44 #include "irc-op.h"
45 #include "irc-oper.h"
46 #include "irc-server.h"
47 #include "irc-write.h"
48 
49 #include "exp.h"
50 
51 
52 COMMAND My_Commands[] =
53 {
54 	{ "ADMIN", IRC_ADMIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
55 	{ "AWAY", IRC_AWAY, CLIENT_USER, 0, 0, 0 },
56 	{ "CONNECT", IRC_CONNECT, CLIENT_USER, 0, 0, 0 },
57 	{ "DIE", IRC_DIE, CLIENT_USER, 0, 0, 0 },
58 	{ "DISCONNECT", IRC_DISCONNECT, CLIENT_USER, 0, 0, 0 },
59 	{ "ERROR", IRC_ERROR, 0xFFFF, 0, 0, 0 },
60 	{ "HELP", IRC_HELP, CLIENT_USER, 0, 0, 0 },
61 	{ "INVITE", IRC_INVITE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
62 	{ "ISON", IRC_ISON, CLIENT_USER, 0, 0, 0 },
63 	{ "JOIN", IRC_JOIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
64 	{ "KICK", IRC_KICK, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
65 	{ "KILL", IRC_KILL, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
66 	{ "LINKS", IRC_LINKS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
67 	{ "LIST", IRC_LIST, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
68 	{ "LUSERS", IRC_LUSERS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
69 	{ "MODE", IRC_MODE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
70 	{ "MOTD", IRC_MOTD, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
71 	{ "NAMES", IRC_NAMES, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
72 	{ "NICK", IRC_NICK, 0xFFFF, 0, 0, 0 },
73 	{ "NJOIN", IRC_NJOIN, CLIENT_SERVER, 0, 0, 0 },
74 	{ "NOTICE", IRC_NOTICE, 0xFFFF, 0, 0, 0 },
75 	{ "OPER", IRC_OPER, CLIENT_USER, 0, 0, 0 },
76 	{ "PART", IRC_PART, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
77 	{ "PASS", IRC_PASS, 0xFFFF, 0, 0, 0 },
78 	{ "PING", IRC_PING, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
79 	{ "PONG", IRC_PONG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
80 	{ "PRIVMSG", IRC_PRIVMSG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
81 	{ "QUIT", IRC_QUIT, 0xFFFF, 0, 0, 0 },
82 	{ "REHASH", IRC_REHASH, CLIENT_USER, 0, 0, 0 },
83 	{ "RESTART", IRC_RESTART, CLIENT_USER, 0, 0, 0 },
84 	{ "SERVER", IRC_SERVER, 0xFFFF, 0, 0, 0 },
85 	{ "SQUIT", IRC_SQUIT, CLIENT_SERVER, 0, 0, 0 },
86 	{ "STATS", IRC_STATS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
87 	{ "TIME", IRC_TIME, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
88 	{ "TOPIC", IRC_TOPIC, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
89 	{ "TRACE", IRC_TRACE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
90 	{ "USER", IRC_USER, 0xFFFF, 0, 0, 0 },
91 	{ "USERHOST", IRC_USERHOST, CLIENT_USER, 0, 0, 0 },
92 	{ "VERSION", IRC_VERSION, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
93 	{ "WHO", IRC_WHO, CLIENT_USER, 0, 0, 0 },
94 	{ "WHOIS", IRC_WHOIS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
95 	{ "WHOWAS", IRC_WHOWAS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
96 #ifdef IRCPLUS
97 	{ "CHANINFO", IRC_CHANINFO, CLIENT_SERVER, 0, 0, 0 },
98 #endif
99 	{ NULL, NULL, 0x0, 0, 0, 0 } /* Ende-Marke */
100 };
101 
102 
103 LOCAL VOID Init_Request PARAMS(( REQUEST *Req ));
104 
105 LOCAL BOOLEAN Validate_Prefix PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
106 LOCAL BOOLEAN Validate_Command PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
107 LOCAL BOOLEAN Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
108 
109 LOCAL BOOLEAN Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
110 
111 
112 GLOBAL COMMAND *
113 Parse_GetCommandStruct( VOID )
114 {
115 	return My_Commands;
116 } /* Parse_GetCommandStruct */
117 
118 
119 GLOBAL BOOLEAN
120 Parse_Request( CONN_ID Idx, CHAR *Request )
121 {
122 	/* Client-Request parsen. Bei einem schwerwiegenden Fehler wird
123 	 * die Verbindung geschlossen und FALSE geliefert.
124 	 * Der Aufbau gueltiger Requests ist in RFC 2812, 2.3 definiert. */
125 
126 	REQUEST req;
127 	CHAR *start, *ptr;
128 	BOOLEAN closed;
129 
130 	assert( Idx >= 0 );
131 	assert( Request != NULL );
132 
133 #ifdef SNIFFER
134 	if( NGIRCd_Sniffer ) Log( LOG_DEBUG, " <- connection %d: '%s'.", Idx, Request );
135 #endif
136 
137 	Init_Request( &req );
138 
139 	/* Fuehrendes und folgendes "Geraffel" verwerfen */
140 	ngt_TrimStr( Request );
141 
142 	/* gibt es ein Prefix? */
143 	if( Request[0] == ':' )
144 	{
145 		/* Prefix vorhanden */
146 		req.prefix = Request + 1;
147 		ptr = strchr( Request, ' ' );
148 		if( ! ptr )
149 		{
150 			Log( LOG_DEBUG, "Connection %d: Parse error: prefix without command!?", Idx );
151 			return Conn_WriteStr( Idx, "ERROR :Prefix without command!?" );
152 		}
153 		*ptr = '\0';
154 #ifndef STRICT_RFC
155 		/* multiple Leerzeichen als Trenner zwischen
156 		 * Prefix und Befehl ignorieren */
157 		while( *(ptr + 1) == ' ' ) ptr++;
158 #endif
159 		start = ptr + 1;
160 	}
161 	else start = Request;
162 
163 	/* Befehl */
164 	ptr = strchr( start, ' ' );
165 	if( ptr )
166 	{
167 		*ptr = '\0';
168 #ifndef STRICT_RFC
169 		/* multiple Leerzeichen als Trenner vor
170 		 * Parametern ignorieren */
171 		while( *(ptr + 1) == ' ' ) ptr++;
172 #endif
173 	}
174 	req.command = start;
175 
176 	/* Argumente, Parameter */
177 	if( ptr )
178 	{
179 		/* Prinzipiell gibt es welche :-) */
180 		start = ptr + 1;
181 		while( start )
182 		{
183 			/* Parameter-String "zerlegen" */
184 			if( start[0] == ':' )
185 			{
186 				req.argv[req.argc] = start + 1;
187 				ptr = NULL;
188 			}
189 			else
190 			{
191 				req.argv[req.argc] = start;
192 				ptr = strchr( start, ' ' );
193 				if( ptr )
194 				{
195 					*ptr = '\0';
196 #ifndef STRICT_RFC
197 					/* multiple Leerzeichen als
198 					 * Parametertrenner ignorieren */
199 					while( *(ptr + 1) == ' ' ) ptr++;
200 #endif
201 				}
202 			}
203 
204 			req.argc++;
205 
206 			if( start[0] == ':' ) break;
207 			if( req.argc > 14 ) break;
208 
209 			if( ptr ) start = ptr + 1;
210 			else start = NULL;
211 		}
212 	}
213 
214 	/* Daten validieren */
215 	if( ! Validate_Prefix( Idx, &req, &closed )) return ! closed;
216 	if( ! Validate_Command( Idx, &req, &closed )) return ! closed;
217 	if( ! Validate_Args( Idx, &req, &closed )) return ! closed;
218 
219 	return Handle_Request( Idx, &req );
220 } /* Parse_Request */
221 
222 
223 LOCAL VOID
224 Init_Request( REQUEST *Req )
225 {
226 	/* Neue Request-Struktur initialisieren */
227 
228 	INT i;
229 
230 	assert( Req != NULL );
231 
232 	Req->prefix = NULL;
233 	Req->command = NULL;
234 	for( i = 0; i < 15; Req->argv[i++] = NULL );
235 	Req->argc = 0;
236 } /* Init_Request */
237 
238 
239 LOCAL BOOLEAN
240 Validate_Prefix( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
241 {
242 	CLIENT *client, *c;
243 
244 	assert( Idx >= 0 );
245 	assert( Req != NULL );
246 
247 	*Closed = FALSE;
248 
249 	/* ist ueberhaupt ein Prefix vorhanden? */
250 	if( ! Req->prefix ) return TRUE;
251 
252 	/* Client-Struktur der Connection ermitteln */
253 	client = Client_GetFromConn( Idx );
254 	assert( client != NULL );
255 
256 	/* nur validieren, wenn bereits registrierte Verbindung */
257 	if(( Client_Type( client ) != CLIENT_USER ) && ( Client_Type( client ) != CLIENT_SERVER ) && ( Client_Type( client ) != CLIENT_SERVICE ))
258 	{
259 		/* noch nicht registrierte Verbindung.
260 		 * Das Prefix wird ignoriert. */
261 		Req->prefix = NULL;
262 		return TRUE;
263 	}
264 
265 	/* pruefen, ob der im Prefix angegebene Client bekannt ist */
266 	c = Client_Search( Req->prefix );
267 	if( ! c )
268 	{
269 		/* im Prefix angegebener Client ist nicht bekannt */
270 		Log( LOG_ERR, "Invalid prefix \"%s\", client not known (connection %d, command %s)!?", Req->prefix, Idx, Req->command );
271 		if( ! Conn_WriteStr( Idx, "ERROR :Invalid prefix \"%s\", client not known!?", Req->prefix )) *Closed = TRUE;
272 		return FALSE;
273 	}
274 
275 	/* pruefen, ob der Client mit dem angegebenen Prefix in Richtung
276 	 * des Senders liegt, d.h. sicherstellen, dass das Prefix nicht
277 	 * gefaelscht ist */
278 	if( Client_NextHop( c ) != client )
279 	{
280 		/* das angegebene Prefix ist aus dieser Richtung, also
281 		 * aus der gegebenen Connection, ungueltig! */
282 		Log( LOG_ERR, "Spoofed prefix \"%s\" from \"%s\" (connection %d, command %s)!", Req->prefix, Client_Mask( Client_GetFromConn( Idx )), Idx, Req->command );
283 		Conn_Close( Idx, NULL, "Spoofed prefix", TRUE );
284 		*Closed = TRUE;
285 		return FALSE;
286 	}
287 
288 	return TRUE;
289 } /* Validate_Prefix */
290 
291 
292 LOCAL BOOLEAN
293 Validate_Command( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
294 {
295 	assert( Idx >= 0 );
296 	assert( Req != NULL );
297 	*Closed = FALSE;
298 
299 	return TRUE;
300 } /* Validate_Comman */
301 
302 
303 LOCAL BOOLEAN
304 Validate_Args( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
305 {
306 	assert( Idx >= 0 );
307 	assert( Req != NULL );
308 	*Closed = FALSE;
309 
310 	return TRUE;
311 } /* Validate_Args */
312 
313 
314 LOCAL BOOLEAN
315 Handle_Request( CONN_ID Idx, REQUEST *Req )
316 {
317 	/* Client-Request verarbeiten. Bei einem schwerwiegenden Fehler
318 	 * wird die Verbindung geschlossen und FALSE geliefert. */
319 
320 	CLIENT *client, *target, *prefix;
321 	CHAR str[LINE_LEN];
322 	BOOLEAN result;
323 	COMMAND *cmd;
324 	INT i;
325 
326 	assert( Idx >= 0 );
327 	assert( Req != NULL );
328 	assert( Req->command != NULL );
329 
330 	client = Client_GetFromConn( Idx );
331 	assert( client != NULL );
332 
333 	/* Statuscode? */
334 	if(( Client_Type( client ) == CLIENT_SERVER ) && ( strlen( Req->command ) == 3 ) && ( atoi( Req->command ) > 100 ))
335 	{
336 		/* Command is a status code from an other server */
337 
338 		/* Determine target */
339 		if( Req->argc > 0 ) target = Client_Search( Req->argv[0] );
340 		else target = NULL;
341 		if( ! target )
342 		{
343 			/* Status code without target!? */
344 			if( Req->argc > 0 ) Log( LOG_WARNING, "Unknown target for status code %s: \"%s\"", Req->command, Req->argv[0] );
345 			else Log( LOG_WARNING, "Unknown target for status code %s!", Req->command );
346 			return TRUE;
347 		}
348 		if( target == Client_ThisServer( ))
349 		{
350 			/* This server is the target, ignore it */
351 			Log( LOG_DEBUG, "Ignored status code %s from \"%s\".", Req->command, Client_ID( client ));
352 			return TRUE;
353 		}
354 
355 		/* Determine source */
356 		if( ! Req->prefix[0] )
357 		{
358 			/* Oops, no prefix!? */
359 			Log( LOG_WARNING, "Got status code %s from \"%s\" without prefix!?", Req->command, Client_ID( client ));
360 			return TRUE;
361 		}
362 		else prefix = Client_Search( Req->prefix );
363 		if( ! prefix )
364 		{
365 			/* Oops, unknown prefix!? */
366 			Log( LOG_WARNING, "Got status code %s from unknown source: \"%s\"", Req->command, Req->prefix );
367 			return TRUE;
368 		}
369 
370 		/* Forward status code */
371 		strlcpy( str, Req->command, sizeof( str ));
372 		for( i = 0; i < Req->argc; i++ )
373 		{
374 			if( i < Req->argc - 1 ) strlcat( str, " ", sizeof( str ));
375 			else strlcat( str, " :", sizeof( str ));
376 			strlcat( str, Req->argv[i], sizeof( str ));
377 		}
378 		return IRC_WriteStrClientPrefix( target, prefix, "%s", str );
379 	}
380 
381 	cmd = My_Commands;
382 	while( cmd->name )
383 	{
384 		/* Befehl suchen */
385 		if( strcasecmp( Req->command, cmd->name ) != 0 )
386 		{
387 			cmd++; continue;
388 		}
389 
390 		if( Client_Type( client ) & cmd->type )
391 		{
392 			/* Command is allowed for this client: call it and count produced bytes */
393 			Conn_ResetWCounter( );
394 			result = (cmd->function)( client, Req );
395 			cmd->bytes += Conn_WCounter( );
396 
397 			/* Adjust counters */
398 			if( Client_Type( client ) != CLIENT_SERVER ) cmd->lcount++;
399 			else cmd->rcount++;
400 
401 			return result;
402 		}
403 		else
404 		{
405 			/* Befehl ist fuer diesen Client-Typ nicht erlaubt! */
406 			return IRC_WriteStrClient( client, ERR_NOTREGISTERED_MSG, Client_ID( client ));
407 		}
408 	}
409 	
410 	/* Unbekannter Befehl */
411 	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" );
412 	if( Client_Type( client ) != CLIENT_SERVER ) return IRC_WriteStrClient( client, ERR_UNKNOWNCOMMAND_MSG, Client_ID( client ), Req->command );
413 	else return TRUE;
414 } /* Handle_Request */
415 
416 
417 /* -eof- */