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 1.58 2003/01/13 18:56:30 alex Exp $";
18 
19 #include "imp.h"
20 #include <assert.h>
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include <string.h>
24 
25 #include "ngircd.h"
26 #include "defines.h"
27 #include "conn-func.h"
28 #include "client.h"
29 #include "channel.h"
30 #include "log.h"
31 #include "messages.h"
32 #include "tool.h"
33 
34 #include "exp.h"
35 #include "parse.h"
36 
37 #include "imp.h"
38 #include "irc.h"
39 #include "irc-channel.h"
40 #include "irc-info.h"
41 #include "irc-login.h"
42 #include "irc-mode.h"
43 #include "irc-op.h"
44 #include "irc-oper.h"
45 #include "irc-server.h"
46 #include "irc-write.h"
47 
48 #include "exp.h"
49 
50 
51 COMMAND My_Commands[] =
52 {
53 	{ "ADMIN", IRC_ADMIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
54 	{ "AWAY", IRC_AWAY, CLIENT_USER, 0, 0, 0 },
55 	{ "CONNECT", IRC_CONNECT, CLIENT_USER, 0, 0, 0 },
56 	{ "DIE", IRC_DIE, CLIENT_USER, 0, 0, 0 },
57 	{ "DISCONNECT", IRC_DISCONNECT, CLIENT_USER, 0, 0, 0 },
58 	{ "ERROR", IRC_ERROR, 0xFFFF, 0, 0, 0 },
59 	{ "INVITE", IRC_INVITE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
60 	{ "ISON", IRC_ISON, CLIENT_USER, 0, 0, 0 },
61 	{ "JOIN", IRC_JOIN, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
62 	{ "KICK", IRC_KICK, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
63 	{ "KILL", IRC_KILL, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
64 	{ "LINKS", IRC_LINKS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
65 	{ "LIST", IRC_LIST, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
66 	{ "LUSERS", IRC_LUSERS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
67 	{ "MODE", IRC_MODE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
68 	{ "MOTD", IRC_MOTD, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
69 	{ "NAMES", IRC_NAMES, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
70 	{ "NICK", IRC_NICK, 0xFFFF, 0, 0, 0 },
71 	{ "NJOIN", IRC_NJOIN, CLIENT_SERVER, 0, 0, 0 },
72 	{ "NOTICE", IRC_NOTICE, 0xFFFF, 0, 0, 0 },
73 	{ "OPER", IRC_OPER, CLIENT_USER, 0, 0, 0 },
74 	{ "PART", IRC_PART, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
75 	{ "PASS", IRC_PASS, 0xFFFF, 0, 0, 0 },
76 	{ "PING", IRC_PING, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
77 	{ "PONG", IRC_PONG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
78 	{ "PRIVMSG", IRC_PRIVMSG, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
79 	{ "QUIT", IRC_QUIT, 0xFFFF, 0, 0, 0 },
80 	{ "REHASH", IRC_REHASH, CLIENT_USER, 0, 0, 0 },
81 	{ "RESTART", IRC_RESTART, CLIENT_USER, 0, 0, 0 },
82 	{ "SERVER", IRC_SERVER, 0xFFFF, 0, 0, 0 },
83 	{ "SQUIT", IRC_SQUIT, CLIENT_SERVER, 0, 0, 0 },
84 	{ "STATS", IRC_STATS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
85 	{ "TIME", IRC_TIME, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
86 	{ "TOPIC", IRC_TOPIC, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
87 	{ "TRACE", IRC_TRACE, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
88 	{ "USER", IRC_USER, 0xFFFF, 0, 0, 0 },
89 	{ "USERHOST", IRC_USERHOST, CLIENT_USER, 0, 0, 0 },
90 	{ "VERSION", IRC_VERSION, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
91 	{ "WHO", IRC_WHO, CLIENT_USER, 0, 0, 0 },
92 	{ "WHOIS", IRC_WHOIS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
93 	{ "WHOWAS", IRC_WHOWAS, CLIENT_USER|CLIENT_SERVER, 0, 0, 0 },
94 #ifdef IRCPLUS
95 	{ "CHANINFO", IRC_CHANINFO, CLIENT_SERVER, 0, 0, 0 },
96 #endif
97 	{ NULL, NULL, 0x0, 0, 0, 0 } /* Ende-Marke */
98 };
99 
100 
101 LOCAL VOID Init_Request PARAMS(( REQUEST *Req ));
102 
103 LOCAL BOOLEAN Validate_Prefix PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
104 LOCAL BOOLEAN Validate_Command PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
105 LOCAL BOOLEAN Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed ));
106 
107 LOCAL BOOLEAN Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
108 
109 
110 GLOBAL COMMAND *
111 Parse_GetCommandStruct( VOID )
112 {
113 	return My_Commands;
114 } /* Parse_GetCommandStruct */
115 
116 
117 GLOBAL BOOLEAN
118 Parse_Request( CONN_ID Idx, CHAR *Request )
119 {
120 	/* Client-Request parsen. Bei einem schwerwiegenden Fehler wird
121 	 * die Verbindung geschlossen und FALSE geliefert.
122 	 * Der Aufbau gueltiger Requests ist in RFC 2812, 2.3 definiert. */
123 
124 	REQUEST req;
125 	CHAR *start, *ptr;
126 	BOOLEAN closed;
127 
128 	assert( Idx >= 0 );
129 	assert( Request != NULL );
130 
131 #ifdef SNIFFER
132 	if( NGIRCd_Sniffer ) Log( LOG_DEBUG, " <- connection %d: '%s'.", Idx, Request );
133 #endif
134 
135 	Init_Request( &req );
136 
137 	/* Fuehrendes und folgendes "Geraffel" verwerfen */
138 	ngt_TrimStr( Request );
139 
140 	/* gibt es ein Prefix? */
141 	if( Request[0] == ':' )
142 	{
143 		/* Prefix vorhanden */
144 		req.prefix = Request + 1;
145 		ptr = strchr( Request, ' ' );
146 		if( ! ptr )
147 		{
148 			Log( LOG_DEBUG, "Connection %d: Parse error: prefix without command!?", Idx );
149 			return Conn_WriteStr( Idx, "ERROR :Prefix without command!?" );
150 		}
151 		*ptr = '\0';
152 #ifndef STRICT_RFC
153 		/* multiple Leerzeichen als Trenner zwischen
154 		 * Prefix und Befehl ignorieren */
155 		while( *(ptr + 1) == ' ' ) ptr++;
156 #endif
157 		start = ptr + 1;
158 	}
159 	else start = Request;
160 
161 	/* Befehl */
162 	ptr = strchr( start, ' ' );
163 	if( ptr )
164 	{
165 		*ptr = '\0';
166 #ifndef STRICT_RFC
167 		/* multiple Leerzeichen als Trenner vor
168 		 * Parametern ignorieren */
169 		while( *(ptr + 1) == ' ' ) ptr++;
170 #endif
171 	}
172 	req.command = start;
173 
174 	/* Argumente, Parameter */
175 	if( ptr )
176 	{
177 		/* Prinzipiell gibt es welche :-) */
178 		start = ptr + 1;
179 		while( start )
180 		{
181 			/* Parameter-String "zerlegen" */
182 			if( start[0] == ':' )
183 			{
184 				req.argv[req.argc] = start + 1;
185 				ptr = NULL;
186 			}
187 			else
188 			{
189 				req.argv[req.argc] = start;
190 				ptr = strchr( start, ' ' );
191 				if( ptr )
192 				{
193 					*ptr = '\0';
194 #ifndef STRICT_RFC
195 					/* multiple Leerzeichen als
196 					 * Parametertrenner ignorieren */
197 					while( *(ptr + 1) == ' ' ) ptr++;
198 #endif
199 				}
200 			}
201 
202 			req.argc++;
203 
204 			if( start[0] == ':' ) break;
205 			if( req.argc > 14 ) break;
206 
207 			if( ptr ) start = ptr + 1;
208 			else start = NULL;
209 		}
210 	}
211 
212 	/* Daten validieren */
213 	if( ! Validate_Prefix( Idx, &req, &closed )) return ! closed;
214 	if( ! Validate_Command( Idx, &req, &closed )) return ! closed;
215 	if( ! Validate_Args( Idx, &req, &closed )) return ! closed;
216 
217 	return Handle_Request( Idx, &req );
218 } /* Parse_Request */
219 
220 
221 LOCAL VOID
222 Init_Request( REQUEST *Req )
223 {
224 	/* Neue Request-Struktur initialisieren */
225 
226 	INT i;
227 
228 	assert( Req != NULL );
229 
230 	Req->prefix = NULL;
231 	Req->command = NULL;
232 	for( i = 0; i < 15; Req->argv[i++] = NULL );
233 	Req->argc = 0;
234 } /* Init_Request */
235 
236 
237 LOCAL BOOLEAN
238 Validate_Prefix( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
239 {
240 	CLIENT *client, *c;
241 
242 	assert( Idx >= 0 );
243 	assert( Req != NULL );
244 
245 	*Closed = FALSE;
246 
247 	/* ist ueberhaupt ein Prefix vorhanden? */
248 	if( ! Req->prefix ) return TRUE;
249 
250 	/* Client-Struktur der Connection ermitteln */
251 	client = Client_GetFromConn( Idx );
252 	assert( client != NULL );
253 
254 	/* nur validieren, wenn bereits registrierte Verbindung */
255 	if(( Client_Type( client ) != CLIENT_USER ) && ( Client_Type( client ) != CLIENT_SERVER ) && ( Client_Type( client ) != CLIENT_SERVICE ))
256 	{
257 		/* noch nicht registrierte Verbindung.
258 		 * Das Prefix wird ignoriert. */
259 		Req->prefix = NULL;
260 		return TRUE;
261 	}
262 
263 	/* pruefen, ob der im Prefix angegebene Client bekannt ist */
264 	c = Client_Search( Req->prefix );
265 	if( ! c )
266 	{
267 		/* im Prefix angegebener Client ist nicht bekannt */
268 		Log( LOG_ERR, "Invalid prefix \"%s\", client not known (connection %d, command %s)!?", Req->prefix, Idx, Req->command );
269 		if( ! Conn_WriteStr( Idx, "ERROR :Invalid prefix \"%s\", client not known!?", Req->prefix )) *Closed = TRUE;
270 		return FALSE;
271 	}
272 
273 	/* pruefen, ob der Client mit dem angegebenen Prefix in Richtung
274 	 * des Senders liegt, d.h. sicherstellen, dass das Prefix nicht
275 	 * gefaelscht ist */
276 	if( Client_NextHop( c ) != client )
277 	{
278 		/* das angegebene Prefix ist aus dieser Richtung, also
279 		 * aus der gegebenen Connection, ungueltig! */
280 		Log( LOG_ERR, "Spoofed prefix \"%s\" from \"%s\" (connection %d, command %s)!", Req->prefix, Client_Mask( Client_GetFromConn( Idx )), Idx, Req->command );
281 		Conn_Close( Idx, NULL, "Spoofed prefix", TRUE );
282 		*Closed = TRUE;
283 		return FALSE;
284 	}
285 
286 	return TRUE;
287 } /* Validate_Prefix */
288 
289 
290 LOCAL BOOLEAN
291 Validate_Command( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
292 {
293 	assert( Idx >= 0 );
294 	assert( Req != NULL );
295 	*Closed = FALSE;
296 
297 	return TRUE;
298 } /* Validate_Comman */
299 
300 
301 LOCAL BOOLEAN
302 Validate_Args( CONN_ID Idx, REQUEST *Req, BOOLEAN *Closed )
303 {
304 	assert( Idx >= 0 );
305 	assert( Req != NULL );
306 	*Closed = FALSE;
307 
308 	return TRUE;
309 } /* Validate_Args */
310 
311 
312 LOCAL BOOLEAN
313 Handle_Request( CONN_ID Idx, REQUEST *Req )
314 {
315 	/* Client-Request verarbeiten. Bei einem schwerwiegenden Fehler
316 	 * wird die Verbindung geschlossen und FALSE geliefert. */
317 
318 	CLIENT *client, *target, *prefix;
319 	CHAR str[LINE_LEN];
320 	BOOLEAN result;
321 	COMMAND *cmd;
322 	INT i;
323 
324 	assert( Idx >= 0 );
325 	assert( Req != NULL );
326 	assert( Req->command != NULL );
327 
328 	client = Client_GetFromConn( Idx );
329 	assert( client != NULL );
330 
331 	/* Statuscode? */
332 	if(( Client_Type( client ) == CLIENT_SERVER ) && ( strlen( Req->command ) == 3 ) && ( atoi( Req->command ) > 100 ))
333 	{
334 		/* Command is a status code from an other server */
335 
336 		/* Determine target */
337 		if( Req->argc > 0 ) target = Client_Search( Req->argv[0] );
338 		else target = NULL;
339 		if( ! target )
340 		{
341 			/* Status code without target!? */
342 			if( Req->argc > 0 ) Log( LOG_WARNING, "Unknown target for status code %s: \"%s\"", Req->command, Req->argv[0] );
343 			else Log( LOG_WARNING, "Unknown target for status code %s!", Req->command );
344 			return TRUE;
345 		}
346 		if( target == Client_ThisServer( ))
347 		{
348 			/* This server is the target, ignore it */
349 			Log( LOG_DEBUG, "Ignored status code %s from \"%s\".", Req->command, Client_ID( client ));
350 			return TRUE;
351 		}
352 
353 		/* Determine source */
354 		if( ! Req->prefix[0] )
355 		{
356 			/* Oops, no prefix!? */
357 			Log( LOG_WARNING, "Got status code %s from \"%s\" without prefix!?", Req->command, Client_ID( client ));
358 			return TRUE;
359 		}
360 		else prefix = Client_Search( Req->prefix );
361 		if( ! prefix )
362 		{
363 			/* Oops, unknown prefix!? */
364 			Log( LOG_WARNING, "Got status code %s from unknown source: \"%s\"", Req->command, Req->prefix );
365 			return TRUE;
366 		}
367 
368 		/* Forward status code */
369 		strlcpy( str, Req->command, sizeof( str ));
370 		for( i = 0; i < Req->argc; i++ )
371 		{
372 			if( i < Req->argc - 1 ) strlcat( str, " ", sizeof( str ));
373 			else strlcat( str, " :", sizeof( str ));
374 			strlcat( str, Req->argv[i], sizeof( str ));
375 		}
376 		return IRC_WriteStrClientPrefix( target, prefix, "%s", str );
377 	}
378 
379 	cmd = My_Commands;
380 	while( cmd->name )
381 	{
382 		/* Befehl suchen */
383 		if( strcasecmp( Req->command, cmd->name ) != 0 )
384 		{
385 			cmd++; continue;
386 		}
387 
388 		if( Client_Type( client ) & cmd->type )
389 		{
390 			/* Command is allowed for this client: call it and count produced bytes */
391 			Conn_ResetWCounter( );
392 			result = (cmd->function)( client, Req );
393 			cmd->bytes += Conn_WCounter( );
394 
395 			/* Adjust counters */
396 			if( Client_Type( client ) != CLIENT_SERVER ) cmd->lcount++;
397 			else cmd->rcount++;
398 
399 			return result;
400 		}
401 		else
402 		{
403 			/* Befehl ist fuer diesen Client-Typ nicht erlaubt! */
404 			return IRC_WriteStrClient( client, ERR_NOTREGISTERED_MSG, Client_ID( client ));
405 		}
406 	}
407 	
408 	/* Unbekannter Befehl */
409 	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" );
410 	if( Client_Type( client ) != CLIENT_SERVER ) return IRC_WriteStrClient( client, ERR_UNKNOWNCOMMAND_MSG, Client_ID( client ), Req->command );
411 	else return TRUE;
412 } /* Handle_Request */
413 
414 
415 /* -eof- */