1 /*
2 * Copyright (C) 2000-2003 Darren Reed
3 *
4 * See the IPFILTER.LICENCE file for details on licencing.
5 *
6 * $Id: ip_irc_pxy.c,v 2.39.2.4 2005/02/04 10:22:55 darrenr Exp $
7 *
8 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
9 * Use is subject to license terms.
10 */
11
12 #define IPF_IRC_PROXY
13
14 #define IPF_IRCBUFSZ 96 /* This *MUST* be >= 64! */
15
16 typedef struct ifs_ircpxy {
17 frentry_t ircnatfr;
18 int irc_proxy_init;
19 } ifs_ircpxy_t;
20
21
22 int ippr_irc_init __P((void **, ipf_stack_t *));
23 void ippr_irc_fini __P((void **, ipf_stack_t *));
24 int ippr_irc_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
25 int ippr_irc_out __P((fr_info_t *, ap_session_t *, nat_t *, void *));
26 int ippr_irc_send __P((fr_info_t *, nat_t *, ifs_ircpxy_t *));
27 int ippr_irc_complete __P((ircinfo_t *, char *, size_t));
28 u_short ipf_irc_atoi __P((char **));
29
30 /*
31 * Initialize local structures.
32 */
33 /*ARGSUSED*/
ippr_irc_init(private,ifs)34 int ippr_irc_init(private, ifs)
35 void **private;
36 ipf_stack_t *ifs;
37 {
38 ifs_ircpxy_t *ifsirc;
39
40 KMALLOC(ifsirc, ifs_ircpxy_t *);
41 if (ifsirc == NULL)
42 return -1;
43
44 bzero((char *)&ifsirc->ircnatfr, sizeof(ifsirc->ircnatfr));
45 ifsirc->ircnatfr.fr_ref = 1;
46 ifsirc->ircnatfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
47 MUTEX_INIT(&ifsirc->ircnatfr.fr_lock, "IRC proxy rule lock");
48 ifsirc->irc_proxy_init = 1;
49
50 *private = (void *)ifsirc;
51
52 return 0;
53 }
54
55
56 /*ARGSUSED*/
ippr_irc_fini(private,ifs)57 void ippr_irc_fini(private, ifs)
58 void **private;
59 ipf_stack_t *ifs;
60 {
61 ifs_ircpxy_t *ifsirc = *((ifs_ircpxy_t **)private);
62
63 if (ifsirc->irc_proxy_init == 1) {
64 MUTEX_DESTROY(&ifsirc->ircnatfr.fr_lock);
65 ifsirc->irc_proxy_init = 0;
66 }
67
68 KFREE(ifsirc);
69 *private = NULL;
70 }
71
72
73 static char *ippr_irc_dcctypes[] = {
74 "CHAT ", /* CHAT chat ipnumber portnumber */
75 "SEND ", /* SEND filename ipnumber portnumber */
76 "MOVE ",
77 "TSEND ",
78 "SCHAT ",
79 NULL,
80 };
81
82
83 /*
84 * :A PRIVMSG B :^ADCC CHAT chat 0 0^A\r\n
85 * PRIVMSG B ^ADCC CHAT chat 0 0^A\r\n
86 */
87
88
ippr_irc_complete(ircp,buf,len)89 int ippr_irc_complete(ircp, buf, len)
90 ircinfo_t *ircp;
91 char *buf;
92 size_t len;
93 {
94 register char *s, c;
95 register size_t i;
96 u_32_t l;
97 int j, k;
98
99 ircp->irc_ipnum = 0;
100 ircp->irc_port = 0;
101
102 if (len < 31)
103 return 0;
104 s = buf;
105 c = *s++;
106 i = len - 1;
107
108 if ((c != ':') && (c != 'P'))
109 return 0;
110
111 if (c == ':') {
112 /*
113 * Loosely check that the source is a nickname of some sort
114 */
115 s++;
116 c = *s;
117 ircp->irc_snick = s;
118 if (!ISALPHA(c))
119 return 0;
120 i--;
121 for (c = *s; !ISSPACE(c) && (i > 0); i--)
122 c = *s++;
123 if (i < 31)
124 return 0;
125 if (c != 'P')
126 return 0;
127 } else
128 ircp->irc_snick = NULL;
129
130 /*
131 * Check command string
132 */
133 if (strncmp(s, "PRIVMSG ", 8))
134 return 0;
135 i -= 8;
136 s += 8;
137 c = *s;
138 ircp->irc_dnick = s;
139
140 /*
141 * Loosely check that the destination is a nickname of some sort
142 */
143 if (!ISALPHA(c))
144 return 0;
145 for (; !ISSPACE(c) && (i > 0); i--)
146 c = *s++;
147 if (i < 20)
148 return 0;
149 s++,
150 i--;
151
152 /*
153 * Look for a ^A to start the DCC
154 */
155 c = *s;
156 if (c == ':') {
157 s++;
158 c = *s;
159 }
160
161 if (strncmp(s, "\001DCC ", 4))
162 return 0;
163
164 i -= 4;
165 s += 4;
166
167 /*
168 * Check for a recognised DCC command
169 */
170 for (j = 0, k = 0; ippr_irc_dcctypes[j]; j++) {
171 k = MIN(strlen(ippr_irc_dcctypes[j]), i);
172 if (!strncmp(ippr_irc_dcctypes[j], s, k))
173 break;
174 }
175 if (!ippr_irc_dcctypes[j])
176 return 0;
177
178 ircp->irc_type = s;
179 i -= k;
180 s += k;
181
182 if (i < 11)
183 return 0;
184
185 /*
186 * Check for the arg
187 */
188 c = *s;
189 if (ISSPACE(c))
190 return 0;
191 ircp->irc_arg = s;
192 for (; (c != ' ') && (c != '\001') && (i > 0); i--)
193 c = *s++;
194
195 if (c == '\001') /* In reality a ^A can quote another ^A...*/
196 return 0;
197
198 if (i < 5)
199 return 0;
200
201 s++;
202 i--;
203 c = *s;
204 if (!ISDIGIT(c))
205 return 0;
206 ircp->irc_addr = s;
207 /*
208 * Get the IP#
209 */
210 for (l = 0; ISDIGIT(c) && (i > 0); i--) {
211 l *= 10;
212 l += c - '0';
213 c = *s++;
214 }
215
216 if (i < 4)
217 return 0;
218
219 if (c != ' ')
220 return 0;
221
222 ircp->irc_ipnum = l;
223 s++;
224 i--;
225 c = *s;
226 if (!ISDIGIT(c))
227 return 0;
228 /*
229 * Get the port#
230 */
231 for (l = 0; ISDIGIT(c) && (i > 0); i--) {
232 l *= 10;
233 l += c - '0';
234 c = *s++;
235 }
236 if (i < 3)
237 return 0;
238 if (strncmp(s, "\001\r\n", 3))
239 return 0;
240 s += 3;
241 ircp->irc_len = s - buf;
242 ircp->irc_port = l;
243 return 1;
244 }
245
246
247 /*ARGSUSED*/
ippr_irc_new(fin,aps,nat,private)248 int ippr_irc_new(fin, aps, nat, private)
249 fr_info_t *fin;
250 ap_session_t *aps;
251 nat_t *nat;
252 void *private;
253 {
254 ircinfo_t *irc;
255
256 KMALLOC(irc, ircinfo_t *);
257 if (irc == NULL)
258 return -1;
259
260 fin = fin; /* LINT */
261 nat = nat; /* LINT */
262
263 aps->aps_data = irc;
264 aps->aps_psiz = sizeof(ircinfo_t);
265
266 bzero((char *)irc, sizeof(*irc));
267 return 0;
268 }
269
270
ippr_irc_send(fin,nat,ifsirc)271 int ippr_irc_send(fin, nat, ifsirc)
272 fr_info_t *fin;
273 nat_t *nat;
274 ifs_ircpxy_t *ifsirc;
275 {
276 char ctcpbuf[IPF_IRCBUFSZ], newbuf[IPF_IRCBUFSZ];
277 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
278 int off, inc = 0, i, dlen;
279 size_t nlen = 0, olen;
280 struct in_addr swip;
281 u_short a5, sp;
282 ircinfo_t *irc;
283 fr_info_t fi;
284 nat_t *nat2;
285 u_int a1;
286 ip_t *ip;
287 mb_t *m;
288 #ifdef MENTAT
289 mb_t *m1;
290 #endif
291
292 m = fin->fin_m;
293 ip = fin->fin_ip;
294 tcp = (tcphdr_t *)fin->fin_dp;
295 bzero(ctcpbuf, sizeof(ctcpbuf));
296 off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
297
298 #ifdef __sgi
299 dlen = fin->fin_plen - off;
300 #else
301 dlen = MSGDSIZE(m) - off;
302 #endif
303 if (dlen <= 0)
304 return 0;
305 COPYDATA(m, off, MIN(sizeof(ctcpbuf), dlen), ctcpbuf);
306
307 if (dlen <= 0)
308 return 0;
309 ctcpbuf[sizeof(ctcpbuf) - 1] = '\0';
310 *newbuf = '\0';
311
312 irc = nat->nat_aps->aps_data;
313 if (ippr_irc_complete(irc, ctcpbuf, dlen) == 0)
314 return 0;
315
316 /*
317 * check that IP address in the PORT/PASV reply is the same as the
318 * sender of the command - prevents using PORT for port scanning.
319 */
320 if (irc->irc_ipnum != ntohl(nat->nat_inip.s_addr))
321 return 0;
322
323 a5 = irc->irc_port;
324
325 /*
326 * Calculate new address parts for the DCC command
327 */
328 a1 = ntohl(ip->ip_src.s_addr);
329 olen = irc->irc_len;
330 i = irc->irc_addr - ctcpbuf;
331 i++;
332 (void) strncpy(newbuf, ctcpbuf, i);
333 /* DO NOT change these! */
334 #if defined(SNPRINTF) && defined(KERNEL)
335 (void) SNPRINTF(newbuf, sizeof(newbuf) - i, "%u %u\001\r\n", a1, a5);
336 #else
337 (void) sprintf(newbuf, "%u %u\001\r\n", a1, a5);
338 #endif
339
340 nlen = strlen(newbuf);
341 inc = nlen - olen;
342
343 if ((inc + ip->ip_len) > 65535)
344 return 0;
345
346 #ifdef MENTAT
347 for (m1 = m; m1->b_cont; m1 = m1->b_cont)
348 ;
349 if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
350 mblk_t *nm;
351
352 /* alloc enough to keep same trailer space for lower driver */
353 nm = allocb(nlen, BPRI_MED);
354 PANIC((!nm),("ippr_irc_out: allocb failed"));
355
356 nm->b_band = m1->b_band;
357 nm->b_wptr += nlen;
358
359 m1->b_wptr -= olen;
360 PANIC((m1->b_wptr < m1->b_rptr),
361 ("ippr_irc_out: cannot handle fragmented data block"));
362
363 linkb(m1, nm);
364 } else {
365 # if SOLARIS && defined(ICK_VALID)
366 if (m1->b_datap->db_struiolim == m1->b_wptr)
367 m1->b_datap->db_struiolim += inc;
368 m1->b_datap->db_struioflag &= ~STRUIO_IP;
369 # endif
370 m1->b_wptr += inc;
371 }
372 #else
373 if (inc < 0)
374 m_adj(m, inc);
375 /* the mbuf chain will be extended if necessary by m_copyback() */
376 #endif
377 COPYBACK(m, off, nlen, newbuf);
378
379 if (inc != 0) {
380 #if defined(MENTAT) || defined(__sgi)
381 register u_32_t sum1, sum2;
382
383 sum1 = ip->ip_len;
384 sum2 = ip->ip_len + inc;
385
386 /* Because ~1 == -2, We really need ~1 == -1 */
387 if (sum1 > sum2)
388 sum2--;
389 sum2 -= sum1;
390 sum2 = (sum2 & 0xffff) + (sum2 >> 16);
391
392 fix_outcksum(&ip->ip_sum, sum2);
393 #endif
394 ip->ip_len += inc;
395 }
396
397 /*
398 * Add skeleton NAT entry for connection which will come back the
399 * other way.
400 */
401 sp = htons(a5);
402 /*
403 * Don't allow the PORT command to specify a port < 1024 due to
404 * security crap.
405 */
406 if (ntohs(sp) < 1024)
407 return 0;
408
409 /*
410 * The server may not make the connection back from port 20, but
411 * it is the most likely so use it here to check for a conflicting
412 * mapping.
413 */
414 bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
415 fi.fin_data[0] = sp;
416 fi.fin_data[1] = fin->fin_data[1];
417 nat2 = nat_outlookup(fin, IPN_TCP, nat->nat_p, nat->nat_inip,
418 ip->ip_dst);
419 if (nat2 == NULL) {
420 bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
421 bzero((char *)tcp2, sizeof(*tcp2));
422 tcp2->th_win = htons(8192);
423 tcp2->th_sport = sp;
424 tcp2->th_dport = 0; /* XXX - don't specify remote port */
425 fi.fin_data[0] = ntohs(sp);
426 fi.fin_data[1] = 0;
427 fi.fin_dp = (char *)tcp2;
428 fi.fin_fr = &ifsirc->ircnatfr;
429 fi.fin_dlen = sizeof(*tcp2);
430 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
431 swip = ip->ip_src;
432 ip->ip_src = nat->nat_inip;
433 nat2 = nat_new(&fi, nat->nat_ptr, NULL,
434 NAT_SLAVE|IPN_TCP|SI_W_DPORT, NAT_OUTBOUND);
435 if (nat2 != NULL) {
436 (void) nat_proto(&fi, nat2, 0);
437 nat_update(&fi, nat2, nat2->nat_ptr);
438
439 (void) fr_addstate(&fi, NULL, SI_W_DPORT);
440 }
441 ip->ip_src = swip;
442 }
443 return inc;
444 }
445
446
ippr_irc_out(fin,aps,nat,private)447 int ippr_irc_out(fin, aps, nat, private)
448 fr_info_t *fin;
449 ap_session_t *aps;
450 nat_t *nat;
451 void *private;
452 {
453 aps = aps; /* LINT */
454 return ippr_irc_send(fin, nat, (ifs_ircpxy_t *)private);
455 }
456