1 /*
2 * Copyright (C) 2012 by Darren Reed.
3 *
4 * See the IPFILTER.LICENCE file for details on licencing.
5 *
6 * $Id$
7 */
8
9 #define IPF_IRC_PROXY
10
11 #define IPF_IRCBUFSZ 96 /* This *MUST* be >= 64! */
12
13
14 void ipf_p_irc_main_load __P((void));
15 void ipf_p_irc_main_unload __P((void));
16 int ipf_p_irc_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
17 int ipf_p_irc_out __P((void *, fr_info_t *, ap_session_t *, nat_t *));
18 int ipf_p_irc_send __P((fr_info_t *, nat_t *));
19 int ipf_p_irc_complete __P((ircinfo_t *, char *, size_t));
20 u_short ipf_irc_atoi __P((char **));
21
22 static frentry_t ircnatfr;
23
24 int irc_proxy_init = 0;
25
26
27 /*
28 * Initialize local structures.
29 */
30 void
ipf_p_irc_main_load()31 ipf_p_irc_main_load()
32 {
33 bzero((char *)&ircnatfr, sizeof(ircnatfr));
34 ircnatfr.fr_ref = 1;
35 ircnatfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
36 MUTEX_INIT(&ircnatfr.fr_lock, "IRC proxy rule lock");
37 irc_proxy_init = 1;
38 }
39
40
41 void
ipf_p_irc_main_unload()42 ipf_p_irc_main_unload()
43 {
44 if (irc_proxy_init == 1) {
45 MUTEX_DESTROY(&ircnatfr.fr_lock);
46 irc_proxy_init = 0;
47 }
48 }
49
50
51 const char *ipf_p_irc_dcctypes[] = {
52 "CHAT ", /* CHAT chat ipnumber portnumber */
53 "SEND ", /* SEND filename ipnumber portnumber */
54 "MOVE ",
55 "TSEND ",
56 "SCHAT ",
57 NULL,
58 };
59
60
61 /*
62 * :A PRIVMSG B :^ADCC CHAT chat 0 0^A\r\n
63 * PRIVMSG B ^ADCC CHAT chat 0 0^A\r\n
64 */
65
66
67 int
ipf_p_irc_complete(ircp,buf,len)68 ipf_p_irc_complete(ircp, buf, len)
69 ircinfo_t *ircp;
70 char *buf;
71 size_t len;
72 {
73 register char *s, c;
74 register size_t i;
75 u_32_t l;
76 int j, k;
77
78 ircp->irc_ipnum = 0;
79 ircp->irc_port = 0;
80
81 if (len < 31)
82 return 0;
83 s = buf;
84 c = *s++;
85 i = len - 1;
86
87 if ((c != ':') && (c != 'P'))
88 return 0;
89
90 if (c == ':') {
91 /*
92 * Loosely check that the source is a nickname of some sort
93 */
94 s++;
95 c = *s;
96 ircp->irc_snick = s;
97 if (!ISALPHA(c))
98 return 0;
99 i--;
100 for (c = *s; !ISSPACE(c) && (i > 0); i--)
101 c = *s++;
102 if (i < 31)
103 return 0;
104 if (c != 'P')
105 return 0;
106 } else
107 ircp->irc_snick = NULL;
108
109 /*
110 * Check command string
111 */
112 if (strncmp(s, "PRIVMSG ", 8))
113 return 0;
114 i -= 8;
115 s += 8;
116 c = *s;
117 ircp->irc_dnick = s;
118
119 /*
120 * Loosely check that the destination is a nickname of some sort
121 */
122 if (!ISALPHA(c))
123 return 0;
124 for (; !ISSPACE(c) && (i > 0); i--)
125 c = *s++;
126 if (i < 20)
127 return 0;
128 s++,
129 i--;
130
131 /*
132 * Look for a ^A to start the DCC
133 */
134 c = *s;
135 if (c == ':') {
136 s++;
137 c = *s;
138 }
139
140 if (strncmp(s, "\001DCC ", 4))
141 return 0;
142
143 i -= 4;
144 s += 4;
145
146 /*
147 * Check for a recognised DCC command
148 */
149 for (j = 0, k = 0; ipf_p_irc_dcctypes[j]; j++) {
150 k = MIN(strlen(ipf_p_irc_dcctypes[j]), i);
151 if (!strncmp(ipf_p_irc_dcctypes[j], s, k))
152 break;
153 }
154 if (!ipf_p_irc_dcctypes[j])
155 return 0;
156
157 ircp->irc_type = s;
158 i -= k;
159 s += k;
160
161 if (i < 11)
162 return 0;
163
164 /*
165 * Check for the arg
166 */
167 c = *s;
168 if (ISSPACE(c))
169 return 0;
170 ircp->irc_arg = s;
171 for (; (c != ' ') && (c != '\001') && (i > 0); i--)
172 c = *s++;
173
174 if (c == '\001') /* In reality a ^A can quote another ^A...*/
175 return 0;
176
177 if (i < 5)
178 return 0;
179
180 s++;
181 i--;
182 c = *s;
183 if (!ISDIGIT(c))
184 return 0;
185 ircp->irc_addr = s;
186 /*
187 * Get the IP#
188 */
189 for (l = 0; ISDIGIT(c) && (i > 0); i--) {
190 l *= 10;
191 l += c - '0';
192 c = *s++;
193 }
194
195 if (i < 4)
196 return 0;
197
198 if (c != ' ')
199 return 0;
200
201 ircp->irc_ipnum = l;
202 s++;
203 i--;
204 c = *s;
205 if (!ISDIGIT(c))
206 return 0;
207 /*
208 * Get the port#
209 */
210 for (l = 0; ISDIGIT(c) && (i > 0); i--) {
211 l *= 10;
212 l += c - '0';
213 c = *s++;
214 }
215 if (i < 3)
216 return 0;
217 if (strncmp(s, "\001\r\n", 3))
218 return 0;
219 s += 3;
220 ircp->irc_len = s - buf;
221 ircp->irc_port = l;
222 return 1;
223 }
224
225
226 int
ipf_p_irc_new(arg,fin,aps,nat)227 ipf_p_irc_new(arg, fin, aps, nat)
228 void *arg;
229 fr_info_t *fin;
230 ap_session_t *aps;
231 nat_t *nat;
232 {
233 ircinfo_t *irc;
234
235 if (fin->fin_v != 4)
236 return -1;
237
238 KMALLOC(irc, ircinfo_t *);
239 if (irc == NULL)
240 return -1;
241
242 nat = nat; /* LINT */
243
244 aps->aps_data = irc;
245 aps->aps_psiz = sizeof(ircinfo_t);
246
247 bzero((char *)irc, sizeof(*irc));
248 return 0;
249 }
250
251
252 int
ipf_p_irc_send(fin,nat)253 ipf_p_irc_send(fin, nat)
254 fr_info_t *fin;
255 nat_t *nat;
256 {
257 char ctcpbuf[IPF_IRCBUFSZ], newbuf[IPF_IRCBUFSZ];
258 tcphdr_t *tcp, tcph, *tcp2 = &tcph;
259 int off, inc = 0, i, dlen;
260 ipf_main_softc_t *softc;
261 size_t nlen = 0, olen;
262 struct in_addr swip;
263 u_short a5, sp;
264 ircinfo_t *irc;
265 fr_info_t fi;
266 nat_t *nat2;
267 u_int a1;
268 ip_t *ip;
269 mb_t *m;
270 #ifdef MENTAT
271 mb_t *m1;
272 #endif
273 softc = fin->fin_main_soft;
274
275 m = fin->fin_m;
276 ip = fin->fin_ip;
277 tcp = (tcphdr_t *)fin->fin_dp;
278 bzero(ctcpbuf, sizeof(ctcpbuf));
279 off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
280
281 dlen = MSGDSIZE(m) - off;
282 if (dlen <= 0)
283 return 0;
284 COPYDATA(m, off, MIN(sizeof(ctcpbuf), dlen), ctcpbuf);
285
286 if (dlen <= 0)
287 return 0;
288 ctcpbuf[sizeof(ctcpbuf) - 1] = '\0';
289 *newbuf = '\0';
290
291 irc = nat->nat_aps->aps_data;
292 if (ipf_p_irc_complete(irc, ctcpbuf, dlen) == 0)
293 return 0;
294
295 /*
296 * check that IP address in the DCC reply is the same as the
297 * sender of the command - prevents use for port scanning.
298 */
299 if (irc->irc_ipnum != ntohl(nat->nat_osrcaddr))
300 return 0;
301
302 a5 = irc->irc_port;
303
304 /*
305 * Calculate new address parts for the DCC command
306 */
307 a1 = ntohl(ip->ip_src.s_addr);
308 olen = irc->irc_len;
309 i = irc->irc_addr - ctcpbuf;
310 i++;
311 (void) strncpy(newbuf, ctcpbuf, i);
312 /* DO NOT change these! */
313 #if defined(SNPRINTF) && defined(KERNEL)
314 SNPRINTF(newbuf, sizeof(newbuf) - i, "%u %u\001\r\n", a1, a5);
315 #else
316 (void) sprintf(newbuf, "%u %u\001\r\n", a1, a5);
317 #endif
318
319 nlen = strlen(newbuf);
320 inc = nlen - olen;
321
322 if ((inc + fin->fin_plen) > 65535)
323 return 0;
324
325 #ifdef MENTAT
326 for (m1 = m; m1->b_cont; m1 = m1->b_cont)
327 ;
328 if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
329 mblk_t *nm;
330
331 /* alloc enough to keep same trailer space for lower driver */
332 nm = allocb(nlen, BPRI_MED);
333 PANIC((!nm),("ipf_p_irc_out: allocb failed"));
334
335 nm->b_band = m1->b_band;
336 nm->b_wptr += nlen;
337
338 m1->b_wptr -= olen;
339 PANIC((m1->b_wptr < m1->b_rptr),
340 ("ipf_p_irc_out: cannot handle fragmented data block"));
341
342 linkb(m1, nm);
343 } else {
344 # if SOLARIS && defined(ICK_VALID)
345 if (m1->b_datap->db_struiolim == m1->b_wptr)
346 m1->b_datap->db_struiolim += inc;
347 m1->b_datap->db_struioflag &= ~STRUIO_IP;
348 # endif
349 m1->b_wptr += inc;
350 }
351 #else
352 if (inc < 0)
353 m_adj(m, inc);
354 /* the mbuf chain will be extended if necessary by m_copyback() */
355 #endif
356 COPYBACK(m, off, nlen, newbuf);
357 fin->fin_flx |= FI_DOCKSUM;
358
359 if (inc != 0) {
360 #if defined(MENTAT)
361 register u_32_t sum1, sum2;
362
363 sum1 = fin->fin_plen;
364 sum2 = fin->fin_plen + inc;
365
366 /* Because ~1 == -2, We really need ~1 == -1 */
367 if (sum1 > sum2)
368 sum2--;
369 sum2 -= sum1;
370 sum2 = (sum2 & 0xffff) + (sum2 >> 16);
371
372 ipf_fix_outcksum(0, &ip->ip_sum, sum2, 0);
373 #endif
374 fin->fin_plen += inc;
375 ip->ip_len = htons(fin->fin_plen);
376 fin->fin_dlen += inc;
377 }
378
379 /*
380 * Add skeleton NAT entry for connection which will come back the
381 * other way.
382 */
383 sp = htons(a5);
384 /*
385 * Don't allow the PORT command to specify a port < 1024 due to
386 * security crap.
387 */
388 if (ntohs(sp) < 1024)
389 return 0;
390
391 /*
392 * The server may not make the connection back from port 20, but
393 * it is the most likely so use it here to check for a conflicting
394 * mapping.
395 */
396 bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
397 fi.fin_data[0] = sp;
398 fi.fin_data[1] = fin->fin_data[1];
399 nat2 = ipf_nat_outlookup(fin, IPN_TCP, nat->nat_pr[1], nat->nat_nsrcip,
400 ip->ip_dst);
401 if (nat2 == NULL) {
402 #ifdef USE_MUTEXES
403 ipf_nat_softc_t *softn = softc->ipf_nat_soft;
404 #endif
405
406 bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
407 bzero((char *)tcp2, sizeof(*tcp2));
408 tcp2->th_win = htons(8192);
409 tcp2->th_sport = sp;
410 tcp2->th_dport = 0; /* XXX - don't specify remote port */
411 fi.fin_data[0] = ntohs(sp);
412 fi.fin_data[1] = 0;
413 fi.fin_dp = (char *)tcp2;
414 fi.fin_fr = &ircnatfr;
415 fi.fin_dlen = sizeof(*tcp2);
416 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
417 swip = ip->ip_src;
418 ip->ip_src = nat->nat_nsrcip;
419 MUTEX_ENTER(&softn->ipf_nat_new);
420 nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL,
421 NAT_SLAVE|IPN_TCP|SI_W_DPORT, NAT_OUTBOUND);
422 MUTEX_EXIT(&softn->ipf_nat_new);
423 if (nat2 != NULL) {
424 (void) ipf_nat_proto(&fi, nat2, 0);
425 MUTEX_ENTER(&nat2->nat_lock);
426 ipf_nat_update(&fi, nat2);
427 MUTEX_EXIT(&nat2->nat_lock);
428
429 (void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT);
430 }
431 ip->ip_src = swip;
432 }
433 return inc;
434 }
435
436
437 int
ipf_p_irc_out(arg,fin,aps,nat)438 ipf_p_irc_out(arg, fin, aps, nat)
439 void *arg;
440 fr_info_t *fin;
441 ap_session_t *aps;
442 nat_t *nat;
443 {
444 aps = aps; /* LINT */
445 return ipf_p_irc_send(fin, nat);
446 }
447