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Avoid a possible buffer overflow in processpap
[l2tpns.git] / radius.c
1 // L2TPNS Radius Stuff
2
3 char const *cvs_id_radius = "$Id: radius.c,v 1.22 2005/01/05 14:35:01 bodea Exp $";
4
5 #include <time.h>
6 #include <stdio.h>
7 #include <sys/types.h>
8 #include <sys/socket.h>
9 #include <malloc.h>
10 #include <string.h>
11 #include <fcntl.h>
12 #include <arpa/inet.h>
13 #include <ctype.h>
14 #include <netinet/in.h>
15 #include "md5.h"
16 #include "constants.h"
17 #include "l2tpns.h"
18 #include "plugin.h"
19 #include "util.h"
20
21 extern radiust *radius;
22 extern sessiont *session;
23 extern tunnelt *tunnel;
24 extern configt *config;
25 extern int *radfds;
26 extern ip_filtert *ip_filters;
27
28 // Set up socket for radius requests
29 void initrad(void)
30 {
31 int i;
32 LOG(3, 0, 0, "Creating %d sockets for RADIUS queries\n", config->num_radfds);
33 radfds = calloc(sizeof(int), config->num_radfds);
34 for (i = 0; i < config->num_radfds; i++)
35 {
36 int flags;
37 radfds[i] = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
38 flags = fcntl(radfds[i], F_GETFL, 0);
39 fcntl(radfds[i], F_SETFL, flags | O_NONBLOCK);
40 }
41 }
42
43 void radiusclear(uint16_t r, sessionidt s)
44 {
45 if (s) session[s].radius = 0;
46 memset(&radius[r], 0, sizeof(radius[r])); // radius[r].state = RADIUSNULL;
47 }
48
49 static uint16_t get_free_radius()
50 {
51 int count;
52 static uint32_t next_radius_id = 0;
53
54 for (count = MAXRADIUS; count > 0 ; --count)
55 {
56 ++next_radius_id; // Find the next ID to check.
57 if (next_radius_id >= MAXRADIUS)
58 next_radius_id = 1;
59
60 if (radius[next_radius_id].state == RADIUSNULL)
61 {
62 return next_radius_id;
63 }
64 }
65
66 LOG(0, 0, 0, "Can't find a free radius session! This is very bad!\n");
67 return 0;
68 }
69
70 uint16_t radiusnew(sessionidt s)
71 {
72 uint16_t r = session[s].radius;
73
74 /* re-use */
75 if (r)
76 {
77 LOG(3, s, session[s].tunnel, "Re-used radius %d\n", r);
78 return r;
79 }
80
81 if (!(r = get_free_radius()))
82 {
83 LOG(1, s, session[s].tunnel, "No free RADIUS sessions\n");
84 STAT(radius_overflow);
85 return 0;
86 };
87
88 memset(&radius[r], 0, sizeof(radius[r]));
89 session[s].radius = r;
90 radius[r].session = s;
91 radius[r].state = RADIUSWAIT;
92 radius[r].retry = TIME + 1200; // Wait at least 120 seconds to re-claim this.
93
94 LOG(3, s, session[s].tunnel, "Allocated radius %d\n", r);
95 return r;
96 }
97
98 // Send a RADIUS request
99 void radiussend(uint16_t r, uint8_t state)
100 {
101 struct sockaddr_in addr;
102 uint8_t b[4096]; // RADIUS packet
103 char pass[129];
104 int pl;
105 uint8_t *p;
106 sessionidt s;
107
108 CSTAT(radiussend);
109
110 s = radius[r].session;
111 if (!config->numradiusservers)
112 {
113 LOG(0, s, session[s].tunnel, "No RADIUS servers\n");
114 return;
115 }
116 if (!*config->radiussecret)
117 {
118 LOG(0, s, session[s].tunnel, "No RADIUS secret\n");
119 return;
120 }
121
122 if (state != RADIUSAUTH && !config->radius_accounting)
123 {
124 // Radius accounting is turned off
125 radiusclear(r, s);
126 return;
127 }
128
129 if (radius[r].state != state)
130 radius[r].try = 0;
131
132 radius[r].state = state;
133 radius[r].retry = backoff(radius[r].try++);
134 LOG(4, s, session[s].tunnel, "Send RADIUS id %d sock %d state %s try %d\n",
135 r >> RADIUS_SHIFT, r & RADIUS_MASK,
136 radius_state(radius[r].state), radius[r].try);
137
138 if (radius[r].try > config->numradiusservers * 2)
139 {
140 if (s)
141 {
142 if (state == RADIUSAUTH)
143 sessionshutdown(s, "RADIUS timeout");
144 else
145 {
146 LOG(1, s, session[s].tunnel, "RADIUS timeout, but in state %s so don't timeout session\n",
147 radius_state(state));
148 radiusclear(r, s);
149 }
150 STAT(radius_timeout);
151 }
152 else
153 {
154 STAT(radius_retries);
155 radius[r].state = RADIUSWAIT;
156 radius[r].retry = 100;
157 }
158 return;
159 }
160 // contruct RADIUS access request
161 switch (state)
162 {
163 case RADIUSAUTH:
164 b[0] = 1; // access request
165 break;
166 case RADIUSSTART:
167 case RADIUSSTOP:
168 b[0] = 4; // accounting request
169 break;
170 default:
171 LOG(0, 0, 0, "Unknown radius state %d\n", state);
172 }
173 b[1] = r >> RADIUS_SHIFT; // identifier
174 memcpy(b + 4, radius[r].auth, 16);
175 p = b + 20;
176 if (s)
177 {
178 *p = 1; // user name
179 p[1] = strlen(session[s].user) + 2;
180 strcpy(p + 2, session[s].user);
181 p += p[1];
182 }
183 if (state == RADIUSAUTH)
184 {
185 if (radius[r].chap)
186 {
187 *p = 3; // CHAP password
188 p[1] = 19; // length
189 p[2] = radius[r].id; // ID
190 memcpy(p + 3, radius[r].pass, 16); // response from CHAP request
191 p += p[1];
192 *p = 60; // CHAP Challenge
193 p[1] = 18; // length
194 memcpy(p + 2, radius[r].auth, 16);
195 p += p[1];
196 }
197 else
198 {
199 strcpy(pass, radius[r].pass);
200 pl = strlen(pass);
201 while (pl & 15)
202 pass[pl++] = 0; // pad
203 if (pl)
204 { // encrypt
205 hasht hash;
206 int p = 0;
207 while (p < pl)
208 {
209 MD5_CTX ctx;
210 MD5Init(&ctx);
211 MD5Update(&ctx, config->radiussecret, strlen(config->radiussecret));
212 if (p)
213 MD5Update(&ctx, pass + p - 16, 16);
214 else
215 MD5Update(&ctx, radius[r].auth, 16);
216 MD5Final(hash, &ctx);
217 do
218 {
219 pass[p] ^= hash[p & 15];
220 p++;
221 }
222 while (p & 15);
223 }
224 }
225 *p = 2; // password
226 p[1] = pl + 2;
227 if (pl)
228 memcpy(p + 2, pass, pl);
229 p += p[1];
230 }
231 }
232 else if (state == RADIUSSTART || state == RADIUSSTOP)
233 { // accounting
234 *p = 40; // accounting type
235 p[1] = 6;
236 *(uint32_t *) (p + 2) = htonl((state == RADIUSSTART) ? 1 : 2);
237 p += p[1];
238 if (s)
239 {
240 *p = 44; // session ID
241 p[1] = 18;
242 sprintf(p + 2, "%08X%08X", session[s].id, session[s].opened);
243 p += p[1];
244 if (state == RADIUSSTOP)
245 { // stop
246 *p = 42; // input octets
247 p[1] = 6;
248 *(uint32_t *) (p + 2) = htonl(session[s].cin);
249 p += p[1];
250 *p = 43; // output octets
251 p[1] = 6;
252 *(uint32_t *) (p + 2) = htonl(session[s].cout);
253 p += p[1];
254 *p = 46; // session time
255 p[1] = 6;
256 *(uint32_t *) (p + 2) = htonl(time(NULL) - session[s].opened);
257 p += p[1];
258 *p = 47; // input packets
259 p[1] = 6;
260 *(uint32_t *) (p + 2) = htonl(session[s].pin);
261 p += p[1];
262 *p = 48; // output spackets
263 p[1] = 6;
264 *(uint32_t *) (p + 2) = htonl(session[s].pout);
265 p += p[1];
266 }
267 else
268 { // start
269 *p = 41; // delay
270 p[1] = 6;
271 *(uint32_t *) (p + 2) = htonl(time(NULL) - session[s].opened);
272 p += p[1];
273 }
274 }
275 }
276 if (s)
277 {
278 *p = 5; // NAS-Port
279 p[1] = 6;
280 *(uint32_t *) (p + 2) = htonl(s);
281 p += p[1];
282 }
283 if (s && session[s].ip)
284 {
285 *p = 8; // Framed-IP-Address
286 p[1] = 6;
287 *(uint32_t *) (p + 2) = htonl(session[s].ip);
288 p += p[1];
289 }
290 if (*session[s].called)
291 {
292 *p = 30; // called
293 p[1] = strlen(session[s].called) + 2;
294 strcpy(p + 2, session[s].called);
295 p += p[1];
296 }
297 if (*radius[r].calling)
298 {
299 *p = 31; // calling
300 p[1] = strlen(radius[r].calling) + 2;
301 strcpy(p + 2, radius[r].calling);
302 p += p[1];
303 }
304 else if (*session[s].calling)
305 {
306 *p = 31; // calling
307 p[1] = strlen(session[s].calling) + 2;
308 strcpy(p + 2, session[s].calling);
309 p += p[1];
310 }
311 // NAS-IP-Address
312 *p = 4;
313 p[1] = 6;
314 *(uint32_t *)(p + 2) = config->bind_address;
315 p += p[1];
316
317 // All AVpairs added
318 *(uint16_t *) (b + 2) = htons(p - b);
319 if (state != RADIUSAUTH)
320 {
321 // Build auth for accounting packet
322 char z[16] = {0};
323 char hash[16] = {0};
324 MD5_CTX ctx;
325 MD5Init(&ctx);
326 MD5Update(&ctx, b, 4);
327 MD5Update(&ctx, z, 16);
328 MD5Update(&ctx, b + 20, (p - b) - 20);
329 MD5Update(&ctx, config->radiussecret, strlen(config->radiussecret));
330 MD5Final(hash, &ctx);
331 memcpy(b + 4, hash, 16);
332 memcpy(radius[r].auth, hash, 16);
333 }
334 memset(&addr, 0, sizeof(addr));
335 addr.sin_family = AF_INET;
336 *(uint32_t *) & addr.sin_addr = config->radiusserver[(radius[r].try - 1) % config->numradiusservers];
337 {
338 // get radius port
339 uint16_t port = config->radiusport[(radius[r].try - 1) % config->numradiusservers];
340 // assume RADIUS accounting port is the authentication port +1
341 addr.sin_port = htons((state == RADIUSAUTH) ? port : port+1);
342 }
343
344 LOG_HEX(5, "RADIUS Send", b, (p - b));
345 sendto(radfds[r & RADIUS_MASK], b, p - b, 0, (void *) &addr, sizeof(addr));
346 }
347
348 // process RADIUS response
349 void processrad(uint8_t *buf, int len, char socket_index)
350 {
351 uint8_t b[MAXCONTROL];
352 MD5_CTX ctx;
353 uint16_t r;
354 sessionidt s;
355 tunnelidt t = 0;
356 hasht hash;
357 uint8_t routes = 0;
358 int r_code;
359 int r_id;
360
361 CSTAT(processrad);
362
363 LOG_HEX(5, "RADIUS Response", buf, len);
364 if (len < 20 || len < ntohs(*(uint16_t *) (buf + 2)))
365 {
366 LOG(1, 0, 0, "Duff RADIUS response length %d\n", len);
367 return ;
368 }
369
370 r_code = buf[0]; // response type
371 r_id = buf[1]; // radius reply indentifier.
372
373 len = ntohs(*(uint16_t *) (buf + 2));
374 r = socket_index | (r_id << RADIUS_SHIFT);
375 s = radius[r].session;
376 LOG(3, s, session[s].tunnel, "Received %s, radius %d response for session %u (%s, id %d)\n",
377 radius_state(radius[r].state), r, s, radius_code(r_code), r_id);
378
379 if (!s && radius[r].state != RADIUSSTOP)
380 {
381 LOG(1, s, session[s].tunnel, " Unexpected RADIUS response\n");
382 return;
383 }
384 if (radius[r].state != RADIUSAUTH && radius[r].state != RADIUSSTART && radius[r].state != RADIUSSTOP)
385 {
386 LOG(1, s, session[s].tunnel, " Unexpected RADIUS response\n");
387 return;
388 }
389 t = session[s].tunnel;
390 MD5Init(&ctx);
391 MD5Update(&ctx, buf, 4);
392 MD5Update(&ctx, radius[r].auth, 16);
393 MD5Update(&ctx, buf + 20, len - 20);
394 MD5Update(&ctx, config->radiussecret, strlen(config->radiussecret));
395 MD5Final(hash, &ctx);
396 do {
397 if (memcmp(hash, buf + 4, 16))
398 {
399 LOG(0, s, session[s].tunnel, " Incorrect auth on RADIUS response!! (wrong secret in radius config?)\n");
400 return; // Do nothing. On timeout, it will try the next radius server.
401 }
402
403 if ((radius[r].state == RADIUSAUTH && r_code != AccessAccept && r_code != AccessReject) ||
404 ((radius[r].state == RADIUSSTART || radius[r].state == RADIUSSTOP) && r_code != AccountingResponse))
405 {
406 LOG(1, s, session[s].tunnel, " Unexpected RADIUS response %s\n", radius_code(r_code));
407 return; // We got something we didn't expect. Let the timeouts take
408 // care off finishing the radius session if that's really correct.
409 }
410
411 if (radius[r].state == RADIUSAUTH)
412 {
413 // run post-auth plugin
414 struct param_post_auth packet = {
415 &tunnel[t],
416 &session[s],
417 session[s].user,
418 (r_code == AccessAccept),
419 radius[r].chap ? PPPCHAP : PPPPAP
420 };
421
422 run_plugins(PLUGIN_POST_AUTH, &packet);
423 r_code = packet.auth_allowed ? AccessAccept : AccessReject;
424
425 // process auth response
426 if (radius[r].chap)
427 {
428 // CHAP
429 uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
430 if (!p) return; // Abort!
431
432 *p = (r_code == AccessAccept) ? 3 : 4; // ack/nak
433 p[1] = radius[r].id;
434 *(uint16_t *) (p + 2) = ntohs(4); // no message
435 tunnelsend(b, (p - b) + 4, t); // send it
436
437 LOG(3, s, session[s].tunnel, " CHAP User %s authentication %s.\n", session[s].user,
438 (r_code == AccessAccept) ? "allowed" : "denied");
439 }
440 else
441 {
442 // PAP
443 uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
444 if (!p) return; // Abort!
445
446 // ack/nak
447 *p = r_code;
448 p[1] = radius[r].id;
449 *(uint16_t *) (p + 2) = ntohs(5);
450 p[4] = 0; // no message
451 tunnelsend(b, (p - b) + 5, t); // send it
452
453 LOG(3, s, session[s].tunnel, " PAP User %s authentication %s.\n", session[s].user,
454 (r_code == AccessAccept) ? "allowed" : "denied");
455 }
456
457 if (r_code == AccessAccept)
458 {
459 // Login successful
460 // Extract IP, routes, etc
461 uint8_t *p = buf + 20;
462 uint8_t *e = buf + len;
463 for (; p + 2 <= e && p[1] && p + p[1] <= e; p += p[1])
464 {
465 if (*p == 8)
466 {
467 // Framed-IP-Address
468 if (p[1] < 6) continue;
469 session[s].ip = ntohl(*(uint32_t *) (p + 2));
470 session[s].ip_pool_index = -1;
471 LOG(3, s, session[s].tunnel, " Radius reply contains IP address %s\n",
472 fmtaddr(htonl(session[s].ip), 0));
473 }
474 else if (*p == 135)
475 {
476 // DNS address
477 if (p[1] < 6) continue;
478 session[s].dns1 = ntohl(*(uint32_t *) (p + 2));
479 LOG(3, s, session[s].tunnel, " Radius reply contains primary DNS address %s\n",
480 fmtaddr(htonl(session[s].dns1), 0));
481 }
482 else if (*p == 136)
483 {
484 // DNS address
485 if (p[1] < 6) continue;
486 session[s].dns2 = ntohl(*(uint32_t *) (p + 2));
487 LOG(3, s, session[s].tunnel, " Radius reply contains secondary DNS address %s\n",
488 fmtaddr(htonl(session[s].dns2), 0));
489 }
490 else if (*p == 22)
491 {
492 // Framed-Route
493 in_addr_t ip = 0, mask = 0;
494 uint8_t u = 0;
495 uint8_t bits = 0;
496 uint8_t *n = p + 2;
497 uint8_t *e = p + p[1];
498 while (n < e && (isdigit(*n) || *n == '.'))
499 {
500 if (*n == '.')
501 {
502 ip = (ip << 8) + u;
503 u = 0;
504 }
505 else
506 u = u * 10 + *n - '0';
507 n++;
508 }
509 ip = (ip << 8) + u;
510 if (*n == '/')
511 {
512 n++;
513 while (n < e && isdigit(*n))
514 bits = bits * 10 + *n++ - '0';
515 mask = (( -1) << (32 - bits));
516 }
517 else if ((ip >> 24) < 128)
518 mask = 0xFF0000;
519 else if ((ip >> 24) < 192)
520 mask = 0xFFFF0000;
521 else
522 mask = 0xFFFFFF00;
523
524 if (routes == MAXROUTE)
525 {
526 LOG(1, s, session[s].tunnel, " Too many routes\n");
527 }
528 else if (ip)
529 {
530 LOG(3, s, session[s].tunnel, " Radius reply contains route for %s/%s\n",
531 fmtaddr(htonl(ip), 0), fmtaddr(htonl(mask), 1));
532
533 session[s].route[routes].ip = ip;
534 session[s].route[routes].mask = mask;
535 routes++;
536 }
537 }
538 else if (*p == 11)
539 {
540 // Filter-Id
541 char *filter = p + 2;
542 int l = p[1] - 2;
543 char *suffix;
544 uint8_t *f = 0;
545 int i;
546
547 LOG(3, s, session[s].tunnel, " Radius reply contains Filter-Id \"%.*s\"\n", l, filter);
548 if ((suffix = memchr(filter, '.', l)))
549 {
550 int b = suffix - filter;
551 if (l - b == 3 && !memcmp("in", suffix+1, 2))
552 f = &session[s].filter_in;
553 else if (l - b == 4 && !memcmp("out", suffix+1, 3))
554 f = &session[s].filter_out;
555
556 l = b;
557 }
558
559 if (!f)
560 {
561 LOG(3, s, session[s].tunnel, " Invalid filter\n");
562 continue;
563 }
564
565 for (*f = 0, i = 0; !*f && i < MAXFILTER; i++)
566 if (strlen(ip_filters[i].name) == l &&
567 !strncmp(ip_filters[i].name, filter, l))
568 *f = i + 1;
569
570 if (*f)
571 ip_filters[*f - 1].used++;
572 else
573 LOG(3, s, session[s].tunnel, " Unknown filter\n");
574
575 }
576 else if (*p == 26 && p[1] >= 7)
577 {
578 // Vendor-Specific Attribute
579 int vendor = ntohl(*(int *)(p + 2));
580 char attrib = *(p + 6);
581 char attrib_length = *(p + 7) - 2;
582 char *avpair, *value, *key, *newp;
583
584 LOG(3, s, session[s].tunnel, " Radius reply contains Vendor-Specific. Vendor=%d Attrib=%d Length=%d\n", vendor, attrib, attrib_length);
585 if (vendor != 9 || attrib != 1)
586 {
587 LOG(3, s, session[s].tunnel, " Unknown vendor-specific\n");
588 continue;
589 }
590
591 if (attrib_length < 0) continue;
592
593 avpair = key = calloc(attrib_length + 1, 1);
594 memcpy(avpair, p + 8, attrib_length);
595 LOG(3, s, session[s].tunnel, " Cisco-Avpair value: %s\n", avpair);
596 do {
597 value = strchr(key, '=');
598 if (!value) break;
599 *value++ = 0;
600
601 // Trim quotes off reply string
602 if (*value == '\'' || *value == '\"')
603 {
604 char *x;
605 value++;
606 x = value + strlen(value) - 1;
607 if (*x == '\'' || *x == '\"')
608 *x = 0;
609 }
610
611 // Run hooks
612 newp = strchr(value, ',');
613 if (newp) *newp++ = 0;
614 {
615 struct param_radius_response p = { &tunnel[session[s].tunnel], &session[s], key, value };
616 run_plugins(PLUGIN_RADIUS_RESPONSE, &p);
617 }
618 key = newp;
619 } while (newp);
620 free(avpair);
621 }
622 }
623 }
624 else if (r_code == AccessReject)
625 {
626 LOG(2, s, session[s].tunnel, " Authentication denied for %s\n", session[s].user);
627 //FIXME: We should tear down the session here!
628 break;
629 }
630
631 if (!session[s].dns1 && config->default_dns1)
632 {
633 session[s].dns1 = htonl(config->default_dns1);
634 LOG(3, s, t, " Sending dns1 = %s\n", fmtaddr(config->default_dns1, 0));
635 }
636 if (!session[s].dns2 && config->default_dns2)
637 {
638 session[s].dns2 = htonl(config->default_dns2);
639 LOG(3, s, t, " Sending dns2 = %s\n", fmtaddr(config->default_dns2, 0));
640 }
641
642 // Valid Session, set it up
643 session[s].unique_id = 0;
644 sessionsetup(t, s);
645 }
646 else
647 {
648 // An ack for a stop or start record.
649 LOG(3, s, t, " RADIUS accounting ack recv in state %s\n", radius_state(radius[r].state));
650 break;
651 }
652 } while (0);
653
654 // finished with RADIUS
655 radiusclear(r, s);
656 }
657
658 // Send a retry for RADIUS/CHAP message
659 void radiusretry(uint16_t r)
660 {
661 sessionidt s = radius[r].session;
662 tunnelidt t = 0;
663
664 CSTAT(radiusretry);
665
666 if (s) t = session[s].tunnel;
667
668 radius[r].retry = backoff(radius[r].try + 1);
669 switch (radius[r].state)
670 {
671 case RADIUSCHAP: // sending CHAP down PPP
672 sendchap(t, s);
673 break;
674 case RADIUSIPCP:
675 sendipcp(t, s); // send IPCP
676 break;
677 case RADIUSAUTH: // sending auth to RADIUS server
678 radiussend(r, RADIUSAUTH);
679 break;
680 case RADIUSSTART: // sending start accounting to RADIUS server
681 radiussend(r, RADIUSSTART);
682 break;
683 case RADIUSSTOP: // sending stop accounting to RADIUS server
684 radiussend(r, RADIUSSTOP);
685 break;
686 default:
687 case RADIUSNULL: // Not in use
688 case RADIUSWAIT: // waiting timeout before available, in case delayed reply from RADIUS server
689 // free up RADIUS task
690 radiusclear(r, s);
691 LOG(3, s, session[s].tunnel, "Freeing up radius session %d\n", r);
692 break;
693 }
694 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"