1 /* $NetBSD: radlib.c,v 1.12 2018/02/05 00:43:06 christos Exp $ */
2
3 /*-
4 * Copyright 1998 Juniper Networks, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #ifdef __FreeBSD__
31 __FBSDID("$FreeBSD: /repoman/r/ncvs/src/lib/libradius/radlib.c,v 1.12 2004/06/14 20:55:30 stefanf Exp $");
32 #else
33 __RCSID("$NetBSD: radlib.c,v 1.12 2018/02/05 00:43:06 christos Exp $");
34 #endif
35
36 #include <sys/types.h>
37 #include <sys/socket.h>
38 #include <sys/time.h>
39 #include <netinet/in.h>
40 #include <arpa/inet.h>
41 #ifdef WITH_SSL
42 #include <openssl/hmac.h>
43 #include <openssl/md5.h>
44 #define MD5Init MD5_Init
45 #define MD5Update MD5_Update
46 #define MD5Final MD5_Final
47 #define MD5Len size_t
48 #define MD5Buf const void *
49 #else
50 #define MD5_DIGEST_LENGTH 16
51 #define MD5Len unsigned int
52 #define MD5Buf const unsigned char *
53 #include <md5.h>
54 #endif
55
56 /* We need the MPPE_KEY_LEN define */
57 #ifdef __FreeBSD__
58 #include <netgraph/ng_mppc.h>
59 #else
60 #define MPPE_KEY_LEN 16
61 #endif
62
63 #include <errno.h>
64 #include <netdb.h>
65 #include <stdarg.h>
66 #include <stddef.h>
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <unistd.h>
71
72 #include "radlib_private.h"
73 #if !defined(__printflike)
74 #define __printflike(fmtarg, firstvararg) \
75 __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
76 #endif
77
78 #ifdef __NetBSD__
79 #define srandomdev(x)
80 #define random arc4random
81 #endif
82
83 static void clear_password(struct rad_handle *);
84 static void generr(struct rad_handle *, const char *, ...)
85 __printflike(2, 3);
86 static void insert_scrambled_password(struct rad_handle *, size_t);
87 static void insert_request_authenticator(struct rad_handle *, size_t);
88 static void insert_message_authenticator(struct rad_handle *, size_t);
89 static int is_valid_response(struct rad_handle *, size_t,
90 const struct sockaddr_in *);
91 static int put_password_attr(struct rad_handle *, int,
92 const void *, size_t);
93 static int put_raw_attr(struct rad_handle *, int,
94 const void *, size_t);
95 static size_t split(char *, const char *[], size_t, char *, size_t);
96
97 static void
clear_password(struct rad_handle * h)98 clear_password(struct rad_handle *h)
99 {
100 if (h->pass_len != 0) {
101 (void)memset(h->pass, 0, h->pass_len);
102 h->pass_len = 0;
103 }
104 h->pass_pos = 0;
105 }
106
107 static void
generr(struct rad_handle * h,const char * format,...)108 generr(struct rad_handle *h, const char *format, ...)
109 {
110 va_list ap;
111
112 va_start(ap, format);
113 vsnprintf(h->errmsg, (size_t)ERRSIZE, format, ap);
114 va_end(ap);
115 }
116
117 static void
insert_scrambled_password(struct rad_handle * h,size_t srv)118 insert_scrambled_password(struct rad_handle *h, size_t srv)
119 {
120 MD5_CTX ctx;
121 unsigned char md5[MD5_DIGEST_LENGTH];
122 const struct rad_server *srvp;
123 size_t padded_len, pos;
124
125 srvp = &h->servers[srv];
126 padded_len = h->pass_len == 0 ? (size_t)16 : (h->pass_len+15) & ~0xf;
127
128 (void)memcpy(md5, &h->request[POS_AUTH], (size_t)LEN_AUTH);
129 for (pos = 0; pos < padded_len; pos += 16) {
130 int i;
131
132 /* Calculate the new scrambler */
133 MD5Init(&ctx);
134 MD5Update(&ctx, (MD5Buf)srvp->secret,
135 (MD5Len)strlen(srvp->secret));
136 MD5Update(&ctx, md5, (MD5Len)16);
137 MD5Final(md5, &ctx);
138
139 /*
140 * Mix in the current chunk of the password, and copy
141 * the result into the right place in the request. Also
142 * modify the scrambler in place, since we will use this
143 * in calculating the scrambler for next time.
144 */
145 for (i = 0; i < 16; i++)
146 h->request[h->pass_pos + pos + i] =
147 md5[i] ^= h->pass[pos + i];
148 }
149 }
150
151 static void
insert_request_authenticator(struct rad_handle * h,size_t srv)152 insert_request_authenticator(struct rad_handle *h, size_t srv)
153 {
154 MD5_CTX ctx;
155 const struct rad_server *srvp;
156
157 srvp = &h->servers[srv];
158
159 /* Create the request authenticator */
160 MD5Init(&ctx);
161 MD5Update(&ctx, &h->request[POS_CODE],
162 (MD5Len)(POS_AUTH - POS_CODE));
163 MD5Update(&ctx, memset(&h->request[POS_AUTH], 0, (size_t)LEN_AUTH),
164 (MD5Len)LEN_AUTH);
165 MD5Update(&ctx, &h->request[POS_ATTRS],
166 (MD5Len)(h->req_len - POS_ATTRS));
167 MD5Update(&ctx, (MD5Buf)srvp->secret,
168 (MD5Len)strlen(srvp->secret));
169 MD5Final(&h->request[POS_AUTH], &ctx);
170 }
171
172 static void
173 /*ARGSUSED*/
insert_message_authenticator(struct rad_handle * h,size_t srv)174 insert_message_authenticator(struct rad_handle *h, size_t srv)
175 {
176 #ifdef WITH_SSL
177 u_char md[EVP_MAX_MD_SIZE];
178 u_int md_len;
179 const struct rad_server *srvp;
180 HMAC_CTX *ctx;
181 srvp = &h->servers[srv];
182
183 if (h->authentic_pos != 0) {
184 ctx = HMAC_CTX_new();
185 HMAC_Init_ex(ctx, srvp->secret,
186 (int)strlen(srvp->secret), EVP_md5(), NULL);
187 HMAC_Update(ctx, &h->request[POS_CODE], (size_t)(POS_AUTH - POS_CODE));
188 HMAC_Update(ctx, &h->request[POS_AUTH], (size_t)LEN_AUTH);
189 HMAC_Update(ctx, &h->request[POS_ATTRS],
190 (size_t)(h->req_len - POS_ATTRS));
191 HMAC_Final(ctx, md, &md_len);
192 HMAC_CTX_free(ctx);
193 (void)memcpy(&h->request[h->authentic_pos + 2], md,
194 (size_t)md_len);
195 }
196 #endif
197 }
198
199 /*
200 * Return true if the current response is valid for a request to the
201 * specified server.
202 */
203 static int
is_valid_response(struct rad_handle * h,size_t srv,const struct sockaddr_in * from)204 is_valid_response(struct rad_handle *h, size_t srv,
205 const struct sockaddr_in *from)
206 {
207 MD5_CTX ctx;
208 unsigned char md5[MD5_DIGEST_LENGTH];
209 const struct rad_server *srvp;
210 size_t len;
211 #ifdef WITH_SSL
212 HMAC_CTX *hctx;
213 u_char resp[MSGSIZE], md[EVP_MAX_MD_SIZE];
214 size_t pos;
215 u_int md_len;
216 #endif
217
218 srvp = &h->servers[srv];
219
220 /* Check the source address */
221 if (from->sin_family != srvp->addr.sin_family ||
222 from->sin_addr.s_addr != srvp->addr.sin_addr.s_addr ||
223 from->sin_port != srvp->addr.sin_port)
224 return 0;
225
226 /* Check the message length */
227 if (h->resp_len < POS_ATTRS)
228 return 0;
229 len = h->response[POS_LENGTH] << 8 | h->response[POS_LENGTH+1];
230 if (len > h->resp_len)
231 return 0;
232
233 /* Check the response authenticator */
234 MD5Init(&ctx);
235 MD5Update(&ctx, &h->response[POS_CODE],
236 (MD5Len)(POS_AUTH - POS_CODE));
237 MD5Update(&ctx, &h->request[POS_AUTH],
238 (MD5Len)LEN_AUTH);
239 MD5Update(&ctx, &h->response[POS_ATTRS],
240 (MD5Len)(len - POS_ATTRS));
241 MD5Update(&ctx, (MD5Buf)srvp->secret,
242 (MD5Len)strlen(srvp->secret));
243 MD5Final(md5, &ctx);
244 if (memcmp(&h->response[POS_AUTH], md5, sizeof md5) != 0)
245 return 0;
246
247 #ifdef WITH_SSL
248 /*
249 * For non accounting responses check the message authenticator,
250 * if any.
251 */
252 if (h->response[POS_CODE] != RAD_ACCOUNTING_RESPONSE) {
253
254 (void)memcpy(resp, h->response, (size_t)MSGSIZE);
255 pos = POS_ATTRS;
256
257 /* Search and verify the Message-Authenticator */
258 while (pos < len - 2) {
259
260 if (h->response[pos] == RAD_MESSAGE_AUTHENTIC) {
261 /* zero fill the Message-Authenticator */
262 (void)memset(&resp[pos + 2], 0,
263 (size_t)MD5_DIGEST_LENGTH);
264
265 hctx = HMAC_CTX_new();
266 HMAC_Init_ex(hctx, srvp->secret,
267 (int)strlen(srvp->secret), EVP_md5(), NULL);
268 HMAC_Update(hctx, &h->response[POS_CODE],
269 (size_t)(POS_AUTH - POS_CODE));
270 HMAC_Update(hctx, &h->request[POS_AUTH],
271 (size_t)LEN_AUTH);
272 HMAC_Update(hctx, &resp[POS_ATTRS],
273 (size_t)(h->resp_len - POS_ATTRS));
274 HMAC_Final(hctx, md, &md_len);
275 HMAC_CTX_free(hctx);
276 if (memcmp(md, &h->response[pos + 2],
277 (size_t)MD5_DIGEST_LENGTH) != 0)
278 return 0;
279 break;
280 }
281 pos += h->response[pos + 1];
282 }
283 }
284 #endif
285 return 1;
286 }
287
288 static int
put_password_attr(struct rad_handle * h,int type,const void * value,size_t len)289 put_password_attr(struct rad_handle *h, int type, const void *value, size_t len)
290 {
291 size_t padded_len;
292 size_t pad_len;
293
294 if (h->pass_pos != 0) {
295 generr(h, "Multiple User-Password attributes specified");
296 return -1;
297 }
298 if (len > PASSSIZE)
299 len = PASSSIZE;
300 padded_len = len == 0 ? 16 : (len + 15) & ~0xf;
301 pad_len = padded_len - len;
302
303 /*
304 * Put in a place-holder attribute containing all zeros, and
305 * remember where it is so we can fill it in later.
306 */
307 clear_password(h);
308 put_raw_attr(h, type, h->pass, padded_len);
309 h->pass_pos = (int)(h->req_len - padded_len);
310
311 /* Save the cleartext password, padded as necessary */
312 (void)memcpy(h->pass, value, len);
313 h->pass_len = len;
314 (void)memset(h->pass + len, 0, pad_len);
315 return 0;
316 }
317
318 static int
put_raw_attr(struct rad_handle * h,int type,const void * value,size_t len)319 put_raw_attr(struct rad_handle *h, int type, const void *value, size_t len)
320 {
321 if (len > 253) {
322 generr(h, "Attribute too long");
323 return -1;
324 }
325 if (h->req_len + 2 + len > MSGSIZE) {
326 generr(h, "Maximum message length exceeded");
327 return -1;
328 }
329 h->request[h->req_len++] = type;
330 h->request[h->req_len++] = (unsigned char)(len + 2);
331 (void)memcpy(&h->request[h->req_len], value, len);
332 h->req_len += len;
333 return 0;
334 }
335
336 int
rad_add_server(struct rad_handle * h,const char * host,int port,const char * secret,int timeout,int tries)337 rad_add_server(struct rad_handle *h, const char *host, int port,
338 const char *secret, int timeout, int tries)
339 {
340 struct rad_server *srvp;
341
342 if (h->num_servers >= MAXSERVERS) {
343 generr(h, "Too many RADIUS servers specified");
344 return -1;
345 }
346 srvp = &h->servers[h->num_servers];
347
348 (void)memset(&srvp->addr, 0, sizeof srvp->addr);
349 srvp->addr.sin_len = sizeof srvp->addr;
350 srvp->addr.sin_family = AF_INET;
351 if (!inet_aton(host, &srvp->addr.sin_addr)) {
352 struct hostent *hent;
353
354 if ((hent = gethostbyname(host)) == NULL) {
355 generr(h, "%s: host not found", host);
356 return -1;
357 }
358 (void)memcpy(&srvp->addr.sin_addr, hent->h_addr,
359 sizeof srvp->addr.sin_addr);
360 }
361 if (port != 0)
362 srvp->addr.sin_port = htons((u_short)port);
363 else {
364 struct servent *sent;
365
366 if (h->type == RADIUS_AUTH)
367 srvp->addr.sin_port =
368 (sent = getservbyname("radius", "udp")) != NULL ?
369 sent->s_port : htons(RADIUS_PORT);
370 else
371 srvp->addr.sin_port =
372 (sent = getservbyname("radacct", "udp")) != NULL ?
373 sent->s_port : htons(RADACCT_PORT);
374 }
375 if ((srvp->secret = strdup(secret)) == NULL) {
376 generr(h, "Out of memory");
377 return -1;
378 }
379 srvp->timeout = timeout;
380 srvp->max_tries = tries;
381 srvp->num_tries = 0;
382 h->num_servers++;
383 return 0;
384 }
385
386 void
rad_close(struct rad_handle * h)387 rad_close(struct rad_handle *h)
388 {
389 size_t srv;
390
391 if (h->fd != -1)
392 close(h->fd);
393 for (srv = 0; srv < h->num_servers; srv++) {
394 (void)memset(h->servers[srv].secret, 0,
395 strlen(h->servers[srv].secret));
396 free(h->servers[srv].secret);
397 }
398 clear_password(h);
399 free(h);
400 }
401
402 int
rad_config(struct rad_handle * h,const char * path)403 rad_config(struct rad_handle *h, const char *path)
404 {
405 FILE *fp;
406 char buf[MAXCONFLINE];
407 int linenum;
408 int retval;
409
410 if (path == NULL)
411 path = PATH_RADIUS_CONF;
412 if ((fp = fopen(path, "r")) == NULL) {
413 generr(h, "Cannot open \"%s\": %s", path, strerror(errno));
414 return -1;
415 }
416 retval = 0;
417 linenum = 0;
418 while (fgets(buf, (int)sizeof buf, fp) != NULL) {
419 size_t len;
420 const char *fields[5];
421 size_t nfields;
422 char msg[ERRSIZE];
423 const char *type;
424 const char *host;
425 char *res;
426 const char *port_str;
427 const char *secret;
428 const char *timeout_str;
429 const char *maxtries_str;
430 char *end;
431 const char *wanttype;
432 unsigned long timeout;
433 unsigned long maxtries;
434 int port;
435 size_t i;
436
437 linenum++;
438 len = strlen(buf);
439 /* We know len > 0, else fgets would have returned NULL. */
440 if (buf[len - 1] != '\n') {
441 if (len == sizeof buf - 1)
442 generr(h, "%s:%d: line too long", path,
443 linenum);
444 else
445 generr(h, "%s:%d: missing newline", path,
446 linenum);
447 retval = -1;
448 break;
449 }
450 buf[len - 1] = '\0';
451
452 /* Extract the fields from the line. */
453 msg[0] = '\0';
454 nfields = split(buf, fields, sizeof(fields) / sizeof(fields[0]),
455 msg, sizeof msg);
456 if (msg[0] != '\0') {
457 generr(h, "%s:%d: %s", path, linenum, msg);
458 retval = -1;
459 break;
460 }
461 if (nfields == 0)
462 continue;
463 /*
464 * The first field should contain "auth" or "acct" for
465 * authentication or accounting, respectively. But older
466 * versions of the file didn't have that field. Default
467 * it to "auth" for backward compatibility.
468 */
469 if (strcmp(fields[0], "auth") != 0 &&
470 strcmp(fields[0], "acct") != 0) {
471 if (nfields >= 5) {
472 generr(h, "%s:%d: invalid service type", path,
473 linenum);
474 retval = -1;
475 break;
476 }
477 nfields++;
478 for (i = nfields; --i > 0; )
479 fields[i] = fields[i - 1];
480 fields[0] = "auth";
481 }
482 if (nfields < 3) {
483 generr(h, "%s:%d: missing shared secret", path,
484 linenum);
485 retval = -1;
486 break;
487 }
488 type = fields[0];
489 host = fields[1];
490 secret = fields[2];
491 timeout_str = fields[3];
492 maxtries_str = fields[4];
493
494 /* Ignore the line if it is for the wrong service type. */
495 wanttype = h->type == RADIUS_AUTH ? "auth" : "acct";
496 if (strcmp(type, wanttype) != 0)
497 continue;
498
499 /* Parse and validate the fields. */
500 res = __UNCONST(host);
501 host = strsep(&res, ":");
502 port_str = strsep(&res, ":");
503 if (port_str != NULL) {
504 port = (int)strtoul(port_str, &end, 10);
505 if (*end != '\0') {
506 generr(h, "%s:%d: invalid port", path,
507 linenum);
508 retval = -1;
509 break;
510 }
511 } else
512 port = 0;
513 if (timeout_str != NULL) {
514 timeout = strtoul(timeout_str, &end, 10);
515 if (*end != '\0') {
516 generr(h, "%s:%d: invalid timeout", path,
517 linenum);
518 retval = -1;
519 break;
520 }
521 } else
522 timeout = TIMEOUT;
523 if (maxtries_str != NULL) {
524 maxtries = strtoul(maxtries_str, &end, 10);
525 if (*end != '\0') {
526 generr(h, "%s:%d: invalid maxtries", path,
527 linenum);
528 retval = -1;
529 break;
530 }
531 } else
532 maxtries = MAXTRIES;
533
534 if (rad_add_server(h, host, port, secret, (int)timeout,
535 (int)maxtries) == -1) {
536 (void)strcpy(msg, h->errmsg);
537 generr(h, "%s:%d: %s", path, linenum, msg);
538 retval = -1;
539 break;
540 }
541 }
542 /* Clear out the buffer to wipe a possible copy of a shared secret */
543 (void)memset(buf, 0, sizeof buf);
544 fclose(fp);
545 return retval;
546 }
547
548 /*
549 * rad_init_send_request() must have previously been called.
550 * Returns:
551 * 0 The application should select on *fd with a timeout of tv before
552 * calling rad_continue_send_request again.
553 * < 0 Failure
554 * > 0 Success
555 */
556 int
rad_continue_send_request(struct rad_handle * h,int selected,int * fd,struct timeval * tv)557 rad_continue_send_request(struct rad_handle *h, int selected, int *fd,
558 struct timeval *tv)
559 {
560 ssize_t n;
561
562 if (selected) {
563 struct sockaddr_in from;
564 socklen_t fromlen;
565 ssize_t rv;
566
567 fromlen = sizeof from;
568 rv = recvfrom(h->fd, h->response, (size_t)MSGSIZE,
569 MSG_WAITALL, (struct sockaddr *)(void *)&from, &fromlen);
570 if (rv == -1) {
571 generr(h, "recvfrom: %s", strerror(errno));
572 return -1;
573 }
574 h->resp_len = rv;
575 if (is_valid_response(h, h->srv, &from)) {
576 h->resp_len = h->response[POS_LENGTH] << 8 |
577 h->response[POS_LENGTH+1];
578 h->resp_pos = POS_ATTRS;
579 return h->response[POS_CODE];
580 }
581 }
582
583 if (h->try == h->total_tries) {
584 generr(h, "No valid RADIUS responses received");
585 return -1;
586 }
587
588 /*
589 * Scan round-robin to the next server that has some
590 * tries left. There is guaranteed to be one, or we
591 * would have exited this loop by now.
592 */
593 while (h->servers[h->srv].num_tries >= h->servers[h->srv].max_tries)
594 if (++h->srv >= h->num_servers)
595 h->srv = 0;
596
597 if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST)
598 /* Insert the request authenticator into the request */
599 insert_request_authenticator(h, h->srv);
600 else
601 /* Insert the scrambled password into the request */
602 if (h->pass_pos != 0)
603 insert_scrambled_password(h, h->srv);
604
605 insert_message_authenticator(h, h->srv);
606
607 /* Send the request */
608 n = sendto(h->fd, h->request, h->req_len, 0,
609 (const struct sockaddr *)(void *)&h->servers[h->srv].addr,
610 (socklen_t)sizeof h->servers[h->srv].addr);
611 if (n != (ssize_t)h->req_len) {
612 if (n == -1)
613 generr(h, "sendto: %s", strerror(errno));
614 else
615 generr(h, "sendto: short write");
616 return -1;
617 }
618
619 h->try++;
620 h->servers[h->srv].num_tries++;
621 tv->tv_sec = h->servers[h->srv].timeout;
622 tv->tv_usec = 0;
623 *fd = h->fd;
624
625 return 0;
626 }
627
628 int
rad_create_request(struct rad_handle * h,int code)629 rad_create_request(struct rad_handle *h, int code)
630 {
631 int i;
632
633 h->request[POS_CODE] = code;
634 h->request[POS_IDENT] = ++h->ident;
635 /* Create a random authenticator */
636 for (i = 0; i < LEN_AUTH; i += 2) {
637 uint32_t r;
638 r = (uint32_t)random();
639 h->request[POS_AUTH+i] = (u_char)r;
640 h->request[POS_AUTH+i+1] = (u_char)(r >> 8);
641 }
642 h->req_len = POS_ATTRS;
643 clear_password(h);
644 h->request_created = 1;
645 return 0;
646 }
647
648 struct in_addr
rad_cvt_addr(const void * data)649 rad_cvt_addr(const void *data)
650 {
651 struct in_addr value;
652
653 (void)memcpy(&value.s_addr, data, sizeof value.s_addr);
654 return value;
655 }
656
657 u_int32_t
rad_cvt_int(const void * data)658 rad_cvt_int(const void *data)
659 {
660 u_int32_t value;
661
662 (void)memcpy(&value, data, sizeof value);
663 return ntohl(value);
664 }
665
666 char *
rad_cvt_string(const void * data,size_t len)667 rad_cvt_string(const void *data, size_t len)
668 {
669 char *s;
670
671 s = malloc(len + 1);
672 if (s != NULL) {
673 (void)memcpy(s, data, len);
674 s[len] = '\0';
675 }
676 return s;
677 }
678
679 /*
680 * Returns the attribute type. If none are left, returns 0. On failure,
681 * returns -1.
682 */
683 int
rad_get_attr(struct rad_handle * h,const void ** value,size_t * len)684 rad_get_attr(struct rad_handle *h, const void **value, size_t *len)
685 {
686 int type;
687
688 if (h->resp_pos >= h->resp_len)
689 return 0;
690 if (h->resp_pos + 2 > h->resp_len) {
691 generr(h, "Malformed attribute in response");
692 return -1;
693 }
694 type = h->response[h->resp_pos++];
695 *len = h->response[h->resp_pos++] - 2;
696 if (h->resp_pos + (int)*len > h->resp_len) {
697 generr(h, "Malformed attribute in response");
698 return -1;
699 }
700 *value = &h->response[h->resp_pos];
701 h->resp_pos += (int)*len;
702 return type;
703 }
704
705 /*
706 * Returns -1 on error, 0 to indicate no event and >0 for success
707 */
708 int
rad_init_send_request(struct rad_handle * h,int * fd,struct timeval * tv)709 rad_init_send_request(struct rad_handle *h, int *fd, struct timeval *tv)
710 {
711 size_t srv;
712
713 /* Make sure we have a socket to use */
714 if (h->fd == -1) {
715 struct sockaddr_in saddr;
716
717 if ((h->fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
718 generr(h, "Cannot create socket: %s", strerror(errno));
719 return -1;
720 }
721 (void)memset(&saddr, 0, sizeof saddr);
722 saddr.sin_len = sizeof saddr;
723 saddr.sin_family = AF_INET;
724 saddr.sin_addr.s_addr = INADDR_ANY;
725 saddr.sin_port = htons(0);
726 if (bind(h->fd, (const struct sockaddr *)(void *)&saddr,
727 (socklen_t)sizeof saddr) == -1) {
728 generr(h, "bind: %s", strerror(errno));
729 close(h->fd);
730 h->fd = -1;
731 return -1;
732 }
733 }
734
735 if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST) {
736 /* Make sure no password given */
737 if (h->pass_pos || h->chap_pass) {
738 generr(h, "User or Chap Password"
739 " in accounting request");
740 return -1;
741 }
742 } else {
743 if (h->eap_msg == 0) {
744 /* Make sure the user gave us a password */
745 if (h->pass_pos == 0 && !h->chap_pass) {
746 generr(h, "No User or Chap Password"
747 " attributes given");
748 return -1;
749 }
750 if (h->pass_pos != 0 && h->chap_pass) {
751 generr(h, "Both User and Chap Password"
752 " attributes given");
753 return -1;
754 }
755 }
756 }
757
758 /* Fill in the length field in the message */
759 h->request[POS_LENGTH] = (unsigned char)(h->req_len >> 8);
760 h->request[POS_LENGTH+1] = (unsigned char)h->req_len;
761
762 /*
763 * Count the total number of tries we will make, and zero the
764 * counter for each server.
765 */
766 h->total_tries = 0;
767 for (srv = 0; srv < h->num_servers; srv++) {
768 h->total_tries += h->servers[srv].max_tries;
769 h->servers[srv].num_tries = 0;
770 }
771 if (h->total_tries == 0) {
772 generr(h, "No RADIUS servers specified");
773 return -1;
774 }
775
776 h->try = h->srv = 0;
777
778 return rad_continue_send_request(h, 0, fd, tv);
779 }
780
781 /*
782 * Create and initialize a rad_handle structure, and return it to the
783 * caller. Can fail only if the necessary memory cannot be allocated.
784 * In that case, it returns NULL.
785 */
786 struct rad_handle *
rad_auth_open(void)787 rad_auth_open(void)
788 {
789 struct rad_handle *h;
790
791 h = (struct rad_handle *)malloc(sizeof(struct rad_handle));
792 if (h != NULL) {
793 srandomdev(0);
794 h->fd = -1;
795 h->num_servers = 0;
796 h->ident = random();
797 h->errmsg[0] = '\0';
798 (void)memset(h->pass, 0, sizeof h->pass);
799 h->pass_len = 0;
800 h->pass_pos = 0;
801 h->chap_pass = 0;
802 h->authentic_pos = 0;
803 h->type = RADIUS_AUTH;
804 h->request_created = 0;
805 h->eap_msg = 0;
806 }
807 return h;
808 }
809
810 struct rad_handle *
rad_acct_open(void)811 rad_acct_open(void)
812 {
813 struct rad_handle *h;
814
815 h = rad_open();
816 if (h != NULL)
817 h->type = RADIUS_ACCT;
818 return h;
819 }
820
821 struct rad_handle *
rad_open(void)822 rad_open(void)
823 {
824 return rad_auth_open();
825 }
826
827 int
rad_put_addr(struct rad_handle * h,int type,struct in_addr addr)828 rad_put_addr(struct rad_handle *h, int type, struct in_addr addr)
829 {
830 return rad_put_attr(h, type, &addr.s_addr, sizeof addr.s_addr);
831 }
832
833 int
rad_put_attr(struct rad_handle * h,int type,const void * value,size_t len)834 rad_put_attr(struct rad_handle *h, int type, const void *value, size_t len)
835 {
836 int result;
837
838 if (!h->request_created) {
839 generr(h, "Please call rad_create_request()"
840 " before putting attributes");
841 return -1;
842 }
843
844 if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST) {
845 if (type == RAD_EAP_MESSAGE) {
846 generr(h, "EAP-Message attribute is not valid"
847 " in accounting requests");
848 return -1;
849 }
850 }
851
852 /*
853 * When proxying EAP Messages, the Message Authenticator
854 * MUST be present; see RFC 3579.
855 */
856 if (type == RAD_EAP_MESSAGE) {
857 if (rad_put_message_authentic(h) == -1)
858 return -1;
859 }
860
861 if (type == RAD_USER_PASSWORD) {
862 result = put_password_attr(h, type, value, len);
863 } else if (type == RAD_MESSAGE_AUTHENTIC) {
864 result = rad_put_message_authentic(h);
865 } else {
866 result = put_raw_attr(h, type, value, len);
867 if (result == 0) {
868 if (type == RAD_CHAP_PASSWORD)
869 h->chap_pass = 1;
870 else if (type == RAD_EAP_MESSAGE)
871 h->eap_msg = 1;
872 }
873 }
874
875 return result;
876 }
877
878 int
rad_put_int(struct rad_handle * h,int type,u_int32_t value)879 rad_put_int(struct rad_handle *h, int type, u_int32_t value)
880 {
881 u_int32_t nvalue;
882
883 nvalue = htonl(value);
884 return rad_put_attr(h, type, &nvalue, sizeof nvalue);
885 }
886
887 int
rad_put_string(struct rad_handle * h,int type,const char * str)888 rad_put_string(struct rad_handle *h, int type, const char *str)
889 {
890 return rad_put_attr(h, type, str, strlen(str));
891 }
892
893 int
rad_put_message_authentic(struct rad_handle * h)894 rad_put_message_authentic(struct rad_handle *h)
895 {
896 #ifdef WITH_SSL
897 u_char md_zero[MD5_DIGEST_LENGTH];
898
899 if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST) {
900 generr(h, "Message-Authenticator is not valid"
901 " in accounting requests");
902 return -1;
903 }
904
905 if (h->authentic_pos == 0) {
906 h->authentic_pos = (int)h->req_len;
907 (void)memset(md_zero, 0, sizeof(md_zero));
908 return (put_raw_attr(h, RAD_MESSAGE_AUTHENTIC, md_zero,
909 sizeof(md_zero)));
910 }
911 return 0;
912 #else
913 generr(h, "Message Authenticator not supported,"
914 " please recompile libradius with SSL support");
915 return -1;
916 #endif
917 }
918
919 /*
920 * Returns the response type code on success, or -1 on failure.
921 */
922 int
rad_send_request(struct rad_handle * h)923 rad_send_request(struct rad_handle *h)
924 {
925 struct timeval timelimit;
926 struct timeval tv;
927 int fd;
928 int n;
929
930 n = rad_init_send_request(h, &fd, &tv);
931
932 if (n != 0)
933 return n;
934
935 gettimeofday(&timelimit, NULL);
936 timeradd(&tv, &timelimit, &timelimit);
937
938 for ( ; ; ) {
939 fd_set readfds;
940
941 FD_ZERO(&readfds);
942 FD_SET(fd, &readfds);
943
944 n = select(fd + 1, &readfds, NULL, NULL, &tv);
945
946 if (n == -1) {
947 generr(h, "select: %s", strerror(errno));
948 return -1;
949 }
950
951 if (!FD_ISSET(fd, &readfds)) {
952 /* Compute a new timeout */
953 gettimeofday(&tv, NULL);
954 timersub(&timelimit, &tv, &tv);
955 if (tv.tv_sec > 0 || (tv.tv_sec == 0 && tv.tv_usec > 0))
956 /* Continue the select */
957 continue;
958 }
959
960 n = rad_continue_send_request(h, n, &fd, &tv);
961
962 if (n != 0)
963 return n;
964
965 gettimeofday(&timelimit, NULL);
966 timeradd(&tv, &timelimit, &timelimit);
967 }
968 }
969
970 const char *
rad_strerror(struct rad_handle * h)971 rad_strerror(struct rad_handle *h)
972 {
973 return h->errmsg;
974 }
975
976 /*
977 * Destructively split a string into fields separated by white space.
978 * `#' at the beginning of a field begins a comment that extends to the
979 * end of the string. Fields may be quoted with `"'. Inside quoted
980 * strings, the backslash escapes `\"' and `\\' are honored.
981 *
982 * Pointers to up to the first maxfields fields are stored in the fields
983 * array. Missing fields get NULL pointers.
984 *
985 * The return value is the actual number of fields parsed, and is always
986 * <= maxfields.
987 *
988 * On a syntax error, places a message in the msg string, and returns
989 * SIZE_MAX.
990 */
991 static size_t
split(char * str,const char * fields[],size_t maxfields,char * msg,size_t msglen)992 split(char *str, const char *fields[], size_t maxfields, char *msg,
993 size_t msglen)
994 {
995 char *p;
996 size_t i;
997 static const char ws[] = " \t";
998
999 for (i = 0; i < maxfields; i++)
1000 fields[i] = NULL;
1001 p = str;
1002 i = 0;
1003 while (*p != '\0') {
1004 p += strspn(p, ws);
1005 if (*p == '#' || *p == '\0')
1006 break;
1007 if (i >= maxfields) {
1008 snprintf(msg, msglen, "line has too many fields");
1009 return SIZE_MAX;
1010 }
1011 if (*p == '"') {
1012 char *dst;
1013
1014 dst = ++p;
1015 fields[i] = dst;
1016 while (*p != '"') {
1017 if (*p == '\\') {
1018 p++;
1019 if (*p != '"' && *p != '\\' &&
1020 *p != '\0') {
1021 snprintf(msg, msglen,
1022 "invalid `\\' escape");
1023 return SIZE_MAX;
1024 }
1025 }
1026 if (*p == '\0') {
1027 snprintf(msg, msglen,
1028 "unterminated quoted string");
1029 return SIZE_MAX;
1030 }
1031 *dst++ = *p++;
1032 }
1033 *dst = '\0';
1034 p++;
1035 if (*fields[i] == '\0') {
1036 snprintf(msg, msglen,
1037 "empty quoted string not permitted");
1038 return SIZE_MAX;
1039 }
1040 if (*p != '\0' && strspn(p, ws) == 0) {
1041 snprintf(msg, msglen, "quoted string not"
1042 " followed by white space");
1043 return SIZE_MAX;
1044 }
1045 } else {
1046 fields[i] = p;
1047 p += strcspn(p, ws);
1048 if (*p != '\0')
1049 *p++ = '\0';
1050 }
1051 i++;
1052 }
1053 return i;
1054 }
1055
1056 int
rad_get_vendor_attr(u_int32_t * vendor,const void ** data,size_t * len)1057 rad_get_vendor_attr(u_int32_t *vendor, const void **data, size_t *len)
1058 {
1059 const struct vendor_attribute *attr;
1060
1061 attr = (const struct vendor_attribute *)*data;
1062 *vendor = ntohl(attr->vendor_value);
1063 *data = attr->attrib_data;
1064 *len = attr->attrib_len - 2;
1065
1066 return (attr->attrib_type);
1067 }
1068
1069 int
rad_put_vendor_addr(struct rad_handle * h,int vendor,int type,struct in_addr addr)1070 rad_put_vendor_addr(struct rad_handle *h, int vendor, int type,
1071 struct in_addr addr)
1072 {
1073 return (rad_put_vendor_attr(h, vendor, type, &addr.s_addr,
1074 sizeof addr.s_addr));
1075 }
1076
1077 int
rad_put_vendor_attr(struct rad_handle * h,int vendor,int type,const void * value,size_t len)1078 rad_put_vendor_attr(struct rad_handle *h, int vendor, int type,
1079 const void *value, size_t len)
1080 {
1081 struct vendor_attribute *attr;
1082 int res;
1083
1084 if (!h->request_created) {
1085 generr(h, "Please call rad_create_request()"
1086 " before putting attributes");
1087 return -1;
1088 }
1089
1090 if ((attr = malloc(len + 6)) == NULL) {
1091 generr(h, "malloc failure (%zu bytes)", len + 6);
1092 return -1;
1093 }
1094
1095 attr->vendor_value = htonl((uint32_t)vendor);
1096 attr->attrib_type = type;
1097 attr->attrib_len = (unsigned char)(len + 2);
1098 (void)memcpy(attr->attrib_data, value, len);
1099
1100 res = put_raw_attr(h, RAD_VENDOR_SPECIFIC, attr, len + 6);
1101 free(attr);
1102 if (res == 0 && vendor == RAD_VENDOR_MICROSOFT
1103 && (type == RAD_MICROSOFT_MS_CHAP_RESPONSE
1104 || type == RAD_MICROSOFT_MS_CHAP2_RESPONSE)) {
1105 h->chap_pass = 1;
1106 }
1107 return (res);
1108 }
1109
1110 int
rad_put_vendor_int(struct rad_handle * h,int vendor,int type,u_int32_t i)1111 rad_put_vendor_int(struct rad_handle *h, int vendor, int type, u_int32_t i)
1112 {
1113 u_int32_t value;
1114
1115 value = htonl(i);
1116 return (rad_put_vendor_attr(h, vendor, type, &value, sizeof value));
1117 }
1118
1119 int
rad_put_vendor_string(struct rad_handle * h,int vendor,int type,const char * str)1120 rad_put_vendor_string(struct rad_handle *h, int vendor, int type,
1121 const char *str)
1122 {
1123 return (rad_put_vendor_attr(h, vendor, type, str, strlen(str)));
1124 }
1125
1126 ssize_t
rad_request_authenticator(struct rad_handle * h,char * buf,size_t len)1127 rad_request_authenticator(struct rad_handle *h, char *buf, size_t len)
1128 {
1129 if (len < LEN_AUTH)
1130 return (-1);
1131 (void)memcpy(buf, h->request + POS_AUTH, (size_t)LEN_AUTH);
1132 if (len > LEN_AUTH)
1133 buf[LEN_AUTH] = '\0';
1134 return (LEN_AUTH);
1135 }
1136
1137 u_char *
rad_demangle(struct rad_handle * h,const void * mangled,size_t mlen)1138 rad_demangle(struct rad_handle *h, const void *mangled, size_t mlen)
1139 {
1140 char R[LEN_AUTH];
1141 const char *S;
1142 int i, Ppos;
1143 MD5_CTX Context;
1144 u_char b[MD5_DIGEST_LENGTH], *demangled;
1145 const u_char *C;
1146
1147 if ((mlen % 16 != 0) || mlen > 128) {
1148 generr(h, "Cannot interpret mangled data of length %lu",
1149 (u_long)mlen);
1150 return NULL;
1151 }
1152
1153 C = (const u_char *)mangled;
1154
1155 /* We need the shared secret as Salt */
1156 S = rad_server_secret(h);
1157
1158 /* We need the request authenticator */
1159 if (rad_request_authenticator(h, R, sizeof R) != LEN_AUTH) {
1160 generr(h, "Cannot obtain the RADIUS request authenticator");
1161 return NULL;
1162 }
1163
1164 demangled = malloc(mlen);
1165 if (!demangled)
1166 return NULL;
1167
1168 MD5Init(&Context);
1169 MD5Update(&Context, (MD5Buf)S, (MD5Len)strlen(S));
1170 MD5Update(&Context, (MD5Buf)R, (MD5Len)LEN_AUTH);
1171 MD5Final(b, &Context);
1172 Ppos = 0;
1173 while (mlen) {
1174
1175 mlen -= 16;
1176 for (i = 0; i < 16; i++)
1177 demangled[Ppos++] = C[i] ^ b[i];
1178
1179 if (mlen) {
1180 MD5Init(&Context);
1181 MD5Update(&Context, (MD5Buf)S, (MD5Len)strlen(S));
1182 MD5Update(&Context, (MD5Buf)C, (MD5Len)16);
1183 MD5Final(b, &Context);
1184 }
1185
1186 C += 16;
1187 }
1188
1189 return demangled;
1190 }
1191
1192 u_char *
rad_demangle_mppe_key(struct rad_handle * h,const void * mangled,size_t mlen,size_t * len)1193 rad_demangle_mppe_key(struct rad_handle *h, const void *mangled,
1194 size_t mlen, size_t *len)
1195 {
1196 char R[LEN_AUTH]; /* variable names as per rfc2548 */
1197 const char *S;
1198 u_char b[MD5_DIGEST_LENGTH], *demangled = NULL;
1199 const u_char *A, *C;
1200 MD5_CTX Context;
1201 size_t Slen, Clen, i, Ppos;
1202 u_char *P;
1203
1204 if (mlen % 16 != SALT_LEN) {
1205 generr(h, "Cannot interpret mangled data of length %lu",
1206 (u_long)mlen);
1207 return NULL;
1208 }
1209
1210 /* We need the RADIUS Request-Authenticator */
1211 if (rad_request_authenticator(h, R, sizeof R) != LEN_AUTH) {
1212 generr(h, "Cannot obtain the RADIUS request authenticator");
1213 return NULL;
1214 }
1215
1216 A = (const u_char *)mangled; /* Salt comes first */
1217 C = (const u_char *)mangled + SALT_LEN; /* Then the ciphertext */
1218 Clen = mlen - SALT_LEN;
1219 S = rad_server_secret(h); /* We need the RADIUS secret */
1220 Slen = strlen(S);
1221 P = malloc(Clen); /* We derive our plaintext */
1222
1223 MD5Init(&Context);
1224 MD5Update(&Context, (MD5Buf)S, (MD5Len)Slen);
1225 MD5Update(&Context, (MD5Buf)R, (MD5Len)LEN_AUTH);
1226 MD5Update(&Context, (MD5Buf)A, (MD5Len)SALT_LEN);
1227 MD5Final(b, &Context);
1228 Ppos = 0;
1229
1230 while (Clen) {
1231 Clen -= 16;
1232
1233 for (i = 0; i < 16; i++)
1234 P[Ppos++] = C[i] ^ b[i];
1235
1236 if (Clen) {
1237 MD5Init(&Context);
1238 MD5Update(&Context, (MD5Buf)S, (MD5Len)Slen);
1239 MD5Update(&Context, (MD5Buf)C, (MD5Len)16);
1240 MD5Final(b, &Context);
1241 }
1242
1243 C += 16;
1244 }
1245
1246 /*
1247 * The resulting plain text consists of a one-byte length, the text and
1248 * maybe some padding.
1249 */
1250 *len = *P;
1251 if (*len > mlen - 1) {
1252 generr(h, "Mangled data seems to be garbage %zu %zu",
1253 *len, mlen-1);
1254 goto out;
1255 }
1256
1257 if (*len > MPPE_KEY_LEN * 2) {
1258 generr(h, "Key to long (%zu) for me max. %d",
1259 *len, MPPE_KEY_LEN * 2);
1260 goto out;
1261 }
1262 demangled = malloc(*len);
1263 if (!demangled)
1264 goto out;
1265
1266 (void)memcpy(demangled, P + 1, *len);
1267 out:
1268 free(P);
1269 return demangled;
1270 }
1271
1272 const char *
rad_server_secret(struct rad_handle * h)1273 rad_server_secret(struct rad_handle *h)
1274 {
1275 return (h->servers[h->srv].secret);
1276 }
1277