2 * radius.c Functions to send/receive radius packets.
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
20 * Copyright 2000-2003,2006 The FreeRADIUS server project
23 #include <freeradius-devel/ident.h>
26 #include <freeradius-devel/libradius.h>
27 #include <freeradius-devel/md5.h>
33 #include <freeradius-devel/udpfromto.h>
41 * The RFC says 4096 octets max, and most packets are less than 256.
43 #define MAX_PACKET_LEN 4096
46 * The maximum number of attributes which we allow in an incoming
47 * request. If there are more attributes than this, the request
50 * This helps to minimize the potential for a DoS, when an
51 * attacker spoofs Access-Request packets, which don't have a
52 * Message-Authenticator attribute. This means that the packet
53 * is unsigned, and the attacker can use resources on the server,
54 * even if the end request is rejected.
56 int fr_max_attributes = 0;
57 FILE *fr_log_fp = NULL;
59 typedef struct radius_packet_t {
63 uint8_t vector[AUTH_VECTOR_LEN];
67 static fr_randctx fr_rand_pool; /* across multiple calls */
68 static int fr_rand_initialized = 0;
69 static unsigned int salt_offset = 0;
71 const char *fr_packet_codes[FR_MAX_PACKET_CODE] = {
77 "Accounting-Response",
93 "Resource-Free-Request",
94 "Resource-Free-Response",
95 "Resource-Query-Request",
96 "Resource-Query-Response",
97 "Alternate-Resource-Reclaim-Request",
99 "NAS-Reboot-Response",
112 "Disconnect-Request",
122 "IP-Address-Allocate",
127 void fr_printf_log(const char *fmt, ...)
132 if ((fr_debug_flag == 0) || !fr_log_fp) {
137 vfprintf(fr_log_fp, fmt, ap);
143 static void print_hex(RADIUS_PACKET *packet)
147 if (!packet->data) return;
149 printf(" Code:\t\t%u\n", packet->data[0]);
150 printf(" Id:\t\t%u\n", packet->data[1]);
151 printf(" Length:\t%u\n", ((packet->data[2] << 8) |
153 printf(" Vector:\t");
154 for (i = 4; i < 20; i++) {
155 printf("%02x", packet->data[i]);
159 if (packet->data_len > 20) {
164 total = packet->data_len - 20;
165 ptr = packet->data + 20;
171 if (total < 2) { /* too short */
172 printf("%02x\n", *ptr);
176 if (ptr[1] > total) { /* too long */
177 for (i = 0; i < total; i++) {
178 printf("%02x ", ptr[i]);
183 printf("%02x %02x ", ptr[0], ptr[1]);
184 attrlen = ptr[1] - 2;
188 for (i = 0; i < attrlen; i++) {
189 if ((i > 0) && ((i & 0x0f) == 0x00))
191 printf("%02x ", ptr[i]);
192 if ((i & 0x0f) == 0x0f) printf("\n");
195 if ((attrlen & 0x0f) != 0x00) printf("\n");
206 * Wrapper for sendto which handles sendfromto, IPv6, and all
207 * possible combinations.
209 static int rad_sendto(int sockfd, void *data, size_t data_len, int flags,
210 fr_ipaddr_t *src_ipaddr, int src_port,
211 fr_ipaddr_t *dst_ipaddr, int dst_port)
213 struct sockaddr_storage dst;
214 socklen_t sizeof_dst;
216 #ifdef WITH_UDPFROMTO
217 struct sockaddr_storage src;
218 socklen_t sizeof_src;
220 fr_ipaddr2sockaddr(src_ipaddr, src_port, &src, &sizeof_src);
222 src_port = src_port; /* -Wunused */
225 if (!fr_ipaddr2sockaddr(dst_ipaddr, dst_port, &dst, &sizeof_dst)) {
229 #ifdef WITH_UDPFROMTO
231 * Only IPv4 is supported for udpfromto.
233 * And if they don't specify a source IP address, don't
236 if ((dst_ipaddr->af == AF_INET) ||
237 (src_ipaddr->af != AF_UNSPEC)) {
238 return sendfromto(sockfd, data, data_len, flags,
239 (struct sockaddr *)&src, sizeof_src,
240 (struct sockaddr *)&dst, sizeof_dst);
243 src_ipaddr = src_ipaddr; /* -Wunused */
247 * No udpfromto, OR an IPv6 socket, fail gracefully.
249 return sendto(sockfd, data, data_len, flags,
250 (struct sockaddr *) &dst, sizeof_dst);
254 void rad_recv_discard(int sockfd)
257 struct sockaddr_storage src;
258 socklen_t sizeof_src = sizeof(src);
260 recvfrom(sockfd, header, sizeof(header), 0,
261 (struct sockaddr *)&src, &sizeof_src);
265 ssize_t rad_recv_header(int sockfd, fr_ipaddr_t *src_ipaddr, int *src_port,
268 ssize_t data_len, packet_len;
270 struct sockaddr_storage src;
271 socklen_t sizeof_src = sizeof(src);
273 data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
274 (struct sockaddr *)&src, &sizeof_src);
276 if ((errno == EAGAIN) || (errno == EINTR)) return 0;
281 * Too little data is available, discard the packet.
284 recvfrom(sockfd, header, sizeof(header), 0,
285 (struct sockaddr *)&src, &sizeof_src);
288 } else { /* we got 4 bytes of data. */
290 * See how long the packet says it is.
292 packet_len = (header[2] * 256) + header[3];
295 * The length in the packet says it's less than
296 * a RADIUS header length: discard it.
298 if (packet_len < AUTH_HDR_LEN) {
299 recvfrom(sockfd, header, sizeof(header), 0,
300 (struct sockaddr *)&src, &sizeof_src);
304 * Enforce RFC requirements, for sanity.
305 * Anything after 4k will be discarded.
307 } else if (packet_len > MAX_PACKET_LEN) {
308 recvfrom(sockfd, header, sizeof(header), 0,
309 (struct sockaddr *)&src, &sizeof_src);
315 * Convert AF. If unknown, discard packet.
317 if (!fr_sockaddr2ipaddr(&src, sizeof_src, src_ipaddr, src_port)) {
318 recvfrom(sockfd, header, sizeof(header), 0,
319 (struct sockaddr *)&src, &sizeof_src);
326 * The packet says it's this long, but the actual UDP
327 * size could still be smaller.
334 * wrapper for recvfrom, which handles recvfromto, IPv6, and all
335 * possible combinations.
337 static ssize_t rad_recvfrom(int sockfd, uint8_t **pbuf, int flags,
338 fr_ipaddr_t *src_ipaddr, uint16_t *src_port,
339 fr_ipaddr_t *dst_ipaddr, uint16_t *dst_port)
341 struct sockaddr_storage src;
342 struct sockaddr_storage dst;
343 socklen_t sizeof_src = sizeof(src);
344 socklen_t sizeof_dst = sizeof(dst);
351 memset(&src, 0, sizeof_src);
352 memset(&dst, 0, sizeof_dst);
355 * Get address family, etc. first, so we know if we
356 * need to do udpfromto.
358 * FIXME: udpfromto also does this, but it's not
359 * a critical problem.
361 if (getsockname(sockfd, (struct sockaddr *)&dst,
362 &sizeof_dst) < 0) return -1;
365 * Read the length of the packet, from the packet.
366 * This lets us allocate the buffer to use for
367 * reading the rest of the packet.
369 data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
370 (struct sockaddr *)&src, &sizeof_src);
372 if ((errno == EAGAIN) || (errno == EINTR)) return 0;
377 * Too little data is available, discard the packet.
380 recvfrom(sockfd, header, sizeof(header), flags,
381 (struct sockaddr *)&src, &sizeof_src);
384 } else { /* we got 4 bytes of data. */
386 * See how long the packet says it is.
388 len = (header[2] * 256) + header[3];
391 * The length in the packet says it's less than
392 * a RADIUS header length: discard it.
394 if (len < AUTH_HDR_LEN) {
395 recvfrom(sockfd, header, sizeof(header), flags,
396 (struct sockaddr *)&src, &sizeof_src);
400 * Enforce RFC requirements, for sanity.
401 * Anything after 4k will be discarded.
403 } else if (len > MAX_PACKET_LEN) {
404 recvfrom(sockfd, header, sizeof(header), flags,
405 (struct sockaddr *)&src, &sizeof_src);
414 * Receive the packet. The OS will discard any data in the
415 * packet after "len" bytes.
417 #ifdef WITH_UDPFROMTO
418 if (dst.ss_family == AF_INET) {
419 data_len = recvfromto(sockfd, buf, len, flags,
420 (struct sockaddr *)&src, &sizeof_src,
421 (struct sockaddr *)&dst, &sizeof_dst);
425 * No udpfromto, OR an IPv6 socket. Fail gracefully.
427 data_len = recvfrom(sockfd, buf, len, flags,
428 (struct sockaddr *)&src, &sizeof_src);
434 if (!fr_sockaddr2ipaddr(&src, sizeof_src, src_ipaddr, &port)) {
436 return -1; /* Unknown address family, Die Die Die! */
440 fr_sockaddr2ipaddr(&dst, sizeof_dst, dst_ipaddr, &port);
444 * Different address families should never happen.
446 if (src.ss_family != dst.ss_family) {
452 * Tell the caller about the data
460 #define AUTH_PASS_LEN (AUTH_VECTOR_LEN)
461 /*************************************************************************
463 * Function: make_secret
465 * Purpose: Build an encrypted secret value to return in a reply
466 * packet. The secret is hidden by xoring with a MD5 digest
467 * created from the shared secret and the authentication
468 * vector. We put them into MD5 in the reverse order from
469 * that used when encrypting passwords to RADIUS.
471 *************************************************************************/
472 static void make_secret(uint8_t *digest, const uint8_t *vector,
473 const char *secret, const uint8_t *value)
478 fr_MD5Init(&context);
479 fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
480 fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
481 fr_MD5Final(digest, &context);
483 for ( i = 0; i < AUTH_VECTOR_LEN; i++ ) {
484 digest[i] ^= value[i];
488 #define MAX_PASS_LEN (128)
489 static void make_passwd(uint8_t *output, size_t *outlen,
490 const uint8_t *input, size_t inlen,
491 const char *secret, const uint8_t *vector)
493 FR_MD5_CTX context, old;
494 uint8_t digest[AUTH_VECTOR_LEN];
495 uint8_t passwd[MAX_PASS_LEN];
500 * If the length is zero, round it up.
504 if (len > MAX_PASS_LEN) len = MAX_PASS_LEN;
506 memcpy(passwd, input, len);
507 memset(passwd + len, 0, sizeof(passwd) - len);
513 else if ((len & 0x0f) != 0) {
519 fr_MD5Init(&context);
520 fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
526 fr_MD5Update(&context, vector, AUTH_PASS_LEN);
528 for (n = 0; n < len; n += AUTH_PASS_LEN) {
531 fr_MD5Update(&context,
532 passwd + n - AUTH_PASS_LEN,
536 fr_MD5Final(digest, &context);
537 for (i = 0; i < AUTH_PASS_LEN; i++) {
538 passwd[i + n] ^= digest[i];
542 memcpy(output, passwd, len);
545 static void make_tunnel_passwd(uint8_t *output, size_t *outlen,
546 const uint8_t *input, size_t inlen, size_t room,
547 const char *secret, const uint8_t *vector)
549 FR_MD5_CTX context, old;
550 uint8_t digest[AUTH_VECTOR_LEN];
551 uint8_t passwd[MAX_STRING_LEN + AUTH_VECTOR_LEN];
558 if (room > 253) room = 253;
561 * Account for 2 bytes of the salt, and round the room
562 * available down to the nearest multiple of 16. Then,
563 * subtract one from that to account for the length byte,
564 * and the resulting number is the upper bound on the data
567 * We could short-cut this calculation just be forcing
568 * inlen to be no more than 239. It would work for all
569 * VSA's, as we don't pack multiple VSA's into one
572 * However, this calculation is more general, if a little
573 * complex. And it will work in the future for all possible
574 * kinds of weird attribute packing.
577 room -= (room & 0x0f);
580 if (inlen > room) inlen = room;
583 * Length of the encrypted data is password length plus
584 * one byte for the length of the password.
587 if ((len & 0x0f) != 0) {
591 *outlen = len + 2; /* account for the salt */
594 * Copy the password over.
596 memcpy(passwd + 3, input, inlen);
597 memset(passwd + 3 + inlen, 0, sizeof(passwd) - 3 - inlen);
600 * Generate salt. The RFC's say:
602 * The high bit of salt[0] must be set, each salt in a
603 * packet should be unique, and they should be random
605 * So, we set the high bit, add in a counter, and then
606 * add in some CSPRNG data. should be OK..
608 passwd[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
610 passwd[1] = fr_rand();
611 passwd[2] = inlen; /* length of the password string */
613 fr_MD5Init(&context);
614 fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
617 fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
618 fr_MD5Update(&context, &passwd[0], 2);
620 for (n = 0; n < len; n += AUTH_PASS_LEN) {
623 fr_MD5Update(&context,
624 passwd + 2 + n - AUTH_PASS_LEN,
628 fr_MD5Final(digest, &context);
629 for (i = 0; i < AUTH_PASS_LEN; i++) {
630 passwd[i + 2 + n] ^= digest[i];
633 memcpy(output, passwd, len + 2);
637 * Returns the end of the data.
639 static uint8_t *vp2data(const RADIUS_PACKET *packet,
640 const RADIUS_PACKET *original,
641 const char *secret, const VALUE_PAIR *vp, uint8_t *ptr,
650 * Set up the default sources for the data.
652 data = vp->vp_octets;
659 case PW_TYPE_IPV6ADDR:
660 case PW_TYPE_IPV6PREFIX:
661 case PW_TYPE_ABINARY:
662 /* nothing more to do */
666 len = 1; /* just in case */
667 array[0] = vp->vp_integer & 0xff;
672 len = 2; /* just in case */
673 array[0] = (vp->vp_integer >> 8) & 0xff;
674 array[1] = vp->vp_integer & 0xff;
678 case PW_TYPE_INTEGER:
679 len = 4; /* just in case */
680 lvalue = htonl(vp->vp_integer);
681 memcpy(array, &lvalue, sizeof(lvalue));
686 data = (const uint8_t *) &vp->vp_ipaddr;
687 len = 4; /* just in case */
691 * There are no tagged date attributes.
694 lvalue = htonl(vp->vp_date);
695 data = (const uint8_t *) &lvalue;
696 len = 4; /* just in case */
703 len = 4; /* just in case */
704 slvalue = htonl(vp->vp_signed);
705 memcpy(array, &slvalue, sizeof(slvalue));
712 fr_strerror_printf("ERROR: Cannot encode NULL TLV");
717 default: /* unknown type: ignore it */
718 fr_strerror_printf("ERROR: Unknown attribute type %d", vp->type);
723 * Bound the data to the calling size
725 if (len > room) len = room;
728 * Encrypt the various password styles
730 * Attributes with encrypted values MUST be less than
733 switch (vp->flags.encrypt) {
734 case FLAG_ENCRYPT_USER_PASSWORD:
735 make_passwd(ptr, &len, data, len,
736 secret, packet->vector);
739 case FLAG_ENCRYPT_TUNNEL_PASSWORD:
741 * Check if there's enough room. If there isn't,
742 * we discard the attribute.
744 * This is ONLY a problem if we have multiple VSA's
745 * in one Vendor-Specific, though.
747 if (room < 18) return ptr;
749 switch (packet->code) {
750 case PW_AUTHENTICATION_ACK:
751 case PW_AUTHENTICATION_REJECT:
752 case PW_ACCESS_CHALLENGE:
755 fr_strerror_printf("ERROR: No request packet, cannot encrypt %s attribute in the vp.", vp->name);
758 make_tunnel_passwd(ptr, &len, data, len, room,
759 secret, original->vector);
761 case PW_ACCOUNTING_REQUEST:
762 case PW_DISCONNECT_REQUEST:
764 make_tunnel_passwd(ptr, &len, data, len, room,
765 secret, packet->vector);
771 * The code above ensures that this attribute
774 case FLAG_ENCRYPT_ASCEND_SECRET:
775 make_secret(ptr, packet->vector, secret, data);
776 len = AUTH_VECTOR_LEN;
782 * Just copy the data over
784 memcpy(ptr, data, len);
786 } /* switch over encryption flags */
792 static VALUE_PAIR *rad_vp2tlv(VALUE_PAIR *vps)
796 unsigned int attribute;
798 VALUE_PAIR *vp, *tlv;
800 attribute = vps->attribute & 0xffff00ff;
801 maxattr = vps->attribute & 0x0ff;
803 tlv = paircreate(attribute, vps->vendor, PW_TYPE_TLV);
804 if (!tlv) return NULL;
807 for (vp = vps; vp != NULL; vp = vp->next) {
809 * Group the attributes ONLY until we see a
812 if (!vp->flags.is_tlv ||
814 (vp->flags.encrypt != FLAG_ENCRYPT_NONE) ||
815 (vp->vendor != vps->vendor) ||
816 ((vp->attribute & 0xffff00ff) != attribute) ||
817 ((vp->attribute & 0x0000ff00) <= maxattr)) {
821 maxattr = vp->attribute & 0xff00;
822 tlv->length += vp->length + 2;
830 tlv->vp_tlv = malloc(tlv->length);
837 maxattr = vps->attribute & 0x0ff;
838 for (vp = vps; vp != NULL; vp = vp->next) {
839 if (!vp->flags.is_tlv ||
841 (vp->flags.encrypt != FLAG_ENCRYPT_NONE) ||
842 ((vp->attribute & 0xffff00ff) != attribute) ||
843 ((vp->attribute & 0x0000ff00) <= maxattr)) {
847 maxattr = vp->attribute & 0xff00;
848 end = vp2data(NULL, NULL, NULL, vp, ptr + 2,
849 tlv->vp_tlv + tlv->length - ptr);
851 vp->length = ptr - vp->vp_tlv;
852 return tlv; /* should be a more serious error... */
855 length = (end - ptr);
856 if (length > 255) return NULL;
859 * Pack the attribute.
861 ptr[0] = (vp->attribute & 0xff00) >> 8;
865 vp->flags.encoded = 1;
872 * Pack data without any encryption.
873 * start == start of RADIUS attribute
874 * ptr == continuation byte (i.e. one after length)
876 static int rad_vp2continuation(const VALUE_PAIR *vp, uint8_t *start,
880 size_t hsize = (ptr - start);
881 uint8_t *this = start;
886 * If it's too long and marked as encrypted, ignore it.
888 if (vp->flags.encrypt != FLAG_ENCRYPT_NONE) {
892 memcpy(header, start, hsize);
903 data = vp->vp_octets;
914 memcpy(this, header, hsize);
921 if (left > (254 - hsize)) {
929 memcpy(ptr, data, piece);
930 this[1] = hsize + piece + 1;
935 this[hsize - 1] = hsize - 6 + 1 + piece;
942 return (ptr - start);
947 * Parse a data structure into a RADIUS attribute.
949 int rad_vp2attr(const RADIUS_PACKET *packet, const RADIUS_PACKET *original,
950 const char *secret, const VALUE_PAIR *vp, uint8_t *start)
953 int len, total_length;
955 uint8_t *ptr, *length_ptr, *vsa_length_ptr, *tlv_length_ptr;
960 vendorcode = total_length = 0;
961 length_ptr = vsa_length_ptr = tlv_length_ptr = NULL;
964 * For interoperability, always put vendor attributes
965 * into their own VSA.
967 if ((vendorcode = vp->vendor) == 0) {
968 *(ptr++) = vp->attribute & 0xff;
977 DICT_VENDOR *dv = dict_vendorbyvalue(vendorcode);
980 * This must be an RFC-format attribute. If it
981 * wasn't, then the "decode" function would have
982 * made a Vendor-Specific attribute (i.e. type
983 * 26), and we would have "vendorcode == 0" here.
987 vsa_llen = dv->length;
988 if (dv->flags) vsa_offset = 1;
992 * Build a VSA header.
994 *ptr++ = PW_VENDOR_SPECIFIC;
995 vsa_length_ptr = ptr;
997 lvalue = htonl(vendorcode);
998 memcpy(ptr, &lvalue, 4);
1004 ptr[0] = (vp->attribute & 0xFF);
1008 ptr[0] = ((vp->attribute >> 8) & 0xFF);
1009 ptr[1] = (vp->attribute & 0xFF);
1015 ptr[2] = ((vp->attribute >> 8) & 0xFF);
1016 ptr[3] = (vp->attribute & 0xFF);
1020 return 0; /* silently discard it */
1026 length_ptr = vsa_length_ptr;
1027 vsa_length_ptr = NULL;
1036 length_ptr = ptr + 1;
1040 return 0; /* silently discard it */
1045 * Allow for some continuation.
1049 * Allow TLV's to be encoded, if someone
1050 * manages to somehow encode the sub-tlv's.
1052 * FIXME: Keep track of room in the packet!
1054 if (vp->length > (((size_t) 254) - (ptr - start))) {
1055 return rad_vp2continuation(vp, start, ptr);
1062 * sub-TLV's can only be in one format.
1064 if (vp->flags.is_tlv) {
1065 *(ptr++) = (vp->attribute & 0xff00) >> 8;
1066 tlv_length_ptr = ptr;
1072 total_length += vsa_tlen + vsa_llen + vsa_offset;
1073 if (vsa_length_ptr) *vsa_length_ptr += vsa_tlen + vsa_llen + vsa_offset;
1074 *length_ptr += vsa_tlen + vsa_llen + vsa_offset;
1078 * Insert tags for string attributes. They go BEFORE
1081 if (vp->flags.has_tag && (vp->type == PW_TYPE_STRING) &&
1082 (TAG_VALID(vp->flags.tag) ||
1083 (vp->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD))) {
1084 ptr[0] = vp->flags.tag;
1085 end = vp2data(packet, original, secret, vp, ptr + 1,
1088 end = vp2data(packet, original, secret, vp, ptr,
1091 if (!end) return -1;
1094 * Insert tags for integer attributes. They go at the START
1095 * of the integer, and over-write the first byte.
1097 if (vp->flags.has_tag && (vp->type == PW_TYPE_INTEGER)) {
1098 ptr[0] = vp->flags.tag;
1102 * RFC 2865 section 5 says that zero-length attributes
1105 * ... and the WiMAX forum ignores this... because of
1106 * one vendor. Don't they have anything better to do
1110 (vp->attribute != PW_CHARGEABLE_USER_IDENTITY)) return 0;
1115 * Update the various lengths.
1118 if (vsa_length_ptr) *vsa_length_ptr += len;
1119 if (tlv_length_ptr) *tlv_length_ptr += len;
1121 total_length += len;
1123 return total_length; /* of attribute */
1130 int rad_encode(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1133 radius_packet_t *hdr;
1135 uint16_t total_length;
1139 char ip_buffer[128];
1142 * For simplicity in the following logic, we allow
1143 * the attributes to "overflow" the 4k maximum
1144 * RADIUS packet size, by one attribute.
1146 * It's uint32_t, for alignment purposes.
1148 uint32_t data[(MAX_PACKET_LEN + 256) / 4];
1150 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
1151 what = fr_packet_codes[packet->code];
1156 DEBUG("Sending %s of id %d to %s port %d\n",
1158 inet_ntop(packet->dst_ipaddr.af,
1159 &packet->dst_ipaddr.ipaddr,
1160 ip_buffer, sizeof(ip_buffer)),
1164 * Double-check some things based on packet code.
1166 switch (packet->code) {
1167 case PW_AUTHENTICATION_ACK:
1168 case PW_AUTHENTICATION_REJECT:
1169 case PW_ACCESS_CHALLENGE:
1171 fr_strerror_printf("ERROR: Cannot sign response packet without a request packet.");
1177 * These packet vectors start off as all zero.
1179 case PW_ACCOUNTING_REQUEST:
1180 case PW_DISCONNECT_REQUEST:
1181 case PW_COA_REQUEST:
1182 memset(packet->vector, 0, sizeof(packet->vector));
1190 * Use memory on the stack, until we know how
1191 * large the packet will be.
1193 hdr = (radius_packet_t *) data;
1196 * Build standard header
1198 hdr->code = packet->code;
1199 hdr->id = packet->id;
1201 memcpy(hdr->vector, packet->vector, sizeof(hdr->vector));
1203 total_length = AUTH_HDR_LEN;
1206 * Load up the configuration values for the user
1212 * FIXME: Loop twice over the reply list. The first time,
1213 * calculate the total length of data. The second time,
1214 * allocate the memory, and fill in the VP's.
1216 * Hmm... this may be slower than just doing a small
1221 * Loop over the reply attributes for the packet.
1223 for (reply = packet->vps; reply; reply = reply->next) {
1225 * Ignore non-wire attributes
1227 if ((reply->vendor == 0) &&
1228 ((reply->attribute & 0xFFFF) > 0xff)) {
1231 * Permit the admin to send BADLY formatted
1232 * attributes with a debug build.
1234 if (reply->attribute == PW_RAW_ATTRIBUTE) {
1235 memcpy(ptr, reply->vp_octets, reply->length);
1236 len = reply->length;
1244 * Set the Message-Authenticator to the correct
1245 * length and initial value.
1247 if (reply->attribute == PW_MESSAGE_AUTHENTICATOR) {
1248 reply->length = AUTH_VECTOR_LEN;
1249 memset(reply->vp_strvalue, 0, AUTH_VECTOR_LEN);
1252 * Cache the offset to the
1253 * Message-Authenticator
1255 packet->offset = total_length;
1259 * Print out ONLY the attributes which
1260 * we're sending over the wire, and print
1261 * them out BEFORE they're encrypted.
1266 * Print them in order, even if they were encoded
1270 if (reply->flags.encoded) goto next;
1272 if (reply->flags.is_tlv) {
1273 VALUE_PAIR *tlv = rad_vp2tlv(reply);
1275 tlv->next = reply->next;
1280 * The encoded flag MUST be set in reply!
1282 reply = reply->next;
1285 len = rad_vp2attr(packet, original, secret, reply, ptr);
1287 if (len < 0) return -1;
1290 * Check that the packet is no more than 4k in
1291 * size, AFTER writing the attribute past the 4k
1292 * boundary, but BEFORE deciding to increase the
1293 * size of the packet. Note that the 'data'
1294 * buffer, above, is one attribute longer than
1295 * necessary, in order to permit this overflow.
1297 if ((total_length + len) > MAX_PACKET_LEN) {
1303 total_length += len;
1304 } /* done looping over all attributes */
1307 * Fill in the rest of the fields, and copy the data over
1308 * from the local stack to the newly allocated memory.
1310 * Yes, all this 'memcpy' is slow, but it means
1311 * that we only allocate the minimum amount of
1312 * memory for a request.
1314 packet->data_len = total_length;
1315 packet->data = (uint8_t *) malloc(packet->data_len);
1316 if (!packet->data) {
1317 fr_strerror_printf("Out of memory");
1321 memcpy(packet->data, hdr, packet->data_len);
1322 hdr = (radius_packet_t *) packet->data;
1324 total_length = htons(total_length);
1325 memcpy(hdr->length, &total_length, sizeof(total_length));
1332 * Sign a previously encoded packet.
1334 int rad_sign(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1337 radius_packet_t *hdr = (radius_packet_t *)packet->data;
1340 * It wasn't assigned an Id, this is bad!
1342 if (packet->id < 0) {
1343 fr_strerror_printf("ERROR: RADIUS packets must be assigned an Id.");
1347 if (!packet->data || (packet->data_len < AUTH_HDR_LEN) ||
1348 (packet->offset < 0)) {
1349 fr_strerror_printf("ERROR: You must call rad_encode() before rad_sign()");
1354 * If there's a Message-Authenticator, update it
1355 * now, BEFORE updating the authentication vector.
1357 if (packet->offset > 0) {
1358 uint8_t calc_auth_vector[AUTH_VECTOR_LEN];
1360 switch (packet->code) {
1361 case PW_ACCOUNTING_REQUEST:
1362 case PW_ACCOUNTING_RESPONSE:
1363 case PW_DISCONNECT_REQUEST:
1364 case PW_DISCONNECT_ACK:
1365 case PW_DISCONNECT_NAK:
1366 case PW_COA_REQUEST:
1369 memset(hdr->vector, 0, AUTH_VECTOR_LEN);
1372 case PW_AUTHENTICATION_ACK:
1373 case PW_AUTHENTICATION_REJECT:
1374 case PW_ACCESS_CHALLENGE:
1376 fr_strerror_printf("ERROR: Cannot sign response packet without a request packet.");
1379 memcpy(hdr->vector, original->vector,
1383 default: /* others have vector already set to zero */
1389 * Set the authentication vector to zero,
1390 * calculate the signature, and put it
1391 * into the Message-Authenticator
1394 fr_hmac_md5(packet->data, packet->data_len,
1395 (const uint8_t *) secret, strlen(secret),
1397 memcpy(packet->data + packet->offset + 2,
1398 calc_auth_vector, AUTH_VECTOR_LEN);
1401 * Copy the original request vector back
1402 * to the raw packet.
1404 memcpy(hdr->vector, packet->vector, AUTH_VECTOR_LEN);
1408 * Switch over the packet code, deciding how to
1411 switch (packet->code) {
1413 * Request packets are not signed, bur
1414 * have a random authentication vector.
1416 case PW_AUTHENTICATION_REQUEST:
1417 case PW_STATUS_SERVER:
1421 * Reply packets are signed with the
1422 * authentication vector of the request.
1429 fr_MD5Init(&context);
1430 fr_MD5Update(&context, packet->data, packet->data_len);
1431 fr_MD5Update(&context, (const uint8_t *) secret,
1433 fr_MD5Final(digest, &context);
1435 memcpy(hdr->vector, digest, AUTH_VECTOR_LEN);
1436 memcpy(packet->vector, digest, AUTH_VECTOR_LEN);
1439 }/* switch over packet codes */
1445 * Reply to the request. Also attach
1446 * reply attribute value pairs and any user message provided.
1448 int rad_send(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
1453 char ip_buffer[128];
1456 * Maybe it's a fake packet. Don't send it.
1458 if (!packet || (packet->sockfd < 0)) {
1462 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
1463 what = fr_packet_codes[packet->code];
1469 * First time through, allocate room for the packet
1471 if (!packet->data) {
1473 * Encode the packet.
1475 if (rad_encode(packet, original, secret) < 0) {
1480 * Re-sign it, including updating the
1481 * Message-Authenticator.
1483 if (rad_sign(packet, original, secret) < 0) {
1488 * If packet->data points to data, then we print out
1489 * the VP list again only for debugging.
1491 } else if (fr_debug_flag) {
1492 DEBUG("Sending %s of id %d to %s port %d\n", what, packet->id,
1493 inet_ntop(packet->dst_ipaddr.af,
1494 &packet->dst_ipaddr.ipaddr,
1495 ip_buffer, sizeof(ip_buffer)),
1498 for (reply = packet->vps; reply; reply = reply->next) {
1499 if ((reply->vendor == 0) &&
1500 ((reply->attribute & 0xFFFF) > 0xff)) continue;
1506 * And send it on it's way.
1508 return rad_sendto(packet->sockfd, packet->data, packet->data_len, 0,
1509 &packet->src_ipaddr, packet->src_port,
1510 &packet->dst_ipaddr, packet->dst_port);
1514 * Do a comparison of two authentication digests by comparing
1515 * the FULL digest. Otehrwise, the server can be subject to
1516 * timing attacks that allow attackers find a valid message
1519 * http://www.cs.rice.edu/~dwallach/pub/crosby-timing2009.pdf
1521 static int digest_cmp(const uint8_t *a, const uint8_t *b, size_t length)
1526 for (i = 0; i < length; i++) {
1527 result |= a[i] ^ b[i];
1530 return result; /* 0 is OK, !0 is !OK, just like memcmp */
1535 * Validates the requesting client NAS. Calculates the
1536 * signature based on the clients private key.
1538 static int calc_acctdigest(RADIUS_PACKET *packet, const char *secret)
1540 uint8_t digest[AUTH_VECTOR_LEN];
1544 * Zero out the auth_vector in the received packet.
1545 * Then append the shared secret to the received packet,
1546 * and calculate the MD5 sum. This must be the same
1547 * as the original MD5 sum (packet->vector).
1549 memset(packet->data + 4, 0, AUTH_VECTOR_LEN);
1552 * MD5(packet + secret);
1554 fr_MD5Init(&context);
1555 fr_MD5Update(&context, packet->data, packet->data_len);
1556 fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
1557 fr_MD5Final(digest, &context);
1560 * Return 0 if OK, 2 if not OK.
1562 if (digest_cmp(digest, packet->vector, AUTH_VECTOR_LEN) != 0) return 2;
1568 * Validates the requesting client NAS. Calculates the
1569 * signature based on the clients private key.
1571 static int calc_replydigest(RADIUS_PACKET *packet, RADIUS_PACKET *original,
1574 uint8_t calc_digest[AUTH_VECTOR_LEN];
1580 if (original == NULL) {
1585 * Copy the original vector in place.
1587 memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);
1590 * MD5(packet + secret);
1592 fr_MD5Init(&context);
1593 fr_MD5Update(&context, packet->data, packet->data_len);
1594 fr_MD5Update(&context, (const uint8_t *) secret, strlen(secret));
1595 fr_MD5Final(calc_digest, &context);
1598 * Copy the packet's vector back to the packet.
1600 memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);
1603 * Return 0 if OK, 2 if not OK.
1605 if (digest_cmp(packet->vector, calc_digest, AUTH_VECTOR_LEN) != 0) return 2;
1611 * See if the data pointed to by PTR is a valid RADIUS packet.
1613 * packet is not 'const * const' because we may update data_len,
1614 * if there's more data in the UDP packet than in the RADIUS packet.
1616 int rad_packet_ok(RADIUS_PACKET *packet, int flags)
1621 radius_packet_t *hdr;
1622 char host_ipaddr[128];
1628 * Check for packets smaller than the packet header.
1630 * RFC 2865, Section 3., subsection 'length' says:
1632 * "The minimum length is 20 ..."
1634 if (packet->data_len < AUTH_HDR_LEN) {
1635 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: too short (received %d < minimum %d)",
1636 inet_ntop(packet->src_ipaddr.af,
1637 &packet->src_ipaddr.ipaddr,
1638 host_ipaddr, sizeof(host_ipaddr)),
1639 (int) packet->data_len, AUTH_HDR_LEN);
1644 * RFC 2865, Section 3., subsection 'length' says:
1646 * " ... and maximum length is 4096."
1648 if (packet->data_len > MAX_PACKET_LEN) {
1649 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: too long (received %d > maximum %d)",
1650 inet_ntop(packet->src_ipaddr.af,
1651 &packet->src_ipaddr.ipaddr,
1652 host_ipaddr, sizeof(host_ipaddr)),
1653 (int) packet->data_len, MAX_PACKET_LEN);
1658 * Check for packets with mismatched size.
1659 * i.e. We've received 128 bytes, and the packet header
1660 * says it's 256 bytes long.
1662 totallen = (packet->data[2] << 8) | packet->data[3];
1663 hdr = (radius_packet_t *)packet->data;
1666 * Code of 0 is not understood.
1667 * Code of 16 or greate is not understood.
1669 if ((hdr->code == 0) ||
1670 (hdr->code >= FR_MAX_PACKET_CODE)) {
1671 fr_strerror_printf("WARNING: Bad RADIUS packet from host %s: unknown packet code%d ",
1672 inet_ntop(packet->src_ipaddr.af,
1673 &packet->src_ipaddr.ipaddr,
1674 host_ipaddr, sizeof(host_ipaddr)),
1680 * Message-Authenticator is required in Status-Server
1681 * packets, otherwise they can be trivially forged.
1683 if (hdr->code == PW_STATUS_SERVER) require_ma = 1;
1686 * It's also required if the caller asks for it.
1688 if (flags) require_ma = 1;
1691 * Repeat the length checks. This time, instead of
1692 * looking at the data we received, look at the value
1693 * of the 'length' field inside of the packet.
1695 * Check for packets smaller than the packet header.
1697 * RFC 2865, Section 3., subsection 'length' says:
1699 * "The minimum length is 20 ..."
1701 if (totallen < AUTH_HDR_LEN) {
1702 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: too short (length %d < minimum %d)",
1703 inet_ntop(packet->src_ipaddr.af,
1704 &packet->src_ipaddr.ipaddr,
1705 host_ipaddr, sizeof(host_ipaddr)),
1706 totallen, AUTH_HDR_LEN);
1711 * And again, for the value of the 'length' field.
1713 * RFC 2865, Section 3., subsection 'length' says:
1715 * " ... and maximum length is 4096."
1717 if (totallen > MAX_PACKET_LEN) {
1718 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: too long (length %d > maximum %d)",
1719 inet_ntop(packet->src_ipaddr.af,
1720 &packet->src_ipaddr.ipaddr,
1721 host_ipaddr, sizeof(host_ipaddr)),
1722 totallen, MAX_PACKET_LEN);
1727 * RFC 2865, Section 3., subsection 'length' says:
1729 * "If the packet is shorter than the Length field
1730 * indicates, it MUST be silently discarded."
1732 * i.e. No response to the NAS.
1734 if (packet->data_len < totallen) {
1735 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: received %d octets, packet length says %d",
1736 inet_ntop(packet->src_ipaddr.af,
1737 &packet->src_ipaddr.ipaddr,
1738 host_ipaddr, sizeof(host_ipaddr)),
1739 (int) packet->data_len, totallen);
1744 * RFC 2865, Section 3., subsection 'length' says:
1746 * "Octets outside the range of the Length field MUST be
1747 * treated as padding and ignored on reception."
1749 if (packet->data_len > totallen) {
1751 * We're shortening the packet below, but just
1752 * to be paranoid, zero out the extra data.
1754 memset(packet->data + totallen, 0, packet->data_len - totallen);
1755 packet->data_len = totallen;
1759 * Walk through the packet's attributes, ensuring that
1760 * they add up EXACTLY to the size of the packet.
1762 * If they don't, then the attributes either under-fill
1763 * or over-fill the packet. Any parsing of the packet
1764 * is impossible, and will result in unknown side effects.
1766 * This would ONLY happen with buggy RADIUS implementations,
1767 * or with an intentional attack. Either way, we do NOT want
1768 * to be vulnerable to this problem.
1771 count = totallen - AUTH_HDR_LEN;
1776 * Attribute number zero is NOT defined.
1779 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: Invalid attribute 0",
1780 inet_ntop(packet->src_ipaddr.af,
1781 &packet->src_ipaddr.ipaddr,
1782 host_ipaddr, sizeof(host_ipaddr)));
1787 * Attributes are at LEAST as long as the ID & length
1788 * fields. Anything shorter is an invalid attribute.
1791 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: attribute %d too short",
1792 inet_ntop(packet->src_ipaddr.af,
1793 &packet->src_ipaddr.ipaddr,
1794 host_ipaddr, sizeof(host_ipaddr)),
1800 * Sanity check the attributes for length.
1803 default: /* don't do anything by default */
1807 * If there's an EAP-Message, we require
1808 * a Message-Authenticator.
1810 case PW_EAP_MESSAGE:
1814 case PW_MESSAGE_AUTHENTICATOR:
1815 if (attr[1] != 2 + AUTH_VECTOR_LEN) {
1816 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: Message-Authenticator has invalid length %d",
1817 inet_ntop(packet->src_ipaddr.af,
1818 &packet->src_ipaddr.ipaddr,
1819 host_ipaddr, sizeof(host_ipaddr)),
1828 * FIXME: Look up the base 255 attributes in the
1829 * dictionary, and switch over their type. For
1830 * integer/date/ip, the attribute length SHOULD
1833 count -= attr[1]; /* grab the attribute length */
1835 num_attributes++; /* seen one more attribute */
1839 * If the attributes add up to a packet, it's allowed.
1841 * If not, we complain, and throw the packet away.
1844 fr_strerror_printf("WARNING: Malformed RADIUS packet from host %s: packet attributes do NOT exactly fill the packet",
1845 inet_ntop(packet->src_ipaddr.af,
1846 &packet->src_ipaddr.ipaddr,
1847 host_ipaddr, sizeof(host_ipaddr)));
1852 * If we're configured to look for a maximum number of
1853 * attributes, and we've seen more than that maximum,
1854 * then throw the packet away, as a possible DoS.
1856 if ((fr_max_attributes > 0) &&
1857 (num_attributes > fr_max_attributes)) {
1858 fr_strerror_printf("WARNING: Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
1859 inet_ntop(packet->src_ipaddr.af,
1860 &packet->src_ipaddr.ipaddr,
1861 host_ipaddr, sizeof(host_ipaddr)),
1862 num_attributes, fr_max_attributes);
1867 * http://www.freeradius.org/rfc/rfc2869.html#EAP-Message
1869 * A packet with an EAP-Message attribute MUST also have
1870 * a Message-Authenticator attribute.
1872 * A Message-Authenticator all by itself is OK, though.
1874 * Similarly, Status-Server packets MUST contain
1875 * Message-Authenticator attributes.
1877 if (require_ma && ! seen_ma) {
1878 fr_strerror_printf("WARNING: Insecure packet from host %s: Packet does not contain required Message-Authenticator attribute",
1879 inet_ntop(packet->src_ipaddr.af,
1880 &packet->src_ipaddr.ipaddr,
1881 host_ipaddr, sizeof(host_ipaddr)));
1886 * Fill RADIUS header fields
1888 packet->code = hdr->code;
1889 packet->id = hdr->id;
1890 memcpy(packet->vector, hdr->vector, AUTH_VECTOR_LEN);
1897 * Receive UDP client requests, and fill in
1898 * the basics of a RADIUS_PACKET structure.
1900 RADIUS_PACKET *rad_recv(int fd, int flags)
1903 RADIUS_PACKET *packet;
1906 * Allocate the new request data structure
1908 if ((packet = malloc(sizeof(*packet))) == NULL) {
1909 fr_strerror_printf("out of memory");
1912 memset(packet, 0, sizeof(*packet));
1915 sock_flags = MSG_PEEK;
1919 packet->data_len = rad_recvfrom(fd, &packet->data, sock_flags,
1920 &packet->src_ipaddr, &packet->src_port,
1921 &packet->dst_ipaddr, &packet->dst_port);
1924 * Check for socket errors.
1926 if (packet->data_len < 0) {
1927 fr_strerror_printf("Error receiving packet: %s", strerror(errno));
1928 /* packet->data is NULL */
1934 * If the packet is too big, then rad_recvfrom did NOT
1935 * allocate memory. Instead, it just discarded the
1938 if (packet->data_len > MAX_PACKET_LEN) {
1939 fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes.");
1940 /* packet->data is NULL */
1946 * Read no data. Continue.
1947 * This check is AFTER the MAX_PACKET_LEN check above, because
1948 * if the packet is larger than MAX_PACKET_LEN, we also have
1949 * packet->data == NULL
1951 if ((packet->data_len == 0) || !packet->data) {
1952 fr_strerror_printf("Empty packet: Socket is not ready.");
1958 * See if it's a well-formed RADIUS packet.
1960 if (!rad_packet_ok(packet, flags)) {
1966 * Remember which socket we read the packet from.
1968 packet->sockfd = fd;
1971 * FIXME: Do even more filtering by only permitting
1972 * certain IP's. The problem is that we don't know
1973 * how to do this properly for all possible clients...
1977 * Explicitely set the VP list to empty.
1981 if (fr_debug_flag) {
1982 char host_ipaddr[128];
1984 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
1985 DEBUG("rad_recv: %s packet from host %s port %d",
1986 fr_packet_codes[packet->code],
1987 inet_ntop(packet->src_ipaddr.af,
1988 &packet->src_ipaddr.ipaddr,
1989 host_ipaddr, sizeof(host_ipaddr)),
1992 DEBUG("rad_recv: Packet from host %s port %d code=%d",
1993 inet_ntop(packet->src_ipaddr.af,
1994 &packet->src_ipaddr.ipaddr,
1995 host_ipaddr, sizeof(host_ipaddr)),
1999 DEBUG(", id=%d, length=%d\n",
2000 packet->id, (int) packet->data_len);
2008 * Verify the signature of a packet.
2010 int rad_verify(RADIUS_PACKET *packet, RADIUS_PACKET *original,
2017 if (!packet || !packet->data) return -1;
2020 * Before we allocate memory for the attributes, do more
2023 ptr = packet->data + AUTH_HDR_LEN;
2024 length = packet->data_len - AUTH_HDR_LEN;
2025 while (length > 0) {
2026 uint8_t msg_auth_vector[AUTH_VECTOR_LEN];
2027 uint8_t calc_auth_vector[AUTH_VECTOR_LEN];
2032 default: /* don't do anything. */
2036 * Note that more than one Message-Authenticator
2037 * attribute is invalid.
2039 case PW_MESSAGE_AUTHENTICATOR:
2040 memcpy(msg_auth_vector, &ptr[2], sizeof(msg_auth_vector));
2041 memset(&ptr[2], 0, AUTH_VECTOR_LEN);
2043 switch (packet->code) {
2047 case PW_ACCOUNTING_REQUEST:
2048 case PW_ACCOUNTING_RESPONSE:
2049 case PW_DISCONNECT_REQUEST:
2050 case PW_DISCONNECT_ACK:
2051 case PW_DISCONNECT_NAK:
2052 case PW_COA_REQUEST:
2055 memset(packet->data + 4, 0, AUTH_VECTOR_LEN);
2058 case PW_AUTHENTICATION_ACK:
2059 case PW_AUTHENTICATION_REJECT:
2060 case PW_ACCESS_CHALLENGE:
2062 fr_strerror_printf("ERROR: Cannot validate Message-Authenticator in response packet without a request packet.");
2065 memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);
2069 fr_hmac_md5(packet->data, packet->data_len,
2070 (const uint8_t *) secret, strlen(secret),
2072 if (digest_cmp(calc_auth_vector, msg_auth_vector,
2073 sizeof(calc_auth_vector)) != 0) {
2075 fr_strerror_printf("Received packet from %s with invalid Message-Authenticator! (Shared secret is incorrect.)",
2076 inet_ntop(packet->src_ipaddr.af,
2077 &packet->src_ipaddr.ipaddr,
2078 buffer, sizeof(buffer)));
2079 /* Silently drop packet, according to RFC 3579 */
2081 } /* else the message authenticator was good */
2084 * Reinitialize Authenticators.
2086 memcpy(&ptr[2], msg_auth_vector, AUTH_VECTOR_LEN);
2087 memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);
2089 } /* switch over the attributes */
2093 } /* loop over the packet, sanity checking the attributes */
2096 * It looks like a RADIUS packet, but we can't validate
2099 if ((packet->code == 0) || (packet->code >= FR_MAX_PACKET_CODE)) {
2101 fr_strerror_printf("Received Unknown packet code %d "
2102 "from client %s port %d: Cannot validate signature.",
2104 inet_ntop(packet->src_ipaddr.af,
2105 &packet->src_ipaddr.ipaddr,
2106 buffer, sizeof(buffer)),
2112 * Calculate and/or verify digest.
2114 switch(packet->code) {
2118 case PW_AUTHENTICATION_REQUEST:
2119 case PW_STATUS_SERVER:
2121 * The authentication vector is random
2122 * nonsense, invented by the client.
2126 case PW_COA_REQUEST:
2127 case PW_DISCONNECT_REQUEST:
2128 case PW_ACCOUNTING_REQUEST:
2129 if (calc_acctdigest(packet, secret) > 1) {
2130 fr_strerror_printf("Received %s packet "
2131 "from %s with invalid signature! (Shared secret is incorrect.)",
2132 fr_packet_codes[packet->code],
2133 inet_ntop(packet->src_ipaddr.af,
2134 &packet->src_ipaddr.ipaddr,
2135 buffer, sizeof(buffer)));
2140 /* Verify the reply digest */
2141 case PW_AUTHENTICATION_ACK:
2142 case PW_AUTHENTICATION_REJECT:
2143 case PW_ACCESS_CHALLENGE:
2144 case PW_ACCOUNTING_RESPONSE:
2145 case PW_DISCONNECT_ACK:
2146 case PW_DISCONNECT_NAK:
2149 rcode = calc_replydigest(packet, original, secret);
2151 fr_strerror_printf("Received %s packet "
2152 "from client %s port %d with invalid signature (err=%d)! (Shared secret is incorrect.)",
2153 fr_packet_codes[packet->code],
2154 inet_ntop(packet->src_ipaddr.af,
2155 &packet->src_ipaddr.ipaddr,
2156 buffer, sizeof(buffer)),
2164 fr_strerror_printf("Received Unknown packet code %d "
2165 "from client %s port %d: Cannot validate signature",
2167 inet_ntop(packet->src_ipaddr.af,
2168 &packet->src_ipaddr.ipaddr,
2169 buffer, sizeof(buffer)),
2178 static VALUE_PAIR *data2vp(const RADIUS_PACKET *packet,
2179 const RADIUS_PACKET *original,
2180 const char *secret, size_t length,
2181 const uint8_t *data, VALUE_PAIR *vp)
2186 * If length is greater than 253, something is SERIOUSLY
2189 if (length > 253) length = 253; /* paranoia (pair-anoia?) */
2191 vp->length = length;
2192 vp->operator = T_OP_EQ;
2198 if (vp->flags.has_tag) {
2199 if (TAG_VALID(data[0]) ||
2200 (vp->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD)) {
2202 * Tunnel passwords REQUIRE a tag, even
2203 * if don't have a valid tag.
2205 vp->flags.tag = data[0];
2207 if ((vp->type == PW_TYPE_STRING) ||
2208 (vp->type == PW_TYPE_OCTETS)) offset = 1;
2213 * Copy the data to be decrypted
2215 memcpy(&vp->vp_octets[0], data + offset, length - offset);
2216 vp->length -= offset;
2219 * Decrypt the attribute.
2221 switch (vp->flags.encrypt) {
2225 case FLAG_ENCRYPT_USER_PASSWORD:
2227 rad_pwdecode((char *)vp->vp_strvalue,
2231 rad_pwdecode((char *)vp->vp_strvalue,
2235 if (vp->attribute == PW_USER_PASSWORD) {
2236 vp->length = strlen(vp->vp_strvalue);
2241 * Tunnel-Password's may go ONLY
2242 * in response packets.
2244 case FLAG_ENCRYPT_TUNNEL_PASSWORD:
2245 if (!original) goto raw;
2247 if (rad_tunnel_pwdecode(vp->vp_octets, &vp->length,
2248 secret, original->vector) < 0) {
2254 * Ascend-Send-Secret
2255 * Ascend-Receive-Secret
2257 case FLAG_ENCRYPT_ASCEND_SECRET:
2261 uint8_t my_digest[AUTH_VECTOR_LEN];
2262 make_secret(my_digest,
2265 memcpy(vp->vp_strvalue, my_digest,
2267 vp->vp_strvalue[AUTH_VECTOR_LEN] = '\0';
2268 vp->length = strlen(vp->vp_strvalue);
2274 } /* switch over encryption flags */
2278 case PW_TYPE_STRING:
2279 case PW_TYPE_OCTETS:
2280 case PW_TYPE_ABINARY:
2281 /* nothing more to do */
2285 if (vp->length != 1) goto raw;
2287 vp->vp_integer = vp->vp_octets[0];
2292 if (vp->length != 2) goto raw;
2294 vp->vp_integer = (vp->vp_octets[0] << 8) | vp->vp_octets[1];
2297 case PW_TYPE_INTEGER:
2298 if (vp->length != 4) goto raw;
2300 memcpy(&vp->vp_integer, vp->vp_octets, 4);
2301 vp->vp_integer = ntohl(vp->vp_integer);
2303 if (vp->flags.has_tag) vp->vp_integer &= 0x00ffffff;
2306 * Try to get named VALUEs
2310 dval = dict_valbyattr(vp->attribute, vp->vendor,
2313 strlcpy(vp->vp_strvalue,
2315 sizeof(vp->vp_strvalue));
2321 if (vp->length != 4) goto raw;
2323 memcpy(&vp->vp_date, vp->vp_octets, 4);
2324 vp->vp_date = ntohl(vp->vp_date);
2328 case PW_TYPE_IPADDR:
2329 if (vp->length != 4) goto raw;
2331 memcpy(&vp->vp_ipaddr, vp->vp_octets, 4);
2335 * IPv6 interface ID is 8 octets long.
2338 if (vp->length != 8) goto raw;
2339 /* vp->vp_ifid == vp->vp_octets */
2343 * IPv6 addresses are 16 octets long
2345 case PW_TYPE_IPV6ADDR:
2346 if (vp->length != 16) goto raw;
2347 /* vp->vp_ipv6addr == vp->vp_octets */
2351 * IPv6 prefixes are 2 to 18 octets long.
2353 * RFC 3162: The first octet is unused.
2354 * The second is the length of the prefix
2355 * the rest are the prefix data.
2357 * The prefix length can have value 0 to 128.
2359 case PW_TYPE_IPV6PREFIX:
2360 if (vp->length < 2 || vp->length > 18) goto raw;
2361 if (vp->vp_octets[1] > 128) goto raw;
2364 * FIXME: double-check that
2365 * (vp->vp_octets[1] >> 3) matches vp->length + 2
2367 if (vp->length < 18) {
2368 memset(vp->vp_octets + vp->length, 0,
2373 case PW_TYPE_SIGNED:
2374 if (vp->length != 4) goto raw;
2377 * Overload vp_integer for ntohl, which takes
2378 * uint32_t, not int32_t
2380 memcpy(&vp->vp_integer, vp->vp_octets, 4);
2381 vp->vp_integer = ntohl(vp->vp_integer);
2382 memcpy(&vp->vp_signed, &vp->vp_integer, 4);
2386 vp->length = length;
2387 vp->vp_tlv = malloc(length);
2390 fr_strerror_printf("No memory");
2393 memcpy(vp->vp_tlv, data, length);
2396 case PW_TYPE_COMBO_IP:
2397 if (vp->length == 4) {
2398 vp->type = PW_TYPE_IPADDR;
2399 memcpy(&vp->vp_ipaddr, vp->vp_octets, 4);
2402 } else if (vp->length == 16) {
2403 vp->type = PW_TYPE_IPV6ADDR;
2404 /* vp->vp_ipv6addr == vp->vp_octets */
2412 vp->type = PW_TYPE_OCTETS;
2413 vp->length = length;
2414 memcpy(vp->vp_octets, data, length);
2418 * Ensure there's no encryption or tag stuff,
2419 * we just pass the attribute as-is.
2421 memset(&vp->flags, 0, sizeof(vp->flags));
2427 static void rad_sortvp(VALUE_PAIR **head)
2430 VALUE_PAIR *vp, **tail;
2433 * Walk over the VP's, sorting them in order. Did I
2434 * mention that I hate WiMAX continuations?
2436 * And bubble sort! WTF is up with that?
2443 if (!vp->next) break;
2445 if (vp->attribute > vp->next->attribute) {
2447 vp->next = (*tail)->next;
2458 * Walk the packet, looking for continuations of this attribute.
2460 * This is (worst-case) O(N^2) in the number of RADIUS
2461 * attributes. That happens only when perverse clients create
2462 * continued attributes, AND separate the fragmented portions
2463 * with a lot of other attributes.
2465 * Sane clients should put the fragments next to each other, in
2466 * which case this is O(N), in the number of fragments.
2468 static uint8_t *rad_coalesce(unsigned int attribute, int vendor,
2469 size_t length, uint8_t *data,
2470 size_t packet_length, size_t *ptlv_length)
2474 size_t tlv_length = length;
2475 uint8_t *ptr, *tlv, *tlv_data;
2477 for (ptr = data + length;
2478 ptr != (data + packet_length);
2480 /* FIXME: Check that there are 6 bytes of data here... */
2481 if ((ptr[0] != PW_VENDOR_SPECIFIC) ||
2482 (ptr[1] < (2 + 4 + 3)) || /* WiMAX VSA with continuation */
2483 (ptr[2] != 0) || (ptr[3] != 0) || /* our requirement */
2484 (ptr[4] != ((vendor >> 8) & 0xff)) ||
2485 (ptr[5] != (vendor & 0xff))) {
2489 memcpy(&lvalue, ptr + 2, 4); /* Vendor Id */
2490 lvalue = ntohl(lvalue);
2492 lvalue |= ptr[2 + 4]; /* add in VSA number */
2493 if (lvalue != attribute) continue;
2496 * If the vendor-length is too small, it's badly
2497 * formed, so we stop.
2499 if ((ptr[2 + 4 + 1]) < 3) break;
2501 tlv_length += ptr[2 + 4 + 1] - 3;
2502 if ((ptr[2 + 4 + 1 + 1] & 0x80) == 0) break;
2505 tlv = tlv_data = malloc(tlv_length);
2506 if (!tlv_data) return NULL;
2508 memcpy(tlv, data, length);
2512 * Now we walk the list again, copying the data over to
2513 * our newly created memory.
2515 for (ptr = data + length;
2516 ptr != (data + packet_length);
2520 if ((ptr[0] != PW_VENDOR_SPECIFIC) ||
2521 (ptr[1] < (2 + 4 + 3)) || /* WiMAX VSA with continuation */
2522 (ptr[2] != 0) || (ptr[3] != 0)) { /* our requirement */
2526 memcpy(&lvalue, ptr + 2, 4);
2527 lvalue = ntohl(lvalue);
2529 lvalue |= ptr[2 + 4];
2530 if (lvalue != attribute) continue;
2533 * If the vendor-length is too small, it's badly
2534 * formed, so we stop.
2536 if ((ptr[2 + 4 + 1]) < 3) break;
2538 this_length = ptr[2 + 4 + 1] - 3;
2539 memcpy(tlv, ptr + 2 + 4 + 3, this_length);
2542 ptr[2 + 4] = 0; /* What a hack! */
2543 if ((ptr[2 + 4 + 1 + 1] & 0x80) == 0) break;
2546 *ptlv_length = tlv_length;
2551 * Start at the *data* portion of a continued attribute. search
2552 * through the rest of the attributes to find a matching one, and
2553 * add it's contents to our contents.
2555 static VALUE_PAIR *rad_continuation2vp(const RADIUS_PACKET *packet,
2556 const RADIUS_PACKET *original,
2557 const char *secret, int attribute,
2559 int length, /* CANNOT be zero */
2560 uint8_t *data, size_t packet_length,
2561 int flag, DICT_ATTR *da)
2563 size_t tlv_length, left;
2566 VALUE_PAIR *vp, *head, **tail;
2569 * Ensure we have data that hasn't been split across
2570 * multiple attributes.
2573 tlv_data = rad_coalesce(attribute, vendor, length,
2574 data, packet_length, &tlv_length);
2575 if (!tlv_data) return NULL;
2578 tlv_length = length;
2582 * Non-TLV types cannot be continued across multiple
2583 * attributes. This is true even of keys that are
2584 * encrypted with the tunnel-password method. The spec
2585 * says that they can be continued... but also that the
2586 * keys are 160 bits, which means that they CANNOT be
2589 * Note that we don't check "flag" here. The calling
2592 if (!da || (da->type != PW_TYPE_TLV)) {
2594 if (tlv_data == data) { /* true if we had 'goto' */
2595 tlv_data = malloc(tlv_length);
2596 if (!tlv_data) return NULL;
2597 memcpy(tlv_data, data, tlv_length);
2600 vp = paircreate(attribute, vendor, PW_TYPE_OCTETS);
2601 if (!vp) return NULL;
2603 vp->type = PW_TYPE_TLV;
2604 vp->flags.encrypt = FLAG_ENCRYPT_NONE;
2605 vp->flags.has_tag = 0;
2606 vp->flags.is_tlv = 0;
2607 vp->vp_tlv = tlv_data;
2608 vp->length = tlv_length;
2610 } /* else it WAS a TLV, go decode the sub-tlv's */
2613 * Now (sigh) we walk over the TLV, seeing if it is
2617 for (ptr = tlv_data;
2618 ptr != (tlv_data + tlv_length);
2623 goto not_well_formed;
2629 * Now we walk over the TLV *again*, creating sub-tlv's.
2634 for (ptr = tlv_data;
2635 ptr != (tlv_data + tlv_length);
2637 vp = paircreate(attribute | (ptr[0] << 8), vendor, PW_TYPE_OCTETS);
2640 goto not_well_formed;
2643 if (!data2vp(packet, original, secret,
2644 ptr[1] - 2, ptr + 2, vp)) {
2646 goto not_well_formed;
2654 * TLV's MAY be continued, but sometimes they're not.
2656 if (tlv_data != data) free(tlv_data);
2658 if (head->next) rad_sortvp(&head);
2665 * Parse a RADIUS attribute into a data structure.
2667 VALUE_PAIR *rad_attr2vp(const RADIUS_PACKET *packet,
2668 const RADIUS_PACKET *original,
2669 const char *secret, int attribute, int vendor,
2670 int length, const uint8_t *data)
2674 vp = paircreate(attribute, vendor, PW_TYPE_OCTETS);
2675 if (!vp) return NULL;
2677 return data2vp(packet, original, secret, length, data, vp);
2682 * Calculate/check digest, and decode radius attributes.
2684 * -1 on decoding error
2687 int rad_decode(RADIUS_PACKET *packet, RADIUS_PACKET *original,
2691 uint32_t vendorcode;
2694 uint8_t *ptr, *vsa_ptr;
2699 radius_packet_t *hdr;
2700 int vsa_tlen, vsa_llen, vsa_offset;
2701 DICT_VENDOR *dv = NULL;
2702 int num_attributes = 0;
2705 * Extract attribute-value pairs
2707 hdr = (radius_packet_t *)packet->data;
2709 packet_length = packet->data_len - AUTH_HDR_LEN;
2712 * There may be VP's already in the packet. Don't
2715 for (tail = &packet->vps; *tail != NULL; tail = &((*tail)->next)) {
2721 vsa_tlen = vsa_llen = 1;
2725 * We have to read at least two bytes.
2727 * rad_recv() above ensures that this is OK.
2729 while (packet_length > 0) {
2734 * Normal attribute, handle it like normal.
2736 if (vendorcode == 0) {
2738 * No room to read attr/length,
2739 * or bad attribute, or attribute is
2740 * too short, or attribute is too long,
2741 * stop processing the packet.
2743 if ((packet_length < 2) ||
2744 (ptr[0] == 0) || (ptr[1] < 2) ||
2745 (ptr[1] > packet_length)) break;
2753 if (attribute != PW_VENDOR_SPECIFIC) goto create_pair;
2756 * No vendor code, or ONLY vendor code.
2758 if (attrlen <= 4) goto create_pair;
2764 * Handle Vendor-Specific
2766 if (vendorlen == 0) {
2772 * attrlen was checked above.
2774 memcpy(&lvalue, ptr, 4);
2775 myvendor = ntohl(lvalue);
2778 * Zero isn't allowed.
2780 if (myvendor == 0) goto create_pair;
2783 * This is an implementation issue.
2784 * We currently pack vendor into the upper
2785 * 16 bits of a 32-bit attribute number,
2786 * so we can't handle vendor numbers larger
2789 if (myvendor > 65535) goto create_pair;
2791 vsa_tlen = vsa_llen = 1;
2793 dv = dict_vendorbyvalue(myvendor);
2795 vsa_tlen = dv->type;
2796 vsa_llen = dv->length;
2797 if (dv->flags) vsa_offset = 1;
2801 * Sweep through the list of VSA's,
2802 * seeing if they exactly fill the
2803 * outer Vendor-Specific attribute.
2805 * If not, create a raw Vendor-Specific.
2808 sublen = attrlen - 4;
2811 * See if we can parse it.
2817 * Not enough room for one more
2820 if (sublen < (vsa_tlen + vsa_llen + vsa_offset)) goto create_pair;
2823 * Ensure that the attribute number
2832 myattr = (subptr[0] << 8) | subptr[1];
2836 if ((subptr[0] != 0) ||
2837 (subptr[1] != 0)) goto create_pair;
2839 myattr = (subptr[2] << 8) | subptr[3];
2843 * Our dictionary is broken.
2852 ptr += 4 + vsa_tlen;
2853 attrlen -= (4 + vsa_tlen);
2854 packet_length -= 4 + vsa_tlen;
2858 if (subptr[vsa_tlen] < (vsa_tlen + vsa_llen + vsa_offset))
2861 if (subptr[vsa_tlen] > sublen)
2866 * Reserved bits MUST be
2870 ((subptr[vsa_tlen + vsa_llen] & 0x7f) != 0))
2873 sublen -= subptr[vsa_tlen];
2874 subptr += subptr[vsa_tlen];
2878 if (subptr[vsa_tlen] != 0) goto create_pair;
2879 if (subptr[vsa_tlen + 1] < (vsa_tlen + vsa_llen))
2881 if (subptr[vsa_tlen + 1] > sublen)
2883 sublen -= subptr[vsa_tlen + 1];
2884 subptr += subptr[vsa_tlen + 1];
2888 * Our dictionaries are
2894 } while (sublen > 0);
2896 vendorcode = myvendor;
2897 vendorlen = attrlen - 4;
2904 * attrlen is the length of this attribute.
2905 * total_len is the length of the encompassing
2914 attribute = (ptr[0] << 8) | ptr[1];
2917 default: /* can't hit this. */
2925 attrlen = ptr[0] - (vsa_tlen + vsa_llen + vsa_offset);
2929 attrlen = ptr[1] - (vsa_tlen + vsa_llen);
2932 default: /* can't hit this. */
2936 ptr += vsa_llen + vsa_offset;
2937 vendorlen -= vsa_tlen + vsa_llen + vsa_offset + attrlen;
2938 if (vendorlen == 0) vendorcode = 0;
2939 packet_length -= (vsa_tlen + vsa_llen + vsa_offset);
2942 * Ignore VSAs that have no data.
2944 if (attrlen == 0) goto next;
2947 * WiMAX attributes of type 0 are ignored. They
2948 * are a secret flag to us that the attribute has
2949 * already been dealt with.
2951 if ((vendorcode == VENDORPEC_WIMAX) && (attribute == 0)) {
2958 da = dict_attrbyvalue(attribute, vendorcode);
2961 * If it's NOT continued, AND we know
2962 * about it, AND it's not a TLV, we can
2963 * create a normal pair.
2965 if (((vsa_ptr[2] & 0x80) == 0) &&
2966 da && (da->type != PW_TYPE_TLV)) goto create_pair;
2969 * Else it IS continued, or it's a TLV.
2970 * Go do a lot of work to find the stuff.
2972 pair = rad_continuation2vp(packet, original, secret,
2973 attribute, vendorcode,
2976 ((vsa_ptr[2] & 0x80) != 0),
2982 * Create the attribute, setting the default type
2983 * to 'octets'. If the type in the dictionary
2984 * is different, then the dictionary type will
2985 * over-ride this one.
2987 * If the attribute has no data, then discard it.
2989 * Unless it's CUI. Damn you, CUI!
2993 (attribute != PW_CHARGEABLE_USER_IDENTITY)) goto next;
2995 pair = rad_attr2vp(packet, original, secret,
2996 attribute, vendorcode, attrlen, ptr);
2998 pairfree(&packet->vps);
2999 fr_strerror_printf("out of memory");
3013 * VSA's may not have been counted properly in
3014 * rad_packet_ok() above, as it is hard to count
3015 * then without using the dictionary. We
3016 * therefore enforce the limits here, too.
3018 if ((fr_max_attributes > 0) &&
3019 (num_attributes > fr_max_attributes)) {
3020 char host_ipaddr[128];
3022 pairfree(&packet->vps);
3023 fr_strerror_printf("WARNING: Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
3024 inet_ntop(packet->src_ipaddr.af,
3025 &packet->src_ipaddr.ipaddr,
3026 host_ipaddr, sizeof(host_ipaddr)),
3027 num_attributes, fr_max_attributes);
3033 packet_length -= attrlen;
3037 * Merge information from the outside world into our
3040 fr_rand_seed(packet->data, AUTH_HDR_LEN);
3049 * We assume that the passwd buffer passed is big enough.
3050 * RFC2138 says the password is max 128 chars, so the size
3051 * of the passwd buffer must be at least 129 characters.
3052 * Preferably it's just MAX_STRING_LEN.
3054 * int *pwlen is updated to the new length of the encrypted
3055 * password - a multiple of 16 bytes.
3057 int rad_pwencode(char *passwd, size_t *pwlen, const char *secret,
3058 const uint8_t *vector)
3060 FR_MD5_CTX context, old;
3061 uint8_t digest[AUTH_VECTOR_LEN];
3062 int i, n, secretlen;
3066 * RFC maximum is 128 bytes.
3068 * If length is zero, pad it out with zeros.
3070 * If the length isn't aligned to 16 bytes,
3071 * zero out the extra data.
3075 if (len > 128) len = 128;
3078 memset(passwd, 0, AUTH_PASS_LEN);
3079 len = AUTH_PASS_LEN;
3080 } else if ((len % AUTH_PASS_LEN) != 0) {
3081 memset(&passwd[len], 0, AUTH_PASS_LEN - (len % AUTH_PASS_LEN));
3082 len += AUTH_PASS_LEN - (len % AUTH_PASS_LEN);
3087 * Use the secret to setup the decryption digest
3089 secretlen = strlen(secret);
3091 fr_MD5Init(&context);
3092 fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
3093 old = context; /* save intermediate work */
3096 * Encrypt it in place. Don't bother checking
3097 * len, as we've ensured above that it's OK.
3099 for (n = 0; n < len; n += AUTH_PASS_LEN) {
3101 fr_MD5Update(&context, vector, AUTH_PASS_LEN);
3102 fr_MD5Final(digest, &context);
3105 fr_MD5Update(&context,
3106 (uint8_t *) passwd + n - AUTH_PASS_LEN,
3108 fr_MD5Final(digest, &context);
3111 for (i = 0; i < AUTH_PASS_LEN; i++) {
3112 passwd[i + n] ^= digest[i];
3122 int rad_pwdecode(char *passwd, size_t pwlen, const char *secret,
3123 const uint8_t *vector)
3125 FR_MD5_CTX context, old;
3126 uint8_t digest[AUTH_VECTOR_LEN];
3128 size_t n, secretlen;
3131 * The RFC's say that the maximum is 128.
3132 * The buffer we're putting it into above is 254, so
3133 * we don't need to do any length checking.
3135 if (pwlen > 128) pwlen = 128;
3140 if (pwlen == 0) goto done;
3143 * Use the secret to setup the decryption digest
3145 secretlen = strlen(secret);
3147 fr_MD5Init(&context);
3148 fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
3149 old = context; /* save intermediate work */
3152 * The inverse of the code above.
3154 for (n = 0; n < pwlen; n += AUTH_PASS_LEN) {
3156 fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
3157 fr_MD5Final(digest, &context);
3160 if (pwlen > AUTH_PASS_LEN) {
3161 fr_MD5Update(&context, (uint8_t *) passwd,
3165 fr_MD5Final(digest, &context);
3168 if (pwlen > (n + AUTH_PASS_LEN)) {
3169 fr_MD5Update(&context, (uint8_t *) passwd + n,
3174 for (i = 0; i < AUTH_PASS_LEN; i++) {
3175 passwd[i + n] ^= digest[i];
3180 passwd[pwlen] = '\0';
3181 return strlen(passwd);
3186 * Encode Tunnel-Password attributes when sending them out on the wire.
3188 * int *pwlen is updated to the new length of the encrypted
3189 * password - a multiple of 16 bytes.
3191 * This is per RFC-2868 which adds a two char SALT to the initial intermediate
3194 int rad_tunnel_pwencode(char *passwd, size_t *pwlen, const char *secret,
3195 const uint8_t *vector)
3197 uint8_t buffer[AUTH_VECTOR_LEN + MAX_STRING_LEN + 3];
3198 unsigned char digest[AUTH_VECTOR_LEN];
3200 int i, n, secretlen;
3205 if (len > 127) len = 127;
3208 * Shift the password 3 positions right to place a salt and original
3209 * length, tag will be added automatically on packet send
3211 for (n=len ; n>=0 ; n--) passwd[n+3] = passwd[n];
3215 * save original password length as first password character;
3222 * Generate salt. The RFC's say:
3224 * The high bit of salt[0] must be set, each salt in a
3225 * packet should be unique, and they should be random
3227 * So, we set the high bit, add in a counter, and then
3228 * add in some CSPRNG data. should be OK..
3230 salt[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
3231 (fr_rand() & 0x07));
3232 salt[1] = fr_rand();
3235 * Padd password to multiple of AUTH_PASS_LEN bytes.
3237 n = len % AUTH_PASS_LEN;
3239 n = AUTH_PASS_LEN - n;
3240 for (; n > 0; n--, len++)
3243 /* set new password length */
3247 * Use the secret to setup the decryption digest
3249 secretlen = strlen(secret);
3250 memcpy(buffer, secret, secretlen);
3252 for (n2 = 0; n2 < len; n2+=AUTH_PASS_LEN) {
3254 memcpy(buffer + secretlen, vector, AUTH_VECTOR_LEN);
3255 memcpy(buffer + secretlen + AUTH_VECTOR_LEN, salt, 2);
3256 fr_md5_calc(digest, buffer, secretlen + AUTH_VECTOR_LEN + 2);
3258 memcpy(buffer + secretlen, passwd + n2 - AUTH_PASS_LEN, AUTH_PASS_LEN);
3259 fr_md5_calc(digest, buffer, secretlen + AUTH_PASS_LEN);
3262 for (i = 0; i < AUTH_PASS_LEN; i++) {
3263 passwd[i + n2] ^= digest[i];
3271 * Decode Tunnel-Password encrypted attributes.
3273 * Defined in RFC-2868, this uses a two char SALT along with the
3274 * initial intermediate value, to differentiate it from the
3277 int rad_tunnel_pwdecode(uint8_t *passwd, size_t *pwlen, const char *secret,
3278 const uint8_t *vector)
3280 FR_MD5_CTX context, old;
3281 uint8_t digest[AUTH_VECTOR_LEN];
3283 unsigned i, n, len, reallen;
3288 * We need at least a salt.
3291 fr_strerror_printf("tunnel password is too short");
3296 * There's a salt, but no password. Or, there's a salt
3297 * and a 'data_len' octet. It's wrong, but at least we
3298 * can figure out what it means: the password is empty.
3300 * Note that this means we ignore the 'data_len' field,
3301 * if the attribute length tells us that there's no
3302 * more data. So the 'data_len' field may be wrong,
3311 len -= 2; /* discount the salt */
3314 * Use the secret to setup the decryption digest
3316 secretlen = strlen(secret);
3318 fr_MD5Init(&context);
3319 fr_MD5Update(&context, (const uint8_t *) secret, secretlen);
3320 old = context; /* save intermediate work */
3323 * Set up the initial key:
3325 * b(1) = MD5(secret + vector + salt)
3327 fr_MD5Update(&context, vector, AUTH_VECTOR_LEN);
3328 fr_MD5Update(&context, passwd, 2);
3331 for (n = 0; n < len; n += AUTH_PASS_LEN) {
3335 fr_MD5Final(digest, &context);
3340 * A quick check: decrypt the first octet
3341 * of the password, which is the
3342 * 'data_len' field. Ensure it's sane.
3344 reallen = passwd[2] ^ digest[0];
3345 if (reallen >= len) {
3346 fr_strerror_printf("tunnel password is too long for the attribute");
3350 fr_MD5Update(&context, passwd + 2, AUTH_PASS_LEN);
3354 fr_MD5Final(digest, &context);
3357 fr_MD5Update(&context, passwd + n + 2, AUTH_PASS_LEN);
3360 for (i = base; i < AUTH_PASS_LEN; i++) {
3361 passwd[n + i - 1] = passwd[n + i + 2] ^ digest[i];
3366 * See make_tunnel_password, above.
3368 if (reallen > 239) reallen = 239;
3371 passwd[reallen] = 0;
3377 * Encode a CHAP password
3379 * FIXME: might not work with Ascend because
3380 * we use vp->length, and Ascend gear likes
3381 * to send an extra '\0' in the string!
3383 int rad_chap_encode(RADIUS_PACKET *packet, uint8_t *output, int id,
3384 VALUE_PAIR *password)
3388 uint8_t string[MAX_STRING_LEN * 2 + 1];
3389 VALUE_PAIR *challenge;
3392 * Sanity check the input parameters
3394 if ((packet == NULL) || (password == NULL)) {
3399 * Note that the password VP can be EITHER
3400 * a User-Password attribute (from a check-item list),
3401 * or a CHAP-Password attribute (the client asking
3402 * the library to encode it).
3410 memcpy(ptr, password->vp_strvalue, password->length);
3411 ptr += password->length;
3412 i += password->length;
3415 * Use Chap-Challenge pair if present,
3416 * Request-Authenticator otherwise.
3418 challenge = pairfind(packet->vps, PW_CHAP_CHALLENGE, 0);
3420 memcpy(ptr, challenge->vp_strvalue, challenge->length);
3421 i += challenge->length;
3423 memcpy(ptr, packet->vector, AUTH_VECTOR_LEN);
3424 i += AUTH_VECTOR_LEN;
3428 fr_md5_calc((uint8_t *)output + 1, (uint8_t *)string, i);
3435 * Seed the random number generator.
3437 * May be called any number of times.
3439 void fr_rand_seed(const void *data, size_t size)
3444 * Ensure that the pool is initialized.
3446 if (!fr_rand_initialized) {
3449 memset(&fr_rand_pool, 0, sizeof(fr_rand_pool));
3451 fd = open("/dev/urandom", O_RDONLY);
3457 while (total < sizeof(fr_rand_pool.randrsl)) {
3458 this = read(fd, fr_rand_pool.randrsl,
3459 sizeof(fr_rand_pool.randrsl) - total);
3460 if ((this < 0) && (errno != EINTR)) break;
3461 if (this > 0) total += this;
3465 fr_rand_pool.randrsl[0] = fd;
3466 fr_rand_pool.randrsl[1] = time(NULL);
3467 fr_rand_pool.randrsl[2] = errno;
3470 fr_randinit(&fr_rand_pool, 1);
3471 fr_rand_pool.randcnt = 0;
3472 fr_rand_initialized = 1;
3478 * Hash the user data
3481 if (!hash) hash = fr_rand();
3482 hash = fr_hash_update(data, size, hash);
3484 fr_rand_pool.randmem[fr_rand_pool.randcnt] ^= hash;
3489 * Return a 32-bit random number.
3491 uint32_t fr_rand(void)
3496 * Ensure that the pool is initialized.
3498 if (!fr_rand_initialized) {
3499 fr_rand_seed(NULL, 0);
3502 num = fr_rand_pool.randrsl[fr_rand_pool.randcnt++];
3503 if (fr_rand_pool.randcnt >= 256) {
3504 fr_rand_pool.randcnt = 0;
3505 fr_isaac(&fr_rand_pool);
3513 * Allocate a new RADIUS_PACKET
3515 RADIUS_PACKET *rad_alloc(int newvector)
3519 if ((rp = malloc(sizeof(RADIUS_PACKET))) == NULL) {
3520 fr_strerror_printf("out of memory");
3523 memset(rp, 0, sizeof(*rp));
3529 uint32_t hash, base;
3532 * Don't expose the actual contents of the random
3536 for (i = 0; i < AUTH_VECTOR_LEN; i += sizeof(uint32_t)) {
3537 hash = fr_rand() ^ base;
3538 memcpy(rp->vector + i, &hash, sizeof(hash));
3541 fr_rand(); /* stir the pool again */
3546 RADIUS_PACKET *rad_alloc_reply(RADIUS_PACKET *packet)
3548 RADIUS_PACKET *reply;
3550 if (!packet) return NULL;
3552 reply = rad_alloc(0);
3553 if (!reply) return NULL;
3556 * Initialize the fields from the request.
3558 reply->sockfd = packet->sockfd;
3559 reply->dst_ipaddr = packet->src_ipaddr;
3560 reply->src_ipaddr = packet->dst_ipaddr;
3561 reply->dst_port = packet->src_port;
3562 reply->src_port = packet->dst_port;
3563 reply->id = packet->id;
3564 reply->code = 0; /* UNKNOWN code */
3565 memcpy(reply->vector, packet->vector,
3566 sizeof(reply->vector));
3569 reply->data_len = 0;
3576 * Free a RADIUS_PACKET
3578 void rad_free(RADIUS_PACKET **radius_packet_ptr)
3580 RADIUS_PACKET *radius_packet;
3582 if (!radius_packet_ptr || !*radius_packet_ptr) return;
3583 radius_packet = *radius_packet_ptr;
3585 free(radius_packet->data);
3587 pairfree(&radius_packet->vps);
3589 free(radius_packet);
3591 *radius_packet_ptr = NULL;