1 /* $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $ */
2
3 /*
4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 */
23
24 #define NETDISSECT_REWORKED
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include <tcpdump-stdinc.h>
30
31 #include <string.h>
32 #include <stdlib.h>
33
34 /* Any code in this file that depends on HAVE_LIBCRYPTO depends on
35 * HAVE_OPENSSL_EVP_H too. Undefining the former when the latter isn't defined
36 * is the simplest way of handling the dependency.
37 */
38 #ifdef HAVE_LIBCRYPTO
39 #ifdef HAVE_OPENSSL_EVP_H
40 #include <openssl/evp.h>
41 #else
42 #undef HAVE_LIBCRYPTO
43 #endif
44 #endif
45
46 #include "ip.h"
47 #ifdef INET6
48 #include "ip6.h"
49 #endif
50
51 #include "interface.h"
52 #include "extract.h"
53
54 /*
55 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
56 * All rights reserved.
57 *
58 * Redistribution and use in source and binary forms, with or without
59 * modification, are permitted provided that the following conditions
60 * are met:
61 * 1. Redistributions of source code must retain the above copyright
62 * notice, this list of conditions and the following disclaimer.
63 * 2. Redistributions in binary form must reproduce the above copyright
64 * notice, this list of conditions and the following disclaimer in the
65 * documentation and/or other materials provided with the distribution.
66 * 3. Neither the name of the project nor the names of its contributors
67 * may be used to endorse or promote products derived from this software
68 * without specific prior written permission.
69 *
70 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
71 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
72 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
73 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
74 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
75 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
76 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
77 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
78 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
79 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
80 * SUCH DAMAGE.
81 */
82
83 /*
84 * RFC1827/2406 Encapsulated Security Payload.
85 */
86
87 struct newesp {
88 uint32_t esp_spi; /* ESP */
89 uint32_t esp_seq; /* Sequence number */
90 /*variable size*/ /* (IV and) Payload data */
91 /*variable size*/ /* padding */
92 /*8bit*/ /* pad size */
93 /*8bit*/ /* next header */
94 /*8bit*/ /* next header */
95 /*variable size, 32bit bound*/ /* Authentication data */
96 };
97
98 #ifdef HAVE_LIBCRYPTO
99 union inaddr_u {
100 struct in_addr in4;
101 #ifdef INET6
102 struct in6_addr in6;
103 #endif
104 };
105 struct sa_list {
106 struct sa_list *next;
107 u_int daddr_version;
108 union inaddr_u daddr;
109 uint32_t spi; /* if == 0, then IKEv2 */
110 int initiator;
111 u_char spii[8]; /* for IKEv2 */
112 u_char spir[8];
113 const EVP_CIPHER *evp;
114 int ivlen;
115 int authlen;
116 u_char authsecret[256];
117 int authsecret_len;
118 u_char secret[256]; /* is that big enough for all secrets? */
119 int secretlen;
120 };
121
122 /*
123 * this will adjust ndo_packetp and ndo_snapend to new buffer!
124 */
125 USES_APPLE_DEPRECATED_API
esp_print_decrypt_buffer_by_ikev2(netdissect_options * ndo,int initiator,u_char spii[8],u_char spir[8],u_char * buf,u_char * end)126 int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
127 int initiator,
128 u_char spii[8], u_char spir[8],
129 u_char *buf, u_char *end)
130 {
131 struct sa_list *sa;
132 u_char *iv;
133 int len;
134 EVP_CIPHER_CTX ctx;
135
136 /* initiator arg is any non-zero value */
137 if(initiator) initiator=1;
138
139 /* see if we can find the SA, and if so, decode it */
140 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
141 if (sa->spi == 0
142 && initiator == sa->initiator
143 && memcmp(spii, sa->spii, 8) == 0
144 && memcmp(spir, sa->spir, 8) == 0)
145 break;
146 }
147
148 if(sa == NULL) return 0;
149 if(sa->evp == NULL) return 0;
150
151 /*
152 * remove authenticator, and see if we still have something to
153 * work with
154 */
155 end = end - sa->authlen;
156 iv = buf;
157 buf = buf + sa->ivlen;
158 len = end-buf;
159
160 if(end <= buf) return 0;
161
162 memset(&ctx, 0, sizeof(ctx));
163 if (EVP_CipherInit(&ctx, sa->evp, sa->secret, NULL, 0) < 0)
164 (*ndo->ndo_warning)(ndo, "espkey init failed");
165 EVP_CipherInit(&ctx, NULL, NULL, iv, 0);
166 EVP_Cipher(&ctx, buf, buf, len);
167 EVP_CIPHER_CTX_cleanup(&ctx);
168
169 ndo->ndo_packetp = buf;
170 ndo->ndo_snapend = end;
171
172 return 1;
173
174 }
175 USES_APPLE_RST
176
esp_print_addsa(netdissect_options * ndo,struct sa_list * sa,int sa_def)177 static void esp_print_addsa(netdissect_options *ndo,
178 struct sa_list *sa, int sa_def)
179 {
180 /* copy the "sa" */
181
182 struct sa_list *nsa;
183
184 nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
185 if (nsa == NULL)
186 (*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");
187
188 *nsa = *sa;
189
190 if (sa_def)
191 ndo->ndo_sa_default = nsa;
192
193 nsa->next = ndo->ndo_sa_list_head;
194 ndo->ndo_sa_list_head = nsa;
195 }
196
197
hexdigit(netdissect_options * ndo,char hex)198 static u_int hexdigit(netdissect_options *ndo, char hex)
199 {
200 if (hex >= '0' && hex <= '9')
201 return (hex - '0');
202 else if (hex >= 'A' && hex <= 'F')
203 return (hex - 'A' + 10);
204 else if (hex >= 'a' && hex <= 'f')
205 return (hex - 'a' + 10);
206 else {
207 (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
208 return 0;
209 }
210 }
211
hex2byte(netdissect_options * ndo,char * hexstring)212 static u_int hex2byte(netdissect_options *ndo, char *hexstring)
213 {
214 u_int byte;
215
216 byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
217 return byte;
218 }
219
220 /*
221 * returns size of binary, 0 on failure.
222 */
223 static
espprint_decode_hex(netdissect_options * ndo,u_char * binbuf,unsigned int binbuf_len,char * hex)224 int espprint_decode_hex(netdissect_options *ndo,
225 u_char *binbuf, unsigned int binbuf_len,
226 char *hex)
227 {
228 unsigned int len;
229 int i;
230
231 len = strlen(hex) / 2;
232
233 if (len > binbuf_len) {
234 (*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
235 return 0;
236 }
237
238 i = 0;
239 while (hex[0] != '\0' && hex[1]!='\0') {
240 binbuf[i] = hex2byte(ndo, hex);
241 hex += 2;
242 i++;
243 }
244
245 return i;
246 }
247
248 /*
249 * decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
250 */
251
252 USES_APPLE_DEPRECATED_API
253 static int
espprint_decode_encalgo(netdissect_options * ndo,char * decode,struct sa_list * sa)254 espprint_decode_encalgo(netdissect_options *ndo,
255 char *decode, struct sa_list *sa)
256 {
257 size_t i;
258 const EVP_CIPHER *evp;
259 int authlen = 0;
260 char *colon, *p;
261
262 colon = strchr(decode, ':');
263 if (colon == NULL) {
264 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
265 return 0;
266 }
267 *colon = '\0';
268
269 if (strlen(decode) > strlen("-hmac96") &&
270 !strcmp(decode + strlen(decode) - strlen("-hmac96"),
271 "-hmac96")) {
272 p = strstr(decode, "-hmac96");
273 *p = '\0';
274 authlen = 12;
275 }
276 if (strlen(decode) > strlen("-cbc") &&
277 !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
278 p = strstr(decode, "-cbc");
279 *p = '\0';
280 }
281 evp = EVP_get_cipherbyname(decode);
282
283 if (!evp) {
284 (*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
285 sa->evp = NULL;
286 sa->authlen = 0;
287 sa->ivlen = 0;
288 return 0;
289 }
290
291 sa->evp = evp;
292 sa->authlen = authlen;
293 sa->ivlen = EVP_CIPHER_iv_length(evp);
294
295 colon++;
296 if (colon[0] == '0' && colon[1] == 'x') {
297 /* decode some hex! */
298
299 colon += 2;
300 sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon);
301 if(sa->secretlen == 0) return 0;
302 } else {
303 i = strlen(colon);
304
305 if (i < sizeof(sa->secret)) {
306 memcpy(sa->secret, colon, i);
307 sa->secretlen = i;
308 } else {
309 memcpy(sa->secret, colon, sizeof(sa->secret));
310 sa->secretlen = sizeof(sa->secret);
311 }
312 }
313
314 return 1;
315 }
316 USES_APPLE_RST
317
318 /*
319 * for the moment, ignore the auth algorith, just hard code the authenticator
320 * length. Need to research how openssl looks up HMAC stuff.
321 */
322 static int
espprint_decode_authalgo(netdissect_options * ndo,char * decode,struct sa_list * sa)323 espprint_decode_authalgo(netdissect_options *ndo,
324 char *decode, struct sa_list *sa)
325 {
326 char *colon;
327
328 colon = strchr(decode, ':');
329 if (colon == NULL) {
330 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
331 return 0;
332 }
333 *colon = '\0';
334
335 if(strcasecmp(colon,"sha1") == 0 ||
336 strcasecmp(colon,"md5") == 0) {
337 sa->authlen = 12;
338 }
339 return 1;
340 }
341
esp_print_decode_ikeline(netdissect_options * ndo,char * line,const char * file,int lineno)342 static void esp_print_decode_ikeline(netdissect_options *ndo, char *line,
343 const char *file, int lineno)
344 {
345 /* it's an IKEv2 secret, store it instead */
346 struct sa_list sa1;
347
348 char *init;
349 char *icookie, *rcookie;
350 int ilen, rlen;
351 char *authkey;
352 char *enckey;
353
354 init = strsep(&line, " \t");
355 icookie = strsep(&line, " \t");
356 rcookie = strsep(&line, " \t");
357 authkey = strsep(&line, " \t");
358 enckey = strsep(&line, " \t");
359
360 /* if any fields are missing */
361 if(!init || !icookie || !rcookie || !authkey || !enckey) {
362 (*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u",
363 file, lineno);
364
365 return;
366 }
367
368 ilen = strlen(icookie);
369 rlen = strlen(rcookie);
370
371 if((init[0]!='I' && init[0]!='R')
372 || icookie[0]!='0' || icookie[1]!='x'
373 || rcookie[0]!='0' || rcookie[1]!='x'
374 || ilen!=18
375 || rlen!=18) {
376 (*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.",
377 file, lineno);
378
379 (*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)",
380 init, icookie, ilen, rcookie, rlen);
381
382 return;
383 }
384
385 sa1.spi = 0;
386 sa1.initiator = (init[0] == 'I');
387 if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8)
388 return;
389
390 if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8)
391 return;
392
393 if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return;
394
395 if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return;
396
397 esp_print_addsa(ndo, &sa1, FALSE);
398 }
399
400 /*
401 *
402 * special form: file /name
403 * causes us to go read from this file instead.
404 *
405 */
esp_print_decode_onesecret(netdissect_options * ndo,char * line,const char * file,int lineno)406 static void esp_print_decode_onesecret(netdissect_options *ndo, char *line,
407 const char *file, int lineno)
408 {
409 struct sa_list sa1;
410 int sa_def;
411
412 char *spikey;
413 char *decode;
414
415 spikey = strsep(&line, " \t");
416 sa_def = 0;
417 memset(&sa1, 0, sizeof(struct sa_list));
418
419 /* if there is only one token, then it is an algo:key token */
420 if (line == NULL) {
421 decode = spikey;
422 spikey = NULL;
423 /* sa1.daddr.version = 0; */
424 /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
425 /* sa1.spi = 0; */
426 sa_def = 1;
427 } else
428 decode = line;
429
430 if (spikey && strcasecmp(spikey, "file") == 0) {
431 /* open file and read it */
432 FILE *secretfile;
433 char fileline[1024];
434 int lineno=0;
435 char *nl;
436 char *filename = line;
437
438 secretfile = fopen(filename, FOPEN_READ_TXT);
439 if (secretfile == NULL) {
440 perror(filename);
441 exit(3);
442 }
443
444 while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
445 lineno++;
446 /* remove newline from the line */
447 nl = strchr(fileline, '\n');
448 if (nl)
449 *nl = '\0';
450 if (fileline[0] == '#') continue;
451 if (fileline[0] == '\0') continue;
452
453 esp_print_decode_onesecret(ndo, fileline, filename, lineno);
454 }
455 fclose(secretfile);
456
457 return;
458 }
459
460 if (spikey && strcasecmp(spikey, "ikev2") == 0) {
461 esp_print_decode_ikeline(ndo, line, file, lineno);
462 return;
463 }
464
465 if (spikey) {
466
467 char *spistr, *foo;
468 uint32_t spino;
469
470 spistr = strsep(&spikey, "@");
471
472 spino = strtoul(spistr, &foo, 0);
473 if (spistr == foo || !spikey) {
474 (*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
475 return;
476 }
477
478 sa1.spi = spino;
479
480 #ifdef INET6
481 if (inet_pton(AF_INET6, spikey, &sa1.daddr.in6) == 1) {
482 sa1.daddr_version = 6;
483 } else
484 #endif
485 if (inet_pton(AF_INET, spikey, &sa1.daddr.in4) == 1) {
486 sa1.daddr_version = 4;
487 } else {
488 (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
489 return;
490 }
491 }
492
493 if (decode) {
494 /* skip any blank spaces */
495 while (isspace((unsigned char)*decode))
496 decode++;
497
498 if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
499 return;
500 }
501 }
502
503 esp_print_addsa(ndo, &sa1, sa_def);
504 }
505
506 USES_APPLE_DEPRECATED_API
esp_init(netdissect_options * ndo _U_)507 static void esp_init(netdissect_options *ndo _U_)
508 {
509
510 OpenSSL_add_all_algorithms();
511 EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
512 }
513 USES_APPLE_RST
514
esp_print_decodesecret(netdissect_options * ndo)515 void esp_print_decodesecret(netdissect_options *ndo)
516 {
517 char *line;
518 char *p;
519 static int initialized = 0;
520
521 if (!initialized) {
522 esp_init(ndo);
523 initialized = 1;
524 }
525
526 p = ndo->ndo_espsecret;
527
528 while (p && p[0] != '\0') {
529 /* pick out the first line or first thing until a comma */
530 if ((line = strsep(&p, "\n,")) == NULL) {
531 line = p;
532 p = NULL;
533 }
534
535 esp_print_decode_onesecret(ndo, line, "cmdline", 0);
536 }
537
538 ndo->ndo_espsecret = NULL;
539 }
540
541 #endif
542
543 #ifdef HAVE_LIBCRYPTO
544 USES_APPLE_DEPRECATED_API
545 #endif
546 int
esp_print(netdissect_options * ndo,const u_char * bp,const int length,const u_char * bp2 _U_,int * nhdr _U_,int * padlen _U_)547 esp_print(netdissect_options *ndo,
548 const u_char *bp, const int length, const u_char *bp2
549 #ifndef HAVE_LIBCRYPTO
550 _U_
551 #endif
552 ,
553 int *nhdr
554 #ifndef HAVE_LIBCRYPTO
555 _U_
556 #endif
557 ,
558 int *padlen
559 #ifndef HAVE_LIBCRYPTO
560 _U_
561 #endif
562 )
563 {
564 register const struct newesp *esp;
565 register const u_char *ep;
566 #ifdef HAVE_LIBCRYPTO
567 struct ip *ip;
568 struct sa_list *sa = NULL;
569 #ifdef INET6
570 struct ip6_hdr *ip6 = NULL;
571 #endif
572 int advance;
573 int len;
574 u_char *secret;
575 int ivlen = 0;
576 u_char *ivoff;
577 u_char *p;
578 EVP_CIPHER_CTX ctx;
579 #endif
580
581 esp = (struct newesp *)bp;
582
583 #ifdef HAVE_LIBCRYPTO
584 secret = NULL;
585 advance = 0;
586 #endif
587
588 #if 0
589 /* keep secret out of a register */
590 p = (u_char *)&secret;
591 #endif
592
593 /* 'ep' points to the end of available data. */
594 ep = ndo->ndo_snapend;
595
596 if ((u_char *)(esp + 1) >= ep) {
597 ND_PRINT((ndo, "[|ESP]"));
598 goto fail;
599 }
600 ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi)));
601 ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq)));
602 ND_PRINT((ndo, ", length %u", length));
603
604 #ifndef HAVE_LIBCRYPTO
605 goto fail;
606 #else
607 /* initiailize SAs */
608 if (ndo->ndo_sa_list_head == NULL) {
609 if (!ndo->ndo_espsecret)
610 goto fail;
611
612 esp_print_decodesecret(ndo);
613 }
614
615 if (ndo->ndo_sa_list_head == NULL)
616 goto fail;
617
618 ip = (struct ip *)bp2;
619 switch (IP_V(ip)) {
620 #ifdef INET6
621 case 6:
622 ip6 = (struct ip6_hdr *)bp2;
623 /* we do not attempt to decrypt jumbograms */
624 if (!EXTRACT_16BITS(&ip6->ip6_plen))
625 goto fail;
626 /* if we can't get nexthdr, we do not need to decrypt it */
627 len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
628
629 /* see if we can find the SA, and if so, decode it */
630 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
631 if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
632 sa->daddr_version == 6 &&
633 UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst,
634 sizeof(struct in6_addr)) == 0) {
635 break;
636 }
637 }
638 break;
639 #endif /*INET6*/
640 case 4:
641 /* nexthdr & padding are in the last fragment */
642 if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
643 goto fail;
644 len = EXTRACT_16BITS(&ip->ip_len);
645
646 /* see if we can find the SA, and if so, decode it */
647 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
648 if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
649 sa->daddr_version == 4 &&
650 UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst,
651 sizeof(struct in_addr)) == 0) {
652 break;
653 }
654 }
655 break;
656 default:
657 goto fail;
658 }
659
660 /* if we didn't find the specific one, then look for
661 * an unspecified one.
662 */
663 if (sa == NULL)
664 sa = ndo->ndo_sa_default;
665
666 /* if not found fail */
667 if (sa == NULL)
668 goto fail;
669
670 /* if we can't get nexthdr, we do not need to decrypt it */
671 if (ep - bp2 < len)
672 goto fail;
673 if (ep - bp2 > len) {
674 /* FCS included at end of frame (NetBSD 1.6 or later) */
675 ep = bp2 + len;
676 }
677
678 ivoff = (u_char *)(esp + 1) + 0;
679 ivlen = sa->ivlen;
680 secret = sa->secret;
681 ep = ep - sa->authlen;
682
683 if (sa->evp) {
684 memset(&ctx, 0, sizeof(ctx));
685 if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
686 (*ndo->ndo_warning)(ndo, "espkey init failed");
687
688 p = ivoff;
689 EVP_CipherInit(&ctx, NULL, NULL, p, 0);
690 EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
691 EVP_CIPHER_CTX_cleanup(&ctx);
692 advance = ivoff - (u_char *)esp + ivlen;
693 } else
694 advance = sizeof(struct newesp);
695
696 /* sanity check for pad length */
697 if (ep - bp < *(ep - 2))
698 goto fail;
699
700 if (padlen)
701 *padlen = *(ep - 2) + 2;
702
703 if (nhdr)
704 *nhdr = *(ep - 1);
705
706 ND_PRINT((ndo, ": "));
707 return advance;
708 #endif
709
710 fail:
711 return -1;
712 }
713 #ifdef HAVE_LIBCRYPTO
714 USES_APPLE_RST
715 #endif
716
717 /*
718 * Local Variables:
719 * c-style: whitesmith
720 * c-basic-offset: 8
721 * End:
722 */
723