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 /* \summary: IPSEC Encapsulating Security Payload (ESP) printer */
25
26 #ifdef HAVE_CONFIG_H
27 #include "config.h"
28 #endif
29
30 #include <netdissect-stdinc.h>
31
32 #include <string.h>
33 #include <stdlib.h>
34
35 /* Any code in this file that depends on HAVE_LIBCRYPTO depends on
36 * HAVE_OPENSSL_EVP_H too. Undefining the former when the latter isn't defined
37 * is the simplest way of handling the dependency.
38 */
39 #ifdef HAVE_LIBCRYPTO
40 #ifdef HAVE_OPENSSL_EVP_H
41 #include <openssl/evp.h>
42 #else
43 #undef HAVE_LIBCRYPTO
44 #endif
45 #endif
46
47 #include "netdissect.h"
48 #include "strtoaddr.h"
49 #include "extract.h"
50
51 #include "ascii_strcasecmp.h"
52
53 #include "ip.h"
54 #include "ip6.h"
55
56 /*
57 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
58 * All rights reserved.
59 *
60 * Redistribution and use in source and binary forms, with or without
61 * modification, are permitted provided that the following conditions
62 * are met:
63 * 1. Redistributions of source code must retain the above copyright
64 * notice, this list of conditions and the following disclaimer.
65 * 2. Redistributions in binary form must reproduce the above copyright
66 * notice, this list of conditions and the following disclaimer in the
67 * documentation and/or other materials provided with the distribution.
68 * 3. Neither the name of the project nor the names of its contributors
69 * may be used to endorse or promote products derived from this software
70 * without specific prior written permission.
71 *
72 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
73 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
74 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
75 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
76 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
77 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
78 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
79 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
80 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
81 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
82 * SUCH DAMAGE.
83 */
84
85 /*
86 * RFC1827/2406 Encapsulated Security Payload.
87 */
88
89 struct newesp {
90 uint32_t esp_spi; /* ESP */
91 uint32_t esp_seq; /* Sequence number */
92 /*variable size*/ /* (IV and) Payload data */
93 /*variable size*/ /* padding */
94 /*8bit*/ /* pad size */
95 /*8bit*/ /* next header */
96 /*8bit*/ /* next header */
97 /*variable size, 32bit bound*/ /* Authentication data */
98 };
99
100 #ifdef HAVE_LIBCRYPTO
101 union inaddr_u {
102 struct in_addr in4;
103 struct in6_addr in6;
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 #ifndef HAVE_EVP_CIPHER_CTX_NEW
123 /*
124 * Allocate an EVP_CIPHER_CTX.
125 * Used if we have an older version of OpenSSL that doesn't provide
126 * routines to allocate and free them.
127 */
128 static EVP_CIPHER_CTX *
EVP_CIPHER_CTX_new(void)129 EVP_CIPHER_CTX_new(void)
130 {
131 EVP_CIPHER_CTX *ctx;
132
133 ctx = malloc(sizeof(*ctx));
134 if (ctx == NULL)
135 return (NULL);
136 memset(ctx, 0, sizeof(*ctx));
137 return (ctx);
138 }
139
140 static void
EVP_CIPHER_CTX_free(EVP_CIPHER_CTX * ctx)141 EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
142 {
143 EVP_CIPHER_CTX_cleanup(ctx);
144 free(ctx);
145 }
146 #endif
147
148 /*
149 * this will adjust ndo_packetp and ndo_snapend to new buffer!
150 */
151 USES_APPLE_DEPRECATED_API
esp_print_decrypt_buffer_by_ikev2(netdissect_options * ndo,int initiator,u_char spii[8],u_char spir[8],const u_char * buf,const u_char * end)152 int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
153 int initiator,
154 u_char spii[8], u_char spir[8],
155 const u_char *buf, const u_char *end)
156 {
157 struct sa_list *sa;
158 const u_char *iv;
159 int len;
160 EVP_CIPHER_CTX *ctx;
161
162 /* initiator arg is any non-zero value */
163 if(initiator) initiator=1;
164
165 /* see if we can find the SA, and if so, decode it */
166 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
167 if (sa->spi == 0
168 && initiator == sa->initiator
169 && memcmp(spii, sa->spii, 8) == 0
170 && memcmp(spir, sa->spir, 8) == 0)
171 break;
172 }
173
174 if(sa == NULL) return 0;
175 if(sa->evp == NULL) return 0;
176
177 /*
178 * remove authenticator, and see if we still have something to
179 * work with
180 */
181 end = end - sa->authlen;
182 iv = buf;
183 buf = buf + sa->ivlen;
184 len = end-buf;
185
186 if(end <= buf) return 0;
187
188 ctx = EVP_CIPHER_CTX_new();
189 if (ctx == NULL)
190 return 0;
191 if (EVP_CipherInit(ctx, sa->evp, sa->secret, NULL, 0) < 0)
192 (*ndo->ndo_warning)(ndo, "espkey init failed");
193 EVP_CipherInit(ctx, NULL, NULL, iv, 0);
194 EVP_Cipher(ctx, buf, buf, len);
195 EVP_CIPHER_CTX_free(ctx);
196
197 ndo->ndo_packetp = buf;
198 ndo->ndo_snapend = end;
199
200 return 1;
201
202 }
203 USES_APPLE_RST
204
esp_print_addsa(netdissect_options * ndo,struct sa_list * sa,int sa_def)205 static void esp_print_addsa(netdissect_options *ndo,
206 struct sa_list *sa, int sa_def)
207 {
208 /* copy the "sa" */
209
210 struct sa_list *nsa;
211
212 nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
213 if (nsa == NULL)
214 (*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");
215
216 *nsa = *sa;
217
218 if (sa_def)
219 ndo->ndo_sa_default = nsa;
220
221 nsa->next = ndo->ndo_sa_list_head;
222 ndo->ndo_sa_list_head = nsa;
223 }
224
225
hexdigit(netdissect_options * ndo,char hex)226 static u_int hexdigit(netdissect_options *ndo, char hex)
227 {
228 if (hex >= '0' && hex <= '9')
229 return (hex - '0');
230 else if (hex >= 'A' && hex <= 'F')
231 return (hex - 'A' + 10);
232 else if (hex >= 'a' && hex <= 'f')
233 return (hex - 'a' + 10);
234 else {
235 (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
236 return 0;
237 }
238 }
239
hex2byte(netdissect_options * ndo,char * hexstring)240 static u_int hex2byte(netdissect_options *ndo, char *hexstring)
241 {
242 u_int byte;
243
244 byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
245 return byte;
246 }
247
248 /*
249 * returns size of binary, 0 on failure.
250 */
251 static
espprint_decode_hex(netdissect_options * ndo,u_char * binbuf,unsigned int binbuf_len,char * hex)252 int espprint_decode_hex(netdissect_options *ndo,
253 u_char *binbuf, unsigned int binbuf_len,
254 char *hex)
255 {
256 unsigned int len;
257 int i;
258
259 len = strlen(hex) / 2;
260
261 if (len > binbuf_len) {
262 (*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
263 return 0;
264 }
265
266 i = 0;
267 while (hex[0] != '\0' && hex[1]!='\0') {
268 binbuf[i] = hex2byte(ndo, hex);
269 hex += 2;
270 i++;
271 }
272
273 return i;
274 }
275
276 /*
277 * decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
278 */
279
280 USES_APPLE_DEPRECATED_API
281 static int
espprint_decode_encalgo(netdissect_options * ndo,char * decode,struct sa_list * sa)282 espprint_decode_encalgo(netdissect_options *ndo,
283 char *decode, struct sa_list *sa)
284 {
285 size_t i;
286 const EVP_CIPHER *evp;
287 int authlen = 0;
288 char *colon, *p;
289
290 colon = strchr(decode, ':');
291 if (colon == NULL) {
292 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
293 return 0;
294 }
295 *colon = '\0';
296
297 if (strlen(decode) > strlen("-hmac96") &&
298 !strcmp(decode + strlen(decode) - strlen("-hmac96"),
299 "-hmac96")) {
300 p = strstr(decode, "-hmac96");
301 *p = '\0';
302 authlen = 12;
303 }
304 if (strlen(decode) > strlen("-cbc") &&
305 !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
306 p = strstr(decode, "-cbc");
307 *p = '\0';
308 }
309 evp = EVP_get_cipherbyname(decode);
310
311 if (!evp) {
312 (*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
313 sa->evp = NULL;
314 sa->authlen = 0;
315 sa->ivlen = 0;
316 return 0;
317 }
318
319 sa->evp = evp;
320 sa->authlen = authlen;
321 sa->ivlen = EVP_CIPHER_iv_length(evp);
322
323 colon++;
324 if (colon[0] == '0' && colon[1] == 'x') {
325 /* decode some hex! */
326
327 colon += 2;
328 sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon);
329 if(sa->secretlen == 0) return 0;
330 } else {
331 i = strlen(colon);
332
333 if (i < sizeof(sa->secret)) {
334 memcpy(sa->secret, colon, i);
335 sa->secretlen = i;
336 } else {
337 memcpy(sa->secret, colon, sizeof(sa->secret));
338 sa->secretlen = sizeof(sa->secret);
339 }
340 }
341
342 return 1;
343 }
344 USES_APPLE_RST
345
346 /*
347 * for the moment, ignore the auth algorith, just hard code the authenticator
348 * length. Need to research how openssl looks up HMAC stuff.
349 */
350 static int
espprint_decode_authalgo(netdissect_options * ndo,char * decode,struct sa_list * sa)351 espprint_decode_authalgo(netdissect_options *ndo,
352 char *decode, struct sa_list *sa)
353 {
354 char *colon;
355
356 colon = strchr(decode, ':');
357 if (colon == NULL) {
358 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
359 return 0;
360 }
361 *colon = '\0';
362
363 if(ascii_strcasecmp(colon,"sha1") == 0 ||
364 ascii_strcasecmp(colon,"md5") == 0) {
365 sa->authlen = 12;
366 }
367 return 1;
368 }
369
esp_print_decode_ikeline(netdissect_options * ndo,char * line,const char * file,int lineno)370 static void esp_print_decode_ikeline(netdissect_options *ndo, char *line,
371 const char *file, int lineno)
372 {
373 /* it's an IKEv2 secret, store it instead */
374 struct sa_list sa1;
375
376 char *init;
377 char *icookie, *rcookie;
378 int ilen, rlen;
379 char *authkey;
380 char *enckey;
381
382 init = strsep(&line, " \t");
383 icookie = strsep(&line, " \t");
384 rcookie = strsep(&line, " \t");
385 authkey = strsep(&line, " \t");
386 enckey = strsep(&line, " \t");
387
388 /* if any fields are missing */
389 if(!init || !icookie || !rcookie || !authkey || !enckey) {
390 (*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u",
391 file, lineno);
392
393 return;
394 }
395
396 ilen = strlen(icookie);
397 rlen = strlen(rcookie);
398
399 if((init[0]!='I' && init[0]!='R')
400 || icookie[0]!='0' || icookie[1]!='x'
401 || rcookie[0]!='0' || rcookie[1]!='x'
402 || ilen!=18
403 || rlen!=18) {
404 (*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.",
405 file, lineno);
406
407 (*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)",
408 init, icookie, ilen, rcookie, rlen);
409
410 return;
411 }
412
413 sa1.spi = 0;
414 sa1.initiator = (init[0] == 'I');
415 if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8)
416 return;
417
418 if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8)
419 return;
420
421 if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return;
422
423 if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return;
424
425 esp_print_addsa(ndo, &sa1, FALSE);
426 }
427
428 /*
429 *
430 * special form: file /name
431 * causes us to go read from this file instead.
432 *
433 */
esp_print_decode_onesecret(netdissect_options * ndo,char * line,const char * file,int lineno)434 static void esp_print_decode_onesecret(netdissect_options *ndo, char *line,
435 const char *file, int lineno)
436 {
437 struct sa_list sa1;
438 int sa_def;
439
440 char *spikey;
441 char *decode;
442
443 spikey = strsep(&line, " \t");
444 sa_def = 0;
445 memset(&sa1, 0, sizeof(struct sa_list));
446
447 /* if there is only one token, then it is an algo:key token */
448 if (line == NULL) {
449 decode = spikey;
450 spikey = NULL;
451 /* sa1.daddr.version = 0; */
452 /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
453 /* sa1.spi = 0; */
454 sa_def = 1;
455 } else
456 decode = line;
457
458 if (spikey && ascii_strcasecmp(spikey, "file") == 0) {
459 /* open file and read it */
460 FILE *secretfile;
461 char fileline[1024];
462 int subfile_lineno=0;
463 char *nl;
464 char *filename = line;
465
466 secretfile = fopen(filename, FOPEN_READ_TXT);
467 if (secretfile == NULL) {
468 (*ndo->ndo_error)(ndo, "print_esp: can't open %s: %s\n",
469 filename, strerror(errno));
470 return;
471 }
472
473 while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
474 subfile_lineno++;
475 /* remove newline from the line */
476 nl = strchr(fileline, '\n');
477 if (nl)
478 *nl = '\0';
479 if (fileline[0] == '#') continue;
480 if (fileline[0] == '\0') continue;
481
482 esp_print_decode_onesecret(ndo, fileline, filename, subfile_lineno);
483 }
484 fclose(secretfile);
485
486 return;
487 }
488
489 if (spikey && ascii_strcasecmp(spikey, "ikev2") == 0) {
490 esp_print_decode_ikeline(ndo, line, file, lineno);
491 return;
492 }
493
494 if (spikey) {
495
496 char *spistr, *foo;
497 uint32_t spino;
498
499 spistr = strsep(&spikey, "@");
500
501 spino = strtoul(spistr, &foo, 0);
502 if (spistr == foo || !spikey) {
503 (*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
504 return;
505 }
506
507 sa1.spi = spino;
508
509 if (strtoaddr6(spikey, &sa1.daddr.in6) == 1) {
510 sa1.daddr_version = 6;
511 } else if (strtoaddr(spikey, &sa1.daddr.in4) == 1) {
512 sa1.daddr_version = 4;
513 } else {
514 (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
515 return;
516 }
517 }
518
519 if (decode) {
520 /* skip any blank spaces */
521 while (isspace((unsigned char)*decode))
522 decode++;
523
524 if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
525 return;
526 }
527 }
528
529 esp_print_addsa(ndo, &sa1, sa_def);
530 }
531
532 USES_APPLE_DEPRECATED_API
esp_init(netdissect_options * ndo _U_)533 static void esp_init(netdissect_options *ndo _U_)
534 {
535 /*
536 * 0.9.6 doesn't appear to define OPENSSL_API_COMPAT, so
537 * we check whether it's undefined or it's less than the
538 * value for 1.1.0.
539 */
540 #if !defined(OPENSSL_API_COMPAT) || OPENSSL_API_COMPAT < 0x10100000L
541 OpenSSL_add_all_algorithms();
542 #endif
543 EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
544 }
545 USES_APPLE_RST
546
esp_print_decodesecret(netdissect_options * ndo)547 void esp_print_decodesecret(netdissect_options *ndo)
548 {
549 char *line;
550 char *p;
551 static int initialized = 0;
552
553 if (!initialized) {
554 esp_init(ndo);
555 initialized = 1;
556 }
557
558 p = ndo->ndo_espsecret;
559
560 while (p && p[0] != '\0') {
561 /* pick out the first line or first thing until a comma */
562 if ((line = strsep(&p, "\n,")) == NULL) {
563 line = p;
564 p = NULL;
565 }
566
567 esp_print_decode_onesecret(ndo, line, "cmdline", 0);
568 }
569
570 ndo->ndo_espsecret = NULL;
571 }
572
573 #endif
574
575 #ifdef HAVE_LIBCRYPTO
576 USES_APPLE_DEPRECATED_API
577 #endif
578 int
esp_print(netdissect_options * ndo,const u_char * bp,const int length,const u_char * bp2 _U_,int * nhdr _U_,int * padlen _U_)579 esp_print(netdissect_options *ndo,
580 const u_char *bp, const int length, const u_char *bp2
581 #ifndef HAVE_LIBCRYPTO
582 _U_
583 #endif
584 ,
585 int *nhdr
586 #ifndef HAVE_LIBCRYPTO
587 _U_
588 #endif
589 ,
590 int *padlen
591 #ifndef HAVE_LIBCRYPTO
592 _U_
593 #endif
594 )
595 {
596 register const struct newesp *esp;
597 register const u_char *ep;
598 #ifdef HAVE_LIBCRYPTO
599 const struct ip *ip;
600 struct sa_list *sa = NULL;
601 const struct ip6_hdr *ip6 = NULL;
602 int advance;
603 int len;
604 u_char *secret;
605 int ivlen = 0;
606 const u_char *ivoff;
607 const u_char *p;
608 EVP_CIPHER_CTX *ctx;
609 #endif
610
611 esp = (const struct newesp *)bp;
612
613 #ifdef HAVE_LIBCRYPTO
614 secret = NULL;
615 advance = 0;
616 #endif
617
618 #if 0
619 /* keep secret out of a register */
620 p = (u_char *)&secret;
621 #endif
622
623 /* 'ep' points to the end of available data. */
624 ep = ndo->ndo_snapend;
625
626 if ((const u_char *)(esp + 1) >= ep) {
627 ND_PRINT((ndo, "[|ESP]"));
628 goto fail;
629 }
630 ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi)));
631 ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq)));
632 ND_PRINT((ndo, ", length %u", length));
633
634 #ifndef HAVE_LIBCRYPTO
635 goto fail;
636 #else
637 /* initiailize SAs */
638 if (ndo->ndo_sa_list_head == NULL) {
639 if (!ndo->ndo_espsecret)
640 goto fail;
641
642 esp_print_decodesecret(ndo);
643 }
644
645 if (ndo->ndo_sa_list_head == NULL)
646 goto fail;
647
648 ip = (const struct ip *)bp2;
649 switch (IP_V(ip)) {
650 case 6:
651 ip6 = (const struct ip6_hdr *)bp2;
652 /* we do not attempt to decrypt jumbograms */
653 if (!EXTRACT_16BITS(&ip6->ip6_plen))
654 goto fail;
655 /* if we can't get nexthdr, we do not need to decrypt it */
656 len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
657
658 /* see if we can find the SA, and if so, decode it */
659 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
660 if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
661 sa->daddr_version == 6 &&
662 UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst,
663 sizeof(struct in6_addr)) == 0) {
664 break;
665 }
666 }
667 break;
668 case 4:
669 /* nexthdr & padding are in the last fragment */
670 if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
671 goto fail;
672 len = EXTRACT_16BITS(&ip->ip_len);
673
674 /* see if we can find the SA, and if so, decode it */
675 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
676 if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
677 sa->daddr_version == 4 &&
678 UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst,
679 sizeof(struct in_addr)) == 0) {
680 break;
681 }
682 }
683 break;
684 default:
685 goto fail;
686 }
687
688 /* if we didn't find the specific one, then look for
689 * an unspecified one.
690 */
691 if (sa == NULL)
692 sa = ndo->ndo_sa_default;
693
694 /* if not found fail */
695 if (sa == NULL)
696 goto fail;
697
698 /* if we can't get nexthdr, we do not need to decrypt it */
699 if (ep - bp2 < len)
700 goto fail;
701 if (ep - bp2 > len) {
702 /* FCS included at end of frame (NetBSD 1.6 or later) */
703 ep = bp2 + len;
704 }
705
706 ivoff = (const u_char *)(esp + 1) + 0;
707 ivlen = sa->ivlen;
708 secret = sa->secret;
709 ep = ep - sa->authlen;
710
711 if (sa->evp) {
712 ctx = EVP_CIPHER_CTX_new();
713 if (ctx != NULL) {
714 if (EVP_CipherInit(ctx, sa->evp, secret, NULL, 0) < 0)
715 (*ndo->ndo_warning)(ndo, "espkey init failed");
716
717 p = ivoff;
718 EVP_CipherInit(ctx, NULL, NULL, p, 0);
719 EVP_Cipher(ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
720 EVP_CIPHER_CTX_free(ctx);
721 advance = ivoff - (const u_char *)esp + ivlen;
722 } else
723 advance = sizeof(struct newesp);
724 } else
725 advance = sizeof(struct newesp);
726
727 /* sanity check for pad length */
728 if (ep - bp < *(ep - 2))
729 goto fail;
730
731 if (padlen)
732 *padlen = *(ep - 2) + 2;
733
734 if (nhdr)
735 *nhdr = *(ep - 1);
736
737 ND_PRINT((ndo, ": "));
738 return advance;
739 #endif
740
741 fail:
742 return -1;
743 }
744 #ifdef HAVE_LIBCRYPTO
745 USES_APPLE_RST
746 #endif
747
748 /*
749 * Local Variables:
750 * c-style: whitesmith
751 * c-basic-offset: 8
752 * End:
753 */
754