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 #ifndef lint
25 static const char rcsid[] _U_ =
26 "@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.55.2.1 2005/04/21 06:44:57 guy Exp $ (LBL)";
27 #endif
28
29 #ifdef HAVE_CONFIG_H
30 #include "config.h"
31 #endif
32
33 #include <string.h>
34
35 #include <tcpdump-stdinc.h>
36
37 #include <stdlib.h>
38
39 #ifdef HAVE_LIBCRYPTO
40 #ifdef HAVE_OPENSSL_EVP_H
41 #include <openssl/evp.h>
42 #endif
43 #endif
44
45 #include <stdio.h>
46
47 #include "ip.h"
48 #include "esp.h"
49 #ifdef INET6
50 #include "ip6.h"
51 #endif
52
53 #include "netdissect.h"
54 #include "addrtoname.h"
55 #include "extract.h"
56
57 #ifndef HAVE_SOCKADDR_STORAGE
58 #ifdef INET6
59 struct sockaddr_storage {
60 union {
61 struct sockaddr_in sin;
62 struct sockaddr_in6 sin6;
63 } un;
64 };
65 #else
66 #define sockaddr_storage sockaddr
67 #endif
68 #endif /* HAVE_SOCKADDR_STORAGE */
69
70 #ifdef HAVE_LIBCRYPTO
71 struct sa_list {
72 struct sa_list *next;
73 struct sockaddr_storage daddr;
74 u_int32_t spi;
75 const EVP_CIPHER *evp;
76 int ivlen;
77 int authlen;
78 u_char secret[256]; /* is that big enough for all secrets? */
79 int secretlen;
80 };
81
esp_print_addsa(netdissect_options * ndo,struct sa_list * sa,int sa_def)82 static void esp_print_addsa(netdissect_options *ndo,
83 struct sa_list *sa, int sa_def)
84 {
85 /* copy the "sa" */
86
87 struct sa_list *nsa;
88
89 nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
90 if (nsa == NULL)
91 (*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");
92
93 *nsa = *sa;
94
95 if (sa_def)
96 ndo->ndo_sa_default = nsa;
97
98 nsa->next = ndo->ndo_sa_list_head;
99 ndo->ndo_sa_list_head = nsa;
100 }
101
102
hexdigit(netdissect_options * ndo,char hex)103 static u_int hexdigit(netdissect_options *ndo, char hex)
104 {
105 if (hex >= '0' && hex <= '9')
106 return (hex - '0');
107 else if (hex >= 'A' && hex <= 'F')
108 return (hex - 'A' + 10);
109 else if (hex >= 'a' && hex <= 'f')
110 return (hex - 'a' + 10);
111 else {
112 (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
113 return 0;
114 }
115 }
116
hex2byte(netdissect_options * ndo,char * hexstring)117 static u_int hex2byte(netdissect_options *ndo, char *hexstring)
118 {
119 u_int byte;
120
121 byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
122 return byte;
123 }
124
125 /*
126 * decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
127 *
128 * special form: file /name
129 * causes us to go read from this file instead.
130 *
131 */
esp_print_decode_onesecret(netdissect_options * ndo,char * line)132 static void esp_print_decode_onesecret(netdissect_options *ndo, char *line)
133 {
134 struct sa_list sa1;
135 int sa_def;
136
137 char *spikey;
138 char *decode;
139
140 spikey = strsep(&line, " \t");
141 sa_def = 0;
142 memset(&sa1, 0, sizeof(struct sa_list));
143
144 /* if there is only one token, then it is an algo:key token */
145 if (line == NULL) {
146 decode = spikey;
147 spikey = NULL;
148 /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
149 /* sa1.spi = 0; */
150 sa_def = 1;
151 } else
152 decode = line;
153
154 if (spikey && strcasecmp(spikey, "file") == 0) {
155 /* open file and read it */
156 FILE *secretfile;
157 char fileline[1024];
158 char *nl;
159
160 secretfile = fopen(line, FOPEN_READ_TXT);
161 if (secretfile == NULL) {
162 perror(line);
163 exit(3);
164 }
165
166 while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
167 /* remove newline from the line */
168 nl = strchr(fileline, '\n');
169 if (nl)
170 *nl = '\0';
171 if (fileline[0] == '#') continue;
172 if (fileline[0] == '\0') continue;
173
174 esp_print_decode_onesecret(ndo, fileline);
175 }
176 fclose(secretfile);
177
178 return;
179 }
180
181 if (spikey) {
182 char *spistr, *foo;
183 u_int32_t spino;
184 struct sockaddr_in *sin;
185 #ifdef INET6
186 struct sockaddr_in6 *sin6;
187 #endif
188
189 spistr = strsep(&spikey, "@");
190
191 spino = strtoul(spistr, &foo, 0);
192 if (spistr == foo || !spikey) {
193 (*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
194 return;
195 }
196
197 sa1.spi = spino;
198
199 sin = (struct sockaddr_in *)&sa1.daddr;
200 #ifdef INET6
201 sin6 = (struct sockaddr_in6 *)&sa1.daddr;
202 if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) {
203 #ifdef HAVE_SOCKADDR_SA_LEN
204 sin6->sin6_len = sizeof(struct sockaddr_in6);
205 #endif
206 sin6->sin6_family = AF_INET6;
207 } else
208 #endif
209 if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) {
210 #ifdef HAVE_SOCKADDR_SA_LEN
211 sin->sin_len = sizeof(struct sockaddr_in);
212 #endif
213 sin->sin_family = AF_INET;
214 } else {
215 (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
216 return;
217 }
218 }
219
220 if (decode) {
221 char *colon, *p;
222 u_char espsecret_key[256];
223 int len;
224 size_t i;
225 const EVP_CIPHER *evp;
226 int authlen = 0;
227
228 /* skip any blank spaces */
229 while (isspace((unsigned char)*decode))
230 decode++;
231
232 colon = strchr(decode, ':');
233 if (colon == NULL) {
234 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
235 return;
236 }
237 *colon = '\0';
238
239 len = colon - decode;
240 if (strlen(decode) > strlen("-hmac96") &&
241 !strcmp(decode + strlen(decode) - strlen("-hmac96"),
242 "-hmac96")) {
243 p = strstr(decode, "-hmac96");
244 *p = '\0';
245 authlen = 12;
246 }
247 if (strlen(decode) > strlen("-cbc") &&
248 !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
249 p = strstr(decode, "-cbc");
250 *p = '\0';
251 }
252 evp = EVP_get_cipherbyname(decode);
253 if (!evp) {
254 (*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
255 sa1.evp = NULL;
256 sa1.authlen = 0;
257 sa1.ivlen = 0;
258 return;
259 }
260
261 sa1.evp = evp;
262 sa1.authlen = authlen;
263 sa1.ivlen = EVP_CIPHER_iv_length(evp);
264
265 colon++;
266 if (colon[0] == '0' && colon[1] == 'x') {
267 /* decode some hex! */
268 colon += 2;
269 len = strlen(colon) / 2;
270
271 if (len > 256) {
272 (*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
273 return;
274 }
275
276 i = 0;
277 while (colon[0] != '\0' && colon[1]!='\0') {
278 espsecret_key[i] = hex2byte(ndo, colon);
279 colon += 2;
280 i++;
281 }
282
283 memcpy(sa1.secret, espsecret_key, i);
284 sa1.secretlen = i;
285 } else {
286 i = strlen(colon);
287
288 if (i < sizeof(sa1.secret)) {
289 memcpy(sa1.secret, colon, i);
290 sa1.secretlen = i;
291 } else {
292 memcpy(sa1.secret, colon, sizeof(sa1.secret));
293 sa1.secretlen = sizeof(sa1.secret);
294 }
295 }
296 }
297
298 esp_print_addsa(ndo, &sa1, sa_def);
299 }
300
esp_print_decodesecret(netdissect_options * ndo)301 static void esp_print_decodesecret(netdissect_options *ndo)
302 {
303 char *line;
304 char *p;
305
306 p = ndo->ndo_espsecret;
307
308 while (ndo->ndo_espsecret && ndo->ndo_espsecret[0] != '\0') {
309 /* pick out the first line or first thing until a comma */
310 if ((line = strsep(&ndo->ndo_espsecret, "\n,")) == NULL) {
311 line = ndo->ndo_espsecret;
312 ndo->ndo_espsecret = NULL;
313 }
314
315 esp_print_decode_onesecret(ndo, line);
316 }
317 }
318
esp_init(netdissect_options * ndo _U_)319 static void esp_init(netdissect_options *ndo _U_)
320 {
321
322 OpenSSL_add_all_algorithms();
323 EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
324 }
325 #endif
326
327 int
esp_print(netdissect_options * ndo,const u_char * bp,const int length,const u_char * bp2 _U_,int * nhdr _U_,int * padlen _U_)328 esp_print(netdissect_options *ndo,
329 const u_char *bp, const int length, const u_char *bp2
330 #ifndef HAVE_LIBCRYPTO
331 _U_
332 #endif
333 ,
334 int *nhdr
335 #ifndef HAVE_LIBCRYPTO
336 _U_
337 #endif
338 ,
339 int *padlen
340 #ifndef HAVE_LIBCRYPTO
341 _U_
342 #endif
343 )
344 {
345 register const struct newesp *esp;
346 register const u_char *ep;
347 #ifdef HAVE_LIBCRYPTO
348 struct ip *ip;
349 struct sa_list *sa = NULL;
350 int espsecret_keylen;
351 #ifdef INET6
352 struct ip6_hdr *ip6 = NULL;
353 #endif
354 int advance;
355 int len;
356 u_char *secret;
357 int ivlen = 0;
358 u_char *ivoff;
359 u_char *p;
360 EVP_CIPHER_CTX ctx;
361 int blocksz;
362 static int initialized = 0;
363 #endif
364
365 esp = (struct newesp *)bp;
366
367 #ifdef HAVE_LIBCRYPTO
368 secret = NULL;
369 advance = 0;
370
371 if (!initialized) {
372 esp_init(ndo);
373 initialized = 1;
374 }
375 #endif
376
377 #if 0
378 /* keep secret out of a register */
379 p = (u_char *)&secret;
380 #endif
381
382 /* 'ep' points to the end of available data. */
383 ep = ndo->ndo_snapend;
384
385 if ((u_char *)(esp + 1) >= ep) {
386 fputs("[|ESP]", stdout);
387 goto fail;
388 }
389 (*ndo->ndo_printf)(ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
390 (*ndo->ndo_printf)(ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq));
391 (*ndo->ndo_printf)(ndo, ", length %u", length);
392
393 #ifndef HAVE_LIBCRYPTO
394 goto fail;
395 #else
396 /* initiailize SAs */
397 if (ndo->ndo_sa_list_head == NULL) {
398 if (!ndo->ndo_espsecret)
399 goto fail;
400
401 esp_print_decodesecret(ndo);
402 }
403
404 if (ndo->ndo_sa_list_head == NULL)
405 goto fail;
406
407 ip = (struct ip *)bp2;
408 switch (IP_V(ip)) {
409 #ifdef INET6
410 case 6:
411 ip6 = (struct ip6_hdr *)bp2;
412 /* we do not attempt to decrypt jumbograms */
413 if (!EXTRACT_16BITS(&ip6->ip6_plen))
414 goto fail;
415 /* if we can't get nexthdr, we do not need to decrypt it */
416 len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
417
418 /* see if we can find the SA, and if so, decode it */
419 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
420 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr;
421 if (sa->spi == ntohl(esp->esp_spi) &&
422 sin6->sin6_family == AF_INET6 &&
423 memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
424 sizeof(struct in6_addr)) == 0) {
425 break;
426 }
427 }
428 break;
429 #endif /*INET6*/
430 case 4:
431 /* nexthdr & padding are in the last fragment */
432 if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
433 goto fail;
434 len = EXTRACT_16BITS(&ip->ip_len);
435
436 /* see if we can find the SA, and if so, decode it */
437 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
438 struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr;
439 if (sa->spi == ntohl(esp->esp_spi) &&
440 sin->sin_family == AF_INET &&
441 sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
442 break;
443 }
444 }
445 break;
446 default:
447 goto fail;
448 }
449
450 /* if we didn't find the specific one, then look for
451 * an unspecified one.
452 */
453 if (sa == NULL)
454 sa = ndo->ndo_sa_default;
455
456 /* if not found fail */
457 if (sa == NULL)
458 goto fail;
459
460 /* if we can't get nexthdr, we do not need to decrypt it */
461 if (ep - bp2 < len)
462 goto fail;
463 if (ep - bp2 > len) {
464 /* FCS included at end of frame (NetBSD 1.6 or later) */
465 ep = bp2 + len;
466 }
467
468 ivoff = (u_char *)(esp + 1) + 0;
469 ivlen = sa->ivlen;
470 secret = sa->secret;
471 espsecret_keylen = sa->secretlen;
472 ep = ep - sa->authlen;
473
474 if (sa->evp) {
475 memset(&ctx, 0, sizeof(ctx));
476 if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
477 (*ndo->ndo_warning)(ndo, "espkey init failed");
478
479 blocksz = EVP_CIPHER_CTX_block_size(&ctx);
480
481 p = ivoff;
482 EVP_CipherInit(&ctx, NULL, NULL, p, 0);
483 EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
484 advance = ivoff - (u_char *)esp + ivlen;
485 } else
486 advance = sizeof(struct newesp);
487
488 /* sanity check for pad length */
489 if (ep - bp < *(ep - 2))
490 goto fail;
491
492 if (padlen)
493 *padlen = *(ep - 2) + 2;
494
495 if (nhdr)
496 *nhdr = *(ep - 1);
497
498 (ndo->ndo_printf)(ndo, ": ");
499 return advance;
500 #endif
501
502 fail:
503 return -1;
504 }
505
506 /*
507 * Local Variables:
508 * c-style: whitesmith
509 * c-basic-offset: 8
510 * End:
511 */
512