The Tcpdump Group git mirrors - tcpdump/blob - print-esp.c

   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 *
 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
 141 EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
 142 {
 143         EVP_CIPHER_CTX_cleanup(ctx);
 144         free(ctx);
 145 }
 146 #endif
 147
 148 #ifdef HAVE_EVP_CIPHERINIT_EX
 149 /*
 150  * Initialize the cipher by calling EVP_CipherInit_ex(), because
 151  * calling EVP_CipherInit() will reset the cipher context, clearing
 152  * the cipher, so calling it twice, with the second call having a
 153  * null cipher, will clear the already-set cipher.  EVP_CipherInit_ex(),
 154  * however, won't reset the cipher context, so you can use it to specify
 155  * the IV oin a second call after a first call to EVP_CipherInit_ex()
 156  * to set the cipher and the key.
 157  *
 158  * XXX - is there some reason why we need to make two calls?
 159  */
 160 static int
 161 set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 162                       const unsigned char *key,
 163                       const unsigned char *iv, int enc)
 164 {
 165         return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
 166 }
 167 #else
 168 /*
 169  * Initialize the cipher by calling EVP_CipherInit(), because we don't
 170  * have EVP_CipherInit_ex(); we rely on it not trashing the context.
 171  */
 172 static int
 173 set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 174                       const unsigned char *key,
 175                       const unsigned char *iv, int enc)
 176 {
 177         return EVP_CipherInit(ctx, cipher, key, iv, enc);
 178 }
 179 #endif
 180
 181 /*
 182  * this will adjust ndo_packetp and ndo_snapend to new buffer!
 183  */
 184 USES_APPLE_DEPRECATED_API
 185 int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
 186                                       int initiator,
 187                                       u_char spii[8], u_char spir[8],
 188                                       const u_char *buf, const u_char *end)
 189 {
 190         struct sa_list *sa;
 191         const u_char *iv;
 192         unsigned int len;
 193         EVP_CIPHER_CTX *ctx;
 194         unsigned int block_size, buffer_size;
 195         u_char *input_buffer, *output_buffer;
 196
 197         /* initiator arg is any non-zero value */
 198         if(initiator) initiator=1;
 199
 200         /* see if we can find the SA, and if so, decode it */
 201         for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 202                 if (sa->spi == 0
 203                     && initiator == sa->initiator
 204                     && memcmp(spii, sa->spii, 8) == 0
 205                     && memcmp(spir, sa->spir, 8) == 0)
 206                         break;
 207         }
 208
 209         if(sa == NULL) return 0;
 210         if(sa->evp == NULL) return 0;
 211
 212         /*
 213          * remove authenticator, and see if we still have something to
 214          * work with
 215          */
 216         end = end - sa->authlen;
 217         iv  = buf;
 218         buf = buf + sa->ivlen;
 219         len = end-buf;
 220
 221         if(end <= buf) return 0;
 222
 223         ctx = EVP_CIPHER_CTX_new();
 224         if (ctx == NULL)
 225                 return 0;
 226         if (set_cipher_parameters(ctx, sa->evp, sa->secret, NULL, 0) < 0)
 227                 (*ndo->ndo_warning)(ndo, "espkey init failed");
 228         set_cipher_parameters(ctx, NULL, NULL, iv, 0);
 229         /*
 230          * Allocate buffers for the encrypted and decrypted data.
 231          * Both buffers' sizes must be a multiple of the cipher block
 232          * size, and the output buffer must be separate from the input
 233          * buffer.
 234          */
 235         block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
 236         buffer_size = len + (block_size - len % block_size);
 237
 238         /*
 239          * Attempt to allocate the input buffer.
 240          */
 241         input_buffer = (u_char *)malloc(buffer_size);
 242         if (input_buffer == NULL) {
 243                 EVP_CIPHER_CTX_free(ctx);
 244                 (*ndo->ndo_error)(ndo, "can't allocate memory for encrypted data buffer");
 245         }
 246         /*
 247          * Copy the input data to the encrypted data buffer, and pad it
 248          * with zeroes.
 249          */
 250         memcpy(input_buffer, buf, len);
 251         memset(input_buffer + len, 0, buffer_size - len);
 252
 253         /*
 254          * Attempt to allocate the output buffer.
 255          */
 256         output_buffer = (u_char *)malloc(buffer_size);
 257         if (output_buffer == NULL) {
 258                 free(input_buffer);
 259                 EVP_CIPHER_CTX_free(ctx);
 260                 (*ndo->ndo_error)(ndo, "can't allocate memory for decryption buffer");
 261         }
 262         EVP_Cipher(ctx, output_buffer, input_buffer, len);
 263         EVP_CIPHER_CTX_free(ctx);
 264
 265         /*
 266          * XXX - of course this is wrong, because buf is a const buffer,
 267          * but changing this would require a more complicated fix.
 268          */
 269         memcpy(buf, output_buffer, len);
 270         free(input_buffer);
 271         free(output_buffer);
 272
 273         ndo->ndo_packetp = buf;
 274         ndo->ndo_snapend = end;
 275
 276         return 1;
 277 }
 278 USES_APPLE_RST
 279
 280 static void esp_print_addsa(netdissect_options *ndo,
 281                             struct sa_list *sa, int sa_def)
 282 {
 283         /* copy the "sa" */
 284
 285         struct sa_list *nsa;
 286
 287         nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
 288         if (nsa == NULL)
 289                 (*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");
 290
 291         *nsa = *sa;
 292
 293         if (sa_def)
 294                 ndo->ndo_sa_default = nsa;
 295
 296         nsa->next = ndo->ndo_sa_list_head;
 297         ndo->ndo_sa_list_head = nsa;
 298 }
 299
 300
 301 static u_int hexdigit(netdissect_options *ndo, char hex)
 302 {
 303         if (hex >= '0' && hex <= '9')
 304                 return (hex - '0');
 305         else if (hex >= 'A' && hex <= 'F')
 306                 return (hex - 'A' + 10);
 307         else if (hex >= 'a' && hex <= 'f')
 308                 return (hex - 'a' + 10);
 309         else {
 310                 (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
 311         }
 312 }
 313
 314 static u_int hex2byte(netdissect_options *ndo, char *hexstring)
 315 {
 316         u_int byte;
 317
 318         byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
 319         return byte;
 320 }
 321
 322 /*
 323  * returns size of binary, 0 on failure.
 324  */
 325 static
 326 int espprint_decode_hex(netdissect_options *ndo,
 327                         u_char *binbuf, unsigned int binbuf_len,
 328                         char *hex)
 329 {
 330         unsigned int len;
 331         int i;
 332
 333         len = strlen(hex) / 2;
 334
 335         if (len > binbuf_len) {
 336                 (*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
 337                 return 0;
 338         }
 339
 340         i = 0;
 341         while (hex[0] != '\0' && hex[1]!='\0') {
 342                 binbuf[i] = hex2byte(ndo, hex);
 343                 hex += 2;
 344                 i++;
 345         }
 346
 347         return i;
 348 }
 349
 350 /*
 351  * decode the form:    SPINUM@IP <tab> ALGONAME:0xsecret
 352  */
 353
 354 USES_APPLE_DEPRECATED_API
 355 static int
 356 espprint_decode_encalgo(netdissect_options *ndo,
 357                         char *decode, struct sa_list *sa)
 358 {
 359         size_t i;
 360         const EVP_CIPHER *evp;
 361         int authlen = 0;
 362         char *colon, *p;
 363
 364         colon = strchr(decode, ':');
 365         if (colon == NULL) {
 366                 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
 367                 return 0;
 368         }
 369         *colon = '\0';
 370
 371         if (strlen(decode) > strlen("-hmac96") &&
 372             !strcmp(decode + strlen(decode) - strlen("-hmac96"),
 373                     "-hmac96")) {
 374                 p = strstr(decode, "-hmac96");
 375                 *p = '\0';
 376                 authlen = 12;
 377         }
 378         if (strlen(decode) > strlen("-cbc") &&
 379             !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
 380                 p = strstr(decode, "-cbc");
 381                 *p = '\0';
 382         }
 383         evp = EVP_get_cipherbyname(decode);
 384
 385         if (!evp) {
 386                 (*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
 387                 sa->evp = NULL;
 388                 sa->authlen = 0;
 389                 sa->ivlen = 0;
 390                 return 0;
 391         }
 392
 393         sa->evp = evp;
 394         sa->authlen = authlen;
 395         sa->ivlen = EVP_CIPHER_iv_length(evp);
 396
 397         colon++;
 398         if (colon[0] == '0' && colon[1] == 'x') {
 399                 /* decode some hex! */
 400
 401                 colon += 2;
 402                 sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon);
 403                 if(sa->secretlen == 0) return 0;
 404         } else {
 405                 i = strlen(colon);
 406
 407                 if (i < sizeof(sa->secret)) {
 408                         memcpy(sa->secret, colon, i);
 409                         sa->secretlen = i;
 410                 } else {
 411                         memcpy(sa->secret, colon, sizeof(sa->secret));
 412                         sa->secretlen = sizeof(sa->secret);
 413                 }
 414         }
 415
 416         return 1;
 417 }
 418 USES_APPLE_RST
 419
 420 /*
 421  * for the moment, ignore the auth algorithm, just hard code the authenticator
 422  * length. Need to research how openssl looks up HMAC stuff.
 423  */
 424 static int
 425 espprint_decode_authalgo(netdissect_options *ndo,
 426                          char *decode, struct sa_list *sa)
 427 {
 428         char *colon;
 429
 430         colon = strchr(decode, ':');
 431         if (colon == NULL) {
 432                 (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
 433                 return 0;
 434         }
 435         *colon = '\0';
 436
 437         if(ascii_strcasecmp(colon,"sha1") == 0 ||
 438            ascii_strcasecmp(colon,"md5") == 0) {
 439                 sa->authlen = 12;
 440         }
 441         return 1;
 442 }
 443
 444 static void esp_print_decode_ikeline(netdissect_options *ndo, char *line,
 445                                      const char *file, int lineno)
 446 {
 447         /* it's an IKEv2 secret, store it instead */
 448         struct sa_list sa1;
 449
 450         char *init;
 451         char *icookie, *rcookie;
 452         int   ilen, rlen;
 453         char *authkey;
 454         char *enckey;
 455
 456         init = strsep(&line, " \t");
 457         icookie = strsep(&line, " \t");
 458         rcookie = strsep(&line, " \t");
 459         authkey = strsep(&line, " \t");
 460         enckey  = strsep(&line, " \t");
 461
 462         /* if any fields are missing */
 463         if(!init || !icookie || !rcookie || !authkey || !enckey) {
 464                 (*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u",
 465                                     file, lineno);
 466
 467                 return;
 468         }
 469
 470         ilen = strlen(icookie);
 471         rlen = strlen(rcookie);
 472
 473         if((init[0]!='I' && init[0]!='R')
 474            || icookie[0]!='0' || icookie[1]!='x'
 475            || rcookie[0]!='0' || rcookie[1]!='x'
 476            || ilen!=18
 477            || rlen!=18) {
 478                 (*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.",
 479                                     file, lineno);
 480
 481                 (*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)",
 482                                     init, icookie, ilen, rcookie, rlen);
 483
 484                 return;
 485         }
 486
 487         sa1.spi = 0;
 488         sa1.initiator = (init[0] == 'I');
 489         if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8)
 490                 return;
 491
 492         if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8)
 493                 return;
 494
 495         if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return;
 496
 497         if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return;
 498
 499         esp_print_addsa(ndo, &sa1, FALSE);
 500 }
 501
 502 /*
 503  *
 504  * special form: file /name
 505  * causes us to go read from this file instead.
 506  *
 507  */
 508 static void esp_print_decode_onesecret(netdissect_options *ndo, char *line,
 509                                        const char *file, int lineno)
 510 {
 511         struct sa_list sa1;
 512         int sa_def;
 513
 514         char *spikey;
 515         char *decode;
 516
 517         spikey = strsep(&line, " \t");
 518         sa_def = 0;
 519         memset(&sa1, 0, sizeof(struct sa_list));
 520
 521         /* if there is only one token, then it is an algo:key token */
 522         if (line == NULL) {
 523                 decode = spikey;
 524                 spikey = NULL;
 525                 /* sa1.daddr.version = 0; */
 526                 /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
 527                 /* sa1.spi = 0; */
 528                 sa_def    = 1;
 529         } else
 530                 decode = line;
 531
 532         if (spikey && ascii_strcasecmp(spikey, "file") == 0) {
 533                 /* open file and read it */
 534                 FILE *secretfile;
 535                 char  fileline[1024];
 536                 int   subfile_lineno=0;
 537                 char  *nl;
 538                 char *filename = line;
 539
 540                 secretfile = fopen(filename, FOPEN_READ_TXT);
 541                 if (secretfile == NULL) {
 542                         (*ndo->ndo_error)(ndo, "print_esp: can't open %s: %s\n",
 543                             filename, strerror(errno));
 544                 }
 545
 546                 while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
 547                         subfile_lineno++;
 548                         /* remove newline from the line */
 549                         nl = strchr(fileline, '\n');
 550                         if (nl)
 551                                 *nl = '\0';
 552                         if (fileline[0] == '#') continue;
 553                         if (fileline[0] == '\0') continue;
 554
 555                         esp_print_decode_onesecret(ndo, fileline, filename, subfile_lineno);
 556                 }
 557                 fclose(secretfile);
 558
 559                 return;
 560         }
 561
 562         if (spikey && ascii_strcasecmp(spikey, "ikev2") == 0) {
 563                 esp_print_decode_ikeline(ndo, line, file, lineno);
 564                 return;
 565         }
 566
 567         if (spikey) {
 568
 569                 char *spistr, *foo;
 570                 uint32_t spino;
 571
 572                 spistr = strsep(&spikey, "@");
 573                 if (spistr == NULL) {
 574                         (*ndo->ndo_warning)(ndo, "print_esp: failed to find the @ token");
 575                         return;
 576                 }
 577
 578                 spino = strtoul(spistr, &foo, 0);
 579                 if (spistr == foo || !spikey) {
 580                         (*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
 581                         return;
 582                 }
 583
 584                 sa1.spi = spino;
 585
 586                 if (strtoaddr6(spikey, &sa1.daddr.in6) == 1) {
 587                         sa1.daddr_version = 6;
 588                 } else if (strtoaddr(spikey, &sa1.daddr.in4) == 1) {
 589                         sa1.daddr_version = 4;
 590                 } else {
 591                         (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
 592                         return;
 593                 }
 594         }
 595
 596         if (decode) {
 597                 /* skip any blank spaces */
 598                 while (isspace((unsigned char)*decode))
 599                         decode++;
 600
 601                 if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
 602                         return;
 603                 }
 604         }
 605
 606         esp_print_addsa(ndo, &sa1, sa_def);
 607 }
 608
 609 USES_APPLE_DEPRECATED_API
 610 static void esp_init(netdissect_options *ndo _U_)
 611 {
 612         /*
 613          * 0.9.6 doesn't appear to define OPENSSL_API_COMPAT, so
 614          * we check whether it's undefined or it's less than the
 615          * value for 1.1.0.
 616          */
 617 #if !defined(OPENSSL_API_COMPAT) || OPENSSL_API_COMPAT < 0x10100000L
 618         OpenSSL_add_all_algorithms();
 619 #endif
 620         EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
 621 }
 622 USES_APPLE_RST
 623
 624 void esp_print_decodesecret(netdissect_options *ndo)
 625 {
 626         char *line;
 627         char *p;
 628         static int initialized = 0;
 629
 630         if (!initialized) {
 631                 esp_init(ndo);
 632                 initialized = 1;
 633         }
 634
 635         p = ndo->ndo_espsecret;
 636
 637         while (p && p[0] != '\0') {
 638                 /* pick out the first line or first thing until a comma */
 639                 if ((line = strsep(&p, "\n,")) == NULL) {
 640                         line = p;
 641                         p = NULL;
 642                 }
 643
 644                 esp_print_decode_onesecret(ndo, line, "cmdline", 0);
 645         }
 646
 647         ndo->ndo_espsecret = NULL;
 648 }
 649
 650 #endif
 651
 652 #ifdef HAVE_LIBCRYPTO
 653 USES_APPLE_DEPRECATED_API
 654 #endif
 655 int
 656 esp_print(netdissect_options *ndo,
 657           const u_char *bp, const int length, const u_char *bp2
 658 #ifndef HAVE_LIBCRYPTO
 659         _U_
 660 #endif
 661         ,
 662         int *nhdr
 663 #ifndef HAVE_LIBCRYPTO
 664         _U_
 665 #endif
 666         ,
 667         int *padlen
 668 #ifndef HAVE_LIBCRYPTO
 669         _U_
 670 #endif
 671         )
 672 {
 673         register const struct newesp *esp;
 674         register const u_char *ep;
 675 #ifdef HAVE_LIBCRYPTO
 676         const struct ip *ip;
 677         struct sa_list *sa = NULL;
 678         const struct ip6_hdr *ip6 = NULL;
 679         int advance;
 680         int len;
 681         u_char *secret;
 682         int ivlen = 0;
 683         const u_char *ivoff;
 684         const u_char *p;
 685         EVP_CIPHER_CTX *ctx;
 686         unsigned int block_size, buffer_size;
 687         u_char *input_buffer, *output_buffer;
 688 #endif
 689
 690         esp = (const struct newesp *)bp;
 691
 692 #ifdef HAVE_LIBCRYPTO
 693         secret = NULL;
 694         advance = 0;
 695 #endif
 696
 697 #if 0
 698         /* keep secret out of a register */
 699         p = (u_char *)&secret;
 700 #endif
 701
 702         /* 'ep' points to the end of available data. */
 703         ep = ndo->ndo_snapend;
 704
 705         if ((const u_char *)(esp + 1) >= ep) {
 706                 ND_PRINT((ndo, "[|ESP]"));
 707                 goto fail;
 708         }
 709         ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi)));
 710         ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq)));
 711         ND_PRINT((ndo, ", length %u", length));
 712
 713 #ifndef HAVE_LIBCRYPTO
 714         goto fail;
 715 #else
 716         /* initiailize SAs */
 717         if (ndo->ndo_sa_list_head == NULL) {
 718                 if (!ndo->ndo_espsecret)
 719                         goto fail;
 720
 721                 esp_print_decodesecret(ndo);
 722         }
 723
 724         if (ndo->ndo_sa_list_head == NULL)
 725                 goto fail;
 726
 727         ip = (const struct ip *)bp2;
 728         switch (IP_V(ip)) {
 729         case 6:
 730                 ip6 = (const struct ip6_hdr *)bp2;
 731                 /* we do not attempt to decrypt jumbograms */
 732                 if (!EXTRACT_16BITS(&ip6->ip6_plen))
 733                         goto fail;
 734                 /* if we can't get nexthdr, we do not need to decrypt it */
 735                 len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
 736
 737                 /* see if we can find the SA, and if so, decode it */
 738                 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 739                         if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
 740                             sa->daddr_version == 6 &&
 741                             UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst,
 742                                    sizeof(struct in6_addr)) == 0) {
 743                                 break;
 744                         }
 745                 }
 746                 break;
 747         case 4:
 748                 /* nexthdr & padding are in the last fragment */
 749                 if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
 750                         goto fail;
 751                 len = EXTRACT_16BITS(&ip->ip_len);
 752
 753                 /* see if we can find the SA, and if so, decode it */
 754                 for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 755                         if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
 756                             sa->daddr_version == 4 &&
 757                             UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst,
 758                                    sizeof(struct in_addr)) == 0) {
 759                                 break;
 760                         }
 761                 }
 762                 break;
 763         default:
 764                 goto fail;
 765         }
 766
 767         /* if we didn't find the specific one, then look for
 768          * an unspecified one.
 769          */
 770         if (sa == NULL)
 771                 sa = ndo->ndo_sa_default;
 772
 773         /* if not found fail */
 774         if (sa == NULL)
 775                 goto fail;
 776
 777         /* if we can't get nexthdr, we do not need to decrypt it */
 778         if (ep - bp2 < len)
 779                 goto fail;
 780         if (ep - bp2 > len) {
 781                 /* FCS included at end of frame (NetBSD 1.6 or later) */
 782                 ep = bp2 + len;
 783         }
 784
 785         /* pointer to the IV, if there is one */
 786         ivoff = (const u_char *)(esp + 1) + 0;
 787         /* length of the IV, if there is one; 0, if there isn't */
 788         ivlen = sa->ivlen;
 789         secret = sa->secret;
 790         ep = ep - sa->authlen;
 791
 792         if (sa->evp) {
 793                 ctx = EVP_CIPHER_CTX_new();
 794                 if (ctx != NULL) {
 795                         if (set_cipher_parameters(ctx, sa->evp, secret, NULL, 0) < 0)
 796                                 (*ndo->ndo_warning)(ndo, "espkey init failed");
 797
 798                         p = ivoff;
 799                         set_cipher_parameters(ctx, NULL, NULL, p, 0);
 800                         len = ep - (p + ivlen);
 801
 802                         /*
 803                          * Allocate buffers for the encrypted and decrypted
 804                          * data.  Both buffers' sizes must be a multiple of
 805                          * the cipher block size, and the output buffer must
 806                          * be separate from the input buffer.
 807                          */
 808                         block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
 809                         buffer_size = len + (block_size - len % block_size);
 810
 811                         /*
 812                          * Attempt to allocate the input buffer.
 813                          */
 814                         input_buffer = (u_char *)malloc(buffer_size);
 815                         if (input_buffer == NULL) {
 816                                 EVP_CIPHER_CTX_free(ctx);
 817                                 (*ndo->ndo_error)(ndo, "can't allocate memory for encrypted data buffer");
 818                         }
 819                         /*
 820                          * Copy the input data to the encrypted data buffer,
 821                          * and pad it with zeroes.
 822                          */
 823                         memcpy(input_buffer, p + ivlen, len);
 824                         memset(input_buffer + len, 0, buffer_size - len);
 825
 826                         /*
 827                          * Attempt to allocate the output buffer.
 828                          */
 829                         output_buffer = (u_char *)malloc(buffer_size);
 830                         if (output_buffer == NULL) {
 831                                 free(input_buffer);
 832                                 EVP_CIPHER_CTX_free(ctx);
 833                                 (*ndo->ndo_error)(ndo, "can't allocate memory for decryption buffer");
 834                         }
 835
 836                         EVP_Cipher(ctx, output_buffer, input_buffer, len);
 837                         free(input_buffer);
 838                         EVP_CIPHER_CTX_free(ctx);
 839                         /*
 840                          * XXX - of course this is wrong, because buf is a
 841                          * const buffer, but changing this would require a
 842                          * more complicated fix.
 843                          */
 844                         memcpy(p + ivlen, output_buffer, len);
 845                         free(output_buffer);
 846                         advance = ivoff - (const u_char *)esp + ivlen;
 847                 } else
 848                         advance = sizeof(struct newesp);
 849         } else
 850                 advance = sizeof(struct newesp);
 851
 852         /* sanity check for pad length */
 853         if (ep - bp < *(ep - 2))
 854                 goto fail;
 855
 856         if (padlen)
 857                 *padlen = *(ep - 2) + 2;
 858
 859         if (nhdr)
 860                 *nhdr = *(ep - 1);
 861
 862         ND_PRINT((ndo, ": "));
 863         return advance;
 864 #endif
 865
 866 fail:
 867         return -1;
 868 }
 869 #ifdef HAVE_LIBCRYPTO
 870 USES_APPLE_RST
 871 #endif
 872
 873 /*
 874  * Local Variables:
 875  * c-style: whitesmith
 876  * c-basic-offset: 8
 877  * End:
 878  */