/* $NetBSD: print-esp.c,v 1.6 2004/09/27 23:04:24 dyoung Exp $ */ /* * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include #ifndef lint #if 0 static const char rcsid[] _U_ = "@(#) Header: /tcpdump/master/tcpdump/print-esp.c,v 1.44.2.4 2003/11/19 05:36:40 guy Exp (LBL)"; #else __RCSID("$NetBSD: print-esp.c,v 1.6 2004/09/27 23:04:24 dyoung Exp $"); #endif #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #ifdef HAVE_LIBCRYPTO #ifdef HAVE_OPENSSL_EVP_H #include #endif #endif #include #include "ip.h" #include "esp.h" #ifdef INET6 #include "ip6.h" #endif #if defined(__MINGW32__) || defined(__WATCOMC__) extern char *strsep(char **stringp, const char *delim); /* Missing/strsep.c */ #endif #include "interface.h" #include "addrtoname.h" #include "extract.h" #ifndef HAVE_SOCKADDR_STORAGE #ifdef INET6 struct sockaddr_storage { union { struct sockaddr_in sin; struct sockaddr_in6 sin6; } un; }; #else #define sockaddr_storage sockaddr #endif #endif /* HAVE_SOCKADDR_STORAGE */ #ifdef HAVE_LIBCRYPTO struct sa_list { struct sa_list *next; struct sockaddr_storage daddr; u_int32_t spi; const EVP_CIPHER *evp; int ivlen; int authlen; char secret[256]; /* is that big enough for all secrets? */ int secretlen; }; static struct sa_list *sa_list_head = NULL; static struct sa_list *sa_default = NULL; static void esp_print_addsa(struct sa_list *sa, int sa_def) { /* copy the "sa" */ struct sa_list *nsa; nsa = (struct sa_list *)malloc(sizeof(struct sa_list)); if (nsa == NULL) error("ran out of memory to allocate sa structure"); *nsa = *sa; if (sa_def) sa_default = nsa; nsa->next = sa_list_head; sa_list_head = nsa; } static int hexdigit(char hex) { if (hex >= '0' && hex <= '9') return (hex - '0'); else if (hex >= 'A' && hex <= 'F') return (hex - 'A' + 10); else if (hex >= 'a' && hex <= 'f') return (hex - 'a' + 10); else { printf("invalid hex digit %c in espsecret\n", hex); return 0; } } static int hex2byte(char *hexstring) { int byte; byte = (hexdigit(hexstring[0]) << 4) + hexdigit(hexstring[1]); return byte; } /* * decode the form: SPINUM@IP ALGONAME:0xsecret * * special form: file /name * causes us to go read from this file instead. * */ static void esp_print_decode_onesecret(char *line) { struct sa_list sa1; int sa_def; char *spikey; char *decode; spikey = strsep(&line, " \t"); sa_def = 0; memset(&sa1, 0, sizeof(struct sa_list)); /* if there is only one token, then it is an algo:key token */ if (line == NULL) { decode = spikey; spikey = NULL; /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */ /* sa1.spi = 0; */ sa_def = 1; } else decode = line; if (spikey && strcasecmp(spikey, "file") == 0) { /* open file and read it */ FILE *secretfile; char fileline[1024]; char *nl; secretfile = fopen(line, FOPEN_READ_TXT); if (secretfile == NULL) { perror(line); exit(3); } while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) { /* remove newline from the line */ nl = strchr(fileline, '\n'); if (nl) *nl = '\0'; if (fileline[0] == '#') continue; if (fileline[0] == '\0') continue; esp_print_decode_onesecret(fileline); } fclose(secretfile); return; } if (spikey) { char *spistr, *foo; u_int32_t spino; struct sockaddr_in *sin; #ifdef INET6 struct sockaddr_in6 *sin6; #endif spistr = strsep(&spikey, "@"); spino = strtoul(spistr, &foo, 0); if (spistr == foo || !spikey) { printf("print_esp: failed to decode spi# %s\n", foo); return; } sa1.spi = spino; sin = (struct sockaddr_in *)&sa1.daddr; #ifdef INET6 sin6 = (struct sockaddr_in6 *)&sa1.daddr; if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) { #ifdef HAVE_SOCKADDR_SA_LEN sin6->sin6_len = sizeof(struct sockaddr_in6); #endif sin6->sin6_family = AF_INET6; } else #endif if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) { #ifdef HAVE_SOCKADDR_SA_LEN sin->sin_len = sizeof(struct sockaddr_in); #endif sin->sin_family = AF_INET; } else { printf("print_esp: can not decode IP# %s\n", spikey); return; } } if (decode) { char *colon, *p; char espsecret_key[256]; int len; size_t i; const EVP_CIPHER *evp; int ivlen = 8; int authlen = 0; /* skip any blank spaces */ while (isspace((unsigned char)*decode)) decode++; colon = strchr(decode, ':'); if (colon == NULL) { printf("failed to decode espsecret: %s\n", decode); return; } *colon = '\0'; len = colon - decode; if (strlen(decode) > strlen("-hmac96") && !strcmp(decode + strlen(decode) - strlen("-hmac96"), "-hmac96")) { p = strstr(decode, "-hmac96"); *p = '\0'; authlen = 12; } if (strlen(decode) > strlen("-cbc") && !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) { p = strstr(decode, "-cbc"); *p = '\0'; } evp = EVP_get_cipherbyname(decode); if (!evp) { printf("failed to find cipher algo %s\n", decode); sa1.evp = NULL; sa1.authlen = 0; sa1.ivlen = 0; return; } sa1.evp = evp; sa1.authlen = authlen; sa1.ivlen = ivlen; colon++; if (colon[0] == '0' && colon[1] == 'x') { /* decode some hex! */ colon += 2; len = strlen(colon) / 2; if (len > 256) { printf("secret is too big: %d\n", len); return; } i = 0; while (colon[0] != '\0' && colon[1]!='\0') { espsecret_key[i] = hex2byte(colon); colon += 2; i++; } memcpy(sa1.secret, espsecret_key, i); sa1.secretlen = i; } else { i = strlen(colon); if (i < sizeof(sa1.secret)) { memcpy(sa1.secret, colon, i); sa1.secretlen = i; } else { memcpy(sa1.secret, colon, sizeof(sa1.secret)); sa1.secretlen = sizeof(sa1.secret); } } } esp_print_addsa(&sa1, sa_def); } static void esp_print_decodesecret(void) { char *line; char *p; p = espsecret; while (espsecret && espsecret[0] != '\0') { /* pick out the first line or first thing until a comma */ if ((line = strsep(&espsecret, "\n,")) == NULL) { line = espsecret; espsecret = NULL; } esp_print_decode_onesecret(line); } } static void esp_init(void) { OpenSSL_add_all_algorithms(); EVP_add_cipher_alias(SN_des_ede3_cbc, "3des"); } #endif int esp_print(const u_char *bp, const u_char *bp2 #ifndef HAVE_LIBCRYPTO _U_ #endif , int *nhdr #ifndef HAVE_LIBCRYPTO _U_ #endif , int *padlen #ifndef HAVE_LIBCRYPTO _U_ #endif ) { register const struct newesp *esp; register const u_char *ep; #ifdef HAVE_LIBCRYPTO struct ip *ip; struct sa_list *sa = NULL; int espsecret_keylen; #ifdef INET6 struct ip6_hdr *ip6 = NULL; #endif int advance; int len; char *secret; int ivlen = 0; u_char *ivoff; const u_char *p; EVP_CIPHER_CTX ctx; int blocksz; static int initialized = 0; #endif esp = (struct newesp *)bp; #ifdef HAVE_LIBCRYPTO secret = NULL; advance = 0; if (!initialized) { esp_init(); initialized = 1; } #endif #if 0 /* keep secret out of a register */ p = (u_char *)&secret; #endif /* 'ep' points to the end of available data. */ ep = snapend; if ((u_char *)(esp + 1) >= ep) { fputs("[|ESP]", stdout); goto fail; } printf("ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi)); printf(",seq=0x%x", EXTRACT_32BITS(&esp->esp_seq)); printf(")"); #ifndef HAVE_LIBCRYPTO goto fail; #else /* initiailize SAs */ if (sa_list_head == NULL) { if (!espsecret) goto fail; esp_print_decodesecret(); } if (sa_list_head == NULL) goto fail; ip = (struct ip *)bp2; switch (IP_V(ip)) { #ifdef INET6 case 6: ip6 = (struct ip6_hdr *)bp2; /* we do not attempt to decrypt jumbograms */ if (!EXTRACT_16BITS(&ip6->ip6_plen)) goto fail; /* if we can't get nexthdr, we do not need to decrypt it */ len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen); /* see if we can find the SA, and if so, decode it */ for (sa = sa_list_head; sa != NULL; sa = sa->next) { struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr; if (sa->spi == ntohl(esp->esp_spi) && sin6->sin6_family == AF_INET6 && memcmp(&sin6->sin6_addr, &ip6->ip6_dst, sizeof(struct in6_addr)) == 0) { break; } } break; #endif /*INET6*/ case 4: /* nexthdr & padding are in the last fragment */ if (EXTRACT_16BITS(&ip->ip_off) & IP_MF) goto fail; len = EXTRACT_16BITS(&ip->ip_len); /* see if we can find the SA, and if so, decode it */ for (sa = sa_list_head; sa != NULL; sa = sa->next) { struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr; if (sa->spi == ntohl(esp->esp_spi) && sin->sin_family == AF_INET && sin->sin_addr.s_addr == ip->ip_dst.s_addr) { break; } } break; default: goto fail; } /* if we didn't find the specific one, then look for * an unspecified one. */ if (sa == NULL) sa = sa_default; /* if not found fail */ if (sa == NULL) goto fail; /* if we can't get nexthdr, we do not need to decrypt it */ if (ep - bp2 < len) goto fail; if (ep - bp2 > len) { /* FCS included at end of frame (NetBSD 1.6 or later) */ ep = bp2 + len; } ivoff = (u_char *)(esp + 1) + 0; ivlen = sa->ivlen; secret = sa->secret; espsecret_keylen = sa->secretlen; if (sa->evp) { memset(&ctx, 0, sizeof(ctx)); if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0) printf("espkey init failed"); blocksz = EVP_CIPHER_CTX_block_size(&ctx); p = ivoff; EVP_CipherInit(&ctx, NULL, NULL, p, 0); EVP_Cipher(&ctx, (void *)(p + ivlen), p + ivlen, ep - (p + ivlen)); advance = ivoff - (u_char *)esp + ivlen; } else advance = sizeof(struct newesp); ep = ep - sa->authlen; /* sanity check for pad length */ if (ep - bp < *(ep - 2)) goto fail; if (padlen) *padlen = *(ep - 2) + 2; if (nhdr) *nhdr = *(ep - 1); printf(": "); return advance; #endif fail: return -1; }