From 7adcb5b605cc1328a3084c334f4697ec9771936c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 15 Apr 2024 19:13:01 +0200 Subject: Adding upstream version 4.99.4. Signed-off-by: Daniel Baumann --- print-esp.c | 928 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 928 insertions(+) create mode 100644 print-esp.c (limited to 'print-esp.c') diff --git a/print-esp.c b/print-esp.c new file mode 100644 index 0000000..2cee088 --- /dev/null +++ b/print-esp.c @@ -0,0 +1,928 @@ +/* $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl 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. + */ + +/* \summary: IPSEC Encapsulating Security Payload (ESP) printer */ + +#ifdef HAVE_CONFIG_H +#include +#endif + +#include "netdissect-stdinc.h" + +#include +#include + +/* Any code in this file that depends on HAVE_LIBCRYPTO depends on + * HAVE_OPENSSL_EVP_H too. Undefining the former when the latter isn't defined + * is the simplest way of handling the dependency. + */ +#ifdef HAVE_LIBCRYPTO +#ifdef HAVE_OPENSSL_EVP_H +#include +#else +#undef HAVE_LIBCRYPTO +#endif +#endif + +#include "netdissect.h" +#include "extract.h" + +#include "diag-control.h" + +#ifdef HAVE_LIBCRYPTO +#include "strtoaddr.h" +#include "ascii_strcasecmp.h" +#endif + +#include "ip.h" +#include "ip6.h" + +/* + * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the project 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 BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * RFC1827/2406 Encapsulated Security Payload. + */ + +struct newesp { + nd_uint32_t esp_spi; /* ESP */ + nd_uint32_t esp_seq; /* Sequence number */ + /*variable size*/ /* (IV and) Payload data */ + /*variable size*/ /* padding */ + /*8bit*/ /* pad size */ + /*8bit*/ /* next header */ + /*8bit*/ /* next header */ + /*variable size, 32bit bound*/ /* Authentication data */ +}; + +#ifdef HAVE_LIBCRYPTO +union inaddr_u { + nd_ipv4 in4; + nd_ipv6 in6; +}; +struct sa_list { + struct sa_list *next; + u_int daddr_version; + union inaddr_u daddr; + uint32_t spi; /* if == 0, then IKEv2 */ + int initiator; + u_char spii[8]; /* for IKEv2 */ + u_char spir[8]; + const EVP_CIPHER *evp; + u_int ivlen; + int authlen; + u_char authsecret[256]; + int authsecret_len; + u_char secret[256]; /* is that big enough for all secrets? */ + int secretlen; +}; + +#ifndef HAVE_EVP_CIPHER_CTX_NEW +/* + * Allocate an EVP_CIPHER_CTX. + * Used if we have an older version of OpenSSL that doesn't provide + * routines to allocate and free them. + */ +static EVP_CIPHER_CTX * +EVP_CIPHER_CTX_new(void) +{ + EVP_CIPHER_CTX *ctx; + + ctx = malloc(sizeof(*ctx)); + if (ctx == NULL) + return (NULL); + memset(ctx, 0, sizeof(*ctx)); + return (ctx); +} + +static void +EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx) +{ + EVP_CIPHER_CTX_cleanup(ctx); + free(ctx); +} +#endif + +#ifdef HAVE_EVP_DECRYPTINIT_EX +/* + * Initialize the cipher by calling EVP_DecryptInit_ex(), because + * calling EVP_DecryptInit() will reset the cipher context, clearing + * the cipher, so calling it twice, with the second call having a + * null cipher, will clear the already-set cipher. EVP_DecryptInit_ex(), + * however, won't reset the cipher context, so you can use it to specify + * the IV in a second call after a first call to EVP_DecryptInit_ex() + * to set the cipher and the key. + * + * XXX - is there some reason why we need to make two calls? + */ +static int +set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, + const unsigned char *key, + const unsigned char *iv) +{ + return EVP_DecryptInit_ex(ctx, cipher, NULL, key, iv); +} +#else +/* + * Initialize the cipher by calling EVP_DecryptInit(), because we don't + * have EVP_DecryptInit_ex(); we rely on it not trashing the context. + */ +static int +set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, + const unsigned char *key, + const unsigned char *iv) +{ + return EVP_DecryptInit(ctx, cipher, key, iv); +} +#endif + +static u_char * +do_decrypt(netdissect_options *ndo, const char *caller, struct sa_list *sa, + const u_char *iv, const u_char *ct, unsigned int ctlen) +{ + EVP_CIPHER_CTX *ctx; + unsigned int block_size; + unsigned int ptlen; + u_char *pt; + int len; + + ctx = EVP_CIPHER_CTX_new(); + if (ctx == NULL) { + /* + * Failed to initialize the cipher context. + * From a look at the OpenSSL code, this appears to + * mean "couldn't allocate memory for the cipher context"; + * note that we're not passing any parameters, so there's + * not much else it can mean. + */ + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't allocate memory for cipher context", caller); + return NULL; + } + + if (set_cipher_parameters(ctx, sa->evp, sa->secret, NULL) < 0) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_warning)(ndo, "%s: espkey init failed", caller); + return NULL; + } + if (set_cipher_parameters(ctx, NULL, NULL, iv) < 0) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_warning)(ndo, "%s: IV init failed", caller); + return NULL; + } + + /* + * At least as I read RFC 5996 section 3.14 and RFC 4303 section 2.4, + * if the cipher has a block size of which the ciphertext's size must + * be a multiple, the payload must be padded to make that happen, so + * the ciphertext length must be a multiple of the block size. Fail + * if that's not the case. + */ + block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx); + if ((ctlen % block_size) != 0) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_warning)(ndo, + "%s: ciphertext size %u is not a multiple of the cipher block size %u", + caller, ctlen, block_size); + return NULL; + } + + /* + * Attempt to allocate a buffer for the decrypted data, because + * we can't decrypt on top of the input buffer. + */ + ptlen = ctlen; + pt = (u_char *)calloc(1, ptlen); + if (pt == NULL) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't allocate memory for decryption buffer", caller); + return NULL; + } + + /* + * The size of the ciphertext handed to us is a multiple of the + * cipher block size, so we don't need to worry about padding. + */ + if (!EVP_CIPHER_CTX_set_padding(ctx, 0)) { + free(pt); + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_warning)(ndo, + "%s: EVP_CIPHER_CTX_set_padding failed", caller); + return NULL; + } + if (!EVP_DecryptUpdate(ctx, pt, &len, ct, ctlen)) { + free(pt); + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_warning)(ndo, "%s: EVP_DecryptUpdate failed", + caller); + return NULL; + } + EVP_CIPHER_CTX_free(ctx); + return pt; +} + +/* + * This will allocate a new buffer containing the decrypted data. + * It returns 1 on success and 0 on failure. + * + * It will push the new buffer and the values of ndo->ndo_packetp and + * ndo->ndo_snapend onto the buffer stack, and change ndo->ndo_packetp + * and ndo->ndo_snapend to refer to the new buffer. + * + * Our caller must pop the buffer off the stack when it's finished + * dissecting anything in it and before it does any dissection of + * anything in the old buffer. That will free the new buffer. + */ +DIAG_OFF_DEPRECATION +int esp_decrypt_buffer_by_ikev2_print(netdissect_options *ndo, + int initiator, + const u_char spii[8], + const u_char spir[8], + const u_char *buf, const u_char *end) +{ + struct sa_list *sa; + const u_char *iv; + const u_char *ct; + unsigned int ctlen; + u_char *pt; + + /* initiator arg is any non-zero value */ + if(initiator) initiator=1; + + /* see if we can find the SA, and if so, decode it */ + for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) { + if (sa->spi == 0 + && initiator == sa->initiator + && memcmp(spii, sa->spii, 8) == 0 + && memcmp(spir, sa->spir, 8) == 0) + break; + } + + if(sa == NULL) return 0; + if(sa->evp == NULL) return 0; + + /* + * remove authenticator, and see if we still have something to + * work with + */ + end = end - sa->authlen; + iv = buf; + ct = iv + sa->ivlen; + ctlen = end-ct; + + if(end <= ct) return 0; + + pt = do_decrypt(ndo, __func__, sa, iv, + ct, ctlen); + if (pt == NULL) + return 0; + + /* + * Switch to the output buffer for dissection, and save it + * on the buffer stack so it can be freed; our caller must + * pop it when done. + */ + if (!nd_push_buffer(ndo, pt, pt, ctlen)) { + free(pt); + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't push buffer on buffer stack", __func__); + } + + return 1; +} +DIAG_ON_DEPRECATION + +static void esp_print_addsa(netdissect_options *ndo, + const struct sa_list *sa, int sa_def) +{ + /* copy the "sa" */ + + struct sa_list *nsa; + + /* malloc() return used in a 'struct sa_list': do not free() */ + nsa = (struct sa_list *)malloc(sizeof(struct sa_list)); + if (nsa == NULL) + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: malloc", __func__); + + *nsa = *sa; + + if (sa_def) + ndo->ndo_sa_default = nsa; + + nsa->next = ndo->ndo_sa_list_head; + ndo->ndo_sa_list_head = nsa; +} + + +static u_int hexdigit(netdissect_options *ndo, 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 { + (*ndo->ndo_error)(ndo, S_ERR_ND_ESP_SECRET, + "invalid hex digit %c in espsecret\n", hex); + } +} + +static u_int hex2byte(netdissect_options *ndo, char *hexstring) +{ + u_int byte; + + byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]); + return byte; +} + +/* + * returns size of binary, 0 on failure. + */ +static int +espprint_decode_hex(netdissect_options *ndo, + u_char *binbuf, unsigned int binbuf_len, char *hex) +{ + unsigned int len; + int i; + + len = strlen(hex) / 2; + + if (len > binbuf_len) { + (*ndo->ndo_warning)(ndo, "secret is too big: %u\n", len); + return 0; + } + + i = 0; + while (hex[0] != '\0' && hex[1]!='\0') { + binbuf[i] = hex2byte(ndo, hex); + hex += 2; + i++; + } + + return i; +} + +/* + * decode the form: SPINUM@IP ALGONAME:0xsecret + */ + +DIAG_OFF_DEPRECATION +static int +espprint_decode_encalgo(netdissect_options *ndo, + char *decode, struct sa_list *sa) +{ + size_t i; + const EVP_CIPHER *evp; + int authlen = 0; + char *colon, *p; + + colon = strchr(decode, ':'); + if (colon == NULL) { + (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode); + return 0; + } + *colon = '\0'; + + 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) { + (*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode); + sa->evp = NULL; + sa->authlen = 0; + sa->ivlen = 0; + return 0; + } + + sa->evp = evp; + sa->authlen = authlen; + /* This returns an int, but it should never be negative */ + sa->ivlen = EVP_CIPHER_iv_length(evp); + + colon++; + if (colon[0] == '0' && colon[1] == 'x') { + /* decode some hex! */ + + colon += 2; + sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon); + if(sa->secretlen == 0) return 0; + } else { + i = strlen(colon); + + if (i < sizeof(sa->secret)) { + memcpy(sa->secret, colon, i); + sa->secretlen = i; + } else { + memcpy(sa->secret, colon, sizeof(sa->secret)); + sa->secretlen = sizeof(sa->secret); + } + } + + return 1; +} +DIAG_ON_DEPRECATION + +/* + * for the moment, ignore the auth algorithm, just hard code the authenticator + * length. Need to research how openssl looks up HMAC stuff. + */ +static int +espprint_decode_authalgo(netdissect_options *ndo, + char *decode, struct sa_list *sa) +{ + char *colon; + + colon = strchr(decode, ':'); + if (colon == NULL) { + (*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode); + return 0; + } + *colon = '\0'; + + if(ascii_strcasecmp(decode,"sha1") == 0 || + ascii_strcasecmp(decode,"md5") == 0) { + sa->authlen = 12; + } + return 1; +} + +static void esp_print_decode_ikeline(netdissect_options *ndo, char *line, + const char *file, int lineno) +{ + /* it's an IKEv2 secret, store it instead */ + struct sa_list sa1; + + char *init; + char *icookie, *rcookie; + int ilen, rlen; + char *authkey; + char *enckey; + + init = strsep(&line, " \t"); + icookie = strsep(&line, " \t"); + rcookie = strsep(&line, " \t"); + authkey = strsep(&line, " \t"); + enckey = strsep(&line, " \t"); + + /* if any fields are missing */ + if(!init || !icookie || !rcookie || !authkey || !enckey) { + (*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u", + file, lineno); + + return; + } + + ilen = strlen(icookie); + rlen = strlen(rcookie); + + if((init[0]!='I' && init[0]!='R') + || icookie[0]!='0' || icookie[1]!='x' + || rcookie[0]!='0' || rcookie[1]!='x' + || ilen!=18 + || rlen!=18) { + (*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.", + file, lineno); + + (*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)", + init, icookie, ilen, rcookie, rlen); + + return; + } + + sa1.spi = 0; + sa1.initiator = (init[0] == 'I'); + if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8) + return; + + if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8) + return; + + if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return; + + if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return; + + esp_print_addsa(ndo, &sa1, FALSE); +} + +/* + * + * special form: file /name + * causes us to go read from this file instead. + * + */ +static void esp_print_decode_onesecret(netdissect_options *ndo, char *line, + const char *file, int lineno) +{ + 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; + /* sa1.daddr.version = 0; */ + /* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */ + /* sa1.spi = 0; */ + sa_def = 1; + } else + decode = line; + + if (spikey && ascii_strcasecmp(spikey, "file") == 0) { + /* open file and read it */ + FILE *secretfile; + char fileline[1024]; + int subfile_lineno=0; + char *nl; + char *filename = line; + + secretfile = fopen(filename, FOPEN_READ_TXT); + if (secretfile == NULL) { + (*ndo->ndo_error)(ndo, S_ERR_ND_OPEN_FILE, + "%s: can't open %s: %s\n", + __func__, filename, strerror(errno)); + } + + while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) { + subfile_lineno++; + /* 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(ndo, fileline, filename, subfile_lineno); + } + fclose(secretfile); + + return; + } + + if (spikey && ascii_strcasecmp(spikey, "ikev2") == 0) { + esp_print_decode_ikeline(ndo, line, file, lineno); + return; + } + + if (spikey) { + + char *spistr, *foo; + uint32_t spino; + + spistr = strsep(&spikey, "@"); + if (spistr == NULL) { + (*ndo->ndo_warning)(ndo, "print_esp: failed to find the @ token"); + return; + } + + spino = strtoul(spistr, &foo, 0); + if (spistr == foo || !spikey) { + (*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo); + return; + } + + sa1.spi = spino; + + if (strtoaddr6(spikey, &sa1.daddr.in6) == 1) { + sa1.daddr_version = 6; + } else if (strtoaddr(spikey, &sa1.daddr.in4) == 1) { + sa1.daddr_version = 4; + } else { + (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey); + return; + } + } + + if (decode) { + /* skip any blank spaces */ + while (*decode == ' ' || *decode == '\t' || *decode == '\r' || *decode == '\n') + decode++; + + if(!espprint_decode_encalgo(ndo, decode, &sa1)) { + return; + } + } + + esp_print_addsa(ndo, &sa1, sa_def); +} + +DIAG_OFF_DEPRECATION +static void esp_init(netdissect_options *ndo _U_) +{ + /* + * 0.9.6 doesn't appear to define OPENSSL_API_COMPAT, so + * we check whether it's undefined or it's less than the + * value for 1.1.0. + */ +#if !defined(OPENSSL_API_COMPAT) || OPENSSL_API_COMPAT < 0x10100000L + OpenSSL_add_all_algorithms(); +#endif + EVP_add_cipher_alias(SN_des_ede3_cbc, "3des"); +} +DIAG_ON_DEPRECATION + +void esp_decodesecret_print(netdissect_options *ndo) +{ + char *line; + char *p; + static int initialized = 0; + + if (!initialized) { + esp_init(ndo); + initialized = 1; + } + + p = ndo->ndo_espsecret; + + while (p && p[0] != '\0') { + /* pick out the first line or first thing until a comma */ + if ((line = strsep(&p, "\n,")) == NULL) { + line = p; + p = NULL; + } + + esp_print_decode_onesecret(ndo, line, "cmdline", 0); + } + + ndo->ndo_espsecret = NULL; +} + +#endif + +#ifdef HAVE_LIBCRYPTO +#define USED_IF_LIBCRYPTO +#else +#define USED_IF_LIBCRYPTO _U_ +#endif + +#ifdef HAVE_LIBCRYPTO +DIAG_OFF_DEPRECATION +#endif +void +esp_print(netdissect_options *ndo, + const u_char *bp, u_int length, + const u_char *bp2 USED_IF_LIBCRYPTO, + u_int ver USED_IF_LIBCRYPTO, + int fragmented USED_IF_LIBCRYPTO, + u_int ttl_hl USED_IF_LIBCRYPTO) +{ + const struct newesp *esp; + const u_char *ep; +#ifdef HAVE_LIBCRYPTO + const struct ip *ip; + struct sa_list *sa = NULL; + const struct ip6_hdr *ip6 = NULL; + const u_char *iv; + u_int ivlen; + u_int payloadlen; + const u_char *ct; + u_char *pt; + u_int padlen; + u_int nh; +#endif + + ndo->ndo_protocol = "esp"; + esp = (const struct newesp *)bp; + + /* 'ep' points to the end of available data. */ + ep = ndo->ndo_snapend; + + if ((const u_char *)(esp + 1) >= ep) { + nd_print_trunc(ndo); + return; + } + ND_PRINT("ESP(spi=0x%08x", GET_BE_U_4(esp->esp_spi)); + ND_PRINT(",seq=0x%x)", GET_BE_U_4(esp->esp_seq)); + ND_PRINT(", length %u", length); + +#ifdef HAVE_LIBCRYPTO + /* initialize SAs */ + if (ndo->ndo_sa_list_head == NULL) { + if (!ndo->ndo_espsecret) + return; + + esp_decodesecret_print(ndo); + } + + if (ndo->ndo_sa_list_head == NULL) + return; + + ip = (const struct ip *)bp2; + switch (ver) { + case 6: + ip6 = (const struct ip6_hdr *)bp2; + /* we do not attempt to decrypt jumbograms */ + if (!GET_BE_U_2(ip6->ip6_plen)) + return; + /* XXX - check whether it's fragmented? */ + /* if we can't get nexthdr, we do not need to decrypt it */ + + /* see if we can find the SA, and if so, decode it */ + for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) { + if (sa->spi == GET_BE_U_4(esp->esp_spi) && + sa->daddr_version == 6 && + UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst, + sizeof(nd_ipv6)) == 0) { + break; + } + } + break; + case 4: + /* nexthdr & padding are in the last fragment */ + if (fragmented) + return; + + /* see if we can find the SA, and if so, decode it */ + for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) { + if (sa->spi == GET_BE_U_4(esp->esp_spi) && + sa->daddr_version == 4 && + UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst, + sizeof(nd_ipv4)) == 0) { + break; + } + } + break; + default: + return; + } + + /* if we didn't find the specific one, then look for + * an unspecified one. + */ + if (sa == NULL) + sa = ndo->ndo_sa_default; + + /* if not found fail */ + if (sa == NULL) + return; + + /* pointer to the IV, if there is one */ + iv = (const u_char *)(esp + 1) + 0; + /* length of the IV, if there is one; 0, if there isn't */ + ivlen = sa->ivlen; + + /* + * Get a pointer to the ciphertext. + * + * p points to the beginning of the payload, i.e. to the + * initialization vector, so if we skip past the initialization + * vector, it points to the beginning of the ciphertext. + */ + ct = iv + ivlen; + + /* + * Make sure the authentication data/integrity check value length + * isn't bigger than the total amount of data available after + * the ESP header and initialization vector is removed and, + * if not, slice the authentication data/ICV off. + */ + if (ep - ct < sa->authlen) { + nd_print_trunc(ndo); + return; + } + ep = ep - sa->authlen; + + /* + * Calculate the length of the ciphertext. ep points to + * the beginning of the authentication data/integrity check + * value, i.e. right past the end of the ciphertext; + */ + payloadlen = ep - ct; + + if (sa->evp == NULL) + return; + + /* + * If the next header value is past the end of the available + * data, we won't be able to fetch it once we've decrypted + * the ciphertext, so there's no point in decrypting the data. + * + * Report it as truncation. + */ + if (!ND_TTEST_1(ep - 1)) { + nd_print_trunc(ndo); + return; + } + + pt = do_decrypt(ndo, __func__, sa, iv, ct, payloadlen); + if (pt == NULL) + return; + + /* + * Switch to the output buffer for dissection, and + * save it on the buffer stack so it can be freed. + */ + if (!nd_push_buffer(ndo, pt, pt, payloadlen)) { + free(pt); + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't push buffer on buffer stack", __func__); + } + + /* + * Sanity check for pad length; if it, plus 2 for the pad + * length and next header fields, is bigger than the ciphertext + * length (which is also the plaintext length), it's too big. + * + * XXX - the check can fail if the packet is corrupt *or* if + * it was not decrypted with the correct key, so that the + * "plaintext" is not what was being sent. + */ + padlen = GET_U_1(pt + payloadlen - 2); + if (padlen + 2 > payloadlen) { + nd_print_trunc(ndo); + return; + } + + /* Get the next header */ + nh = GET_U_1(pt + payloadlen - 1); + + ND_PRINT(": "); + + /* + * Don't put padding + padding length(1 byte) + next header(1 byte) + * in the buffer because they are not part of the plaintext to decode. + */ + if (!nd_push_snaplen(ndo, pt, payloadlen - (padlen + 2))) { + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't push snaplen on buffer stack", __func__); + } + + /* Now dissect the plaintext. */ + ip_demux_print(ndo, pt, payloadlen - (padlen + 2), ver, fragmented, + ttl_hl, nh, bp2); + + /* Pop the buffer, freeing it. */ + nd_pop_packet_info(ndo); + /* Pop the nd_push_snaplen */ + nd_pop_packet_info(ndo); +#endif +} +#ifdef HAVE_LIBCRYPTO +DIAG_ON_DEPRECATION +#endif -- cgit v1.2.3