* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
-#ifndef lint
-static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.58 2007-12-07 00:03:07 mcr Exp $ (LBL)";
-#endif
+/* \summary: IPSEC Encapsulating Security Payload (ESP) printer */
#ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
#endif
-#include <string.h>
-
-#include <tcpdump-stdinc.h>
+#include "netdissect-stdinc.h"
+#include <string.h>
#include <stdlib.h>
/* Any code in this file that depends on HAVE_LIBCRYPTO depends on
#endif
#endif
-#include <stdio.h>
+#include "netdissect.h"
+#include "extract.h"
+
+#ifdef HAVE_LIBCRYPTO
+#include "strtoaddr.h"
+#include "ascii_strcasecmp.h"
+#endif
#include "ip.h"
-#include "esp.h"
-#ifdef INET6
#include "ip6.h"
-#endif
-#include "netdissect.h"
-#include "addrtoname.h"
-#include "extract.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.
+ */
-#ifndef HAVE_SOCKADDR_STORAGE
-#ifdef INET6
-struct sockaddr_storage {
- union {
- struct sockaddr_in sin;
- struct sockaddr_in6 sin6;
- } un;
+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 */
};
-#else
-#define sockaddr_storage sockaddr
-#endif
-#endif /* HAVE_SOCKADDR_STORAGE */
#ifdef HAVE_LIBCRYPTO
+union inaddr_u {
+ nd_ipv4 in4;
+ nd_ipv6 in6;
+};
struct sa_list {
struct sa_list *next;
- struct sockaddr_storage daddr;
- u_int32_t spi; /* if == 0, then IKEv2 */
+ 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;
- int ivlen;
+ u_int ivlen;
int authlen;
u_char authsecret[256];
int authsecret_len;
int secretlen;
};
+#ifndef HAVE_EVP_CIPHER_CTX_NEW
/*
- * this will adjust ndo_packetp and ndo_snapend to new buffer!
+ * 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 *)malloc(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.
*/
USES_APPLE_DEPRECATED_API
-int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
+int esp_decrypt_buffer_by_ikev2_print(netdissect_options *ndo,
int initiator,
- u_char spii[8], u_char spir[8],
- u_char *buf, u_char *end)
+ const u_char spii[8],
+ const u_char spir[8],
+ const u_char *buf, const u_char *end)
{
struct sa_list *sa;
- u_char *iv;
- int len;
- EVP_CIPHER_CTX ctx;
+ 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;
*/
end = end - sa->authlen;
iv = buf;
- buf = buf + sa->ivlen;
- len = end-buf;
+ ct = iv + sa->ivlen;
+ ctlen = end-ct;
- if(end <= buf) return 0;
+ if(end <= ct) return 0;
- memset(&ctx, 0, sizeof(ctx));
- if (EVP_CipherInit(&ctx, sa->evp, sa->secret, NULL, 0) < 0)
- (*ndo->ndo_warning)(ndo, "espkey init failed");
- EVP_CipherInit(&ctx, NULL, NULL, iv, 0);
- EVP_Cipher(&ctx, buf, buf, len);
- EVP_CIPHER_CTX_cleanup(&ctx);
+ pt = do_decrypt(ndo, "esp_decrypt_buffer_by_ikev2_print", sa, iv,
+ ct, ctlen);
+ if (pt == NULL)
+ return 0;
- ndo->ndo_packetp = buf;
- ndo->ndo_snapend = end;
+ /*
+ * 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, pt + ctlen)) {
+ free(pt);
+ return 0;
+ }
return 1;
-
}
USES_APPLE_RST
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, "ran out of memory to allocate sa structure");
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "esp_print_addsa: malloc");
*nsa = *sa;
else if (hex >= 'a' && hex <= 'f')
return (hex - 'a' + 10);
else {
- (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
- return 0;
+ (*ndo->ndo_error)(ndo, S_ERR_ND_ESP_SECRET,
+ "invalid hex digit %c in espsecret\n", hex);
}
}
len = strlen(hex) / 2;
if (len > binbuf_len) {
- (*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
+ (*ndo->ndo_warning)(ndo, "secret is too big: %u\n", len);
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++;
USES_APPLE_RST
/*
- * for the moment, ignore the auth algorith, just hard code the authenticator
+ * for the moment, ignore the auth algorithm, just hard code the authenticator
* length. Need to research how openssl looks up HMAC stuff.
*/
static int
}
*colon = '\0';
- if(strcasecmp(colon,"sha1") == 0 ||
- strcasecmp(colon,"md5") == 0) {
+ if(ascii_strcasecmp(decode,"sha1") == 0 ||
+ ascii_strcasecmp(decode,"md5") == 0) {
sa->authlen = 12;
}
return 1;
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 && strcasecmp(spikey, "file") == 0) {
+ if (spikey && ascii_strcasecmp(spikey, "file") == 0) {
/* open file and read it */
FILE *secretfile;
char fileline[1024];
- int lineno=0;
+ int subfile_lineno=0;
char *nl;
char *filename = line;
secretfile = fopen(filename, FOPEN_READ_TXT);
if (secretfile == NULL) {
- perror(filename);
- exit(3);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_OPEN_FILE,
+ "print_esp: can't open %s: %s\n",
+ filename, strerror(errno));
}
while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
- lineno++;
+ subfile_lineno++;
/* remove newline from the line */
nl = strchr(fileline, '\n');
if (nl)
if (fileline[0] == '#') continue;
if (fileline[0] == '\0') continue;
- esp_print_decode_onesecret(ndo, fileline, filename, lineno);
+ esp_print_decode_onesecret(ndo, fileline, filename, subfile_lineno);
}
fclose(secretfile);
return;
}
- if (spikey && strcasecmp(spikey, "ikev2") == 0) {
+ if (spikey && ascii_strcasecmp(spikey, "ikev2") == 0) {
esp_print_decode_ikeline(ndo, line, file, lineno);
return;
}
if (spikey) {
char *spistr, *foo;
- u_int32_t spino;
- struct sockaddr_in *sin;
-#ifdef INET6
- struct sockaddr_in6 *sin6;
-#endif
+ 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) {
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 {
- (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
- return;
- }
+ 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 (isspace((unsigned char)*decode))
+ while (*decode == ' ' || *decode == '\t' || *decode == '\r' || *decode == '\n')
decode++;
if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
USES_APPLE_DEPRECATED_API
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");
}
USES_APPLE_RST
-void esp_print_decodesecret(netdissect_options *ndo)
+void esp_decodesecret_print(netdissect_options *ndo)
{
char *line;
char *p;
#endif
+#ifdef HAVE_LIBCRYPTO
+#define USED_IF_LIBCRYPTO
+#else
+#define USED_IF_LIBCRYPTO _U_
+#endif
+
#ifdef HAVE_LIBCRYPTO
USES_APPLE_DEPRECATED_API
#endif
-int
+void
esp_print(netdissect_options *ndo,
- const u_char *bp, const int length, const u_char *bp2
-#ifndef HAVE_LIBCRYPTO
- _U_
-#endif
- ,
- int *nhdr
-#ifndef HAVE_LIBCRYPTO
- _U_
-#endif
- ,
- int *padlen
-#ifndef HAVE_LIBCRYPTO
- _U_
-#endif
- )
+ 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)
{
- register const struct newesp *esp;
- register const u_char *ep;
+ const struct newesp *esp;
+ const u_char *ep;
#ifdef HAVE_LIBCRYPTO
- struct ip *ip;
+ const struct ip *ip;
struct sa_list *sa = NULL;
-#ifdef INET6
- struct ip6_hdr *ip6 = NULL;
-#endif
- int advance;
- int len;
- u_char *secret;
- int ivlen = 0;
- u_char *ivoff;
- u_char *p;
- EVP_CIPHER_CTX ctx;
+ 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
- esp = (struct newesp *)bp;
-
-#ifdef HAVE_LIBCRYPTO
- secret = NULL;
- advance = 0;
-#endif
-
-#if 0
- /* keep secret out of a register */
- p = (u_char *)&secret;
-#endif
+ ndo->ndo_protocol = "esp";
+ esp = (const struct newesp *)bp;
/* 'ep' points to the end of available data. */
ep = ndo->ndo_snapend;
- if ((u_char *)(esp + 1) >= ep) {
- fputs("[|ESP]", stdout);
- goto fail;
+ if ((const u_char *)(esp + 1) >= ep) {
+ nd_print_trunc(ndo);
+ return;
}
- (*ndo->ndo_printf)(ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
- (*ndo->ndo_printf)(ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq));
- (*ndo->ndo_printf)(ndo, ", length %u", length);
+ 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);
-#ifndef HAVE_LIBCRYPTO
- goto fail;
-#else
+#ifdef HAVE_LIBCRYPTO
/* initiailize SAs */
if (ndo->ndo_sa_list_head == NULL) {
if (!ndo->ndo_espsecret)
- goto fail;
+ return;
- esp_print_decodesecret(ndo);
+ esp_decodesecret_print(ndo);
}
if (ndo->ndo_sa_list_head == NULL)
- goto fail;
+ return;
- ip = (struct ip *)bp2;
- switch (IP_V(ip)) {
-#ifdef INET6
+ ip = (const struct ip *)bp2;
+ switch (ver) {
case 6:
- ip6 = (struct ip6_hdr *)bp2;
+ ip6 = (const struct ip6_hdr *)bp2;
/* we do not attempt to decrypt jumbograms */
- if (!EXTRACT_16BITS(&ip6->ip6_plen))
- goto fail;
+ 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 */
- len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
/* see if we can find the SA, and if so, decode it */
for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
- struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr;
- if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
- sin6->sin6_family == AF_INET6 &&
- memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
- sizeof(struct in6_addr)) == 0) {
+ 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;
-#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);
+ 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) {
- struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr;
- if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
- sin->sin_family == AF_INET &&
- sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
+ 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:
- goto fail;
+ return;
}
/* if we didn't find the specific one, then look for
/* 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;
- }
+ return;
- ivoff = (u_char *)(esp + 1) + 0;
+ /* 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;
- secret = sa->secret;
+
+ /*
+ * 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;
- if (sa->evp) {
- memset(&ctx, 0, sizeof(ctx));
- if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
- (*ndo->ndo_warning)(ndo, "espkey init failed");
+ /*
+ * 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;
- p = ivoff;
- EVP_CipherInit(&ctx, NULL, NULL, p, 0);
- EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
- EVP_CIPHER_CTX_cleanup(&ctx);
- advance = ivoff - (u_char *)esp + ivlen;
- } else
- advance = sizeof(struct newesp);
+ if (sa->evp == NULL)
+ return;
- /* sanity check for pad length */
- if (ep - bp < *(ep - 2))
- goto fail;
+ /*
+ * 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;
+ }
- if (padlen)
- *padlen = *(ep - 2) + 2;
+ pt = do_decrypt(ndo, "esp_print", sa, iv, ct, payloadlen);
+ if (pt == NULL)
+ return;
- if (nhdr)
- *nhdr = *(ep - 1);
+ /*
+ * Switch to the output buffer for dissection, and
+ * save it on the buffer stack so it can be freed.
+ */
+ ep = pt + payloadlen;
+ if (!nd_push_buffer(ndo, pt, pt, ep)) {
+ free(pt);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "esp_print: can't push buffer on buffer stack");
+ }
- (ndo->ndo_printf)(ndo, ": ");
- return advance;
-#endif
+ /*
+ * 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(ep - 2);
+ if (padlen + 2 > payloadlen) {
+ nd_print_trunc(ndo);
+ return;
+ }
+
+ /* Get the next header */
+ nh = GET_U_1(ep - 1);
+
+ ND_PRINT(": ");
+
+ /* Now dissect the plaintext. */
+ ip_demux_print(ndo, pt, payloadlen - (padlen + 2), ver, fragmented,
+ ttl_hl, nh, bp2);
-fail:
- return -1;
+ /* Pop the buffer, freeing it. */
+ nd_pop_packet_info(ndo);
+#endif
}
#ifdef HAVE_LIBCRYPTO
USES_APPLE_RST
#endif
-
-/*
- * Local Variables:
- * c-style: whitesmith
- * c-basic-offset: 8
- * End:
- */
projects / tcpdump / blobdiff