* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
+/* \summary: IPSEC Encapsulating Security Payload (ESP) printer */
+
#ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
#endif
-#include <tcpdump-stdinc.h>
+#include "netdissect-stdinc.h"
#include <string.h>
#include <stdlib.h>
#endif
#endif
-#include "ip.h"
-#ifdef INET6
-#include "ip6.h"
-#endif
-
-#include "interface.h"
+#include "netdissect.h"
+#include "strtoaddr.h"
#include "extract.h"
#include "ascii_strcasecmp.h"
+#include "ip.h"
+#include "ip6.h"
+
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* All rights reserved.
*/
struct newesp {
- uint32_t esp_spi; /* ESP */
- uint32_t esp_seq; /* Sequence number */
+ 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 */
#ifdef HAVE_LIBCRYPTO
union inaddr_u {
struct in_addr in4;
-#ifdef INET6
struct in6_addr in6;
-#endif
};
struct sa_list {
struct sa_list *next;
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_CIPHERINIT_EX
+/*
+ * Initialize the cipher by calling EVP_CipherInit_ex(), because
+ * calling EVP_CipherInit() 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_CipherInit_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_CipherInit_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, int enc)
+{
+ return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
+}
+#else
+/*
+ * Initialize the cipher by calling EVP_CipherInit(), because we don't
+ * have EVP_CipherInit_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, int enc)
+{
+ return EVP_CipherInit(ctx, cipher, key, iv, enc);
+}
+#endif
+
+/*
+ * 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 initiator,
- u_char spii[8], u_char spir[8],
+ 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;
- int len;
- EVP_CIPHER_CTX ctx;
+ const u_char *ct;
+ unsigned int len;
+ EVP_CIPHER_CTX *ctx;
+ unsigned int block_size, buffer_size;
+ u_char *input_buffer, *output_buffer;
+ const 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;
+ len = 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)
+ ctx = EVP_CIPHER_CTX_new();
+ if (ctx == NULL)
+ return 0;
+ if (set_cipher_parameters(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);
+ return 0;
+ }
+ if (set_cipher_parameters(ctx, NULL, NULL, iv, 0) < 0) {
+ (*ndo->ndo_warning)(ndo, "IV init failed");
+ return 0;
+ }
+ /*
+ * Allocate buffers for the encrypted and decrypted data.
+ * Both buffers' sizes must be a multiple of the cipher block
+ * size, and the output buffer must be separate from the input
+ * buffer.
+ */
+ block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
+ buffer_size = len + (block_size - len % block_size);
- ndo->ndo_packetp = buf;
- ndo->ndo_snapend = end;
+ /*
+ * Attempt to allocate the input buffer.
+ */
+ input_buffer = (u_char *)malloc(buffer_size);
+ if (input_buffer == NULL) {
+ EVP_CIPHER_CTX_free(ctx);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "can't allocate memory for encrypted data buffer");
+ }
+ /*
+ * Copy the input data to the encrypted data buffer, and pad it
+ * with zeroes.
+ */
+ memcpy(input_buffer, ct, len);
+ memset(input_buffer + len, 0, buffer_size - len);
- return 1;
+ /*
+ * Attempt to allocate the output buffer.
+ */
+ output_buffer = (u_char *)malloc(buffer_size);
+ if (output_buffer == NULL) {
+ free(input_buffer);
+ EVP_CIPHER_CTX_free(ctx);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "can't allocate memory for decryption buffer");
+ }
+ if (!EVP_Cipher(ctx, output_buffer, input_buffer, len)) {
+ (*ndo->ndo_warning)(ndo, "EVP_Cipher failed");
+ return 0;
+ }
+ EVP_CIPHER_CTX_free(ctx);
+
+ /*
+ * Free the input buffer; we no longer need it.
+ */
+ free(input_buffer);
+ /*
+ * Get a pointer to the plaintext.
+ */
+ pt = output_buffer;
+
+ /*
+ * 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, output_buffer, pt, pt + len)) {
+ free(output_buffer);
+ 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
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) {
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;
-#ifdef INET6
- if (inet_pton(AF_INET6, spikey, &sa1.daddr.in6) == 1) {
+ if (strtoaddr6(spikey, &sa1.daddr.in6) == 1) {
sa1.daddr_version = 6;
- } else
-#endif
- if (inet_pton(AF_INET, spikey, &sa1.daddr.in4) == 1) {
- sa1.daddr_version = 4;
- } else {
- (*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
- return;
- }
+ } 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) {
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
#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
const struct ip *ip;
struct sa_list *sa = NULL;
-#ifdef INET6
const struct ip6_hdr *ip6 = NULL;
-#endif
- int advance;
- int len;
- u_char *secret;
- int ivlen = 0;
- const u_char *ivoff;
- const u_char *p;
- EVP_CIPHER_CTX ctx;
+ const u_char *iv;
+ u_int ivlen;
+ const u_char *ct;
+ u_int ctlen;
+ EVP_CIPHER_CTX *ctx;
+ unsigned int block_size, buffer_size;
+ u_char *input_buffer, *output_buffer;
+ const u_char *pt;
+ u_int ptlen;
+ u_int padlen;
+ u_int nh;
#endif
+ ndo->ndo_protocol = "esp";
esp = (const struct newesp *)bp;
-#ifdef HAVE_LIBCRYPTO
- secret = NULL;
- advance = 0;
-#endif
-
-#if 0
- /* keep secret out of a register */
- p = (u_char *)&secret;
-#endif
-
/* 'ep' points to the end of available data. */
ep = ndo->ndo_snapend;
if ((const u_char *)(esp + 1) >= ep) {
- ND_PRINT((ndo, "[|ESP]"));
- goto fail;
+ nd_print_trunc(ndo);
+ return;
}
- ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi)));
- ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq)));
- ND_PRINT((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);
}
if (ndo->ndo_sa_list_head == NULL)
- goto fail;
+ return;
ip = (const struct ip *)bp2;
- switch (IP_V(ip)) {
-#ifdef INET6
+ switch (ver) {
case 6:
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) {
- if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
+ if (sa->spi == GET_BE_U_4(esp->esp_spi) &&
sa->daddr_version == 6 &&
UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst,
- sizeof(struct in6_addr)) == 0) {
+ 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) {
- if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
+ if (sa->spi == GET_BE_U_4(esp->esp_spi) &&
sa->daddr_version == 4 &&
UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst,
- sizeof(struct in_addr)) == 0) {
+ 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 = (const 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;
+ */
+ ctlen = ep - ct;
+
+ if (sa->evp == NULL)
+ return;
- 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 - (const u_char *)esp + ivlen;
- } else
- advance = sizeof(struct newesp);
+ /*
+ * 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;
+ }
+
+ 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,
+ "esp_print: can't allocate memory for cipher context");
+ }
+
+ if (set_cipher_parameters(ctx, sa->evp, sa->secret, NULL, 0) < 0) {
+ (*ndo->ndo_warning)(ndo, "espkey init failed");
+ return;
+ }
- /* sanity check for pad length */
- if (ep - bp < *(ep - 2))
- goto fail;
+ if (set_cipher_parameters(ctx, NULL, NULL, iv, 0) < 0) {
+ (*ndo->ndo_warning)(ndo, "IV init failed");
+ return;
+ }
- if (padlen)
- *padlen = *(ep - 2) + 2;
+ /*
+ * Allocate buffers for the encrypted and decrypted
+ * data. Both buffers' sizes must be a multiple of
+ * the cipher block size, and the output buffer must
+ * be separate from the input buffer.
+ */
+ block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
+ buffer_size = ctlen + (block_size - ctlen % block_size);
- if (nhdr)
- *nhdr = *(ep - 1);
+ /*
+ * Attempt to allocate the input buffer.
+ */
+ input_buffer = (u_char *)malloc(buffer_size);
+ if (input_buffer == NULL) {
+ EVP_CIPHER_CTX_free(ctx);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "esp_print: can't allocate memory for encrypted data buffer");
+ }
+ /*
+ * Copy the input data to the encrypted data buffer,
+ * and pad it with zeroes.
+ */
+ memcpy(input_buffer, ct, ctlen);
+ memset(input_buffer + ctlen, 0, buffer_size - ctlen);
- ND_PRINT((ndo, ": "));
- return advance;
-#endif
+ /*
+ * Attempt to allocate the output buffer.
+ */
+ output_buffer = (u_char *)malloc(buffer_size);
+ if (output_buffer == NULL) {
+ free(input_buffer);
+ EVP_CIPHER_CTX_free(ctx);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "esp_print: can't allocate memory for decryption buffer");
+ }
-fail:
- return -1;
+ if (!EVP_Cipher(ctx, output_buffer, input_buffer, ctlen)) {
+ free(input_buffer);
+ (*ndo->ndo_warning)(ndo, "EVP_Cipher failed");
+ return;
+ }
+ free(input_buffer);
+ EVP_CIPHER_CTX_free(ctx);
+
+ /*
+ * Pointer to the plaintext.
+ */
+ pt = output_buffer;
+
+ /*
+ * Length of the plaintext, which is the same as the length
+ * of the ciphertext.
+ */
+ ptlen = ctlen;
+
+ /*
+ * Switch to the output buffer for dissection, and
+ * save it on the buffer stack so it can be freed.
+ */
+ if (!nd_push_buffer(ndo, output_buffer, pt, pt + ctlen)) {
+ free(output_buffer);
+ (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+ "esp_print: can't push buffer on buffer stack");
+ }
+ ep = pt + ptlen;
+
+ /*
+ * 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 > ptlen) {
+ nd_print_trunc(ndo);
+ return;
+ }
+
+ /* Get the next header */
+ nh = GET_U_1(ep - 1);
+
+ ND_PRINT(": ");
+
+ /* Now dissect the plaintext. */
+ ip_print_demux(ndo, pt, ptlen - (padlen + 2), ver, fragmented,
+ ttl_hl, nh, bp2);
+
+ /* Pop the buffer, freeing it. */
+ nd_pop_buffer(ndo);
+#endif
}
#ifdef HAVE_LIBCRYPTO
USES_APPLE_RST
#endif
-
-/*
- * Local Variables:
- * c-style: whitesmith
- * c-basic-offset: 8
- * End:
- */
projects / tcpdump / blobdiff