const struct ip *ip;
struct sa_list *sa = NULL;
const struct ip6_hdr *ip6 = NULL;
- int advance;
- u_int ctlen;
- u_char *secret;
+ const u_char *ivptr;
u_int ivlen;
- const u_char *ivoff;
- const u_char *p;
+ const u_char *ctptr;
+ u_int ctlen;
EVP_CIPHER_CTX *ctx;
unsigned int block_size, buffer_size;
u_char *input_buffer, *output_buffer;
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;
return;
/* pointer to the IV, if there is one */
- ivoff = (const u_char *)(esp + 1) + 0;
+ ivptr = (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.
+ */
+ ctptr = ivptr + ivlen;
+
/*
* Make sure the authentication data/integrity check value length
- * isn't bigger than the total amount of data available and, if
- * not, slice that off.
+ * 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 - bp < sa->authlen) {
+ if (ep - ctptr < 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;
+ */
+ ctlen = ep - ctptr;
+
if (sa->evp == NULL)
return;
"esp_print: can't allocate memory for cipher context");
}
- if (set_cipher_parameters(ctx, sa->evp, secret, NULL, 0) < 0) {
+ if (set_cipher_parameters(ctx, sa->evp, sa->secret, NULL, 0) < 0) {
(*ndo->ndo_warning)(ndo, "espkey init failed");
return;
}
- p = ivoff;
- if (set_cipher_parameters(ctx, NULL, NULL, p, 0) < 0) {
+ if (set_cipher_parameters(ctx, NULL, NULL, ivptr, 0) < 0) {
(*ndo->ndo_warning)(ndo, "IV init failed");
return;
}
- /*
- * 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; 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.
- */
- ctlen = ep - (p + ivlen);
-
/*
* Allocate buffers for the encrypted and decrypted
* data. Both buffers' sizes must be a multiple of
* Copy the input data to the encrypted data buffer,
* and pad it with zeroes.
*/
- memcpy(input_buffer, p + ivlen, ctlen);
+ memcpy(input_buffer, ctptr, ctlen);
memset(input_buffer + ctlen, 0, buffer_size - ctlen);
/*
* const buffer, but changing this would require a
* more complicated fix.
*/
- memcpy(p + ivlen, output_buffer, ctlen);
+ memcpy(ctptr, output_buffer, ctlen);
free(output_buffer);
- advance = ivoff - (const u_char *)esp + ivlen;
/*
- * Sanity check for pad length.
+ * 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 (ep - bp < padlen) {
- nd_print_trunc(ndo);
- return;
- }
-
- /*
- * Sanity check for payload length; +2 is for the pad length
- * and next header fields.
- *
- * 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.
- */
- if (length <= advance + padlen + 2) {
+ if (padlen + 2 > ctlen) {
nd_print_trunc(ndo);
return;
}
- bp += advance;
- length -= advance + padlen + 2;
/* Get the next header */
nh = GET_U_1(ep - 1);
ND_PRINT(": ");
/* Now print the payload. */
- ip_print_demux(ndo, bp, length, ver, fragmented, ttl_hl, nh, bp2);
+ ip_print_demux(ndo, ctptr, ctlen - (padlen + 2), ver, fragmented,
+ ttl_hl, nh, bp2);
#endif
}
#ifdef HAVE_LIBCRYPTO
1 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x1), length 116 [|esp]
- 2 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x2), length 116: ip-proto-227 49
- 3 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x3), length 116: PIMv13, length 10
+ 2 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x2), length 116: ip-proto-227 37
+ 3 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x3), length 116 [|esp]
4 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x4), length 116 [|esp]
5 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x5), length 116 [|esp]
- 6 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x6), length 116: ip-proto-183 28
- 7 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x7), length 116: ip-proto-72 34
- 8 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x8), length 116: ip-proto-224 59
+ 6 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x6), length 116: ip-proto-183 16
+ 7 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x7), length 116: ip-proto-72 22
+ 8 00:00:00.000000 IP 192.1.2.23.4500 > 192.1.2.45.4500: UDP-encap: ESP(spi=0x12345678,seq=0x8), length 116: ip-proto-224 47
projects / tcpdump / commitdiff
