You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

204 lines
6.2 KiB

/**
* (C) 2007-20 - ntop.org and contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not see see <http://www.gnu.org/licenses/>
*
*/
#include "n2n.h"
#define N2N_SPECK_IVEC_SIZE 16
#define SPECK_KEY_BYTES (256/8)
/* Speck plaintext preamble */
#define TRANSOP_SPECK_PREAMBLE_SIZE (N2N_SPECK_IVEC_SIZE)
typedef unsigned char n2n_speck_ivec_t[N2N_SPECK_IVEC_SIZE];
typedef struct transop_speck {
speck_context_t ctx; /* the round keys for payload encryption & decryption */
} transop_speck_t;
/* ****************************************************** */
static int transop_deinit_speck(n2n_trans_op_t *arg) {
transop_speck_t *priv = (transop_speck_t *)arg->priv;
if(priv)
#if defined (SPECK_ALIGNED_CTX)
_mm_free (priv);
#else
free (priv);
#endif
return 0;
}
/* ****************************************************** */
static void set_speck_iv(transop_speck_t *priv, n2n_speck_ivec_t ivec) {
// keep in mind the following condition: N2N_SPECK_IVEC_SIZE % sizeof(rand_value) == 0 !
uint64_t rand_value;
uint8_t i;
for (i = 0; i < N2N_SPECK_IVEC_SIZE; i += sizeof(rand_value)) {
rand_value = n2n_rand();
memcpy(ivec + i, &rand_value, sizeof(rand_value));
}
}
/* ****************************************************** */
/** The Speck packet format consists of:
*
* - a 128-bit random IV
* - encrypted payload.
*
* [IIII|DDDDDDDDDDDDDDDDDDDDD]
* |<---- encrypted ---->|
*/
static int transop_encode_speck(n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac) {
int len=-1;
transop_speck_t * priv = (transop_speck_t *)arg->priv;
if(in_len <= N2N_PKT_BUF_SIZE) {
if((in_len + TRANSOP_SPECK_PREAMBLE_SIZE) <= out_len) {
size_t idx=0;
n2n_speck_ivec_t enc_ivec = {0};
traceEvent(TRACE_DEBUG, "encode_speck %lu bytes", in_len);
/* Generate and encode the IV. */
set_speck_iv(priv, enc_ivec);
encode_buf(outbuf, &idx, &enc_ivec, N2N_SPECK_IVEC_SIZE);
/* Encrypt the payload and write the ciphertext after the iv. */
/* len is set to the length of the cipher plain text to be encrpyted
which is (in this case) identical to original packet lentgh */
len = in_len;
speck_ctr (outbuf + TRANSOP_SPECK_PREAMBLE_SIZE, inbuf, in_len, enc_ivec,
#if defined (SPECK_CTX_BYVAL)
(priv->ctx));
#else
&(priv->ctx));
#endif
traceEvent(TRACE_DEBUG, "encode_speck: encrypted %u bytes.\n", in_len);
len += TRANSOP_SPECK_PREAMBLE_SIZE; /* size of data carried in UDP. */
} else
traceEvent(TRACE_ERROR, "encode_speck outbuf too small.");
} else
traceEvent(TRACE_ERROR, "encode_speck inbuf too big to encrypt.");
return len;
}
/* ****************************************************** */
/* See transop_encode_speck for packet format */
static int transop_decode_speck(n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac) {
int len=0;
transop_speck_t * priv = (transop_speck_t *)arg->priv;
if(((in_len - TRANSOP_SPECK_PREAMBLE_SIZE) <= N2N_PKT_BUF_SIZE) /* Cipher text fits in buffer */
&& (in_len >= TRANSOP_SPECK_PREAMBLE_SIZE) /* Has at least iv */
)
{
size_t rem=in_len;
size_t idx=0;
n2n_speck_ivec_t dec_ivec = {0};
traceEvent(TRACE_DEBUG, "decode_speck %lu bytes", in_len);
len = (in_len - TRANSOP_SPECK_PREAMBLE_SIZE);
/* Get the IV */
decode_buf((uint8_t *)&dec_ivec, N2N_SPECK_IVEC_SIZE, inbuf, &rem, &idx);
speck_ctr (outbuf, inbuf + TRANSOP_SPECK_PREAMBLE_SIZE, len, dec_ivec,
#if defined (SPECK_CTX_BYVAL)
(priv->ctx));
#else
&(priv->ctx));
#endif
traceEvent(TRACE_DEBUG, "decode_speck: decrypted %u bytes.\n", len);
} else
traceEvent(TRACE_ERROR, "decode_speck inbuf wrong size (%ul) to decrypt.", in_len);
return len;
}
/* ****************************************************** */
static int setup_speck_key(transop_speck_t *priv, const uint8_t *key, ssize_t key_size) {
uint8_t key_mat_buf[32] = { 0x00 };
/* Clear out any old possibly longer key matter. */
memset(&(priv->ctx), 0, sizeof(speck_context_t) );
/* the input key always gets hashed to make a more unpredictable and more complete use of the key space */
pearson_hash_256 (key_mat_buf, key, key_size);
/* expand the key material to the context (= round keys) */
speck_expand_key (key_mat_buf, &(priv->ctx));
traceEvent(TRACE_DEBUG, "Speck key setup completed\n");
return(0);
}
/* ****************************************************** */
static void transop_tick_speck(n2n_trans_op_t * arg, time_t now) { ; }
/* ****************************************************** */
/* Speck initialization function */
int n2n_transop_speck_init(const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) {
transop_speck_t *priv;
const u_char *encrypt_key = (const u_char *)conf->encrypt_key;
size_t encrypt_key_len = strlen(conf->encrypt_key);
memset(ttt, 0, sizeof(*ttt));
ttt->transform_id = N2N_TRANSFORM_ID_SPECK;
ttt->tick = transop_tick_speck;
ttt->deinit = transop_deinit_speck;
ttt->fwd = transop_encode_speck;
ttt->rev = transop_decode_speck;
#if defined (SPECK_ALIGNED_CTX)
priv = (transop_speck_t*) _mm_malloc (sizeof(transop_speck_t), SPECK_ALIGNED_CTX);
#else
priv = (transop_speck_t*) calloc (1, sizeof(transop_speck_t));
#endif
if(!priv) {
traceEvent(TRACE_ERROR, "cannot allocate transop_speck_t memory");
return(-1);
}
ttt->priv = priv;
/* Setup the cipher and key */
return(setup_speck_key(priv, encrypt_key, encrypt_key_len));
}