"Fossies" - the Fresh Open Source Software Archive  

Source code changes of the file "src/transform_cc20.c" between
n2n-2.8.tar.gz and n2n-3.0.tar.gz

About: n2n is a layer-two peer-to-peer virtual private network (VPN) which allows bypassing intermediate firewalls.

transform_cc20.c  (n2n-2.8):transform_cc20.c  (n2n-3.0)
/** /**
* (C) 2007-20 - ntop.org and contributors * (C) 2007-21 - ntop.org and contributors
* *
* This program is free software; you can redistribute it and/or modify * 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 * it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or * the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version. * (at your option) any later version.
* *
* This program is distributed in the hope that it will be useful, * This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of * but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details. * GNU General Public License for more details.
* *
* You should have received a copy of the GNU General Public License * 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/> * along with this program; if not see see <http://www.gnu.org/licenses/>
* *
*/ */
#include "n2n.h" #include "n2n.h"
#ifdef HAVE_OPENSSL_1_1 // ChaCha20 plaintext preamble
#define CC20_PREAMBLE_SIZE (CC20_IV_SIZE)
#include <openssl/sha.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#define N2N_CC20_TRANSFORM_VERSION 1 /* version of the transform encoding
*/
#define N2N_CC20_IVEC_SIZE 16
#define CC20_KEY_BYTES (256/8)
/* ChaCha20 plaintext preamble */
#define TRANSOP_CC20_VER_SIZE 1 /* Support minor variants in encoding
in one module. */
#define TRANSOP_CC20_PREAMBLE_SIZE (TRANSOP_CC20_VER_SIZE + N2N_CC20_IVEC_SIZE)
typedef unsigned char n2n_cc20_ivec_t[N2N_CC20_IVEC_SIZE];
typedef struct transop_cc20 { typedef struct transop_cc20 {
EVP_CIPHER_CTX *enc_ctx; /* openssl's reusable evp_* encrypt cc20_context_t *ctx;
ion context */
EVP_CIPHER_CTX *dec_ctx; /* openssl's reusable evp_* decrypt
ion context */
const EVP_CIPHER *cipher; /* cipher to use: EVP_chacha20() */
uint8_t key[32]; /* the pure key data for payload encryption
& decryption */
} transop_cc20_t; } transop_cc20_t;
/* ****************************************************** */ static int transop_deinit_cc20 (n2n_trans_op_t *arg) {
static int transop_deinit_cc20(n2n_trans_op_t *arg) { transop_cc20_t *priv = (transop_cc20_t *)arg->priv;
transop_cc20_t *priv = (transop_cc20_t *)arg->priv;
EVP_CIPHER_CTX_free(priv->enc_ctx); if(priv->ctx)
EVP_CIPHER_CTX_free(priv->dec_ctx); cc20_deinit(priv->ctx);
if(priv) if(priv)
free(priv); free(priv);
return 0;
}
// the ChaCha20 packet format consists of
//
// - a 128-bit random iv
// - encrypted payload
//
// [IIII|DDDDDDDDDDDDDDDDDDDDD]
// |<---- encrypted ---->|
//
static int transop_encode_cc20 (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_cc20_t *priv = (transop_cc20_t *)arg->priv;
if(in_len <= N2N_PKT_BUF_SIZE) {
if((in_len + CC20_PREAMBLE_SIZE) <= out_len) {
size_t idx = 0;
traceEvent(TRACE_DEBUG, "encode_cc20 %lu bytes", in_len);
// full iv sized random value (128 bit)
encode_uint64(outbuf, &idx, n2n_rand());
encode_uint64(outbuf, &idx, n2n_rand());
len = in_len;
cc20_crypt(outbuf + CC20_PREAMBLE_SIZE,
inbuf,
in_len,
outbuf, /* iv */
priv->ctx);
// size of datacarried in UDP
len += CC20_PREAMBLE_SIZE;
} else
traceEvent(TRACE_ERROR, "encode_cc20 outbuf too small.");
} else
traceEvent(TRACE_ERROR, "encode_cc20 inbuf too big to encrypt.");
return 0; return len;
} }
/* ****************************************************** */ // see transop_encode_cc20 for packet format
static int transop_decode_cc20 (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) {
/* get any erorr message out of openssl int len = 0;
taken from https://en.wikibooks.org/wiki/OpenSSL/Error_handling */ transop_cc20_t *priv = (transop_cc20_t *)arg->priv;
static char *openssl_err_as_string (void) {
BIO *bio = BIO_new (BIO_s_mem ());
ERR_print_errors (bio);
char *buf = NULL;
size_t len = BIO_get_mem_data (bio, &buf);
char *ret = (char *) calloc (1, 1 + len);
if(ret) if(((in_len - CC20_PREAMBLE_SIZE) <= N2N_PKT_BUF_SIZE) /* cipher text fits i
memcpy (ret, buf, len); n assembly */
&& (in_len >= CC20_PREAMBLE_SIZE)) { /* has at least iv */
BIO_free (bio); traceEvent(TRACE_DEBUG, "decode_cc20 %lu bytes", in_len);
return ret;
}
/* ****************************************************** */
static void set_cc20_iv(transop_cc20_t *priv, n2n_cc20_ivec_t ivec) {
// keep in mind the following condition: N2N_CC20_IVEC_SIZE % sizeof(rand_valu
e) == 0 !
uint64_t rand_value;
for (uint8_t i = 0; i < N2N_CC20_IVEC_SIZE; i += sizeof(rand_value)) {
rand_value = n2n_rand();
memcpy(ivec + i, &rand_value, sizeof(rand_value));
}
}
/* ****************************************************** */ len = (in_len - CC20_PREAMBLE_SIZE);
/** The ChaCha20 packet format consists of: cc20_crypt(outbuf,
* inbuf + CC20_PREAMBLE_SIZE,
* - a 8-bit cc20 encoding version in clear text in_len,
* - a 128-bit random IV inbuf, /* iv */
* - encrypted payload. priv->ctx);
*
* [V|IIII|DDDDDDDDDDDDDDDDDDDDD]
* |<---- encrypted ---->|
*/
static int transop_encode_cc20(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_cc20_t * priv = (transop_cc20_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE] = {0};
if(in_len <= N2N_PKT_BUF_SIZE) {
if((in_len + TRANSOP_CC20_PREAMBLE_SIZE) <= out_len) {
size_t idx=0;
n2n_cc20_ivec_t enc_ivec = {0};
traceEvent(TRACE_DEBUG, "encode_cc20 %lu bytes", in_len);
/* Encode the ChaCha20 format version. */
encode_uint8(outbuf, &idx, N2N_CC20_TRANSFORM_VERSION);
/* Generate and encode the IV. */
set_cc20_iv(priv, enc_ivec);
encode_buf(outbuf, &idx, &enc_ivec, N2N_CC20_IVEC_SIZE);
/* Encrypt the assembly contents 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;
/* The assembly buffer is a source for encrypting data.
* The whole contents of assembly are encrypted. */
memcpy(assembly, inbuf, in_len);
EVP_CIPHER_CTX *ctx = priv->enc_ctx;
int evp_len;
int evp_ciphertext_len;
if(1 == EVP_EncryptInit_ex(ctx, priv->cipher, NULL, priv->key, enc_ivec))
{
if(1 == EVP_CIPHER_CTX_set_padding(ctx, 0)) {
if(1 == EVP_EncryptUpdate(ctx, outbuf + TRANSOP_CC20_PREAMBLE_SIZE, &ev
p_len, assembly, len)) {
evp_ciphertext_len = evp_len;
if(1 == EVP_EncryptFinal_ex(ctx, outbuf + TRANSOP_CC20_PREAMBLE_SIZE
+ evp_len, &evp_len)) {
evp_ciphertext_len += evp_len;
if(evp_ciphertext_len != len)
traceEvent(TRACE_ERROR, "encode_cc20 openssl encryption: encrypte
d %u bytes where %u were expected.\n",
evp_ciphertext_len, len);
} else
traceEvent(TRACE_ERROR, "encode_cc20 openssl final encryption: %s\n
", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_cc20 openssl encrpytion: %s\n", opens
sl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_cc20 openssl padding setup: %s\n", open
ssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_cc20 openssl init: %s\n", openssl_err_as_
string());
EVP_CIPHER_CTX_reset(ctx);
len += TRANSOP_CC20_PREAMBLE_SIZE; /* size of data carried in UDP. */
} else } else
traceEvent(TRACE_ERROR, "encode_cc20 outbuf too small."); traceEvent(TRACE_ERROR, "decode_cc20 inbuf wrong size (%ul) to decrypt."
} else , in_len);
traceEvent(TRACE_ERROR, "encode_cc20 inbuf too big to encrypt.");
return len; return len;
} }
/* ****************************************************** */ static int setup_cc20_key (transop_cc20_t *priv, const uint8_t *password, ssize_ t password_len) {
/* See transop_encode_cc20 for packet format */ uint8_t key_mat[CC20_KEY_BYTES];
static int transop_decode_cc20(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_cc20_t * priv = (transop_cc20_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE];
if(((in_len - TRANSOP_CC20_PREAMBLE_SIZE) <= N2N_PKT_BUF_SIZE) /* Cipher text
fits in assembly */
&& (in_len >= TRANSOP_CC20_PREAMBLE_SIZE) /* Has at least version, iv */
)
{
size_t rem=in_len;
size_t idx=0;
uint8_t cc20_enc_ver=0;
n2n_cc20_ivec_t dec_ivec = {0};
/* Get the encoding version to make sure it is supported */
decode_uint8(&cc20_enc_ver, inbuf, &rem, &idx );
if(N2N_CC20_TRANSFORM_VERSION == cc20_enc_ver) {
traceEvent(TRACE_DEBUG, "decode_cc20 %lu bytes", in_len);
len = (in_len - TRANSOP_CC20_PREAMBLE_SIZE);
/* Get the IV */
decode_buf((uint8_t *)&dec_ivec, N2N_CC20_IVEC_SIZE, inbuf, &rem, &idx);
EVP_CIPHER_CTX *ctx = priv->dec_ctx;
int evp_len;
int evp_plaintext_len;
if(1 == EVP_DecryptInit_ex(ctx, priv->cipher, NULL, priv->key, dec_ivec))
{
if(1 == EVP_CIPHER_CTX_set_padding(ctx, 0)) {
if(1 == EVP_DecryptUpdate(ctx, assembly, &evp_len, inbuf + TRANSOP_CC20
_PREAMBLE_SIZE, len)) {
evp_plaintext_len = evp_len;
if(1 == EVP_DecryptFinal_ex(ctx, assembly + evp_len, &evp_len)) {
evp_plaintext_len += evp_len;
if(evp_plaintext_len != len)
traceEvent(TRACE_ERROR, "decode_cc20 openssl decryption: decrypte
d %u bytes where %u were expected.\n",
evp_plaintext_len, len);
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl final decryption: %s\n
", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl decrpytion: %s\n", opens
sl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl padding setup: %s\n", open
ssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl init: %s\n", openssl_err_as
_string());
EVP_CIPHER_CTX_reset(ctx); // the input key always gets hashed to make a more unpredictable and more co
mplete use of the key space
pearson_hash_256(key_mat, password, password_len);
memcpy(outbuf, assembly, len); if(cc20_init(key_mat, &(priv->ctx))) {
} else traceEvent(TRACE_ERROR, "setup_cc20_key setup unsuccessful");
traceEvent(TRACE_ERROR, "decode_cc20 unsupported ChaCha20 version %u.", cc return -1;
20_enc_ver); }
} else
traceEvent(TRACE_ERROR, "decode_cc20 inbuf wrong size (%ul) to decrypt.", in_l
en);
return len;
}
/* ****************************************************** */ traceEvent(TRACE_DEBUG, "setup_cc20_key completed");
static int setup_cc20_key(transop_cc20_t *priv, const uint8_t *key, ssize_t key_ return 0;
size) { }
uint8_t key_mat_buf[SHA256_DIGEST_LENGTH];
priv->cipher = EVP_chacha20();
/* Clear out any old possibly longer key matter. */
memset(&(priv->key), 0, sizeof(priv->key) );
/* The input key always gets hashed to make a more unpredictable and more comp
lete use of the key space */
SHA256(key, key_size, key_mat_buf);
memcpy (priv->key, key_mat_buf, SHA256_DIGEST_LENGTH);
traceEvent(TRACE_DEBUG, "ChaCha20 key setup completed\n"); static void transop_tick_cc20 (n2n_trans_op_t *arg, time_t now) {
return(0); // no tick action
} }
/* ****************************************************** */ // ChaCha20 initialization function
int n2n_transop_cc20_init (const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) {
static void transop_tick_cc20(n2n_trans_op_t * arg, time_t now) { ; } transop_cc20_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_CHACHA20;
/* ChaCha20 initialization function */ ttt->tick = transop_tick_cc20;
int n2n_transop_cc20_init(const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) { ttt->deinit = transop_deinit_cc20;
transop_cc20_t *priv; ttt->fwd = transop_encode_cc20;
const u_char *encrypt_key = (const u_char *)conf->encrypt_key; ttt->rev = transop_decode_cc20;
size_t encrypt_key_len = strlen(conf->encrypt_key);
memset(ttt, 0, sizeof(*ttt));
ttt->transform_id = N2N_TRANSFORM_ID_CHACHA20;
ttt->tick = transop_tick_cc20;
ttt->deinit = transop_deinit_cc20;
ttt->fwd = transop_encode_cc20;
ttt->rev = transop_decode_cc20;
priv = (transop_cc20_t*) calloc(1, sizeof(transop_cc20_t));
if(!priv) {
traceEvent(TRACE_ERROR, "cannot allocate transop_cc20_t memory");
return(-1);
}
ttt->priv = priv;
/* Setup openssl's reusable evp_* contexts for encryption and decryption*/
if(!(priv->enc_ctx = EVP_CIPHER_CTX_new())) {
traceEvent(TRACE_ERROR, "openssl's evp_* encryption context creation: %s\n",
openssl_err_as_string());
return(-1);
}
if(!(priv->dec_ctx = EVP_CIPHER_CTX_new())) {
traceEvent(TRACE_ERROR, "openssl's evp_* decryption context creation: %s\n",
openssl_err_as_string());
return(-1);
}
/* Setup the cipher and key */ priv = (transop_cc20_t*)calloc(1, sizeof(transop_cc20_t));
return(setup_cc20_key(priv, encrypt_key, encrypt_key_len)); if(!priv) {
} traceEvent(TRACE_ERROR, "cannot allocate transop_cc20_t memory");
return -1;
}
ttt->priv = priv;
#endif /* HAVE_OPENSSL_1_1 */ // setup the cipher and key
return setup_cc20_key(priv, encrypt_key, encrypt_key_len);
}
 End of changes. 30 change blocks. 
267 lines changed or deleted 109 lines changed or added

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