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reworked cc20

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This commit is contained in:
Logan007 2020-09-01 15:13:25 +05:45
parent b3d4f21c91
commit 399ecf8801
4 changed files with 208 additions and 138 deletions
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57
include/cc20.h Normal file
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@ -0,0 +1,57 @@
/**
* (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/>
*
*/
#ifndef CC20_H
#define CC20_H
#include "n2n.h" // HAVE_OPENSSL_1_1, traceEvent ...
#ifdef HAVE_OPENSSL_1_1
#include <stdint.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#define CC20_IV_SIZE 16
#define CC20_KEY_BYTES (256/8)
typedef struct cc20_context_t {
EVP_CIPHER_CTX *ctx; /* openssl's reusable evp_* en/de-cryption context */
const EVP_CIPHER *cipher; /* cipher to use: e.g. EVP_chacha20() */
uint8_t key[CC20_KEY_BYTES]; /* the pure key data for payload encryption & decryption */
} cc20_context_t;
int cc20_crypt (unsigned char *out, const unsigned char *in, size_t in_len,
const unsigned char *iv, cc20_context_t *ctx);
int cc20_init (const unsigned char *key, cc20_context_t **ctx);
int cc20_deinit (cc20_context_t *ctx);
#endif // HAVE_OPENSSL_1_1
#endif // CC20_H

1
include/n2n.h
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@ -160,6 +160,7 @@ typedef struct ether_hdr ether_hdr_t;
#include "pearson.h"
#include "portable_endian.h"
#include "aes.h"
#include "cc20.h"
#include "speck.h"
#include "n2n_regex.h"

110
src/cc20.c Normal file
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@ -0,0 +1,110 @@
/**
* (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 "cc20.h"
#ifdef HAVE_OPENSSL_1_1
/* ****************************************************** */
/* get any erorr message out of openssl
taken from https://en.wikibooks.org/wiki/OpenSSL/Error_handling */
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)
memcpy (ret, buf, len);
BIO_free (bio);
return ret;
}
/* ****************************************************** */
// encryption == decryption
int cc20_crypt (unsigned char *out, const unsigned char *in, size_t in_len,
const unsigned char *iv, cc20_context_t *ctx) {
int evp_len;
int evp_ciphertext_len;
if(1 == EVP_EncryptInit_ex(ctx->ctx, ctx->cipher, NULL, ctx->key, iv)) {
if(1 == EVP_CIPHER_CTX_set_padding(ctx->ctx, 0)) {
if(1 == EVP_EncryptUpdate(ctx->ctx, out, &evp_len, in, in_len)) {
evp_ciphertext_len = evp_len;
if(1 == EVP_EncryptFinal_ex(ctx->ctx, out + evp_len, &evp_len)) {
evp_ciphertext_len += evp_len;
if(evp_ciphertext_len != in_len)
traceEvent(TRACE_ERROR, "cc20_crypt openssl encryption: encrypted %u bytes where %u were expected",
evp_ciphertext_len, in_len);
} else
traceEvent(TRACE_ERROR, "cc20_crypt openssl final encryption: %s",
openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "cc20_encrypt openssl encrpytion: %s",
openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "cc20_encrypt openssl padding setup: %s",
openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "cc20_encrypt openssl init: %s",
openssl_err_as_string());
EVP_CIPHER_CTX_reset(ctx->ctx);
return 0;
}
int cc20_init (const unsigned char *key, cc20_context_t **ctx) {
// allocate context...
*ctx = (cc20_context_t*) calloc(1, sizeof(cc20_context_t));
if (!(*ctx))
return -1;
if(!((*ctx)->ctx = EVP_CIPHER_CTX_new())) {
traceEvent(TRACE_ERROR, "cc20_init openssl's evp_* encryption context creation failed: %s",
openssl_err_as_string());
return -1;
}
(*ctx)->cipher = EVP_chacha20();
memcpy((*ctx)->key, key, CC20_KEY_BYTES);
return 0;
}
int cc20_deinit (cc20_context_t *ctx) {
if (ctx->ctx) EVP_CIPHER_CTX_free(ctx->ctx);
return 0;
}
#endif // HAVE_OPENSSL_1_1

178
src/transform_cc20.c
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@ -20,33 +20,21 @@
#ifdef HAVE_OPENSSL_1_1
#include <openssl/sha.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#define N2N_CC20_IVEC_SIZE 16
#define CC20_KEY_BYTES (256/8)
/* ChaCha20 plaintext preamble */
#define TRANSOP_CC20_PREAMBLE_SIZE (N2N_CC20_IVEC_SIZE)
typedef unsigned char n2n_cc20_ivec_t[N2N_CC20_IVEC_SIZE];
#define CC20_PREAMBLE_SIZE (CC20_IV_SIZE)
typedef struct transop_cc20 {
EVP_CIPHER_CTX *enc_ctx; /* openssl's reusable evp_* encryption context */
EVP_CIPHER_CTX *dec_ctx; /* openssl's reusable evp_* decryption context */
const EVP_CIPHER *cipher; /* cipher to use: EVP_chacha20() */
uint8_t key[32]; /* the pure key data for payload encryption & decryption */
cc20_context_t *ctx;
} transop_cc20_t;
/* ****************************************************** */
static int transop_deinit_cc20(n2n_trans_op_t *arg) {
transop_cc20_t *priv = (transop_cc20_t *)arg->priv;
EVP_CIPHER_CTX_free(priv->enc_ctx);
EVP_CIPHER_CTX_free(priv->dec_ctx);
if(priv->ctx)
cc20_deinit(priv->ctx);
if(priv)
free(priv);
@ -56,35 +44,6 @@ static int transop_deinit_cc20(n2n_trans_op_t *arg) {
/* ****************************************************** */
/* get any erorr message out of openssl
taken from https://en.wikibooks.org/wiki/OpenSSL/Error_handling */
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)
memcpy (ret, buf, len);
BIO_free (bio);
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_value) == 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));
}
}
/* ****************************************************** */
/** The ChaCha20 packet format consists of:
*
* - a 128-bit random IV
@ -99,56 +58,30 @@ static int transop_encode_cc20(n2n_trans_op_t * arg,
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) {
if((in_len + 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);
/* Generate and encode the IV. */
set_cc20_iv(priv, enc_ivec);
encode_buf(outbuf, &idx, &enc_ivec, N2N_CC20_IVEC_SIZE);
// full IV sized random value (128 bit)
encode_uint64(outbuf, &idx, n2n_rand());
encode_uint64(outbuf, &idx, n2n_rand());
/* 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;
cc20_crypt(outbuf + CC20_PREAMBLE_SIZE,
inbuf,
in_len,
outbuf, // IV
priv->ctx);
/* 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, &evp_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: encrypted %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", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_cc20 openssl padding setup: %s\n", openssl_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. */
len += CC20_PREAMBLE_SIZE; /* size of data carried in UDP. */
} else
traceEvent(TRACE_ERROR, "encode_cc20 outbuf too small.");
} else
@ -166,72 +99,51 @@ static int transop_decode_cc20(n2n_trans_op_t * arg,
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 iv */
if(((in_len - CC20_PREAMBLE_SIZE) <= N2N_PKT_BUF_SIZE) /* Cipher text fits in assembly */
&& (in_len >= CC20_PREAMBLE_SIZE) /* Has at least iv */
)
{
size_t rem=in_len;
size_t idx=0;
n2n_cc20_ivec_t dec_ivec = {0};
traceEvent(TRACE_DEBUG, "decode_cc20 %lu bytes", in_len);
len = (in_len - TRANSOP_CC20_PREAMBLE_SIZE);
traceEvent(TRACE_DEBUG, "decode_cc20 %lu bytes", in_len);
/* Get the IV */
decode_buf((uint8_t *)&dec_ivec, N2N_CC20_IVEC_SIZE, inbuf, &rem, &idx);
len = (in_len - CC20_PREAMBLE_SIZE);
EVP_CIPHER_CTX *ctx = priv->dec_ctx;
int evp_len;
int evp_plaintext_len;
cc20_crypt(outbuf,
inbuf + CC20_PREAMBLE_SIZE,
in_len,
inbuf, // IV
priv->ctx);
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: decrypted %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", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl padding setup: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_cc20 openssl init: %s\n", openssl_err_as_string());
EVP_CIPHER_CTX_reset(ctx);
memcpy(outbuf, assembly, len);
} else
traceEvent(TRACE_ERROR, "decode_cc20 inbuf wrong size (%ul) to decrypt.", in_len);
traceEvent(TRACE_ERROR, "decode_cc20 inbuf wrong size (%ul) to decrypt.", in_len);
return len;
}
/* ****************************************************** */
static int setup_cc20_key(transop_cc20_t *priv, const uint8_t *key, ssize_t key_size) {
uint8_t key_mat_buf[SHA256_DIGEST_LENGTH];
static int setup_cc20_key(transop_cc20_t *priv, const uint8_t *password, ssize_t password_len) {
priv->cipher = EVP_chacha20();
uint8_t key_mat[CC20_KEY_BYTES];
/* 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 complete use of the key space */
SHA256(key, key_size, key_mat_buf);
memcpy (priv->key, key_mat_buf, SHA256_DIGEST_LENGTH);
pearson_hash_256(key_mat, password, password_len);
traceEvent(TRACE_DEBUG, "ChaCha20 key setup completed\n");
if(cc20_init(key_mat, &(priv->ctx))) {
traceEvent(TRACE_ERROR, "setup_cc20_key setup unsuccessful");
return -1;
}
return(0);
traceEvent(TRACE_DEBUG, "setup_cc20_key completed");
return 0;
}
/* ****************************************************** */
@ -242,6 +154,7 @@ static void transop_tick_cc20(n2n_trans_op_t * arg, time_t now) { ; }
/* ChaCha20 initialization function */
int n2n_transop_cc20_init(const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) {
transop_cc20_t *priv;
const u_char *encrypt_key = (const u_char *)conf->encrypt_key;
size_t encrypt_key_len = strlen(conf->encrypt_key);
@ -261,19 +174,8 @@ int n2n_transop_cc20_init(const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) {
}
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 */
return(setup_cc20_key(priv, encrypt_key, encrypt_key_len));
return setup_cc20_key(priv, encrypt_key, encrypt_key_len);
}
#endif /* HAVE_OPENSSL_1_1 */