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Port to libsodium, switch to AES256-GCM, revamp authentication

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This commit is contained in:
Frank Denis 2015-10-08 19:17:30 +02:00
parent 9aac84a0ce
commit ed49289d7b
10 changed files with 211 additions and 852 deletions
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91
auth.c
View File

@ -27,6 +27,7 @@
#include "config.h"
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
@ -56,67 +57,45 @@
#include "auth.h"
/* Encryption and Decryption of the challenge key */
#ifdef HAVE_SSL
#include <sodium.h>
#include <openssl/md5.h>
#include <openssl/blowfish.h>
#include <openssl/rand.h>
static void gen_chal(char *buf)
static int derive_key(struct vtun_host *host)
{
RAND_bytes(buf, VTUN_CHAL_SIZE);
unsigned char salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
int ret = -1;
if (host->key != NULL) {
return 0;
}
if ((host->key = sodium_malloc(HOST_KEYBYTES)) == NULL) {
return -1;
}
memset(salt, 0xd1, sizeof salt);
if (crypto_pwhash_scryptsalsa208sha256
(host->key, HOST_KEYBYTES, host->passwd, strlen(host->passwd), salt,
crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE,
crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE) == 0) {
ret = 0;
}
sodium_memzero(host->passwd, strlen(host->passwd));
free(host->passwd);
host->passwd = NULL;
vtun_syslog(LOG_DEBUG,"Key ready for host %s.", host->host);
return ret;
}
static void encrypt_chal(char *chal, char *pwd)
static void gen_chal(char *chal)
{
register int i;
BF_KEY key;
BF_set_key(&key, 16, MD5(pwd,strlen(pwd),NULL));
for(i=0; i < VTUN_CHAL_SIZE; i += 8 )
BF_ecb_encrypt(chal + i, chal + i, &key, BF_ENCRYPT);
randombytes_buf((unsigned char *) chal, VTUN_CHAL_SIZE);
}
static void decrypt_chal(char *chal, char *pwd)
static void auth_chal(char *chal, const struct vtun_host *host)
{
register int i;
BF_KEY key;
BF_set_key(&key, 16, MD5(pwd,strlen(pwd),NULL));
for(i=0; i < VTUN_CHAL_SIZE; i += 8 )
BF_ecb_encrypt(chal + i, chal + i, &key, BF_DECRYPT);
crypto_generichash(chal, VTUN_CHAL_SIZE, chal, VTUN_CHAL_SIZE,
host->key, HOST_KEYBYTES);
}
#else /* HAVE_SSL */
static void encrypt_chal(char *chal, char *pwd)
{
char * xor_msk = pwd;
register int i, xor_len = strlen(xor_msk);
for(i=0; i < VTUN_CHAL_SIZE; i++)
chal[i] ^= xor_msk[i%xor_len];
}
static void inline decrypt_chal(char *chal, char *pwd)
{
encrypt_chal(chal, pwd);
}
/* Generate PSEUDO random challenge key. */
static void gen_chal(char *buf)
{
register int i;
srand(time(NULL));
for(i=0; i < VTUN_CHAL_SIZE; i++)
buf[i] = (unsigned int)(255.0 * rand()/RAND_MAX);
}
#endif /* HAVE_SSL */
/*
* Functions to convert binary flags to character string.
* string format: <CS64>
@ -348,10 +327,10 @@ struct vtun_host * auth_server(int fd)
if( !(h = find_host(host)) )
break;
derive_key(h);
auth_chal(chal_req, h);
decrypt_chal(chal_res, h->passwd);
if( !memcmp(chal_req, chal_res, VTUN_CHAL_SIZE) ){
if( !sodium_memcmp(chal_req, chal_res, VTUN_CHAL_SIZE) ){
/* Auth successeful. */
/* Lock host */
@ -400,8 +379,8 @@ int auth_client(int fd, struct vtun_host *host)
case ST_HOST:
if( !strncmp(buf,"OK",2) && cs2cl(buf,chal)){
stage = ST_CHAL;
encrypt_chal(chal,host->passwd);
derive_key(host);
auth_chal(chal, host);
print_p(fd,"CHAL: %s\n", cl2cs(chal));
continue;

1
cfg_file.y
View File

@ -107,6 +107,7 @@ statement: '\n'
memcpy(parse_host, &default_host, sizeof(struct vtun_host));
parse_host->host = strdup($1);
parse_host->passwd = NULL;
parse_host->key = NULL;
parse_host->sopt.host = strdup($1);
/* Copy local address */

13
cfg_kwords.h
View File

@ -86,17 +86,6 @@ struct kword cfg_param[] = {
{ "inetd", VTUN_INETD },
{ "stand", VTUN_STAND_ALONE },
{ "keep", VTUN_PERSIST_KEEPIF },
{ "blowfish128cbc", VTUN_ENC_BF128CBC },
{ "blowfish128cfb", VTUN_ENC_BF128CFB },
{ "blowfish128ofb", VTUN_ENC_BF128OFB },
{ "blowfish256cbc", VTUN_ENC_BF256CBC },
{ "blowfish256cfb", VTUN_ENC_BF256CFB },
{ "blowfish256ofb", VTUN_ENC_BF256OFB },
{ "aes128cbc", VTUN_ENC_AES128CBC },
{ "aes128cfb", VTUN_ENC_AES128CFB },
{ "aes128ofb", VTUN_ENC_AES128OFB },
{ "aes256cbc", VTUN_ENC_AES256CBC },
{ "aes256cfb", VTUN_ENC_AES256CFB },
{ "aes256ofb", VTUN_ENC_AES256OFB },
{ "aes256gcm",VTUN_ENC_AES256GCM },
{ NULL , 0 }
};

78
configure.ac
View File

@ -17,10 +17,10 @@ AC_ARG_ENABLE(shaper,
SHAPER=yes
)
dnl Encryption support
AC_ARG_ENABLE(ssl,
--disable-ssl Don not compile encryption module,
SSL=$enableval,
SSL=yes
AC_ARG_ENABLE(sodium,
--disable-sodium Don not compile encryption module,
SODIUM=$enableval,
SODIUM=yes
)
dnl ZLIB support
AC_ARG_ENABLE(zlib,
@ -48,13 +48,13 @@ AC_ARG_ENABLE(nathack,
NATHACK=yes
)
AC_ARG_WITH(ssl-headers,
--with-ssl-headers=DIR Crypto Include files location,
SSL_HDR_DIR="$withval"
AC_ARG_WITH(sodium-headers,
--with-sodium-headers=DIR Crypto Include files location,
SODIUM_HDR_DIR="$withval"
CPPFLAGS="$CPPFLAGS -I$withval"
)
AC_ARG_WITH(ssl-lib,
--with-ssl-lib=DIR Crypto Library location,
AC_ARG_WITH(sodium-lib,
--with-sodium-lib=DIR Crypto Library location,
LIBS="$LIBS -L$withval"
)
@ -165,60 +165,16 @@ if test "$LZO" = "yes"; then
fi
fi
if test "$SSL" = "yes"; then
if test "$SODIUM" = "yes"; then
AC_MSG_RESULT()
AC_CHECKING( for md5 Library and Header files ... )
AC_SEARCH_HEADERS(md5.h,
$SSL_HDR_DIR /usr/include/openssl "" /usr/include /usr/include/ssl /usr/local/include /usr/local/ssl/include /usr/include/sys,
AC_CHECKING( for Sodium Library and Header files ... )
AC_SEARCH_LIBS(crypto_aead_aes256gcm_aesni_encrypt, [sodium],
[AC_DEFINE(HAVE_SODIUM, [1], [Define to 1 if you have Sodium])],
AC_ERROR([libsodium with crypto_aead_aes256gcm_aesni_encrypt not found]))
AC_SEARCH_HEADERS(sodium.h,
$SSL_HDR_DIR /usr/include /usr/local/include /opt/include,
,
AC_MSG_ERROR( SSL headers not found. )
)
fi
if test "$SSL" = "yes"; then
AC_MSG_RESULT()
AC_CHECKING( for blowfish Library and Header files ... )
AC_SEARCH_HEADERS(blowfish.h,
$BLOWFISH_HDR_DIR /usr/include/ssl /usr/include/openssl /usr/include /usr/local/include /usr/local/ssl/include /usr/include/crypto,
AC_CHECK_LIB(crypto, BF_set_key,
[
LIBS="$LIBS -lcrypto"
AC_DEFINE(HAVE_SSL, [1], [Define to 1 if you have openssl])
AC_DEFINE(HAVE_SSL_BLOWFISH, [1], [Define to 1 if you have blowfish in openssl])
],
AC_MSG_ERROR( SSL library not found. )
),
AC_MSG_ERROR( SSL headers not found. )
)
fi
if test "$SSL" = "yes"; then
AC_MSG_RESULT()
AC_CHECKING( for AES Library and Header files ... )
AC_SEARCH_HEADERS(aes.h,
$SSL_HDR_DIR /usr/include/ssl /usr/include/openssl /usr/include /usr/local/include /usr/local/ssl/include /usr/include/crypto,
AC_CHECK_LIB(crypto, AES_set_encrypt_key,
[
AC_DEFINE(HAVE_SSL_AES, [1], [Define to 1 if you have AES in openssl])
],
AC_MSG_ERROR( AES library not found. )
),
AC_MSG_ERROR( AES headers not found. )
)
fi
if test "$SSL" = "yes"; then
AC_MSG_RESULT()
AC_CHECKING( for EVP Library and Header files ... )
AC_SEARCH_HEADERS(evp.h,
$SSL_HDR_DIR /usr/include/ssl /usr/include/openssl /usr/include /usr/local/include /usr/local/ssl/include /usr/include/crypto,
AC_CHECK_LIB(crypto, EVP_EncryptInit,
[
AC_DEFINE(HAVE_SSL_EVP, [1], [Define to 1 if you have EVP in openssl])
],
AC_MSG_ERROR( EVP library not found. )
),
AC_MSG_ERROR( EVP headers not found. )
AC_MSG_ERROR( Sodium headers not found. )
)
fi

796
lfd_encrypt.c
View File

@ -1,707 +1,172 @@
/*
VTun - Virtual Tunnel over TCP/IP network.
Copyright (C) 1998-2008 Maxim Krasnyansky <max_mk@yahoo.com>
VTun has been derived from VPPP package by Maxim Krasnyansky.
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 2 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.
*/
/*
Encryption module uses software developed by the OpenSSL Project
for use in the OpenSSL Toolkit. (http://www.openssl.org/)
Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
*/
/*
* This lfd_encrypt module uses MD5 to create 128 bits encryption
* keys and BlowFish for actual data encryption.
* It is based on code written by Chris Todd<christ@insynq.com> with
* several improvements and modifications by me.
*/
/*
* The current lfd_encrypt module is based on code attributed above and
* uses new code written by Dale Fountain <dpf-vtun@fountainbay.com> to
* allow multiple ciphers, modes, and key sizes. Feb 2004.
*/
#include "config.h"
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <syslog.h>
#include <strings.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include "vtun.h"
#include "linkfd.h"
#include "lib.h"
#ifdef HAVE_SSL
#ifdef HAVE_SODIUM
#include <sodium.h>
/* OpenSSL includes */
#include <openssl/evp.h>
#include <openssl/md5.h>
#include <openssl/blowfish.h>
#include <openssl/rand.h>
#define crypto_aead_NPUBBYTES crypto_aead_aes256gcm_NPUBBYTES
#define crypto_aead_ABYTES crypto_aead_aes256gcm_ABYTES
#define crypto_aead_KEYBYTES crypto_aead_aes256gcm_KEYBYTES
/*
* #define LFD_ENCRYPT_DEBUG
*/
#define MESSAGE_MAX_SIZE VTUN_FRAME_SIZE
#define CIPHERTEXT_ABYTES (crypto_aead_ABYTES + crypto_aead_NPUBBYTES)
#define CIPHERTEXT_MAX_SIZE MESSAGE_MAX_SIZE
#define CIPHERTEXT_MAX_TOTAL_SIZE (CIPHERTEXT_MAX_SIZE + CIPHERTEXT_ABYTES)
#define ENC_BUF_SIZE VTUN_FRAME_SIZE + 128
#define ENC_KEY_SIZE 16
#define MINIMUM_DATE 1444341043UL
#define SLEEP_WHEN_CLOCK_IS_OFF 10
static BF_KEY key;
static char * enc_buf;
static char * dec_buf;
typedef struct CryptoCtx {
crypto_aead_aes256gcm_aesni_state *state;
unsigned char *ciphertext;
unsigned char *key;
unsigned char *message;
unsigned char *nonce;
unsigned char *previous_decrypted_nonce;
} CryptoCtx;
#define CIPHER_INIT 0
#define CIPHER_CODE 1
#define CIPHER_SEQUENCE 2
#define CIPHER_REQ_INIT 3
static CryptoCtx ctx;
static struct vtun_host *phost;
extern int send_a_packet;
/* out of sync packet threshold before forcing a re-init */
#define MAX_GIBBERISH 10
#define MIN_GIBBERISH 1
#define MAX_GIBBERISH_TIME 2
static int gibberish;
static time_t gib_time_start;
static int cipher_enc_state;
static int cipher_dec_state;
static int cipher;
static int blocksize;
static int keysize;
static int enc_init_first_time;
static int dec_init_first_time;
static unsigned long sequence_num;
static char * pkey;
static char * iv_buf;
static EVP_CIPHER_CTX ctx_enc; /* encrypt */
static EVP_CIPHER_CTX ctx_dec; /* decrypt */
static EVP_CIPHER_CTX ctx_enc_ecb; /* sideband ecb encrypt */
static EVP_CIPHER_CTX ctx_dec_ecb; /* sideband ecb decrypt */
static int send_msg(int len, char *in, char **out);
static int recv_msg(int len, char *in, char **out);
static int send_ib_mesg(int *len, char **in);
static int recv_ib_mesg(int *len, char **in);
static int prep_key(char **key, int size, struct vtun_host *host)
static int
derive_key(unsigned char *key, size_t key_size, struct vtun_host *host)
{
int tmplen, halflen;
char *hashkey;
if ( !(hashkey = malloc(size)) )
{
vtun_syslog(LOG_ERR,"Can't allocate buffer for key hash");
return -1;
}
memset(hashkey,0,size);
if (size == 32)
{
tmplen = strlen(host->passwd);
if (tmplen != 0) halflen = tmplen>>1;
else halflen = 0;
MD5(host->passwd, halflen, hashkey);
MD5((host->passwd)+halflen, tmplen-halflen, hashkey+16);
}
else if (size == 16)
{
MD5(host->passwd,strlen(host->passwd), hashkey);
}
else
{
/* don't know what to do */
free(hashkey);
*key = NULL;
return -1;
}
*key = hashkey;
return 0;
crypto_generichash(key, key_size, host->key, HOST_KEYBYTES, NULL, 0U);
sodium_free(host->key);
host->key = NULL;
}
static void free_key (char *key)
static int
init_nonce(unsigned char *nonce, size_t nonce_size)
{
free(key);
time_t now;
if (nonce_size < 5) {
return -1;
}
time(&now);
if (now < MINIMUM_DATE) {
sleep(SLEEP_WHEN_CLOCK_IS_OFF);
randombytes_buf(nonce, nonce_size);
} else {
randombytes_buf(nonce + 4, nonce_size - 4);
now <<= 2;
memcpy(nonce, &now, 3);
nonce[3] = (nonce[3] & 0x3) ^ *(((unsigned char *) &now) + 3);
}
return 0;
}
static int alloc_encrypt(struct vtun_host *host)
static int
alloc_encrypt(struct vtun_host *host)
{
int sb_init = 0;
int var_key = 0;
const EVP_CIPHER *cipher_type;
char tmpstr[64];
char cipher_name[32];
EVP_CIPHER_CTX *pctx_enc;
EVP_CIPHER_CTX *pctx_dec;
enc_init_first_time = 1;
dec_init_first_time = 1;
if( !(enc_buf = lfd_alloc(ENC_BUF_SIZE)) ){
vtun_syslog(LOG_ERR,"Can't allocate buffer for encryptor");
return -1;
}
if( !(dec_buf = lfd_alloc(ENC_BUF_SIZE)) ){
vtun_syslog(LOG_ERR,"Can't allocate buffer for decryptor");
return -1;
}
RAND_bytes((char *)&sequence_num, 4);
gibberish = 0;
gib_time_start = 0;
phost = host;
cipher = host->cipher;
switch(cipher)
{
case VTUN_ENC_AES128OFB:
case VTUN_ENC_AES128CFB:
case VTUN_ENC_AES128CBC:
blocksize = 16;
keysize = 16;
sb_init=1;
cipher_type = EVP_aes_128_ecb();
pctx_enc = &ctx_enc_ecb;
pctx_dec = &ctx_dec_ecb;
break;
case VTUN_ENC_BF256OFB:
case VTUN_ENC_BF256CFB:
case VTUN_ENC_BF256CBC:
blocksize = 8;
keysize = 32;
var_key = 1;
sb_init = 1;
cipher_type = EVP_bf_ecb();
pctx_enc = &ctx_enc_ecb;
pctx_dec = &ctx_dec_ecb;
break;
case VTUN_ENC_BF128OFB:
case VTUN_ENC_BF128CFB:
case VTUN_ENC_BF128CBC:
blocksize = 8;
keysize = 16;
var_key = 1;
sb_init = 1;
cipher_type = EVP_bf_ecb();
pctx_enc = &ctx_enc_ecb;
pctx_dec = &ctx_dec_ecb;
break;
case VTUN_ENC_AES256OFB:
case VTUN_ENC_AES256CFB:
case VTUN_ENC_AES256CBC:
default:
blocksize = 16;
keysize = 32;
sb_init = 1;
cipher_type = EVP_aes_256_ecb();
pctx_enc = &ctx_enc_ecb;
pctx_dec = &ctx_dec_ecb;
strcpy(cipher_name,"AES-256-CBC");
} /* switch(host->cipher) */
if (prep_key(&pkey, keysize, host) != 0) return -1;
EVP_CIPHER_CTX_init(pctx_enc);
EVP_CIPHER_CTX_init(pctx_dec);
EVP_EncryptInit_ex(pctx_enc, cipher_type, NULL, NULL, NULL);
EVP_DecryptInit_ex(pctx_dec, cipher_type, NULL, NULL, NULL);
if (var_key)
{
EVP_CIPHER_CTX_set_key_length(pctx_enc, keysize);
EVP_CIPHER_CTX_set_key_length(pctx_dec, keysize);
}
EVP_EncryptInit_ex(pctx_enc, NULL, NULL, pkey, NULL);
EVP_DecryptInit_ex(pctx_dec, NULL, NULL, pkey, NULL);
EVP_CIPHER_CTX_set_padding(pctx_enc, 0);
EVP_CIPHER_CTX_set_padding(pctx_dec, 0);
if (sb_init)
{
cipher_enc_state=CIPHER_INIT;
cipher_dec_state=CIPHER_INIT;
}
else
{
cipher_enc_state=CIPHER_CODE;
cipher_dec_state=CIPHER_CODE;
sprintf(tmpstr,"%s encryption initialized", cipher_name);
vtun_syslog(LOG_INFO, tmpstr);
}
return 0;
if (sodium_init() < 0) {
return -1;
}
ctx.state = sodium_malloc(sizeof *ctx.state);
ctx.key = sodium_malloc(crypto_aead_KEYBYTES);
ctx.message = sodium_malloc(MESSAGE_MAX_SIZE);
ctx.ciphertext = sodium_malloc(CIPHERTEXT_MAX_TOTAL_SIZE);
ctx.nonce = sodium_malloc(crypto_aead_NPUBBYTES);
ctx.previous_decrypted_nonce = sodium_malloc(crypto_aead_NPUBBYTES);
if (ctx.state == NULL || ctx.key == NULL || ctx.message == NULL ||
ctx.ciphertext == NULL || ctx.ciphertext == NULL || ctx.nonce == NULL ||
ctx.previous_decrypted_nonce == NULL) {
abort();
}
if (init_nonce(ctx.nonce, crypto_aead_NPUBBYTES) != 0) {
return -1;
}
if (derive_key(ctx.key, crypto_aead_KEYBYTES, host) != 0) {
return -1;
}
crypto_aead_aes256gcm_aesni_beforenm(ctx.state, ctx.key);
sodium_free(ctx.key);
ctx.key = NULL;
return 0;
}
static int free_encrypt()
static int
free_encrypt(void)
{
free_key(pkey); pkey = NULL;
sodium_free(ctx.key);
sodium_free(ctx.message);
sodium_free(ctx.ciphertext);
sodium_free(ctx.nonce);
sodium_free(ctx.previous_decrypted_nonce);
lfd_free(enc_buf); enc_buf = NULL;
lfd_free(dec_buf); dec_buf = NULL;
EVP_CIPHER_CTX_cleanup(&ctx_enc);
EVP_CIPHER_CTX_cleanup(&ctx_dec);
EVP_CIPHER_CTX_cleanup(&ctx_enc_ecb);
EVP_CIPHER_CTX_cleanup(&ctx_dec_ecb);
return 0;
return 0;
}
static int encrypt_buf(int len, char *in, char **out)
static int
is_lower_or_equal(const unsigned char *a, const unsigned char *b, size_t size)
{
register int pad, p, msg_len;
int outlen;
char *in_ptr, *out_ptr = enc_buf;
size_t i;
msg_len = send_msg(len, in, out);
in = *out;
in_ptr = in+msg_len;
memcpy(out_ptr,in,msg_len);
out_ptr += msg_len;
send_ib_mesg(&len, &in_ptr);
if (!len) return 0;
/* ( len % blocksize ) */
p = (len & (blocksize-1)); pad = blocksize - p;
memset(in_ptr+len, pad, pad);
outlen=len+pad;
if (pad == blocksize)
RAND_bytes(in_ptr+len, blocksize-1);
EVP_EncryptUpdate(&ctx_enc, out_ptr, &outlen, in_ptr, len+pad);
*out = enc_buf;
sequence_num++;
return outlen+msg_len;
for (i = 0U; i < size; i++) {
if (a[i] > b[i]) {
return 0;
}
}
return 1;
}
static int decrypt_buf(int len, char *in, char **out)
static int
encrypt_buf(int message_len_, char *message_, char ** const ciphertext_p)
{
register int pad;
char *tmp_ptr, *in_ptr, *out_ptr = dec_buf;
int outlen;
const unsigned char *message = (const unsigned char *) message_;
const size_t message_len = (size_t) message_len_;
unsigned long long ciphertext_len;
len = recv_msg(len, in, out);
in = *out;
in_ptr = in;
if (message_len_ < 0 || message_len > MESSAGE_MAX_SIZE) {
return -1;
}
crypto_aead_aes256gcm_aesni_encrypt_afternm(ctx.ciphertext, &ciphertext_len,
message, message_len,
NULL, 0ULL,
NULL, ctx.nonce, ctx.state);
memcpy(ctx.ciphertext + message_len + crypto_aead_ABYTES,
ctx.nonce, crypto_aead_NPUBBYTES);
sodium_increment(ctx.nonce, crypto_aead_NPUBBYTES);
*ciphertext_p = ctx.ciphertext;
outlen=len;
if (!len) return 0;
EVP_DecryptUpdate(&ctx_dec, out_ptr, &outlen, in_ptr, len);
recv_ib_mesg(&outlen, &out_ptr);
if (!outlen) return 0;
tmp_ptr = out_ptr + outlen; tmp_ptr--;
pad = *tmp_ptr;
if (pad < 1 || pad > blocksize) {
vtun_syslog(LOG_INFO, "decrypt_buf: bad pad length");
return 0;
}
*out = out_ptr;
return outlen - pad;
return (int) ciphertext_len + crypto_aead_NPUBBYTES;
}
static int cipher_enc_init(char * iv)
static int
decrypt_buf(int ciphertext_len_, char *ciphertext_, char ** const message_p)
{
int var_key = 0;
const EVP_CIPHER *cipher_type;
char tmpstr[64];
char cipher_name[32];
const unsigned char *ciphertext = (const unsigned char *) ciphertext_;
const unsigned char *nonce;
size_t ciphertext_len = (size_t) ciphertext_len_;
unsigned long long message_len;
switch(cipher)
{
case VTUN_ENC_AES256OFB:
cipher_type = EVP_aes_256_ofb();
strcpy(cipher_name, "AES-256-OFB");
break;
if (ciphertext_len_ < CIPHERTEXT_ABYTES ||
ciphertext_len > CIPHERTEXT_MAX_SIZE) {
return -1;
}
ciphertext_len -= crypto_aead_NPUBBYTES;
nonce = ciphertext + ciphertext_len;
if (is_lower_or_equal(nonce, ctx.previous_decrypted_nonce, crypto_aead_NPUBBYTES) ||
crypto_aead_aes256gcm_aesni_decrypt_afternm(ctx.message, &message_len, NULL,
ciphertext, ciphertext_len,
NULL, 0ULL, nonce, ctx.state) != 0) {
return -1;
}
memcpy(ctx.previous_decrypted_nonce, nonce, crypto_aead_NPUBBYTES);
*message_p = ctx.message;
case VTUN_ENC_AES256CFB:
cipher_type = EVP_aes_256_cfb();
strcpy(cipher_name, "AES-256-CFB");
break;
case VTUN_ENC_AES256CBC:
cipher_type = EVP_aes_256_cbc();
strcpy(cipher_name, "AES-256-CBC");
break;
case VTUN_ENC_AES128OFB:
cipher_type = EVP_aes_128_ofb();
strcpy(cipher_name, "AES-128-OFB");
break;
case VTUN_ENC_AES128CFB:
cipher_type = EVP_aes_128_cfb();
strcpy(cipher_name, "AES-128-CFB");
break;
case VTUN_ENC_AES128CBC:
cipher_type = EVP_aes_128_cbc();
strcpy(cipher_name, "AES-128-CBC");
break;
case VTUN_ENC_BF256OFB:
var_key = 1;
cipher_type = EVP_bf_ofb();
strcpy(cipher_name, "Blowfish-256-OFB");
break;
case VTUN_ENC_BF256CFB:
var_key = 1;
cipher_type = EVP_bf_cfb();
strcpy(cipher_name, "Blowfish-256-CFB");
break;
case VTUN_ENC_BF256CBC:
var_key = 1;
cipher_type = EVP_bf_cbc();
strcpy(cipher_name, "Blowfish-256-CBC");
break;
case VTUN_ENC_BF128OFB:
var_key = 1;
cipher_type = EVP_bf_ofb();
strcpy(cipher_name, "Blowfish-128-OFB");
break;
case VTUN_ENC_BF128CFB:
var_key = 1;
cipher_type = EVP_bf_cfb();
strcpy(cipher_name, "Blowfish-128-CFB");
break;
case VTUN_ENC_BF128CBC:
var_key = 1;
cipher_type = EVP_bf_cbc();
strcpy(cipher_name, "Blowfish-128-CBC");
break;
default:
/* if we're here, something weird's going on */
return -1;
break;
} /* switch(cipher) */
EVP_CIPHER_CTX_init(&ctx_enc);
EVP_EncryptInit_ex(&ctx_enc, cipher_type, NULL, NULL, NULL);
if (var_key)
EVP_CIPHER_CTX_set_key_length(&ctx_enc, keysize);
EVP_EncryptInit_ex(&ctx_enc, NULL, NULL, pkey, NULL);
EVP_EncryptInit_ex(&ctx_enc, NULL, NULL, NULL, iv);
EVP_CIPHER_CTX_set_padding(&ctx_enc, 0);
if (enc_init_first_time)
{
sprintf(tmpstr,"%s encryption initialized", cipher_name);
vtun_syslog(LOG_INFO, tmpstr);
enc_init_first_time = 0;
}
return 0;
return (int) message_len;
}
static int cipher_dec_init(char * iv)
{
int var_key = 0;
const EVP_CIPHER *cipher_type;
char tmpstr[64];
char cipher_name[32];
switch(cipher)
{
case VTUN_ENC_AES256OFB:
cipher_type = EVP_aes_256_ofb();
strcpy(cipher_name, "AES-256-OFB");
break;
case VTUN_ENC_AES256CFB:
cipher_type = EVP_aes_256_cfb();
strcpy(cipher_name, "AES-256-CFB");
break;
case VTUN_ENC_AES256CBC:
cipher_type = EVP_aes_256_cbc();
strcpy(cipher_name, "AES-256-CBC");
break;
case VTUN_ENC_AES128OFB:
cipher_type = EVP_aes_128_ofb();
strcpy(cipher_name, "AES-128-OFB");
break;
case VTUN_ENC_AES128CFB:
cipher_type = EVP_aes_128_cfb();
strcpy(cipher_name, "AES-128-CFB");
break;
case VTUN_ENC_AES128CBC:
cipher_type = EVP_aes_128_cbc();
strcpy(cipher_name, "AES-128-CBC");
break;
case VTUN_ENC_BF256OFB:
var_key = 1;
cipher_type = EVP_bf_ofb();
strcpy(cipher_name, "Blowfish-256-OFB");
break;
case VTUN_ENC_BF256CFB:
var_key = 1;
cipher_type = EVP_bf_cfb();
strcpy(cipher_name, "Blowfish-256-CFB");
break;
case VTUN_ENC_BF256CBC:
var_key = 1;
cipher_type = EVP_bf_cbc();
strcpy(cipher_name, "Blowfish-256-CBC");
break;
case VTUN_ENC_BF128OFB:
var_key = 1;
cipher_type = EVP_bf_ofb();
strcpy(cipher_name, "Blowfish-128-OFB");
break;
case VTUN_ENC_BF128CFB:
var_key = 1;
cipher_type = EVP_bf_cfb();
strcpy(cipher_name, "Blowfish-128-CFB");
break;
case VTUN_ENC_BF128CBC:
var_key = 1;
cipher_type = EVP_bf_cbc();
strcpy(cipher_name, "Blowfish-128-CBC");
break;
default:
/* if we're here, something weird's going on */
return -1;
break;
} /* switch(cipher) */
EVP_CIPHER_CTX_init(&ctx_dec);
EVP_DecryptInit_ex(&ctx_dec, cipher_type, NULL, NULL, NULL);
if (var_key)
EVP_CIPHER_CTX_set_key_length(&ctx_dec, keysize);
EVP_DecryptInit_ex(&ctx_dec, NULL, NULL, pkey, NULL);
EVP_DecryptInit_ex(&ctx_dec, NULL, NULL, NULL, iv);
EVP_CIPHER_CTX_set_padding(&ctx_dec, 0);
if (dec_init_first_time)
{
sprintf(tmpstr,"%s decryption initialized", cipher_name);
vtun_syslog(LOG_INFO, tmpstr);
dec_init_first_time = 0;
}
return 0;
}
static int send_msg(int len, char *in, char **out)
{
char * iv; char * in_ptr;
int outlen;
switch(cipher_enc_state)
{
case CIPHER_INIT:
in_ptr = in - blocksize*2;
iv = malloc(blocksize);
RAND_bytes(iv, blocksize);
strncpy(in_ptr,"ivec",4);
in_ptr += 4;
memcpy(in_ptr,iv,blocksize);
in_ptr += blocksize;
cipher_enc_init(iv);
memset(iv,0,blocksize); free(iv); iv = NULL;
RAND_bytes(in_ptr, in - in_ptr);
in_ptr = in - blocksize*2;
outlen = blocksize*2;
EVP_EncryptUpdate(&ctx_enc_ecb, in_ptr,
&outlen, in_ptr, blocksize*2);
*out = in_ptr;
len = outlen;
cipher_enc_state = CIPHER_SEQUENCE;
break;
case CIPHER_CODE:
default:
*out = in;
len = 0;
break;
}
return len;
}
static int recv_msg(int len, char *in, char **out)
{
char * iv; char * in_ptr;
int outlen;
switch(cipher_dec_state)
{
case CIPHER_INIT:
in_ptr = in;
iv = malloc(blocksize);
outlen = blocksize*2;
EVP_DecryptUpdate(&ctx_dec_ecb, in_ptr, &outlen, in_ptr, blocksize*2);
if ( !strncmp(in_ptr, "ivec", 4) )
{
memcpy(iv, in_ptr+4, blocksize);
cipher_dec_init(iv);
*out = in_ptr + blocksize*2;
len -= blocksize*2;
cipher_dec_state = CIPHER_SEQUENCE;
gibberish = 0;
gib_time_start = 0;
}
else
{
len = 0;
*out = in;
gibberish++;
if (gibberish == 1) gib_time_start = time(NULL);
if (gibberish == MIN_GIBBERISH)
{
cipher_enc_state = CIPHER_REQ_INIT;
send_a_packet = 1;
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO,
"Min. gibberish threshold reached");
#endif
}
if (gibberish >= MAX_GIBBERISH ||
difftime(time(NULL), gib_time_start) >= MAX_GIBBERISH_TIME)
{
gibberish = 0;
gib_time_start = 0;
send_a_packet = 1;
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO,
"Max. gibberish threshold reached");
#endif
if (cipher_enc_state != CIPHER_INIT)
{
cipher_enc_state = CIPHER_INIT;
EVP_CIPHER_CTX_cleanup(&ctx_enc);
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO,
"Forcing local encryptor re-init");
#endif
}
}
}
memset(iv,0,blocksize); free(iv); iv = NULL;
memset(in_ptr,0,blocksize*2);
break;
case CIPHER_CODE:
default:
*out = in;
break;
}
return len;
}
/* Send In-Band Message */
static int send_ib_mesg(int *len, char **in)
{
char *in_ptr = *in;
/* To simplify matters, I assume that blocksize
will not be less than 8 bytes */
if (cipher_enc_state == CIPHER_SEQUENCE)
{
in_ptr -= blocksize;
memset(in_ptr,0,blocksize);
strncpy(in_ptr,"seq#",4);
in_ptr+=4;
*((unsigned long *)in_ptr) = htonl(sequence_num);
in_ptr-=4;
*in = in_ptr;
*len += blocksize;
}
else if (cipher_enc_state == CIPHER_REQ_INIT)
{
in_ptr -= blocksize;
memset(in_ptr,0,blocksize);
strncpy(in_ptr,"rsyn",4);
in_ptr+=4;
*((unsigned long *)in_ptr) = htonl(sequence_num);
in_ptr-=4;
*in = in_ptr;
*len += blocksize;
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO, "Requesting remote encryptor re-init");
#endif
cipher_enc_state = CIPHER_SEQUENCE;
send_a_packet = 1;
}
return 0;
}
/* Receive In-Band Message */
static int recv_ib_mesg(int *len, char **in)
{
char *in_ptr = *in;
if (cipher_dec_state == CIPHER_SEQUENCE)
{
/* To simplify matters, I assume that blocksize
will not be less than 8 bytes */
if ( !strncmp(in_ptr, "seq#", 4) )
{
*in += blocksize;
*len -= blocksize;
}
else if ( !strncmp(in_ptr, "rsyn", 4) )
{
*in += blocksize;
*len -= blocksize;
if (cipher_enc_state != CIPHER_INIT)
{
cipher_enc_state = CIPHER_INIT;
EVP_CIPHER_CTX_cleanup(&ctx_enc);
}
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO, "Remote requests encryptor re-init");
#endif
}
else
{
*len = 0;
if (cipher_dec_state != CIPHER_INIT &&
cipher_enc_state != CIPHER_REQ_INIT &&
cipher_enc_state != CIPHER_INIT)
{
EVP_CIPHER_CTX_cleanup (&ctx_dec);
cipher_dec_state = CIPHER_INIT;
cipher_enc_state = CIPHER_REQ_INIT;
}
#ifdef LFD_ENCRYPT_DEBUG
vtun_syslog(LOG_INFO, "Local decryptor out of sync");
#endif
}
}
return 0;
}
/*
* Module structure.
*/
struct lfd_mod lfd_encrypt = {
"Encryptor",
alloc_encrypt,
@ -714,9 +179,10 @@ struct lfd_mod lfd_encrypt = {
NULL
};
#else /* HAVE_SSL */
#else /* HAVE_SODIUM */
static int no_encrypt(struct vtun_host *host)
static int
no_encrypt(struct vtun_host *host)
{
vtun_syslog(LOG_INFO, "Encryption is not supported");
return -1;
@ -727,4 +193,4 @@ struct lfd_mod lfd_encrypt = {
no_encrypt, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};
#endif /* HAVE_SSL */
#endif

10
main.c
View File

@ -35,6 +35,10 @@
#include <netinet/in.h>
#endif
#ifdef HAVE_SODIUM
#include <sodium.h>
#endif
#include "vtun.h"
#include "lib.h"
#include "compat.h"
@ -194,6 +198,12 @@ int main(int argc, char *argv[], char *env[])
break;
}
#ifdef HAVE_SODIUM
if (sodium_init() != 0) {
abort();
}
#endif
if( daemon ){
#ifdef HAVE_WORKING_FORK
if( dofork && fork() )

17
vtun.h
View File

@ -82,9 +82,12 @@ struct vtun_addr {
#define VTUN_ADDR_IFACE 0x01
#define VTUN_ADDR_NAME 0x02
#define HOST_KEYBYTES 32
struct vtun_host {
char *host;
char *passwd;
unsigned char *key;
char *dev;
llist up;
@ -138,19 +141,7 @@ extern llist host_list;
#define VTUN_ENCRYPT 0x0008
/* Cipher options */
#define VTUN_ENC_BF128CBC 2
#define VTUN_ENC_BF128CFB 3
#define VTUN_ENC_BF128OFB 4
#define VTUN_ENC_BF256CBC 6
#define VTUN_ENC_BF256CFB 7
#define VTUN_ENC_BF256OFB 8
#define VTUN_ENC_AES128CBC 10
#define VTUN_ENC_AES128CFB 11
#define VTUN_ENC_AES128OFB 12
#define VTUN_ENC_AES256CBC 14
#define VTUN_ENC_AES256CFB 15
#define VTUN_ENC_AES256OFB 16
#define VTUN_ENC_AES256GCM 17
/* Mask to drop the flags which will be supplied by the server */
#define VTUN_CLNT_MASK 0xf000

13
vtund.conf
View File

@ -150,18 +150,7 @@
# -----------
# encrypt - Enable 'yes' or disable 'no' encryption.
# It is also possible to specify a method:
# 'blowfish128cbc' - Blowfish cipher, 128 bit key, mode CBC
# 'blowfish128cfb' - Blowfish cipher, 128 bit key, mode CFB
# 'blowfish128ofb' - Blowfish cipher, 128 bit key, mode OFB
# 'blowfish256cbc' - Blowfish cipher, 256 bit key, mode CBC
# 'blowfish256cfb' - Blowfish cipher, 256 bit key, mode CFB
# 'blowfish256ofb' - Blowfish cipher, 256 bit key, mode OFB
# 'aes128cbc' - AES cipher, 128 bit key, mode CBC
# 'aes128cfb' - AES cipher, 128 bit key, mode CFB
# 'aes128ofb' - AES cipher, 128 bit key, mode OFB
# 'aes256cbc' - AES cipher, 256 bit key, mode CBC
# 'aes256cfb' - AES cipher, 256 bit key, mode CFB
# 'aes256ofb' - AES cipher, 256 bit key, mode OFB
# 'aes256gcm' - AES cipher, 256 bit key, mode GCM
#
# Ignored by the client.
#

26
vtund.conf.5
View File

@ -199,30 +199,8 @@ specifies encryption method to use. Encryption \fImethod\fRs include:
no encryption
.IP \fByes\fR
default encryption method
.IP \fBblowfish128cbc\fR
Blowfish cipher, 128 bit key, mode CBC
.IP \fBblowfish128cfb\fR
Blowfish cipher, 128 bit key, mode CFB
.IP \fBblowfish128ofb\fR
Blowfish cipher, 128 bit key, mode OFB
.IP \fBblowfish256cbc\fR
Blowfish cipher, 256 bit key, mode CBC
.IP \fBblowfish256cfb\fR
Blowfish cipher, 256 bit key, mode CFB
.IP \fBblowfish256ofb\fR
Blowfish cipher, 256 bit key, mode OFB
.IP \fBaes128cbc\fR
AES cipher, 128 bit key, mode CBC
.IP \fBaes128cfb\fR
AES cipher, 128 bit key, mode CFB
.IP \fBaes128ofb\fR
AES cipher, 128 bit key, mode OFB
.IP \fBaes256cbc\fR
AES cipher, 256 bit key, mode CBC
.IP \fBaes256cfb\fR
AES cipher, 256 bit key, mode CFB
.IP \fBaes256ofb\fR
AES cipher, 256 bit key, mode OFB
.IP \fBaes256gcm\fR
AES cipher, 256 bit key, mode GCM
.RE
.IP
This option is ignored by the client.