void blufi_dh_negotiate_data_handler(uint8_t *data, int len, uint8_t **output_data, int *output_len, bool *need_free)
{
int ret;
uint8_t type = data[0];
if (blufi_sec == NULL) {
BLUFI_ERROR("BLUFI Security is not initialized");
return;
}
switch (type) {
case SEC_TYPE_DH_PARAM_LEN:
blufi_sec->dh_param_len = ((data[1]<<8)|data[2]);
if (blufi_sec->dh_param) {
free(blufi_sec->dh_param);
}
blufi_sec->dh_param = (uint8_t *)malloc(blufi_sec->dh_param_len);
if (blufi_sec->dh_param == NULL) {
return;
}
break;
case SEC_TYPE_DH_PARAM_DATA:
memcpy(blufi_sec->dh_param, &data[1], blufi_sec->dh_param_len);
ret = mbedtls_dhm_read_params(&blufi_sec->dhm, &blufi_sec->dh_param, &blufi_sec->dh_param[blufi_sec->dh_param_len]);
if (ret) {
BLUFI_ERROR("%s read param failed %d\n", __func__, ret);
return;
}
ret = mbedtls_dhm_make_public(&blufi_sec->dhm, (int) mbedtls_mpi_size( &blufi_sec->dhm.P ), blufi_sec->self_public_key, blufi_sec->dhm.len, myrand, NULL);
if (ret) {
BLUFI_ERROR("%s make public failed %d\n", __func__, ret);
return;
}
mbedtls_dhm_calc_secret( &blufi_sec->dhm,
blufi_sec->share_key,
SHARE_KEY_BIT_LEN,
&blufi_sec->share_len,
NULL, NULL);
mbedtls_md5(blufi_sec->share_key, blufi_sec->share_len, blufi_sec->psk);
mbedtls_aes_setkey_enc(&blufi_sec->aes, blufi_sec->psk, 128);
/* alloc output data */
*output_data = &blufi_sec->self_public_key[0];
*output_len = blufi_sec->dhm.len;
*need_free = false;
break;
case SEC_TYPE_DH_P:
break;
case SEC_TYPE_DH_G:
break;
case SEC_TYPE_DH_PUBLIC:
break;
}
}
int DHMContext::calcSecret(State & state, mbedtls_dhm_context * context){
Stack * stack = state.stack;
CTRDRBGContext * interfaceCTRDRBGContext = OBJECT_IFACE(CTRDRBGContext);
mbedtls_ctr_drbg_context * drbg = interfaceCTRDRBGContext->get(1);
if (stack->is<LUA_TNUMBER>(2) && drbg){
size_t n = static_cast<size_t>(stack->to<int>(2));
unsigned char * buffer = new unsigned char[n];
size_t olen = 0;
int result = mbedtls_dhm_calc_secret(context, buffer, n, &olen, mbedtls_ctr_drbg_random, drbg);
if (result == 0){
stack->push<bool>(true);
stack->pushLString(std::string(reinterpret_cast<char*>(buffer), olen));
}
else{
stack->push<bool>(false);
stack->push<int>(result);
}
delete[] buffer;
return 2;
}
return 0;
}
int main( void )
{
FILE *f;
int ret;
size_t n, buflen;
mbedtls_net_context server_fd;
unsigned char *p, *end;
unsigned char buf[2048];
unsigned char hash[32];
const char *pers = "dh_client";
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_rsa_context rsa;
mbedtls_dhm_context dhm;
mbedtls_aes_context aes;
mbedtls_net_init( &server_fd );
mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_SHA256 );
mbedtls_dhm_init( &dhm );
mbedtls_aes_init( &aes );
mbedtls_ctr_drbg_init( &ctr_drbg );
/*
* 1. Setup the RNG
*/
mbedtls_printf( "\n . Seeding the random number generator" );
fflush( stdout );
mbedtls_entropy_init( &entropy );
if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
(const unsigned char *) pers,
strlen( pers ) ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
goto exit;
}
/*
* 2. Read the server's public RSA key
*/
mbedtls_printf( "\n . Reading public key from rsa_pub.txt" );
fflush( stdout );
if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
{
ret = 1;
mbedtls_printf( " failed\n ! Could not open rsa_pub.txt\n" \
" ! Please run rsa_genkey first\n\n" );
goto exit;
}
mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
if( ( ret = mbedtls_mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
( ret = mbedtls_mpi_read_file( &rsa.E, 16, f ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret );
goto exit;
}
rsa.len = ( mbedtls_mpi_bitlen( &rsa.N ) + 7 ) >> 3;
fclose( f );
/*
* 3. Initiate the connection
*/
mbedtls_printf( "\n . Connecting to tcp/%s/%s", SERVER_NAME,
SERVER_PORT );
fflush( stdout );
if( ( ret = mbedtls_net_connect( &server_fd, SERVER_NAME,
SERVER_PORT, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_net_connect returned %d\n\n", ret );
goto exit;
}
/*
* 4a. First get the buffer length
*/
mbedtls_printf( "\n . Receiving the server's DH parameters" );
fflush( stdout );
memset( buf, 0, sizeof( buf ) );
if( ( ret = mbedtls_net_recv( &server_fd, buf, 2 ) ) != 2 )
{
mbedtls_printf( " failed\n ! mbedtls_net_recv returned %d\n\n", ret );
goto exit;
}
n = buflen = ( buf[0] << 8 ) | buf[1];
if( buflen < 1 || buflen > sizeof( buf ) )
{
mbedtls_printf( " failed\n ! Got an invalid buffer length\n\n" );
goto exit;
}
/*
* 4b. Get the DHM parameters: P, G and Ys = G^Xs mod P
*/
memset( buf, 0, sizeof( buf ) );
if( ( ret = mbedtls_net_recv( &server_fd, buf, n ) ) != (int) n )
{
mbedtls_printf( " failed\n ! mbedtls_net_recv returned %d\n\n", ret );
goto exit;
}
p = buf, end = buf + buflen;
if( ( ret = mbedtls_dhm_read_params( &dhm, &p, end ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_dhm_read_params returned %d\n\n", ret );
goto exit;
}
if( dhm.len < 64 || dhm.len > 512 )
{
ret = 1;
mbedtls_printf( " failed\n ! Invalid DHM modulus size\n\n" );
goto exit;
}
/*
* 5. Check that the server's RSA signature matches
* the SHA-256 hash of (P,G,Ys)
*/
mbedtls_printf( "\n . Verifying the server's RSA signature" );
fflush( stdout );
p += 2;
if( ( n = (size_t) ( end - p ) ) != rsa.len )
{
ret = 1;
mbedtls_printf( " failed\n ! Invalid RSA signature size\n\n" );
goto exit;
}
mbedtls_sha1( buf, (int)( p - 2 - buf ), hash );
if( ( ret = mbedtls_rsa_pkcs1_verify( &rsa, NULL, NULL, MBEDTLS_RSA_PUBLIC,
MBEDTLS_MD_SHA256, 0, hash, p ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_rsa_pkcs1_verify returned %d\n\n", ret );
goto exit;
}
/*
* 6. Send our public value: Yc = G ^ Xc mod P
*/
mbedtls_printf( "\n . Sending own public value to server" );
fflush( stdout );
n = dhm.len;
if( ( ret = mbedtls_dhm_make_public( &dhm, (int) dhm.len, buf, n,
mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_dhm_make_public returned %d\n\n", ret );
goto exit;
}
if( ( ret = mbedtls_net_send( &server_fd, buf, n ) ) != (int) n )
{
mbedtls_printf( " failed\n ! mbedtls_net_send returned %d\n\n", ret );
goto exit;
}
/*
* 7. Derive the shared secret: K = Ys ^ Xc mod P
*/
mbedtls_printf( "\n . Shared secret: " );
fflush( stdout );
if( ( ret = mbedtls_dhm_calc_secret( &dhm, buf, sizeof( buf ), &n,
mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_dhm_calc_secret returned %d\n\n", ret );
goto exit;
}
for( n = 0; n < 16; n++ )
mbedtls_printf( "%02x", buf[n] );
/*
* 8. Setup the AES-256 decryption key
*
* This is an overly simplified example; best practice is
* to hash the shared secret with a random value to derive
* the keying material for the encryption/decryption keys,
* IVs and MACs.
*/
mbedtls_printf( "...\n . Receiving and decrypting the ciphertext" );
fflush( stdout );
mbedtls_aes_setkey_dec( &aes, buf, 256 );
memset( buf, 0, sizeof( buf ) );
if( ( ret = mbedtls_net_recv( &server_fd, buf, 16 ) ) != 16 )
{
mbedtls_printf( " failed\n ! mbedtls_net_recv returned %d\n\n", ret );
goto exit;
}
mbedtls_aes_crypt_ecb( &aes, MBEDTLS_AES_DECRYPT, buf, buf );
buf[16] = '\0';
mbedtls_printf( "\n . Plaintext is \"%s\"\n\n", (char *) buf );
exit:
mbedtls_net_free( &server_fd );
mbedtls_aes_free( &aes );
mbedtls_rsa_free( &rsa );
mbedtls_dhm_free( &dhm );
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
#if defined(_WIN32)
mbedtls_printf( " + Press Enter to exit this program.\n" );
fflush( stdout ); getchar();
#endif
return( ret );
}
