int send_packet( const packet *p, const char *why )
{
int ret;
mbedtls_net_context *dst = p->dst;
/* insert corrupted ApplicationData record? */
if( opt.bad_ad &&
strcmp( p->type, "ApplicationData" ) == 0 )
{
unsigned char buf[MAX_MSG_SIZE];
memcpy( buf, p->buf, p->len );
++buf[p->len - 1];
print_packet( p, "corrupted" );
if( ( ret = mbedtls_net_send( dst, buf, p->len ) ) <= 0 )
{
mbedtls_printf( " ! mbedtls_net_send returned %d\n", ret );
return( ret );
}
}
print_packet( p, why );
if( ( ret = mbedtls_net_send( dst, p->buf, p->len ) ) <= 0 )
{
mbedtls_printf( " ! mbedtls_net_send returned %d\n", ret );
return( ret );
}
/* Don't duplicate Application Data, only handshake covered */
if( opt.duplicate != 0 &&
strcmp( p->type, "ApplicationData" ) != 0 &&
rand() % opt.duplicate == 0 )
{
print_packet( p, "duplicated" );
if( ( ret = mbedtls_net_send( dst, p->buf, p->len ) ) <= 0 )
{
mbedtls_printf( " ! mbedtls_net_send returned %d\n", ret );
return( ret );
}
}
return( 0 );
}
int dslink_socket_write(Socket *sock, char *buf, size_t len) {
int r;
if (sock->secure) {
r = mbedtls_ssl_write(((SslSocket *) sock)->ssl,
(unsigned char *) buf, len);
} else {
r = mbedtls_net_send(sock->socket_fd, (unsigned char *) buf, len);
}
if (r < 0) {
errno = r;
return DSLINK_SOCK_WRITE_ERR;
}
return r;
}
static int write_and_get_response( mbedtls_net_context *sock_fd, unsigned char *buf, size_t len )
{
int ret;
unsigned char data[128];
char code[4];
size_t i, idx = 0;
mbedtls_printf("\n%s", buf);
if( len && ( ret = mbedtls_net_send( sock_fd, buf, len ) ) <= 0 )
{
mbedtls_printf( " failed\n ! mbedtls_ssl_write returned %d\n\n", ret );
return -1;
}
do
{
len = sizeof( data ) - 1;
memset( data, 0, sizeof( data ) );
ret = mbedtls_net_recv( sock_fd, data, len );
if( ret <= 0 )
{
mbedtls_printf( "failed\n ! read returned %d\n\n", ret );
return -1;
}
data[len] = '\0';
mbedtls_printf("\n%s", data);
len = ret;
for( i = 0; i < len; i++ )
{
if( data[i] != '\n' )
{
if( idx < 4 )
code[ idx++ ] = data[i];
continue;
}
if( idx == 4 && code[0] >= '0' && code[0] <= '9' && code[3] == ' ' )
{
code[3] = '\0';
return atoi( code );
}
idx = 0;
}
}
while( 1 );
}
static int ctx_buffer_flush( ctx_buffer *buf )
{
int ret;
mbedtls_printf( " %05u flush %s: %u bytes, %u datagrams, last %u ms\n",
ellapsed_time(), buf->description,
(unsigned) buf->len, buf->num_datagrams,
ellapsed_time() - buf->packet_lifetime );
ret = mbedtls_net_send( buf->ctx, buf->data, buf->len );
buf->len = 0;
buf->num_datagrams = 0;
return( ret );
}
int
mtls_write(mtlsctx_t* ctx, const void* buf, int len)
{
int rv;
TRACE("called\n");
if (ctx->usessl == 0) {
rv = mbedtls_net_send(&ctx->net, buf, len);
} else {
rv = mbedtls_ssl_write(&ctx->ssl, buf, len);
}
if (rv < 0) {
ERROR("mtls_write failed: %s\n", mtls_errmsg(rv));
return rv;
}
TRACE("%d bytes\n", rv);
return rv;
}
static int dispatch_data( mbedtls_net_context *ctx,
const unsigned char * data,
size_t len )
{
#if defined(MBEDTLS_TIMING_C)
ctx_buffer *buf = NULL;
if( opt.pack > 0 )
{
if( outbuf[0].ctx == ctx )
buf = &outbuf[0];
else if( outbuf[1].ctx == ctx )
buf = &outbuf[1];
if( buf == NULL )
return( -1 );
return( ctx_buffer_append( buf, data, len ) );
}
#endif /* MBEDTLS_TIMING_C */
return( mbedtls_net_send( ctx, data, len ) );
}
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 );
}
static void session_receive_from_backend(EV_P_ session_context *sc) {
int ret;
packet_data *pd;
packet_data temp = { .length = sizeof(temp.payload) };
ret = mbedtls_ssl_read(&sc->ssl, temp.payload, temp.length);
switch (ret) {
case MBEDTLS_ERR_SSL_WANT_READ:
case MBEDTLS_ERR_SSL_WANT_WRITE:
case MBEDTLS_ERR_NET_RECV_FAILED:
case MBEDTLS_ERR_SSL_TIMEOUT:
session_mark_activity(EV_A_ sc);
return;
case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
log_info("(%s:%d) Backend asked to close DTLS session",
sc->options->backend_host, sc->options->backend_port);
ev_io_start(EV_A_ &sc->backend_wr_watcher);
sc->step = GOLDY_SESSION_STEP_FLUSH_TO_CLIENT;
return;
default:
if (ret < 0) {
session_deferred_free_after_error(sc, ret, "session_receive_from_backend - unknwon error");
return;
}
/* ret is the number of plaintext bytes received */
log_debug("(%s:%d) %d bytes read from DTLS socket",
sc->options->backend_host, sc->options->backend_port, ret);
if (ret > PACKET_DATA_BUFFER_SIZE) {
session_deferred_free_after_error(sc, 0, "session_receive_from_backend - packet payload too big");
return;
}
pd = calloc(1, sizeof(packet_data));
memcpy(pd->payload, temp.payload, ret);
pd->length = ret;
pd->next = 0;
LL_APPEND(sc->from_backend, pd);
session_mark_activity(EV_A_ sc);
ev_io_start(EV_A_ &sc->client_wr_watcher);
return;
}
}
static void session_send_to_client(EV_P_ session_context *sc) {
int ret;
packet_data* head = sc->from_backend;
if (!head) {
ev_io_stop(EV_A_ &sc->client_wr_watcher);
return;
}
ret = mbedtls_net_send(&sc->client_fd, head->payload, head->length);
if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
session_mark_activity(EV_A_ sc);
return;
}
if (ret < 0) {
session_deferred_free_after_error(sc, ret, "session_send_to_client");
return;
}
log_debug("(%s:%d) %d bytes sent to client server",
sc->client_ip_str, sc->client_port, ret);
if ((size_t)ret != head->length) {
log_error("Sent only %d bytes out of %d", ret, head->length);
}
session_mark_activity(EV_A_ sc);
LL_DELETE(sc->from_backend, head);
free(head);
if (!sc->from_backend) {
ev_io_stop(EV_A_ &sc->client_wr_watcher);
}
return;
}
