/**
* Negotiates crypto between the calling programm and the prompt
*
* Reads data from the transport section of input_data and sends the public key back
* in the transport section of the output_data.
*
* Returns TRUE on success
**/
static gboolean
negotiate_transport_crypto (void)
{
gcry_mpi_t base, prime, peer;
gcry_mpi_t key, pub, priv;
gboolean ret = FALSE;
gpointer ikm;
gsize n_ikm;
g_assert (!the_key);
base = prime = peer = NULL;
key = pub = priv = NULL;
/* The DH stuff coming in from our caller */
if (gku_prompt_util_decode_mpi (input_data, "transport", "prime", &prime) &&
gku_prompt_util_decode_mpi (input_data, "transport", "base", &base) &&
gku_prompt_util_decode_mpi (input_data, "transport", "public", &peer)) {
/* Generate our own public/priv, and then a key, send it back */
if (egg_dh_gen_pair (prime, base, 0, &pub, &priv)) {
gku_prompt_util_encode_mpi (output_data, "transport", "public", pub);
/* Build up a key we can use */
ikm = egg_dh_gen_secret (peer, priv, prime, &n_ikm);
if (ikm != NULL) {
n_the_key = 16;
the_key = egg_secure_alloc (n_the_key);
if (!egg_hkdf_perform ("sha256", ikm, n_ikm, NULL, 0, NULL, 0, the_key, n_the_key))
g_return_val_if_reached (FALSE);
ret = TRUE;
}
}
}
gcry_mpi_release (base);
gcry_mpi_release (prime);
gcry_mpi_release (peer);
gcry_mpi_release (key);
gcry_mpi_release (pub);
gcry_mpi_release (priv);
return ret;
}
/**
* Negotiates crypto between the calling programm and the prompt
*
* Reads data from the transport section of input_data and sends the public key back
* in the transport section of the output_data.
*
* Returns TRUE on success
**/
static gboolean
negotiate_transport_crypto (void)
{
gcry_mpi_t base, prime, peer;
gcry_mpi_t key, pub, priv;
gboolean ret = FALSE;
g_assert (!the_key);
base = prime = peer = NULL;
key = pub = priv = NULL;
/* The DH stuff coming in from our caller */
if (gku_prompt_util_decode_mpi (input_data, "transport", "prime", &prime) &&
gku_prompt_util_decode_mpi (input_data, "transport", "base", &base) &&
gku_prompt_util_decode_mpi (input_data, "transport", "public", &peer)) {
/* Generate our own public/priv, and then a key, send it back */
if (egg_dh_gen_pair (prime, base, 0, &pub, &priv)) {
gku_prompt_util_encode_mpi (output_data, "transport", "public", pub);
/* Build up a key we can use */
n_the_key = 16;
the_key = egg_dh_gen_secret (peer, priv, prime, n_the_key);
ret = (the_key != NULL);
}
}
gcry_mpi_release (base);
gcry_mpi_release (prime);
gcry_mpi_release (peer);
gcry_mpi_release (key);
gcry_mpi_release (pub);
gcry_mpi_release (priv);
return ret;
}