/**
* gcr_secret_exchange_get_protocol:
* @self: a #GcrSecretExchange object
* Get the secret exchange protocol.
*
* Will return %NULL if no protocol was specified, and either
* gcr_secret_exchange_begin() or gcr_secret_exchange_receive() have not been
* called successfully.
*
* Returns: the protocol or %NULL
*/
const gchar *
gcr_secret_exchange_get_protocol (GcrSecretExchange *self)
{
g_return_val_if_fail (GCR_IS_SECRET_EXCHANGE (self), NULL);
if (self->pv->explicit_protocol || self->pv->generated)
return GCR_SECRET_EXCHANGE_PROTOCOL_1;
return NULL;
}
/**
* gcr_secret_exchange_receive:
* @self: a #GcrSecretExchange object
* @exchange: the string received
*
* Receive a string from the other side of secret exchange. This string will
* have been created by gcr_secret_exchange_begin() or gcr_secret_exchange_send().
*
* After this call completes successfully the value returned from
* gcr_secret_exchange_get_secret() will have changed.
*
* Returns: whether the string was successfully parsed and received
*/
gboolean
gcr_secret_exchange_receive (GcrSecretExchange *self,
const gchar *exchange)
{
GcrSecretExchangeClass *klass;
gchar *secret = NULL;
gsize n_secret = 0;
GKeyFile *input;
gboolean ret;
g_return_val_if_fail (GCR_IS_SECRET_EXCHANGE (self), FALSE);
g_return_val_if_fail (exchange != NULL, FALSE);
klass = GCR_SECRET_EXCHANGE_GET_CLASS (self);
g_return_val_if_fail (klass->generate_exchange_key, FALSE);
g_return_val_if_fail (klass->derive_transport_key, FALSE);
gchar *string = g_strescape (exchange, "");
g_debug ("receiving secret exchange: %s", string);
g_free (string);
/* Parse the input */
input = g_key_file_new ();
if (!g_key_file_load_from_data (input, exchange, strlen (exchange),
G_KEY_FILE_NONE, NULL)) {
g_key_file_free (input);
g_message ("couldn't parse secret exchange data");
return FALSE;
}
if (!self->pv->generated) {
if (!(klass->generate_exchange_key) (self, GCR_SECRET_EXCHANGE_PROTOCOL_1,
&self->pv->publi, &self->pv->n_publi))
g_return_val_if_reached (FALSE);
self->pv->generated = TRUE;
}
ret = TRUE;
if (!self->pv->derived) {
if (!derive_key (self, input))
ret = FALSE;
}
if (ret && g_key_file_has_key (input, GCR_SECRET_EXCHANGE_PROTOCOL_1, "secret", NULL))
ret = perform_decrypt (self, input, (guchar **)&secret, &n_secret);
if (ret) {
egg_secure_free (self->pv->secret);
self->pv->secret = secret;
self->pv->n_secret = n_secret;
}
g_key_file_free (input);
return ret;
}
/**
* gcr_secret_exchange_get_secret:
* @self: a #GcrSecretExchange object
* @secret_len: (allow-none): optionally, a location to store the length of returned secret
*
* Returns the last secret received. If no secret has yet been received this
* will return %NULL. The string is owned by the #GcrSecretExchange object
* and will be valid until the next time that gcr_secret_exchange_receive()
* is called on this object, or the object is destroyed.
*
* Depending on the secret passed into the other side of the secret exchange,
* the result may be a binary string. It does however have a null terminator,
* so if you're certain that it is does not contain arbitrary binary data,
* it can be used as a string.
*
* Returns: (transfer none) (array length=secret_len): the last secret received
*/
const gchar *
gcr_secret_exchange_get_secret (GcrSecretExchange *self,
gsize *secret_len)
{
g_return_val_if_fail (GCR_IS_SECRET_EXCHANGE (self), NULL);
if (secret_len)
*secret_len = self->pv->n_secret;
return self->pv->secret;
}
/**
* gcr_secret_exchange_send:
* @self: a #GcrSecretExchange object
* @secret: (allow-none): optionally, a secret to send to the other side
* @secret_len: length of @secret, or -1 if null terminated
*
* Send a reply to the other side of the secret exchange, optionally sending a
* secret.
*
* gcr_secret_exchange_receive() must have been successfully called at least
* once on this object. In other words this object must have received data
* from the other side of the secret exchange, before we can send a secret.
*
* Returns: (transfer full): a newly allocated string to be sent to the other
* side of the secret exchange
*/
gchar *
gcr_secret_exchange_send (GcrSecretExchange *self,
const gchar *secret,
gssize secret_len)
{
GKeyFile *output;
gchar *result;
g_return_val_if_fail (GCR_IS_SECRET_EXCHANGE (self), NULL);
if (!self->pv->derived) {
g_warning ("gcr_secret_exchange_receive() must be called "
"before calling this function");
return NULL;
}
output = g_key_file_new ();
key_file_set_base64 (output, GCR_SECRET_EXCHANGE_PROTOCOL_1, "public", self->pv->publi,
self->pv->n_publi);
if (secret != NULL) {
if (secret_len < 0)
secret_len = strlen (secret);
if (!perform_encrypt (self, output, secret, secret_len)) {
g_key_file_free (output);
return NULL;
}
}
result = g_key_file_to_data (output, NULL, NULL);
g_return_val_if_fail (result != NULL, NULL);
g_strchug (result);
gchar *string = g_strescape (result, "");
g_debug ("sending the secret exchange: %s", string);
g_free (string);
if (!g_str_has_prefix (result, SECRET_EXCHANGE_PROTOCOL_1_PREFIX))
g_warning ("the prepared data does not have the correct protocol prefix: %s", result);
g_key_file_free (output);
return result;
}
/**
* gcr_secret_exchange_begin:
* @self: a #GcrSecretExchange object
*
* Begin the secret exchange. The resulting string should be sent to the other
* side of the exchange. The other side should use gcr_secret_exchange_receive()
* to process the string.
*
* Returns: (transfer full): A newly allocated string to be sent to the other
* side of the secret exchange
*/
gchar *
gcr_secret_exchange_begin (GcrSecretExchange *self)
{
GcrSecretExchangeClass *klass;
GKeyFile *output;
gchar *result;
g_return_val_if_fail (GCR_IS_SECRET_EXCHANGE (self), NULL);
klass = GCR_SECRET_EXCHANGE_GET_CLASS (self);
g_return_val_if_fail (klass->generate_exchange_key, NULL);
clear_secret_exchange (self);
output = g_key_file_new ();
if (!(klass->generate_exchange_key) (self, GCR_SECRET_EXCHANGE_PROTOCOL_1,
&self->pv->publi, &self->pv->n_publi))
g_return_val_if_reached (NULL);
self->pv->generated = TRUE;
key_file_set_base64 (output, GCR_SECRET_EXCHANGE_PROTOCOL_1, "public",
self->pv->publi, self->pv->n_publi);
result = g_key_file_to_data (output, NULL, NULL);
g_return_val_if_fail (result != NULL, NULL);
g_strchug (result);
gchar *string = g_strescape (result, "");
g_debug ("beginning the secret exchange: %s", string);
g_free (string);
if (!g_str_has_prefix (result, SECRET_EXCHANGE_PROTOCOL_1_PREFIX))
g_warning ("the prepared data does not have the correct protocol prefix");
g_key_file_free (output);
return result;
}
