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exchange/src/lib/exchange_api_withdraw.c

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/*
This file is part of TALER
Copyright (C) 2014-2022 Taler Systems SA
TALER 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 3, or (at your option) any later version.
TALER 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.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see
<http://www.gnu.org/licenses/>
*/
/**
* @file lib/exchange_api_withdraw.c
* @brief Implementation of /reserves/$RESERVE_PUB/withdraw requests with blinding/unblinding
* @author Christian Grothoff
*/
#include "platform.h"
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_exchange_service.h"
#include "taler_json_lib.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* @brief A Withdraw Handle
*/
struct TALER_EXCHANGE_WithdrawHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* Handle for the actual (internal) withdraw operation.
*/
struct TALER_EXCHANGE_Withdraw2Handle *wh2;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_WithdrawCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Reserve private key.
*/
const struct TALER_ReservePrivateKeyP *reserve_priv;
/**
* Seed of the planchet.
*/
struct TALER_PlanchetMasterSecretP ps;
/**
* blinding secret
*/
union TALER_DenominationBlindingKeyP bks;
/**
* Private key of the coin we are withdrawing.
*/
struct TALER_CoinSpendPrivateKeyP priv;
/**
* Details of the planchet.
*/
struct TALER_PlanchetDetail pd;
/**
* Values of the @cipher selected
*/
struct TALER_ExchangeWithdrawValues alg_values;
/**
* Hash of the age commitment for this coin, if applicable. Maybe NULL
*/
const struct TALER_AgeCommitmentHash *ach;
/**
* Denomination key we are withdrawing.
*/
struct TALER_EXCHANGE_DenomPublicKey pk;
/**
* Hash of the public key of the coin we are signing.
*/
struct TALER_CoinPubHashP c_hash;
/**
* Handler for the CS R request (only used for TALER_DENOMINATION_CS denominations)
*/
struct TALER_EXCHANGE_CsRWithdrawHandle *csrh;
};
/**
* Function called when we're done processing the
* HTTP /reserves/$RESERVE_PUB/withdraw request.
*
* @param cls the `struct TALER_EXCHANGE_WithdrawHandle`
* @param hr HTTP response data
* @param blind_sig blind signature over the coin, NULL on error
*/
static void
handle_reserve_withdraw_finished (
void *cls,
const struct TALER_EXCHANGE_HttpResponse *hr,
const struct TALER_BlindedDenominationSignature *blind_sig)
{
struct TALER_EXCHANGE_WithdrawHandle *wh = cls;
struct TALER_EXCHANGE_WithdrawResponse wr = {
.hr = *hr
};
wh->wh2 = NULL;
switch (hr->http_status)
{
case MHD_HTTP_OK:
{
struct TALER_FreshCoin fc;
if (GNUNET_OK !=
TALER_planchet_to_coin (&wh->pk.key,
blind_sig,
&wh->bks,
&wh->priv,
wh->ach,
&wh->c_hash,
&wh->alg_values,
&fc))
{
wr.hr.http_status = 0;
wr.hr.ec = TALER_EC_EXCHANGE_WITHDRAW_UNBLIND_FAILURE;
break;
}
wr.details.success.coin_priv = wh->priv;
wr.details.success.bks = wh->bks;
wr.details.success.sig = fc.sig;
wr.details.success.exchange_vals = wh->alg_values;
break;
}
case MHD_HTTP_ACCEPTED:
{
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_uint64 ("payment_target_uuid",
&wr.details.accepted.payment_target_uuid),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (hr->reply,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
wr.hr.http_status = 0;
wr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
}
break;
default:
break;
}
wh->cb (wh->cb_cls,
&wr);
if (MHD_HTTP_OK == hr->http_status)
TALER_denom_sig_free (&wr.details.success.sig);
TALER_EXCHANGE_withdraw_cancel (wh);
}
/**
* Function called when stage 1 of CS withdraw is finished (request r_pub's)
*
* @param cls the `struct TALER_EXCHANGE_WithdrawHandle`
* @param csrr replies from the /csr-withdraw request
*/
static void
withdraw_cs_stage_two_callback (
void *cls,
const struct TALER_EXCHANGE_CsRWithdrawResponse *csrr)
{
struct TALER_EXCHANGE_WithdrawHandle *wh = cls;
struct TALER_EXCHANGE_WithdrawResponse wr = {
.hr = csrr->hr
};
wh->csrh = NULL;
GNUNET_assert (TALER_DENOMINATION_CS == wh->pk.key.cipher);
switch (csrr->hr.http_status)
{
case MHD_HTTP_OK:
wh->alg_values = csrr->details.success.alg_values;
TALER_planchet_setup_coin_priv (&wh->ps,
&wh->alg_values,
&wh->priv);
TALER_planchet_blinding_secret_create (&wh->ps,
&wh->alg_values,
&wh->bks);
/* This initializes the 2nd half of the
wh->pd.blinded_planchet! */
if (GNUNET_OK !=
TALER_planchet_prepare (&wh->pk.key,
&wh->alg_values,
&wh->bks,
&wh->priv,
wh->ach,
&wh->c_hash,
&wh->pd))
{
GNUNET_break (0);
GNUNET_free (wh);
}
wh->wh2 = TALER_EXCHANGE_withdraw2 (wh->exchange,
&wh->pd,
wh->reserve_priv,
&handle_reserve_withdraw_finished,
wh);
return;
default:
break;
}
wh->cb (wh->cb_cls,
&wr);
TALER_EXCHANGE_withdraw_cancel (wh);
}
struct TALER_EXCHANGE_WithdrawHandle *
TALER_EXCHANGE_withdraw (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_ReservePrivateKeyP *reserve_priv,
const struct TALER_PlanchetMasterSecretP *ps,
const struct TALER_AgeCommitmentHash *ach,
TALER_EXCHANGE_WithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_EXCHANGE_WithdrawHandle *wh;
wh = GNUNET_new (struct TALER_EXCHANGE_WithdrawHandle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
wh->reserve_priv = reserve_priv;
wh->ps = *ps;
wh->ach = ach;
wh->pk = *pk;
TALER_denom_pub_deep_copy (&wh->pk.key,
&pk->key);
switch (pk->key.cipher)
{
case TALER_DENOMINATION_RSA:
{
wh->alg_values.cipher = TALER_DENOMINATION_RSA;
TALER_planchet_setup_coin_priv (ps,
&wh->alg_values,
&wh->priv);
TALER_planchet_blinding_secret_create (ps,
&wh->alg_values,
&wh->bks);
if (GNUNET_OK !=
TALER_planchet_prepare (&pk->key,
&wh->alg_values,
&wh->bks,
&wh->priv,
wh->ach,
&wh->c_hash,
&wh->pd))
{
GNUNET_break (0);
GNUNET_free (wh);
return NULL;
}
wh->wh2 = TALER_EXCHANGE_withdraw2 (exchange,
&wh->pd,
wh->reserve_priv,
&handle_reserve_withdraw_finished,
wh);
break;
}
case TALER_DENOMINATION_CS:
{
TALER_cs_withdraw_nonce_derive (
ps,
&wh->pd.blinded_planchet.details.cs_blinded_planchet.nonce);
/* Note that we only initialize the first half
of the blinded_planchet here; the other part
will be done after the /csr-withdraw request! */
wh->pd.blinded_planchet.cipher = TALER_DENOMINATION_CS;
wh->csrh = TALER_EXCHANGE_csr_withdraw (
exchange,
pk,
&wh->pd.blinded_planchet.details.cs_blinded_planchet.nonce,
&withdraw_cs_stage_two_callback,
wh);
break;
}
default:
GNUNET_break (0);
GNUNET_free (wh);
return NULL;
}
return wh;
}
void
TALER_EXCHANGE_withdraw_cancel (struct TALER_EXCHANGE_WithdrawHandle *wh)
{
TALER_blinded_planchet_free (&wh->pd.blinded_planchet);
if (NULL != wh->csrh)
{
TALER_EXCHANGE_csr_withdraw_cancel (wh->csrh);
wh->csrh = NULL;
}
if (NULL != wh->wh2)
{
TALER_EXCHANGE_withdraw2_cancel (wh->wh2);
wh->wh2 = NULL;
}
TALER_denom_pub_free (&wh->pk.key);
GNUNET_free (wh);
}
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