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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_batch_withdraw.c
* @brief Implementation of /reserves/$RESERVE_PUB/batch-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"
/**
* Data we keep per coin in the batch.
*/
struct CoinData
{
/**
* Denomination key we are withdrawing.
*/
struct TALER_EXCHANGE_DenomPublicKey pk;
/**
* Master key material for the coin.
*/
struct TALER_PlanchetMasterSecretP ps;
/**
* Age commitment for the coin.
*/
const struct TALER_AgeCommitmentHash *ach;
/**
* 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 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;
/**
* Batch withdraw this coin is part of.
*/
struct TALER_EXCHANGE_BatchWithdrawHandle *wh;
};
/**
* @brief A batch withdraw handle
*/
struct TALER_EXCHANGE_BatchWithdrawHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* Handle for the actual (internal) batch withdraw operation.
*/
struct TALER_EXCHANGE_BatchWithdraw2Handle *wh2;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_BatchWithdrawCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Reserve private key.
*/
const struct TALER_ReservePrivateKeyP *reserve_priv;
/**
* Array of per-coin data.
*/
struct CoinData *coins;
/**
* Length of the @e coins array.
*/
unsigned int num_coins;
/**
* Number of CS requests still pending.
*/
unsigned int cs_pending;
};
/**
* Function called when we're done processing the
* HTTP /reserves/$RESERVE_PUB/batch-withdraw request.
*
* @param cls the `struct TALER_EXCHANGE_BatchWithdrawHandle`
* @param hr HTTP response data
* @param blind_sigs array of blind signatures over the coins, NULL on error
* @param blind_sigs_length length of the @a blind_sigs array
*/
static void
handle_reserve_batch_withdraw_finished (
void *cls,
const struct TALER_EXCHANGE_HttpResponse *hr,
const struct TALER_BlindedDenominationSignature *blind_sigs,
unsigned int blind_sigs_length)
{
struct TALER_EXCHANGE_BatchWithdrawHandle *wh = cls;
struct TALER_EXCHANGE_BatchWithdrawResponse wr = {
.hr = *hr
};
struct TALER_EXCHANGE_PrivateCoinDetails coins[wh->num_coins];
wh->wh2 = NULL;
memset (coins,
0,
sizeof (coins));
if (blind_sigs_length != wh->num_coins)
{
GNUNET_break_op (0);
wr.hr.http_status = 0;
wr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
}
switch (hr->http_status)
{
case MHD_HTTP_OK:
{
for (unsigned int i = 0; i<wh->num_coins; i++)
{
struct CoinData *cd = &wh->coins[i];
struct TALER_EXCHANGE_PrivateCoinDetails *coin = &coins[i];
struct TALER_FreshCoin fc;
if (GNUNET_OK !=
TALER_planchet_to_coin (&cd->pk.key,
&blind_sigs[i],
&cd->bks,
&cd->priv,
cd->ach,
&cd->c_hash,
&cd->alg_values,
&fc))
{
wr.hr.http_status = 0;
wr.hr.ec = TALER_EC_EXCHANGE_WITHDRAW_UNBLIND_FAILURE;
break;
}
coin->coin_priv = cd->priv;
coin->bks = cd->bks;
coin->sig = fc.sig;
coin->exchange_vals = cd->alg_values;
}
wr.details.success.coins = coins;
wr.details.success.num_coins = wh->num_coins;
break;
}
case MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS:
{
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_uint64 ("legitimization_uuid",
&wr.details.accepted.legitimization_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);
for (unsigned int i = 0; i<wh->num_coins; i++)
TALER_denom_sig_free (&coins[i].sig);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
}
/**
* Runs phase two, the actual withdraw operation.
* Started once the preparation for CS-denominations is
* done.
*
* @param[in,out] wh batch withdraw to start phase 2 for
*/
static void
phase_two (struct TALER_EXCHANGE_BatchWithdrawHandle *wh)
{
struct TALER_PlanchetDetail pds[wh->num_coins];
for (unsigned int i = 0; i<wh->num_coins; i++)
{
struct CoinData *cd = &wh->coins[i];
pds[i] = cd->pd;
}
wh->wh2 = TALER_EXCHANGE_batch_withdraw2 (
wh->exchange,
wh->reserve_priv,
pds,
wh->num_coins,
&handle_reserve_batch_withdraw_finished,
wh);
}
/**
* Function called when stage 1 of CS withdraw is finished (request r_pub's)
*
* @param cls the `struct CoinData *`
* @param csrr replies from the /csr-withdraw request
*/
static void
withdraw_cs_stage_two_callback (
void *cls,
const struct TALER_EXCHANGE_CsRWithdrawResponse *csrr)
{
struct CoinData *cd = cls;
struct TALER_EXCHANGE_BatchWithdrawHandle *wh = cd->wh;
struct TALER_EXCHANGE_BatchWithdrawResponse wr = {
.hr = csrr->hr
};
cd->csrh = NULL;
GNUNET_assert (TALER_DENOMINATION_CS == cd->pk.key.cipher);
switch (csrr->hr.http_status)
{
case MHD_HTTP_OK:
cd->alg_values = csrr->details.success.alg_values;
TALER_planchet_setup_coin_priv (&cd->ps,
&cd->alg_values,
&cd->priv);
TALER_planchet_blinding_secret_create (&cd->ps,
&cd->alg_values,
&cd->bks);
/* This initializes the 2nd half of the
wh->pd.blinded_planchet! */
if (GNUNET_OK !=
TALER_planchet_prepare (&cd->pk.key,
&cd->alg_values,
&cd->bks,
&cd->priv,
cd->ach,
&cd->c_hash,
&cd->pd))
{
GNUNET_break (0);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
}
wh->cs_pending--;
if (0 == wh->cs_pending)
phase_two (wh);
return;
default:
break;
}
wh->cb (wh->cb_cls,
&wr);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
}
struct TALER_EXCHANGE_BatchWithdrawHandle *
TALER_EXCHANGE_batch_withdraw (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_ReservePrivateKeyP *reserve_priv,
const struct TALER_EXCHANGE_WithdrawCoinInput *wcis,
unsigned int wci_length,
TALER_EXCHANGE_BatchWithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_EXCHANGE_BatchWithdrawHandle *wh;
wh = GNUNET_new (struct TALER_EXCHANGE_BatchWithdrawHandle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
wh->reserve_priv = reserve_priv;
wh->num_coins = wci_length;
wh->coins = GNUNET_new_array (wh->num_coins,
struct CoinData);
for (unsigned int i = 0; i<wci_length; i++)
{
struct CoinData *cd = &wh->coins[i];
const struct TALER_EXCHANGE_WithdrawCoinInput *wci = &wcis[i];
cd->wh = wh;
cd->ps = *wci->ps;
cd->ach = wci->ach;
cd->pk = *wci->pk;
TALER_denom_pub_deep_copy (&cd->pk.key,
&wci->pk->key);
switch (wci->pk->key.cipher)
{
case TALER_DENOMINATION_RSA:
{
cd->alg_values.cipher = TALER_DENOMINATION_RSA;
TALER_planchet_setup_coin_priv (&cd->ps,
&cd->alg_values,
&cd->priv);
TALER_planchet_blinding_secret_create (&cd->ps,
&cd->alg_values,
&cd->bks);
if (GNUNET_OK !=
TALER_planchet_prepare (&cd->pk.key,
&cd->alg_values,
&cd->bks,
&cd->priv,
cd->ach,
&cd->c_hash,
&cd->pd))
{
GNUNET_break (0);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
return NULL;
}
break;
}
case TALER_DENOMINATION_CS:
{
TALER_cs_withdraw_nonce_derive (
&cd->ps,
&cd->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! */
cd->pd.blinded_planchet.cipher = TALER_DENOMINATION_CS;
cd->csrh = TALER_EXCHANGE_csr_withdraw (
exchange,
&cd->pk,
&cd->pd.blinded_planchet.details.cs_blinded_planchet.nonce,
&withdraw_cs_stage_two_callback,
cd);
if (NULL == cd->csrh)
{
GNUNET_break (0);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
return NULL;
}
wh->cs_pending++;
break;
}
default:
GNUNET_break (0);
TALER_EXCHANGE_batch_withdraw_cancel (wh);
return NULL;
}
}
if (0 == wh->cs_pending)
phase_two (wh);
return wh;
}
void
TALER_EXCHANGE_batch_withdraw_cancel (
struct TALER_EXCHANGE_BatchWithdrawHandle *wh)
{
for (unsigned int i = 0; i<wh->num_coins; i++)
{
struct CoinData *cd = &wh->coins[i];
if (NULL != cd->csrh)
{
TALER_EXCHANGE_csr_withdraw_cancel (cd->csrh);
cd->csrh = NULL;
}
TALER_blinded_planchet_free (&cd->pd.blinded_planchet);
TALER_denom_pub_free (&cd->pk.key);
}
GNUNET_free (wh->coins);
if (NULL != wh->wh2)
{
TALER_EXCHANGE_batch_withdraw2_cancel (wh->wh2);
wh->wh2 = NULL;
}
GNUNET_free (wh);
}
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