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/*
This file is part of TALER
Copyright (C) 2015 GNUnet e.V.
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, If not, see
<http://www.gnu.org/licenses/>
*/
/**
* @file exchange-lib/exchange_api_common.c
* @brief common functions for the exchange API
* @author Christian Grothoff
*/
#include "platform.h"
#include "exchange_api_common.h"
#include "taler_json_lib.h"
#include "exchange_api_context.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
/**
* Verify a coins transaction history as returned by the exchange.
*
* @param currency expected currency for the coin
* @param coin_pub public key of the coin
* @param history history of the coin in json encoding
* @param[out] total how much of the coin has been spent according to @a history
* @return #GNUNET_OK if @a history is valid, #GNUNET_SYSERR if not
*/
int
TALER_EXCHANGE_verify_coin_history_ (const char *currency,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
json_t *history,
struct TALER_Amount *total)
{
size_t len;
size_t off;
if (NULL == history)
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
len = json_array_size (history);
if (0 == len)
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
TALER_amount_get_zero (currency,
total);
for (off=0;off<len;off++)
{
json_t *transaction;
struct TALER_Amount amount;
struct TALER_CoinSpendSignatureP sig;
void *details;
size_t details_size;
const char *type;
struct GNUNET_JSON_Specification spec[] = {
TALER_JSON_spec_amount ("amount",
&amount),
GNUNET_JSON_spec_string ("type",
&type),
GNUNET_JSON_spec_fixed_auto ("signature",
&sig),
GNUNET_JSON_spec_varsize ("details",
&details,
&details_size),
GNUNET_JSON_spec_end()
};
transaction = json_array_get (history,
off);
if (GNUNET_OK !=
GNUNET_JSON_parse (transaction,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (0 == strcasecmp (type,
"DEPOSIT"))
{
const struct TALER_DepositRequestPS *dr;
struct TALER_Amount dr_amount;
if (details_size != sizeof (struct TALER_DepositRequestPS))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
dr = (const struct TALER_DepositRequestPS *) details;
if (details_size != ntohl (dr->purpose.size))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT,
&dr->purpose,
&sig.eddsa_signature,
&coin_pub->eddsa_pub))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
// FIXME: check sig!
TALER_amount_ntoh (&dr_amount,
&dr->amount_with_fee);
if (0 != TALER_amount_cmp (&dr_amount,
&amount))
{
GNUNET_break (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
}
else if (0 == strcasecmp (type,
"MELT"))
{
const struct TALER_RefreshMeltCoinAffirmationPS *rm;
struct TALER_Amount rm_amount;
if (details_size != sizeof (struct TALER_RefreshMeltCoinAffirmationPS))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
rm = (const struct TALER_RefreshMeltCoinAffirmationPS *) details;
if (details_size != ntohl (rm->purpose.size))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_MELT,
&rm->purpose,
&sig.eddsa_signature,
&coin_pub->eddsa_pub))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
TALER_amount_ntoh (&rm_amount,
&rm->amount_with_fee);
if (0 != TALER_amount_cmp (&rm_amount,
&amount))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
}
else
{
/* signature not supported, new version on server? */
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_amount_add (total,
total,
&amount))
{
/* overflow in history already!? inconceivable! Bad exchange! */
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
GNUNET_JSON_parse_free (spec);
}
return GNUNET_OK;
}
/* end of exchange_api_common.c */
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