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Diffstat (limited to 'src/exchange-lib/exchange_api_common.c')
| -rw-r--r-- | src/exchange-lib/exchange_api_common.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/src/exchange-lib/exchange_api_common.c b/src/exchange-lib/exchange_api_common.c new file mode 100644 index 000000000..805c3fc4e --- /dev/null +++ b/src/exchange-lib/exchange_api_common.c @@ -0,0 +1,194 @@ +/* + 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 "exchange_api_json.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 MAJ_Specification spec[] = { + MAJ_spec_amount ("amount", + &amount), + MAJ_spec_string ("type", + &type), + MAJ_spec_fixed_auto ("signature", + &sig), + MAJ_spec_varsize ("details", + &details, + &details_size), + MAJ_spec_end + }; + + transaction = json_array_get (history, + off); + if (GNUNET_OK != + MAJ_parse_json (transaction, + spec)) + { + 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); + MAJ_parse_free (spec); + return GNUNET_SYSERR; + } + dr = (const struct TALER_DepositRequestPS *) details; + if (details_size != ntohl (dr->purpose.size)) + { + GNUNET_break_op (0); + MAJ_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); + MAJ_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); + MAJ_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); + MAJ_parse_free (spec); + return GNUNET_SYSERR; + } + rm = (const struct TALER_RefreshMeltCoinAffirmationPS *) details; + if (details_size != ntohl (rm->purpose.size)) + { + GNUNET_break_op (0); + MAJ_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); + MAJ_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); + MAJ_parse_free (spec); + return GNUNET_SYSERR; + } + } + else + { + /* signature not supported, new version on server? */ + GNUNET_break_op (0); + MAJ_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); + MAJ_parse_free (spec); + return GNUNET_SYSERR; + } + MAJ_parse_free (spec); + } + return GNUNET_OK; +} + + +/* end of exchange_api_common.c */ |