From 302070b86e8c8130f66dc00573af96005c48f7f4 Mon Sep 17 00:00:00 2001 From: Christian Grothoff Date: Fri, 6 May 2016 13:33:20 +0200 Subject: [PATCH] support REFUNDS in transaction history in libtalerexchange --- src/exchange-lib/exchange_api_common.c | 131 ++++++++++++++++-- src/exchange/taler-exchange-httpd_responses.c | 54 +++++++- 2 files changed, 165 insertions(+), 20 deletions(-) diff --git a/src/exchange-lib/exchange_api_common.c b/src/exchange-lib/exchange_api_common.c index 15c73acca..6831984fc 100644 --- a/src/exchange-lib/exchange_api_common.c +++ b/src/exchange-lib/exchange_api_common.c @@ -40,10 +40,12 @@ int TALER_EXCHANGE_verify_coin_history (const char *currency, const struct TALER_CoinSpendPublicKeyP *coin_pub, json_t *history, - struct TALER_Amount *total) + struct TALER_Amount *total) { size_t len; size_t off; + int add; + struct TALER_Amount rtotal; if (NULL == history) { @@ -58,6 +60,8 @@ TALER_EXCHANGE_verify_coin_history (const char *currency, } TALER_amount_get_zero (currency, total); + TALER_amount_get_zero (currency, + &rtotal); for (off=0;offamount_with_fee); if (0 != TALER_amount_cmp (&dr_amount, &amount)) - { - GNUNET_break (0); - GNUNET_JSON_parse_free (spec); - return GNUNET_SYSERR; - } + { + GNUNET_break (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + add = GNUNET_YES; } else if (0 == strcasecmp (type, "MELT")) @@ -167,6 +173,67 @@ TALER_EXCHANGE_verify_coin_history (const char *currency, GNUNET_JSON_parse_free (spec); return GNUNET_SYSERR; } + add = GNUNET_YES; + } + else if (0 == strcasecmp (type, + "REFUND")) + { + const struct TALER_RefundRequestPS *rr; + struct TALER_Amount rr_amount; + struct TALER_Amount rr_fee; + struct TALER_Amount rr_delta; + + if (details_size != sizeof (struct TALER_RefundRequestPS)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + rr = (const struct TALER_RefundRequestPS *) details; + if (details_size != ntohl (rr->purpose.size)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + if (GNUNET_OK != + GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_REFUND, + &rr->purpose, + &sig.eddsa_signature, + &rr->merchant.eddsa_pub)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + TALER_amount_ntoh (&rr_amount, + &rr->refund_amount); + TALER_amount_ntoh (&rr_fee, + &rr->refund_fee); + if (GNUNET_OK != + TALER_amount_subtract (&rr_delta, + &rr_amount, + &rr_fee)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + if (0 != TALER_amount_cmp (&rr_delta, + &amount)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } + /* NOTE/FIXME: theoretically, we could also check that the given + transaction_id and merchant_pub and h_contract appear in the + history under deposits. However, there is really no benefit + for the exchange to lie here, so not checking is probably OK + (an auditor ought to check, though). Then again, we similarly + had no reason to check the merchant's signature (other than a + well-formendess check). */ + add = GNUNET_NO; } else { @@ -175,18 +242,54 @@ TALER_EXCHANGE_verify_coin_history (const char *currency, GNUNET_JSON_parse_free (spec); return GNUNET_SYSERR; } - if (GNUNET_OK != - TALER_amount_add (total, - total, - &amount)) + if (GNUNET_YES == add) { - /* overflow in history already!? inconceivable! Bad exchange! */ - GNUNET_break_op (0); - GNUNET_JSON_parse_free (spec); - return GNUNET_SYSERR; + /* This amount should be added to the total */ + 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; + } + } + else + { + /* This amount should be subtracted from the total. + + However, for the implementation, we first *add* up all of + these negative amounts, as we might get refunds before + deposits from a semi-evil exchange. Then, at the end, we do + the subtraction by calculating "total = total - rtotal" */ + GNUNET_assert (GNUNET_NO == add); + if (GNUNET_OK != + TALER_amount_add (&rtotal, + &rtotal, + &amount)) + { + /* overflow in refund history? inconceivable! Bad exchange! */ + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return GNUNET_SYSERR; + } } GNUNET_JSON_parse_free (spec); } + + /* Finally, subtract 'rtotal' from total to handle the subtractions */ + if (GNUNET_OK != + TALER_amount_subtract (total, + total, + &rtotal)) + { + /* underflow in history? inconceivable! Bad exchange! */ + GNUNET_break_op (0); + return GNUNET_SYSERR; + } + return GNUNET_OK; } diff --git a/src/exchange/taler-exchange-httpd_responses.c b/src/exchange/taler-exchange-httpd_responses.c index 2011a5e49..6a21d8ac4 100644 --- a/src/exchange/taler-exchange-httpd_responses.c +++ b/src/exchange/taler-exchange-httpd_responses.c @@ -408,7 +408,7 @@ compile_transaction_history (const struct TALER_EXCHANGEDB_TransactionList *tl) const char *type; struct TALER_Amount value; json_t *history; - const struct TALER_CoinSpendSignatureP *sig; + const struct GNUNET_CRYPTO_EddsaSignature *sig; const struct TALER_EXCHANGEDB_TransactionList *pos; history = json_array (); @@ -436,12 +436,12 @@ compile_transaction_history (const struct TALER_EXCHANGEDB_TransactionList *tl) &deposit->deposit_fee); dr.merchant = deposit->merchant_pub; dr.coin_pub = deposit->coin.coin_pub; - sig = &deposit->csig; + sig = &deposit->csig.eddsa_signature; /* internal sanity check before we hand out a bogus sig... */ if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT, &dr.purpose, - &sig->eddsa_signature, + sig, &deposit->coin.coin_pub.eddsa_pub)) { GNUNET_break (0); @@ -468,12 +468,12 @@ compile_transaction_history (const struct TALER_EXCHANGEDB_TransactionList *tl) TALER_amount_hton (&ms.melt_fee, &melt->melt_fee); ms.coin_pub = melt->coin.coin_pub; - sig = &melt->coin_sig; + sig = &melt->coin_sig.eddsa_signature; /* internal sanity check before we hand out a bogus sig... */ if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_MELT, &ms.purpose, - &sig->eddsa_signature, + sig, &melt->coin.coin_pub.eddsa_pub)) { GNUNET_break (0); @@ -485,6 +485,48 @@ compile_transaction_history (const struct TALER_EXCHANGEDB_TransactionList *tl) sizeof (struct TALER_RefreshMeltCoinAffirmationPS)); } break; + case TALER_EXCHANGEDB_TT_REFUND: + { + struct TALER_RefundRequestPS rr; + const struct TALER_EXCHANGEDB_Refund *refund = pos->details.refund; + + type = "REFUND"; + if (GNUNET_OK != + TALER_amount_subtract (&value, + &refund->refund_amount, + &refund->refund_fee)) + { + GNUNET_break (0); + json_decref (history); + return NULL; + } + rr.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_REFUND); + rr.purpose.size = htonl (sizeof (struct TALER_RefundRequestPS)); + rr.h_contract = refund->h_contract; + rr.transaction_id = GNUNET_htonll (refund->transaction_id); + rr.coin_pub = refund->coin.coin_pub; + rr.merchant = refund->merchant_pub; + rr.rtransaction_id = GNUNET_htonll (refund->rtransaction_id); + TALER_amount_hton (&rr.refund_amount, + &refund->refund_amount); + TALER_amount_hton (&rr.refund_fee, + &refund->refund_fee); + /* internal sanity check before we hand out a bogus sig... */ + if (GNUNET_OK != + GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_REFUND, + &rr.purpose, + sig, + &refund->merchant_pub.eddsa_pub)) + { + GNUNET_break (0); + json_decref (history); + return NULL; + } + sig = &refund->merchant_sig.eddsa_sig; + details = GNUNET_JSON_from_data (&rr.purpose, + sizeof (struct TALER_RefundRequestPS)); + } + break; default: GNUNET_assert (0); } @@ -493,7 +535,7 @@ compile_transaction_history (const struct TALER_EXCHANGEDB_TransactionList *tl) "type", type, "amount", TALER_JSON_from_amount (&value), "signature", GNUNET_JSON_from_data (sig, - sizeof (struct TALER_CoinSpendSignatureP)), + sizeof (struct GNUNET_CRYPTO_EddsaSignature)), "details", details)); } return history;