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authorChristian Grothoff <christian@grothoff.org>2019-01-11 21:27:34 +0100
committerChristian Grothoff <christian@grothoff.org>2019-01-11 21:43:15 +0100
commit54fc83ee6b910d482948c6ec8185df7aab1b0cb1 (patch)
tree10c04cad1392659a9ccef469271f866e393ebb48 /src/lib/exchange_api_common.c
parent57ab9f9fdba607fcc3817adf58f37c5390f8d220 (diff)
downloadexchange-54fc83ee6b910d482948c6ec8185df7aab1b0cb1.tar.gz
exchange-54fc83ee6b910d482948c6ec8185df7aab1b0cb1.tar.bz2
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fix cyclic dependency by combining exchange-lib and auditor-lib directories
Diffstat (limited to 'src/lib/exchange_api_common.c')
-rw-r--r--src/lib/exchange_api_common.c353
1 files changed, 353 insertions, 0 deletions
diff --git a/src/lib/exchange_api_common.c b/src/lib/exchange_api_common.c
new file mode 100644
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+++ b/src/lib/exchange_api_common.c
@@ -0,0 +1,353 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2015-2017 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 exchange-lib/exchange_api_common.c
+ * @brief common functions for the exchange API
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_json_lib.h"
+#include <gnunet/gnunet_curl_lib.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;
+ int add;
+ struct TALER_Amount rtotal;
+
+ 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;
+ }
+ GNUNET_assert (GNUNET_OK ==
+ TALER_amount_get_zero (currency,
+ total));
+ GNUNET_assert (GNUNET_OK ==
+ TALER_amount_get_zero (currency,
+ &rtotal));
+ for (size_t off=0;off<len;off++)
+ {
+ json_t *transaction;
+ struct TALER_Amount amount;
+ const char *type;
+ struct GNUNET_JSON_Specification spec_glob[] = {
+ TALER_JSON_spec_amount ("amount",
+ &amount),
+ GNUNET_JSON_spec_string ("type",
+ &type),
+ GNUNET_JSON_spec_end()
+ };
+
+ transaction = json_array_get (history,
+ off);
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (transaction,
+ spec_glob,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ add = GNUNET_SYSERR;
+ if (0 == strcasecmp (type,
+ "DEPOSIT"))
+ {
+ struct TALER_DepositRequestPS dr;
+ struct TALER_CoinSpendSignatureP sig;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_fixed_auto ("coin_sig",
+ &sig),
+ GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
+ &dr.h_contract_terms),
+ GNUNET_JSON_spec_fixed_auto ("h_wire",
+ &dr.h_wire),
+ GNUNET_JSON_spec_absolute_time_nbo ("timestamp",
+ &dr.timestamp),
+ GNUNET_JSON_spec_absolute_time_nbo ("refund_deadline",
+ &dr.refund_deadline),
+ TALER_JSON_spec_amount_nbo ("deposit_fee",
+ &dr.deposit_fee),
+ GNUNET_JSON_spec_fixed_auto ("merchant_pub",
+ &dr.merchant),
+ GNUNET_JSON_spec_end()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (transaction,
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ dr.purpose.size = htonl (sizeof (dr));
+ dr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_DEPOSIT);
+ TALER_amount_hton (&dr.amount_with_fee,
+ &amount);
+ dr.coin_pub = *coin_pub;
+ 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);
+ return GNUNET_SYSERR;
+ }
+ /* TODO: check that deposit fee and coin value match
+ our expectations from /keys! */
+ add = GNUNET_YES;
+ }
+ else if (0 == strcasecmp (type,
+ "MELT"))
+ {
+ struct TALER_RefreshMeltCoinAffirmationPS rm;
+ struct TALER_CoinSpendSignatureP sig;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_fixed_auto ("coin_sig",
+ &sig),
+ GNUNET_JSON_spec_fixed_auto ("rc",
+ &rm.rc),
+ TALER_JSON_spec_amount_nbo ("melt_fee",
+ &rm.melt_fee),
+ GNUNET_JSON_spec_end()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (transaction,
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ rm.purpose.size = htonl (sizeof (rm));
+ rm.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_MELT);
+ TALER_amount_hton (&rm.amount_with_fee,
+ &amount);
+ rm.coin_pub = *coin_pub;
+ 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);
+ return GNUNET_SYSERR;
+ }
+ /* TODO: check that deposit fee and coin value match
+ our expectations from /keys! */
+ add = GNUNET_YES;
+ }
+ else if (0 == strcasecmp (type,
+ "REFUND"))
+ {
+ struct TALER_RefundRequestPS rr;
+ struct TALER_MerchantSignatureP sig;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_fixed_auto ("merchant_sig",
+ &sig),
+ GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
+ &rr.h_contract_terms),
+ GNUNET_JSON_spec_fixed_auto ("merchant_pub",
+ &rr.merchant),
+ GNUNET_JSON_spec_uint64 ("rtransaction_id",
+ &rr.rtransaction_id),
+ TALER_JSON_spec_amount_nbo ("refund_fee",
+ &rr.refund_fee),
+ GNUNET_JSON_spec_end()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (transaction,
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ rr.purpose.size = htonl (sizeof (rr));
+ rr.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_REFUND);
+ rr.coin_pub = *coin_pub;
+ TALER_amount_hton (&rr.refund_amount,
+ &amount);
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_REFUND,
+ &rr.purpose,
+ &sig.eddsa_sig,
+ &rr.merchant.eddsa_pub))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ /* NOTE: theoretically, we could also check that the given
+ merchant_pub and h_contract_terms 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). */
+ /* TODO: check that deposit fee and coin value match
+ our expectations from /keys! */
+ add = GNUNET_NO;
+ }
+ else if (0 == strcasecmp (type,
+ "PAYBACK"))
+ {
+ struct TALER_PaybackConfirmationPS pc;
+ struct TALER_ExchangePublicKeyP exchange_pub;
+ struct TALER_ExchangeSignatureP exchange_sig;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_fixed_auto ("exchange_sig",
+ &exchange_sig),
+ GNUNET_JSON_spec_fixed_auto ("exchange_pub",
+ &exchange_pub),
+ GNUNET_JSON_spec_fixed_auto ("reserve_pub",
+ &pc.reserve_pub),
+ GNUNET_JSON_spec_absolute_time_nbo ("timestamp",
+ &pc.timestamp),
+ GNUNET_JSON_spec_end()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (transaction,
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ pc.purpose.size = htonl (sizeof (pc));
+ pc.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK);
+ pc.coin_pub = *coin_pub;
+ TALER_amount_hton (&pc.payback_amount,
+ &amount);
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK,
+ &pc.purpose,
+ &exchange_sig.eddsa_signature,
+ &exchange_pub.eddsa_pub))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ add = GNUNET_YES;
+ }
+ else
+ {
+ /* signature not supported, new version on server? */
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ if (GNUNET_YES == add)
+ {
+ /* 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);
+ 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);
+ return GNUNET_SYSERR;
+ }
+ }
+ }
+
+ /* 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;
+}
+
+
+/**
+ * Obtain meta data about an exchange (online) signing
+ * key.
+ *
+ * @param keys from where to obtain the meta data
+ * @param exchange_pub public key to lookup
+ * @return NULL on error (@a exchange_pub not known)
+ */
+const struct TALER_EXCHANGE_SigningPublicKey *
+TALER_EXCHANGE_get_exchange_signing_key_info (const struct TALER_EXCHANGE_Keys *keys,
+ const struct TALER_ExchangePublicKeyP *exchange_pub)
+{
+ for (unsigned int i=0;i<keys->num_sign_keys;i++)
+ {
+ const struct TALER_EXCHANGE_SigningPublicKey *spk;
+
+ spk = &keys->sign_keys[i];
+ if (0 == memcmp (exchange_pub,
+ &spk->key,
+ sizeof (struct TALER_ExchangePublicKeyP)))
+ return spk;
+ }
+ return NULL;
+}
+
+/* end of exchange_api_common.c */