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-rw-r--r--src/exchange-lib/exchange_api_common.c194
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 */