renaming mint->exchange

1 files changed, 569 insertions, 0 deletions

diff --git a/src/exchange-lib/exchange_api_deposit.c b/src/exchange-lib/exchange_api_deposit.c
new file mode 100644
index 000000000..deba4877d
--- /dev/null
+++ b/src/exchange-lib/exchange_api_deposit.c
@@ -0,0 +1,569 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014, 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_deposit.c
+ * @brief Implementation of the /deposit request of the exchange's HTTP API
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <curl/curl.h>
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_exchange_service.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"
+
+
+/**
+ * @brief A Deposit Handle
+ */
+struct TALER_EXCHANGE_DepositHandle
+{
+
+  /**
+   * The connection to exchange this request handle will use
+   */
+  struct TALER_EXCHANGE_Handle *exchange;
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * JSON encoding of the request to POST.
+   */
+  char *json_enc;
+
+  /**
+   * Handle for the request.
+   */
+  struct MAC_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_DepositResultCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Download buffer
+   */
+  struct MAC_DownloadBuffer db;
+
+  /**
+   * Information the exchange should sign in response.
+   */
+  struct TALER_DepositConfirmationPS depconf;
+
+  /**
+   * Value of the /deposit transaction, including fee.
+   */
+  struct TALER_Amount amount_with_fee;
+
+  /**
+   * Total value of the coin being transacted with.
+   */
+  struct TALER_Amount coin_value;
+
+};
+
+
+/**
+ * Verify that the signature on the "200 OK" response
+ * from the exchange is valid.
+ *
+ * @param dh deposit handle
+ * @param json json reply with the signature
+ * @return #GNUNET_OK if the signature is valid, #GNUNET_SYSERR if not
+ */
+static int
+verify_deposit_signature_ok (const struct TALER_EXCHANGE_DepositHandle *dh,
+                             json_t *json)
+{
+  struct TALER_ExchangeSignatureP exchange_sig;
+  struct TALER_ExchangePublicKeyP exchange_pub;
+  const struct TALER_EXCHANGE_Keys *key_state;
+  struct MAJ_Specification spec[] = {
+    MAJ_spec_fixed_auto ("sig", &exchange_sig),
+    MAJ_spec_fixed_auto ("pub", &exchange_pub),
+    MAJ_spec_end
+  };
+
+  if (GNUNET_OK !=
+      MAJ_parse_json (json,
+                      spec))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  key_state = TALER_EXCHANGE_get_keys (dh->exchange);
+  if (GNUNET_OK !=
+      TALER_EXCHANGE_test_signing_key (key_state,
+                                   &exchange_pub))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT,
+                                  &dh->depconf.purpose,
+                                  &exchange_sig.eddsa_signature,
+                                  &exchange_pub.eddsa_pub))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Verify that the signatures on the "403 FORBIDDEN" response from the
+ * exchange demonstrating customer double-spending are valid.
+ *
+ * @param dh deposit handle
+ * @param json json reply with the signature(s) and transaction history
+ * @return #GNUNET_OK if the signature(s) is valid, #GNUNET_SYSERR if not
+ */
+static int
+verify_deposit_signature_forbidden (const struct TALER_EXCHANGE_DepositHandle *dh,
+                                    json_t *json)
+{
+  json_t *history;
+  struct TALER_Amount total;
+
+  history = json_object_get (json,
+                             "history");
+  if (GNUNET_OK !=
+      TALER_EXCHANGE_verify_coin_history_ (dh->coin_value.currency,
+                                       &dh->depconf.coin_pub,
+                                       history,
+                                       &total))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK !=
+      TALER_amount_add (&total,
+                        &total,
+                        &dh->amount_with_fee))
+  {
+    /* clearly not OK if our transaction would have caused
+       the overflow... */
+    return GNUNET_OK;
+  }
+
+  if (0 >= TALER_amount_cmp (&total,
+                             &dh->coin_value))
+  {
+    /* transaction should have still fit */
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  /* everything OK, proof of double-spending was provided */
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /deposit request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_DepositHandle`
+ * @param eh the curl request handle
+ */
+static void
+handle_deposit_finished (void *cls,
+                         CURL *eh)
+{
+  struct TALER_EXCHANGE_DepositHandle *dh = cls;
+  long response_code;
+  json_t *json;
+
+  dh->job = NULL;
+  json = MAC_download_get_result (&dh->db,
+                                  eh,
+                                  &response_code);
+  switch (response_code)
+  {
+  case 0:
+    break;
+  case MHD_HTTP_OK:
+    if (GNUNET_OK !=
+        verify_deposit_signature_ok (dh,
+                                     json))
+    {
+      GNUNET_break_op (0);
+      response_code = 0;
+    }
+    break;
+  case MHD_HTTP_BAD_REQUEST:
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    /* Double spending; check signatures on transaction history */
+    if (GNUNET_OK !=
+        verify_deposit_signature_forbidden (dh,
+                                            json))
+    {
+      GNUNET_break_op (0);
+      response_code = 0;
+    }
+    break;
+  case MHD_HTTP_UNAUTHORIZED:
+    /* Nothing really to verify, exchange says one of the signatures is
+       invalid; as we checked them, this should never happen, we
+       should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    /* Nothing really to verify, this should never
+       happen, we should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u\n",
+                response_code);
+    GNUNET_break (0);
+    response_code = 0;
+    break;
+  }
+  dh->cb (dh->cb_cls,
+          response_code,
+          json);
+  json_decref (json);
+  TALER_EXCHANGE_deposit_cancel (dh);
+}
+
+
+/**
+ * Verify signature information about the deposit.
+ *
+ * @param dki public key information
+ * @param amount the amount to be deposited
+ * @param h_wire hash of the merchant’s account details
+ * @param h_contract hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
+ * @param coin_pub coin’s public key
+ * @param denom_pub denomination key with which the coin is signed
+ * @param denom_sig exchange’s unblinded signature of the coin
+ * @param timestamp timestamp when the contract was finalized, must match approximately the current time of the exchange
+ * @param transaction_id transaction id for the transaction between merchant and customer
+ * @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
+ * @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed)
+ * @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
+ * @return #GNUNET_OK if signatures are OK, #GNUNET_SYSERR if not
+ */
+static int
+verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
+                   const struct TALER_Amount *amount,
+                   const struct GNUNET_HashCode *h_wire,
+                   const struct GNUNET_HashCode *h_contract,
+                   const struct TALER_CoinSpendPublicKeyP *coin_pub,
+                   const struct TALER_DenominationSignature *denom_sig,
+                   const struct TALER_DenominationPublicKey *denom_pub,
+                   struct GNUNET_TIME_Absolute timestamp,
+                   uint64_t transaction_id,
+                   const struct TALER_MerchantPublicKeyP *merchant_pub,
+                   struct GNUNET_TIME_Absolute refund_deadline,
+                   const struct TALER_CoinSpendSignatureP *coin_sig)
+{
+  struct TALER_DepositRequestPS dr;
+  struct TALER_CoinPublicInfo coin_info;
+
+  dr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_DEPOSIT);
+  dr.purpose.size = htonl (sizeof (struct TALER_DepositRequestPS));
+  dr.h_contract = *h_contract;
+  dr.h_wire = *h_wire;
+  dr.timestamp = GNUNET_TIME_absolute_hton (timestamp);
+  dr.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
+  dr.transaction_id = GNUNET_htonll (transaction_id);
+  TALER_amount_hton (&dr.amount_with_fee,
+                     amount);
+  TALER_amount_hton (&dr.deposit_fee,
+                     &dki->fee_deposit);
+  dr.merchant = *merchant_pub;
+  dr.coin_pub = *coin_pub;
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT,
+                                  &dr.purpose,
+                                  &coin_sig->eddsa_signature,
+                                  &coin_pub->eddsa_pub))
+  {
+    TALER_LOG_WARNING ("Invalid coin signature on /deposit request\n");
+    {
+      char *s;
+      s = TALER_amount_to_string (amount);
+      TALER_LOG_DEBUG ("... amount_with_fee was %s\n", s);
+      GNUNET_free (s);
+      s = TALER_amount_to_string (&dki->fee_deposit);
+      TALER_LOG_DEBUG ("... deposit_fee was %s\n", s);
+      GNUNET_free (s);
+    }
+
+    return GNUNET_SYSERR;
+  }
+
+  /* check coin signature */
+  coin_info.coin_pub = *coin_pub;
+  coin_info.denom_pub = *denom_pub;
+  coin_info.denom_sig = *denom_sig;
+  if (GNUNET_YES !=
+      TALER_test_coin_valid (&coin_info))
+  {
+    TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
+    return GNUNET_SYSERR;
+  }
+  if (0 < TALER_amount_cmp (&dki->fee_deposit,
+                            amount))
+  {
+    TALER_LOG_WARNING ("Deposit amount smaller than fee\n");
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Submit a deposit permission to the exchange and get the exchange's response.
+ * Note that while we return the response verbatim to the caller for
+ * further processing, we do already verify that the response is
+ * well-formed (i.e. that signatures included in the response are all
+ * valid).  If the exchange's reply is not well-formed, we return an
+ * HTTP status code of zero to @a cb.
+ *
+ * We also verify that the @a coin_sig is valid for this deposit
+ * request, and that the @a ub_sig is a valid signature for @a
+ * coin_pub.  Also, the @a exchange must be ready to operate (i.e.  have
+ * finished processing the /keys reply).  If either check fails, we do
+ * NOT initiate the transaction with the exchange and instead return NULL.
+ *
+ * @param exchange the exchange handle; the exchange must be ready to operate
+ * @param amount the amount to be deposited
+ * @param wire_deadline date until which the merchant would like the exchange to settle the balance (advisory, the exchange cannot be
+ *        forced to settle in the past or upon very short notice, but of course a well-behaved exchange will limit aggregation based on the advice received)
+ * @param wire_details the merchant’s account details, in a format supported by the exchange
+ * @param h_contract hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
+ * @param coin_pub coin’s public key
+ * @param denom_pub denomination key with which the coin is signed
+ * @param denom_sig exchange’s unblinded signature of the coin
+ * @param timestamp timestamp when the contract was finalized, must match approximately the current time of the exchange
+ * @param transaction_id transaction id for the transaction between merchant and customer
+ * @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
+ * @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed)
+ * @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
+ * @param cb the callback to call when a reply for this request is available
+ * @param cb_cls closure for the above callback
+ * @return a handle for this request; NULL if the inputs are invalid (i.e.
+ *         signatures fail to verify).  In this case, the callback is not called.
+ */
+struct TALER_EXCHANGE_DepositHandle *
+TALER_EXCHANGE_deposit (struct TALER_EXCHANGE_Handle *exchange,
+                    const struct TALER_Amount *amount,
+                    struct GNUNET_TIME_Absolute wire_deadline,
+                    json_t *wire_details,
+                    const struct GNUNET_HashCode *h_contract,
+                    const struct TALER_CoinSpendPublicKeyP *coin_pub,
+                    const struct TALER_DenominationSignature *denom_sig,
+                    const struct TALER_DenominationPublicKey *denom_pub,
+                    struct GNUNET_TIME_Absolute timestamp,
+                    uint64_t transaction_id,
+                    const struct TALER_MerchantPublicKeyP *merchant_pub,
+                    struct GNUNET_TIME_Absolute refund_deadline,
+                    const struct TALER_CoinSpendSignatureP *coin_sig,
+                    TALER_EXCHANGE_DepositResultCallback cb,
+                    void *cb_cls)
+{
+  const struct TALER_EXCHANGE_Keys *key_state;
+  const struct TALER_EXCHANGE_DenomPublicKey *dki;
+  struct TALER_EXCHANGE_DepositHandle *dh;
+  struct TALER_EXCHANGE_Context *ctx;
+  json_t *deposit_obj;
+  CURL *eh;
+  struct GNUNET_HashCode h_wire;
+  struct TALER_Amount amount_without_fee;
+
+  (void) TALER_round_abs_time (&wire_deadline);
+  if (GNUNET_YES !=
+      MAH_handle_is_ready (exchange))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  /* initialize h_wire */
+  if (GNUNET_OK !=
+      TALER_hash_json (wire_details,
+                       &h_wire))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  key_state = TALER_EXCHANGE_get_keys (exchange);
+  dki = TALER_EXCHANGE_get_denomination_key (key_state,
+                                         denom_pub);
+  if (NULL == dki)
+  {
+    TALER_LOG_WARNING ("Denomination key unknown to exchange\n");
+    return NULL;
+  }
+  if (GNUNET_SYSERR ==
+      TALER_amount_subtract (&amount_without_fee,
+                             amount,
+                             &dki->fee_deposit))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  if (GNUNET_OK !=
+      verify_signatures (dki,
+                         amount,
+                         &h_wire,
+                         h_contract,
+                         coin_pub,
+                         denom_sig,
+                         denom_pub,
+                         timestamp,
+                         transaction_id,
+                         merchant_pub,
+                         refund_deadline,
+                         coin_sig))
+  {
+    GNUNET_break_op (0);
+    return NULL;
+  }
+
+  deposit_obj = json_pack ("{s:o, s:O," /* f/wire */
+                           " s:o, s:o," /* H_wire, H_contract */
+                           " s:o, s:o," /* coin_pub, denom_pub */
+                           " s:o, s:o," /* ub_sig, timestamp */
+                           " s:I, s:o," /* transaction id, merchant_pub */
+                           " s:o, s:o," /* refund_deadline, wire_deadline */
+                           " s:o}",     /* coin_sig */
+                           "f", TALER_json_from_amount (amount),
+                           "wire", wire_details,
+                           "H_wire", TALER_json_from_data (&h_wire,
+                                                           sizeof (h_wire)),
+                           "H_contract", TALER_json_from_data (h_contract,
+                                                               sizeof (struct GNUNET_HashCode)),
+                           "coin_pub", TALER_json_from_data (coin_pub,
+                                                             sizeof (*coin_pub)),
+                           "denom_pub", TALER_json_from_rsa_public_key (denom_pub->rsa_public_key),
+                           "ub_sig", TALER_json_from_rsa_signature (denom_sig->rsa_signature),
+                           "timestamp", TALER_json_from_abs (timestamp),
+                           "transaction_id", (json_int_t) transaction_id,
+                           "merchant_pub", TALER_json_from_data (merchant_pub,
+                                                                 sizeof (*merchant_pub)),
+                           "refund_deadline", TALER_json_from_abs (refund_deadline),
+                           "edate", TALER_json_from_abs (wire_deadline),
+                           "coin_sig", TALER_json_from_data (coin_sig,
+                                                             sizeof (*coin_sig))
+                           );
+
+  dh = GNUNET_new (struct TALER_EXCHANGE_DepositHandle);
+  dh->exchange = exchange;
+  dh->cb = cb;
+  dh->cb_cls = cb_cls;
+  dh->url = MAH_path_to_url (exchange, "/deposit");
+  dh->depconf.purpose.size = htonl (sizeof (struct TALER_DepositConfirmationPS));
+  dh->depconf.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT);
+  dh->depconf.h_contract = *h_contract;
+  dh->depconf.h_wire = h_wire;
+  dh->depconf.transaction_id = GNUNET_htonll (transaction_id);
+  dh->depconf.timestamp = GNUNET_TIME_absolute_hton (timestamp);
+  dh->depconf.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
+  TALER_amount_hton (&dh->depconf.amount_without_fee,
+                     &amount_without_fee);
+  dh->depconf.coin_pub = *coin_pub;
+  dh->depconf.merchant = *merchant_pub;
+  dh->amount_with_fee = *amount;
+  dh->coin_value = dki->value;
+
+  eh = curl_easy_init ();
+  GNUNET_assert (NULL != (dh->json_enc =
+                          json_dumps (deposit_obj,
+                                      JSON_COMPACT)));
+  json_decref (deposit_obj);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "URL for deposit: `%s'\n",
+              dh->url);
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_URL,
+                                   dh->url));
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_POSTFIELDS,
+                                   dh->json_enc));
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_POSTFIELDSIZE,
+                                   strlen (dh->json_enc)));
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_WRITEFUNCTION,
+                                   &MAC_download_cb));
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_WRITEDATA,
+                                   &dh->db));
+  ctx = MAH_handle_to_context (exchange);
+  dh->job = MAC_job_add (ctx,
+                         eh,
+                         GNUNET_YES,
+                         &handle_deposit_finished,
+                         dh);
+  return dh;
+}
+
+
+/**
+ * Cancel a deposit permission request.  This function cannot be used
+ * on a request handle if a response is already served for it.
+ *
+ * @param deposit the deposit permission request handle
+ */
+void
+TALER_EXCHANGE_deposit_cancel (struct TALER_EXCHANGE_DepositHandle *deposit)
+{
+  if (NULL != deposit->job)
+  {
+    MAC_job_cancel (deposit->job);
+    deposit->job = NULL;
+  }
+  GNUNET_free_non_null (deposit->db.buf);
+  GNUNET_free (deposit->url);
+  GNUNET_free (deposit->json_enc);
+  GNUNET_free (deposit);
+}
+
+
+/* end of exchange_api_deposit.c */