-wip on p2p payments

2 files changed, 503 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-httpd_reserves_purse.c b/src/exchange/taler-exchange-httpd_reserves_purse.c
new file mode 100644
index 000000000..a8ae8c1b3
--- /dev/null
+++ b/src/exchange/taler-exchange-httpd_reserves_purse.c
@@ -0,0 +1,502 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2022 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_reserves_purse.c
+ * @brief Handle /reserves/$RID/purse requests; parses the POST and JSON and
+ *        verifies the coin signature before handing things off
+ *        to the database.
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <jansson.h>
+#include <microhttpd.h>
+#include <pthread.h>
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
+#include "taler-exchange-httpd_reserves_purse.h"
+#include "taler-exchange-httpd_responses.h"
+#include "taler_exchangedb_lib.h"
+#include "taler-exchange-httpd_keys.h"
+
+
+/**
+ * Closure for #purse_transaction.
+ */
+struct ReservePurseContext
+{
+
+  /**
+   * Public key of the reserve we are creating a purse for.
+   */
+  const struct TALER_ReservePublicKeyP *reserve_pub;
+
+  /**
+   * Public key of the purse we are creating.
+   */
+  struct TALER_PurseContractPublicKeyP purse_pub;
+
+  /**
+   * Total amount to be put into the purse.
+   */
+  struct TALER_Amount amount;
+
+  /**
+   * When should the purse expire.
+   */
+  struct GNUNET_TIME_Timestamp purse_expiration;
+
+  /**
+   * Our current time.
+   */
+  struct GNUNET_TIME_Timestamp exchange_timestamp;
+
+  /**
+   * Merge key for the purse.
+   */
+  struct TALER_PurseMergePublicKeyP merge_pub;
+
+  /**
+   * Contract decryption key for the purse.
+   */
+  struct TALER_ContractDiffiePublicP contract_pub;
+
+  /**
+   * Signature of the client affiming this request.
+   */
+  struct TALER_PurseContractSignatureP purse_sig;
+
+  /**
+   * Signature of the client affiming this encrypted contract.
+   */
+  struct TALER_PurseContractSignatureP econtract_sig;
+
+  /**
+   * Hash of the contract terms of the purse.
+   */
+  struct TALER_PrivateContractHashP h_contract_terms;
+
+  /**
+   * Encrypted contract, can be NULL.
+   */
+  void *econtract;
+
+  /**
+   * Number of bytes in @e econtract.
+   */
+  size_t econtract_size;
+
+  /**
+   * Minimum age for deposits into this purse.
+   */
+  uint32_t min_age;
+};
+
+
+/**
+ * Send confirmation of purse creation success to client.
+ *
+ * @param connection connection to the client
+ * @param rpc details about the request that succeeded
+ * @return MHD result code
+ */
+static MHD_RESULT
+reply_purse_success (struct MHD_Connection *connection,
+                     const struct ReservePurseContext *rpc)
+{
+  struct TALER_ExchangePublicKeyP pub;
+  struct TALER_ExchangeSignatureP sig;
+  enum TALER_ErrorCode ec;
+
+  if (TALER_EC_NONE !=
+      (ec = TALER_exchange_online_purse_pursed_sign (
+         &TEH_keys_exchange_sign_,
+         rpc->exchange_timestamp,
+         rpc->purse_expiration,
+         &rpc->amount,
+         &rpc->deposit_total,
+         rpc->purse_pub,
+         &rpc->merge_pub,
+         &rpc->h_contract_terms,
+         &pub,
+         &sig)))
+  {
+    GNUNET_break (0);
+    return TALER_MHD_reply_with_ec (connection,
+                                    ec,
+                                    NULL);
+  }
+  return TALER_MHD_REPLY_JSON_PACK (
+    connection,
+    MHD_HTTP_OK,
+    TALER_JSON_pack_amount ("total_deposited",
+                            &rpc->deposit_total),
+    GNUNET_JSON_pack_timestamp ("exchange_timestamp",
+                                rpc->exchange_timestamp),
+    GNUNET_JSON_pack_data_auto ("exchange_sig",
+                                &sig),
+    GNUNET_JSON_pack_data_auto ("exchange_pub",
+                                &pub));
+}
+
+
+/**
+ * Execute database transaction for /reserves/$PID/purse.  Runs the transaction
+ * logic; IF it returns a non-error code, the transaction logic MUST NOT queue
+ * a MHD response.  IF it returns an hard error, the transaction logic MUST
+ * queue a MHD response and set @a mhd_ret.  IF it returns the soft error
+ * code, the function MAY be called again to retry and MUST not queue a MHD
+ * response.
+ *
+ * @param cls a `struct ReservePurseContext`
+ * @param connection MHD request context
+ * @param[out] mhd_ret set to MHD status on error
+ * @return transaction status
+ */
+static enum GNUNET_DB_QueryStatus
+purse_transaction (void *cls,
+                   struct MHD_Connection *connection,
+                   MHD_RESULT *mhd_ret)
+{
+  struct ReservePurseContext *rpc = cls;
+  enum GNUNET_DB_QueryStatus qs;
+  bool in_conflict = true;
+
+  /* 1) store purse */
+  qs = TEH_plugin->insert_purse_request (TEH_plugin->cls,
+                                         &rpc->purse_pub,
+                                         &rpc->merge_pub,
+                                         rpc->purse_expiration,
+                                         &rpc->h_contract_terms,
+                                         rpc->min_age,
+                                         &rpc->amount,
+                                         &rpc->purse_sig,
+                                         &in_conflict);
+  if (qs < 0)
+  {
+    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+      return qs;
+    TALER_LOG_WARNING (
+      "Failed to store purse purse information in database\n");
+    *mhd_ret =
+      TALER_MHD_reply_with_error (connection,
+                                  MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                  TALER_EC_GENERIC_DB_STORE_FAILED,
+                                  "insert purse request");
+    return qs;
+  }
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
+    return qs;
+  if (in_conflict)
+  {
+    struct TALER_PurseMergePublicKeyP merge_pub;
+    struct GNUNET_TIME_Timestamp purse_expiration;
+    struct TALER_PrivateContractHashP h_contract_terms;
+    struct TALER_Amount target_amount;
+    struct TALER_Amount balance;
+    struct TALER_PurseContractSignatureP purse_sig;
+    uint32_t min_age;
+
+    TEH_plugin->rollback (TEH_plugin->cls);
+    qs = TEH_plugin->select_purse_request (TEH_plugin->cls,
+                                           rpc->purse_pub,
+                                           &merge_pub,
+                                           &purse_expiration,
+                                           &h_contract_terms,
+                                           &min_age,
+                                           &target_amount,
+                                           &balance,
+                                           &purse_sig);
+    if (qs < 0)
+    {
+      GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
+      TALER_LOG_WARNING ("Failed to fetch purse information from database\n");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             "select purse request");
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+    *mhd_ret
+      = TALER_MHD_REPLY_JSON_PACK (
+          connection,
+          MHD_HTTP_CONFLICT,
+          TALER_JSON_pack_ec (
+            TALER_EC_EXCHANGE_PURSE_PURSE_CONFLICTING_META_DATA),
+          TALER_JSON_pack_amount ("amount",
+                                  &target_amount),
+          GNUNET_JSON_pack_uint64 ("min_age",
+                                   min_age),
+          GNUNET_JSON_pack_timestamp ("purse_expiration",
+                                      purse_expiration),
+          GNUNET_JSON_pack_data_auto ("purse_sig",
+                                      &purse_sig),
+          GNUNET_JSON_pack_data_auto ("h_contract_terms",
+                                      &h_contract_terms),
+          GNUNET_JSON_pack_data_auto ("merge_pub",
+                                      &merge_pub));
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+
+  /* 2) merge purse with reserve (and debit reserve) */
+
+
+  /* 3) if present, persist contract */
+  in_conflict = true;
+  qs = TEH_plugin->insert_contract (TEH_plugin->cls,
+                                    rpc->purse_pub,
+                                    &rpc->contract_pub,
+                                    rpc->econtract_size,
+                                    rpc->econtract,
+                                    &rpc->econtract_sig,
+                                    &in_conflict);
+  if (qs < 0)
+  {
+    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+      return qs;
+    TALER_LOG_WARNING ("Failed to store purse information in database\n");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_GENERIC_DB_STORE_FAILED,
+                                           "purse purse contract");
+    return qs;
+  }
+  if (in_conflict)
+  {
+    struct TALER_ContractDiffiePublicP pub_ckey;
+    struct TALER_PurseContractSignatureP econtract_sig;
+    size_t econtract_size;
+    void *econtract;
+    struct GNUNET_HashCode h_econtract;
+
+    qs = TEH_plugin->select_contract_by_purse (TEH_plugin->cls,
+                                               rpc->purse_pub,
+                                               &pub_ckey,
+                                               &econtract_sig,
+                                               &econtract_size,
+                                               &econtract);
+    if (qs <= 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      TALER_LOG_WARNING (
+        "Failed to store fetch contract information from database\n");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             "select contract");
+      return qs;
+    }
+    GNUNET_CRYPTO_hash (econtract,
+                        econtract_size,
+                        &h_econtract);
+    *mhd_ret
+      = TALER_MHD_REPLY_JSON_PACK (
+          connection,
+          MHD_HTTP_CONFLICT,
+          TALER_JSON_pack_ec (
+            TALER_EC_EXCHANGE_PURSE_ECONTRACT_CONFLICTING_META_DATA),
+          GNUNET_JSON_pack_data_auto ("h_econtract",
+                                      &h_econtract),
+          GNUNET_JSON_pack_data_auto ("econtract_sig",
+                                      &econtract_sig),
+          GNUNET_JSON_pack_data_auto ("pub_ckey",
+                                      &pub_ckey));
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+
+  return qs;
+}
+
+
+MHD_RESULT
+TEH_handler_reserves_purse (
+  struct MHD_Connection *connection,
+  const struct TALER_ReservePublicKeyP *reserve_pub,
+  const json_t *root)
+{
+  struct ReservePurseContext rpc = {
+    .reserve_pub = reserve_pub,
+    .exchange_timestamp = GNUNET_TIME_timestamp_get ()
+  };
+  json_t *deposits;
+  json_t *deposit;
+  unsigned int idx;
+  struct GNUNET_JSON_Specification spec[] = {
+    TALER_JSON_spec_amount ("amount",
+                            TEH_currency,
+                            &rpc.amount),
+    GNUNET_JSON_spec_uint32 ("min_age",
+                             &rpc.min_age),
+    GNUNET_JSON_spec_mark_optional (
+      GNUNET_JSON_spec_varsize ("econtract",
+                                &rpc.econtract,
+                                &rpc.econtract_size),
+      NULL),
+    GNUNET_JSON_spec_mark_optional (
+      GNUNET_JSON_spec_fixed_auto ("econtract_sig",
+                                   &rpc.econtract_sig),
+      NULL),
+    GNUNET_JSON_spec_mark_optional (
+      GNUNET_JSON_spec_fixed_auto ("contract_pub",
+                                   &rpc.contract_pub),
+      NULL),
+    GNUNET_JSON_spec_fixed_auto ("merge_pub",
+                                 &rpc.merge_pub),
+    GNUNET_JSON_spec_fixed_auto ("purse_sig",
+                                 &rpc.purse_sig),
+    GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
+                                 &rpc.h_contract_terms),
+    GNUNET_JSON_spec_timestamp ("purse_expiration",
+                                &rpc.purse_expiration),
+    GNUNET_JSON_spec_timestamp ("merge_timestamp",
+                                &rpc.merge_timestamp),
+    GNUNET_JSON_spec_end ()
+  };
+  const struct TEH_GlobalFee *gf;
+
+  {
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     root,
+                                     spec);
+    if (GNUNET_SYSERR == res)
+    {
+      GNUNET_break (0);
+      return MHD_NO; /* hard failure */
+    }
+    if (GNUNET_NO == res)
+    {
+      GNUNET_break_op (0);
+      return MHD_YES; /* failure */
+    }
+  }
+  GNUNET_assert (GNUNET_OK ==
+                 TALER_amount_set_zero (TEH_currency,
+                                        &rpc.deposit_total));
+  if (GNUNET_TIME_timestamp_cmp (rpc.purse_expiration,
+                                 <,
+                                 rpc.exchange_timestamp))
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_EXCHANGE_PURSE_PURSE_EXPIRATION_BEFORE_NOW,
+                                       NULL);
+  }
+  if (GNUNET_TIME_absolute_is_never (rpc.purse_expiration.abs_time))
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_EXCHANGE_PURSE_PURSE_EXPIRATION_IS_NEVER,
+                                       NULL);
+  }
+  gf = TEH_keys_global_fee_by_time (TEH_keys_get_state (),
+                                    rpc.exchange_timestamp);
+  if (NULL == gf)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Cannot purse purse: global fees not configured!\n");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_GENERIC_GLOBAL_FEES_MISSING,
+                                       NULL);
+  }
+
+  TEH_METRICS_num_verifications[TEH_MT_SIGNATURE_EDDSA]++;
+  if (GNUNET_OK !=
+      TALER_wallet_purse_purse_verify (rpc.purse_expiration,
+                                       &rpc.h_contract_terms,
+                                       &rpc.merge_pub,
+                                       rpc.min_age,
+                                       &rpc.amount,
+                                       rpc.purse_pub,
+                                       &rpc.purse_sig))
+  {
+    TALER_LOG_WARNING ("Invalid signature on /reserves/$PID/purse request\n");
+    GNUNET_JSON_parse_free (spec);
+    GNUNET_free (rpc.coins);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_UNAUTHORIZED,
+                                       TALER_EC_EXCHANGE_PURSE_PURSE_SIGNATURE_INVALID,
+                                       NULL);
+  }
+  if ( (NULL != rpc.econtract) &&
+       (GNUNET_OK !=
+        TALER_wallet_econtract_upload_verify (rpc.econtract,
+                                              rpc.econtract_size,
+                                              &rpc.contract_pub,
+                                              purse_pub,
+                                              &rpc.econtract_sig)) )
+  {
+    TALER_LOG_WARNING ("Invalid signature on /reserves/$PID/purse request\n");
+    GNUNET_JSON_parse_free (spec);
+    GNUNET_free (rpc.coins);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_UNAUTHORIZED,
+                                       TALER_EC_EXCHANGE_PURSE_ECONTRACT_SIGNATURE_INVALID,
+                                       NULL);
+  }
+
+
+  if (GNUNET_SYSERR ==
+      TEH_plugin->preflight (TEH_plugin->cls))
+  {
+    GNUNET_break (0);
+    GNUNET_JSON_parse_free (spec);
+    GNUNET_free (rpc.coins);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_GENERIC_DB_START_FAILED,
+                                       "preflight failure");
+  }
+
+  /* execute transaction */
+  {
+    MHD_RESULT mhd_ret;
+
+    if (GNUNET_OK !=
+        TEH_DB_run_transaction (connection,
+                                "execute purse purse",
+                                TEH_MT_REQUEST_PURSE_PURSE,
+                                &mhd_ret,
+                                &purse_transaction,
+                                &rpc))
+    {
+      GNUNET_JSON_parse_free (spec);
+      GNUNET_free (rpc.coins);
+      return mhd_ret;
+    }
+  }
+
+  /* generate regular response */
+  {
+    MHD_RESULT res;
+
+    res = reply_purse_success (connection,
+                               &rpc);
+    GNUNET_JSON_parse_free (spec);
+    return res;
+  }
+}
+
+
+/* end of taler-exchange-httpd_reserves_purse.c */
diff --git a/src/testing/testing_api_cmd_contract_get.c b/src/testing/testing_api_cmd_contract_get.c
index bf7777207..9432fdeef 100644
--- a/src/testing/testing_api_cmd_contract_get.c
+++ b/src/testing/testing_api_cmd_contract_get.c
@@ -171,6 +171,7 @@ get_run (void *cls,
   ds->is = is;
   ref = TALER_TESTING_interpreter_lookup_command (ds->is,
                                                   ds->contract_ref);
+  GNUNET_assert (NULL != ref);
   if (GNUNET_OK !=
       TALER_TESTING_get_trait_contract_priv (ref,
                                              &contract_priv))