skeleton for /purses//deposit

1 files changed, 609 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-httpd_purses_deposit.c b/src/exchange/taler-exchange-httpd_purses_deposit.c
new file mode 100644
index 000000000..193953a4e
--- /dev/null
+++ b/src/exchange/taler-exchange-httpd_purses_deposit.c
@@ -0,0 +1,609 @@
+/*
+  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_purses_create.c
+ * @brief Handle /purses/$PID/deposit 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_purses_deposit.h"
+#include "taler-exchange-httpd_responses.h"
+#include "taler_exchangedb_lib.h"
+#include "taler-exchange-httpd_keys.h"
+
+
+/**
+ * Information about an individual coin being deposited.
+ */
+struct Coin
+{
+  /**
+   * Public information about the coin.
+   */
+  struct TALER_CoinPublicInfo cpi;
+
+  /**
+   * Signature affirming spending the coin.
+   */
+  struct TALER_CoinSpendSignatureP coin_sig;
+
+  /**
+   * Amount to be put into the purse from this coin.
+   */
+  struct TALER_Amount amount;
+
+  /**
+   * Deposit fee applicable for this coin.
+   */
+  struct TALER_Amount deposit_fee;
+
+  /**
+   * Amount to be put into the purse from this coin.
+   */
+  struct TALER_Amount amount_minus_fee;
+
+  /**
+   * ID of the coin in known_coins.
+   */
+  uint64_t known_coin_id;
+};
+
+
+/**
+ * Closure for #deposit_transaction.
+ */
+struct PurseDepositContext
+{
+  /**
+   * Public key of the purse we are creating.
+   */
+  const struct TALER_PurseContractPublicKeyP *purse_pub;
+
+  /**
+   * Total amount to be put into the purse.
+   */
+  struct TALER_Amount amount;
+
+  /**
+   * Total actually deposited by all the coins.
+   */
+  struct TALER_Amount deposit_total;
+
+  /**
+   * When should the purse expire.
+   */
+  struct GNUNET_TIME_Timestamp purse_expiration;
+
+  /**
+   * Our current time.
+   */
+  struct GNUNET_TIME_Timestamp exchange_timestamp;
+
+  /**
+   * Array of coins being deposited.
+   */
+  struct Coin *coins;
+
+  /**
+   * Length of the @e coins array.
+   */
+  unsigned int num_coins;
+
+  /**
+   * 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 pcc details about the request that succeeded
+ * @return MHD result code
+ */
+static MHD_RESULT
+reply_deposit_success (struct MHD_Connection *connection,
+                       const struct PurseDepositContext *pcc)
+{
+  struct TALER_ExchangePublicKeyP pub;
+  struct TALER_ExchangeSignatureP sig;
+  enum TALER_ErrorCode ec;
+
+  if (TALER_EC_NONE !=
+      (ec = TALER_exchange_online_purse_deposited_sign (
+         &TEH_keys_exchange_sign_,
+         pcc->exchange_timestamp,
+         pcc->purse_expiration,
+         &pcc->amount,
+         &pcc->deposit_total,
+         pcc->purse_pub,
+         &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",
+                            &pcc->deposit_total),
+    GNUNET_JSON_pack_timestamp ("exchange_timestamp",
+                                pcc->exchange_timestamp),
+    GNUNET_JSON_pack_data_auto ("exchange_sig",
+                                &sig),
+    GNUNET_JSON_pack_data_auto ("exchange_pub",
+                                &pub));
+}
+
+
+/**
+ * Execute database transaction for /purses/$PID/deposit.  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 PurseDepositContext`
+ * @param connection MHD request context
+ * @param[out] mhd_ret set to MHD status on error
+ * @return transaction status
+ */
+static enum GNUNET_DB_QueryStatus
+deposit_transaction (void *cls,
+                     struct MHD_Connection *connection,
+                     MHD_RESULT *mhd_ret)
+{
+  struct PurseDepositContext *pcc = cls;
+  enum GNUNET_DB_QueryStatus qs;
+  bool in_conflict = true;
+
+  for (unsigned int i = 0; i<pcc->num_coins; i++)
+  {
+    struct Coin *coin = &pcc->coins[i];
+    bool balance_ok = false;
+    bool conflict = true;
+
+    qs = TEH_plugin->do_purse_deposit (TEH_plugin->cls,
+                                       pcc->purse_pub,
+                                       &coin->cpi.coin_pub,
+                                       &coin->amount,
+                                       &coin->coin_sig,
+                                       &coin->amount_minus_fee,
+                                       &balance_ok,
+                                       &conflict);
+    if (qs <= 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      TALER_LOG_WARNING (
+        "Failed to store purse deposit information in database\n");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_STORE_FAILED,
+                                             "purse deposit deposit");
+      return qs;
+    }
+    if (! balance_ok)
+    {
+      *mhd_ret
+        = TEH_RESPONSE_reply_coin_insufficient_funds (
+            connection,
+            TALER_EC_EXCHANGE_GENERIC_INSUFFICIENT_FUNDS,
+            &coin->cpi.coin_pub);
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+    if (conflict)
+    {
+      struct TALER_Amount amount;
+      struct TALER_CoinSpendPublicKeyP coin_pub;
+      struct TALER_CoinSpendSignatureP coin_sig;
+      char *partner_url = NULL;
+
+      TEH_plugin->rollback (TEH_plugin->cls);
+      qs = TEH_plugin->get_purse_deposit (TEH_plugin->cls,
+                                          pcc->purse_pub,
+                                          &coin->cpi.coin_pub,
+                                          &amount,
+                                          &coin_sig,
+                                          &partner_url);
+      if (qs < 0)
+      {
+        GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
+        TALER_LOG_WARNING (
+          "Failed to fetch purse deposit information from database\n");
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                               "get purse deposit");
+        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_DEPOSIT_CONFLICTING_META_DATA),
+            GNUNET_JSON_pack_data_auto ("coin_pub",
+                                        &coin_pub),
+            GNUNET_JSON_pack_data_auto ("coin_sig",
+                                        &coin_sig),
+            GNUNET_JSON_pack_allow_null (
+              GNUNET_JSON_pack_string ("partner_url",
+                                       partner_url)),
+            TALER_JSON_pack_amount ("amount",
+                                    &amount));
+      GNUNET_free (partner_url);
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+  }
+  return qs;
+}
+
+
+/**
+ * Parse a coin and check signature of the coin and the denomination
+ * signature over the coin.
+ *
+ * @param[in,out] our HTTP connection
+ * @param[in,out] request context
+ * @param[out] coin coin to initialize
+ * @param jcoin coin to parse
+ * @return #GNUNET_OK on success, #GNUNET_NO if an error was returned,
+ *         #GNUNET_SYSERR on failure and no error could be returned
+ */
+static enum GNUNET_GenericReturnValue
+parse_coin (struct MHD_Connection *connection,
+            struct PurseDepositContext *pcc,
+            struct Coin *coin,
+            const json_t *jcoin)
+{
+  struct GNUNET_JSON_Specification spec[] = {
+    TALER_JSON_spec_amount ("amount",
+                            TEH_currency,
+                            &coin->amount),
+    GNUNET_JSON_spec_fixed_auto ("denom_pub_hash",
+                                 &coin->cpi.denom_pub_hash),
+    TALER_JSON_spec_denom_sig ("ub_sig",
+                               &coin->cpi.denom_sig),
+    GNUNET_JSON_spec_mark_optional (
+      GNUNET_JSON_spec_fixed_auto ("h_age_commitment",
+                                   &coin->cpi.h_age_commitment),
+      &coin->cpi.no_age_commitment),
+    GNUNET_JSON_spec_fixed_auto ("coin_sig",
+                                 &coin->coin_sig),
+    GNUNET_JSON_spec_fixed_auto ("coin_pub",
+                                 &coin->cpi.coin_pub),
+    GNUNET_JSON_spec_end ()
+  };
+
+  {
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     jcoin,
+                                     spec);
+    if (GNUNET_OK != res)
+      return res;
+  }
+
+  if (GNUNET_OK !=
+      TALER_wallet_purse_deposit_verify (TEH_base_url,
+                                         pcc->purse_pub,
+                                         &pcc->amount,
+                                         &coin->cpi.coin_pub,
+                                         &coin->coin_sig))
+  {
+    TALER_LOG_WARNING ("Invalid signature on /purses/$PID/deposit request\n");
+    GNUNET_JSON_parse_free (spec);
+    return (MHD_YES ==
+            TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_FORBIDDEN,
+                                        TALER_EC_EXCHANGE_PURSE_DEPOSIT_COIN_SIGNATURE_INVALID,
+                                        TEH_base_url))
+           ? GNUNET_NO : GNUNET_SYSERR;
+  }
+  /* check denomination exists and is valid */
+  {
+    struct TEH_DenominationKey *dk;
+    MHD_RESULT mret;
+
+    dk = TEH_keys_denomination_by_hash (&coin->cpi.denom_pub_hash,
+                                        connection,
+                                        &mret);
+    if (NULL == dk)
+    {
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES == mret) ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (0 > TALER_amount_cmp (&dk->meta.value,
+                              &coin->amount))
+    {
+      GNUNET_break_op (0);
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_BAD_REQUEST,
+                                          TALER_EC_EXCHANGE_GENERIC_AMOUNT_EXCEEDS_DENOMINATION_VALUE,
+                                          NULL))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (GNUNET_TIME_absolute_is_past (dk->meta.expire_deposit.abs_time))
+    {
+      /* This denomination is past the expiration time for deposits */
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TEH_RESPONSE_reply_expired_denom_pub_hash (
+                connection,
+                &coin->cpi.denom_pub_hash,
+                TALER_EC_EXCHANGE_GENERIC_DENOMINATION_EXPIRED,
+                "PURSE DEPOSIT"))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (GNUNET_TIME_absolute_is_future (dk->meta.start.abs_time))
+    {
+      /* This denomination is not yet valid */
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TEH_RESPONSE_reply_expired_denom_pub_hash (
+                connection,
+                &coin->cpi.denom_pub_hash,
+                TALER_EC_EXCHANGE_GENERIC_DENOMINATION_VALIDITY_IN_FUTURE,
+                "PURSE DEPOSIT"))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (dk->recoup_possible)
+    {
+      /* This denomination has been revoked */
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TEH_RESPONSE_reply_expired_denom_pub_hash (
+                connection,
+                &coin->cpi.denom_pub_hash,
+                TALER_EC_EXCHANGE_GENERIC_DENOMINATION_REVOKED,
+                "PURSE DEPOSIT"))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (dk->denom_pub.cipher != coin->cpi.denom_sig.cipher)
+    {
+      /* denomination cipher and denomination signature cipher not the same */
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_BAD_REQUEST,
+                                          TALER_EC_EXCHANGE_GENERIC_CIPHER_MISMATCH,
+                                          NULL))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+
+    coin->deposit_fee = dk->meta.fees.deposit;
+    if (0 < TALER_amount_cmp (&coin->deposit_fee,
+                              &coin->amount))
+    {
+      GNUNET_break_op (0);
+      GNUNET_JSON_parse_free (spec);
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_BAD_REQUEST,
+                                         TALER_EC_EXCHANGE_DEPOSIT_NEGATIVE_VALUE_AFTER_FEE,
+                                         NULL);
+    }
+    GNUNET_assert (0 <=
+                   TALER_amount_subtract (&coin->amount_minus_fee,
+                                          &coin->amount,
+                                          &coin->deposit_fee));
+    /* check coin signature */
+    switch (dk->denom_pub.cipher)
+    {
+    case TALER_DENOMINATION_RSA:
+      TEH_METRICS_num_verifications[TEH_MT_SIGNATURE_RSA]++;
+      break;
+    case TALER_DENOMINATION_CS:
+      TEH_METRICS_num_verifications[TEH_MT_SIGNATURE_CS]++;
+      break;
+    default:
+      break;
+    }
+    if (GNUNET_YES !=
+        TALER_test_coin_valid (&coin->cpi,
+                               &dk->denom_pub))
+    {
+      TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
+      GNUNET_JSON_parse_free (spec);
+      return (MHD_YES ==
+              TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_FORBIDDEN,
+                                          TALER_EC_EXCHANGE_DENOMINATION_SIGNATURE_INVALID,
+                                          NULL))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (0 >
+        TALER_amount_add (&pcc->deposit_total,
+                          &pcc->deposit_total,
+                          &coin->amount_minus_fee))
+    {
+      GNUNET_break (0);
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                         TALER_EC_GENERIC_FAILED_COMPUTE_AMOUNT,
+                                         "total deposit contribution");
+    }
+  }
+  {
+    MHD_RESULT mhd_ret = MHD_NO;
+    enum GNUNET_DB_QueryStatus qs;
+
+    /* make sure coin is 'known' in database */
+    for (unsigned int tries = 0; tries<MAX_TRANSACTION_COMMIT_RETRIES; tries++)
+    {
+      qs = TEH_make_coin_known (&coin->cpi,
+                                connection,
+                                &coin->known_coin_id,
+                                &mhd_ret);
+      /* no transaction => no serialization failures should be possible */
+      if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
+        break;
+    }
+    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+    {
+      GNUNET_break (0);
+      return (MHD_YES ==
+              TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                          TALER_EC_GENERIC_DB_COMMIT_FAILED,
+                                          "make_coin_known"))
+             ? GNUNET_NO : GNUNET_SYSERR;
+    }
+    if (qs < 0)
+      return (MHD_YES == mhd_ret) ? GNUNET_NO : GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+MHD_RESULT
+TEH_handler_purses_deposit (
+  struct MHD_Connection *connection,
+  const struct TALER_PurseContractPublicKeyP *purse_pub,
+  const json_t *root)
+{
+  struct PurseDepositContext pcc = {
+    .purse_pub = purse_pub,
+    .exchange_timestamp = GNUNET_TIME_timestamp_get ()
+  };
+  json_t *deposits;
+  json_t *deposit;
+  unsigned int idx;
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_json ("deposits",
+                           &deposits),
+    GNUNET_JSON_spec_end ()
+  };
+
+  {
+    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,
+                                        &pcc.deposit_total));
+  pcc.num_coins = json_array_size (deposits);
+  if ( (0 == pcc.num_coins) ||
+       (pcc.num_coins > TALER_MAX_FRESH_COINS) )
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_GENERIC_PARAMETER_MALFORMED,
+                                       "deposits");
+  }
+  /* FIXME: fetch basic purse properties
+     (min age, purse_expiration, amount) from
+     DB. Generate 404 or 410 (Gone) replies if
+     applicable. */
+
+  /* parse deposits */
+  pcc.coins = GNUNET_new_array (pcc.num_coins,
+                                struct Coin);
+  json_array_foreach (deposits, idx, deposit)
+  {
+    enum GNUNET_GenericReturnValue res;
+    struct Coin *coin = &pcc.coins[idx];
+
+    res = parse_coin (connection,
+                      &pcc,
+                      coin,
+                      deposit);
+    if (GNUNET_OK != res)
+    {
+      GNUNET_JSON_parse_free (spec);
+      GNUNET_free (pcc.coins);
+      return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
+    }
+  }
+
+  if (GNUNET_SYSERR ==
+      TEH_plugin->preflight (TEH_plugin->cls))
+  {
+    GNUNET_break (0);
+    GNUNET_JSON_parse_free (spec);
+    GNUNET_free (pcc.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 deposit",
+                                TEH_MT_REQUEST_PURSE_DEPOSIT,
+                                &mhd_ret,
+                                &deposit_transaction,
+                                &pcc))
+    {
+      GNUNET_JSON_parse_free (spec);
+      GNUNET_free (pcc.coins);
+      return mhd_ret;
+    }
+  }
+
+  /* generate regular response */
+  {
+    MHD_RESULT res;
+
+    res = reply_deposit_success (connection,
+                                 &pcc);
+    GNUNET_free (pcc.coins);
+    GNUNET_JSON_parse_free (spec);
+    return res;
+  }
+}
+
+
+/* end of taler-exchange-httpd_purses_deposit.c */