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exchange/src/exchange/taler-exchange-httpd_deposit.c
Christian Grothoff e61a53806e
save 2ms on deposit by not doing idempotency check twice
2021-12-04 23:24:50 +01:00

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19 KiB
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/*
This file is part of TALER
Copyright (C) 2014-2021 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_deposit.c
* @brief Handle /deposit requests; parses the POST and JSON and
* verifies the coin signature before handing things off
* to the database.
* @author Florian Dold
* @author Benedikt Mueller
* @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_deposit.h"
#include "taler-exchange-httpd_responses.h"
#include "taler_exchangedb_lib.h"
#include "taler-exchange-httpd_keys.h"
/**
* Send confirmation of deposit success to client. This function
* will create a signed message affirming the given information
* and return it to the client. By this, the exchange affirms that
* the coin had sufficient (residual) value for the specified
* transaction and that it will execute the requested deposit
* operation with the given wiring details.
*
* @param connection connection to the client
* @param coin_pub public key of the coin
* @param h_wire hash of wire details
* @param h_contract_terms hash of contract details
* @param exchange_timestamp exchange's timestamp
* @param refund_deadline until when this deposit be refunded
* @param merchant merchant public key
* @param amount_without_fee fraction of coin value to deposit, without the fee
* @return MHD result code
*/
static MHD_RESULT
reply_deposit_success (struct MHD_Connection *connection,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_MerchantWireHash *h_wire,
const struct TALER_ExtensionContractHash *h_extensions,
const struct TALER_PrivateContractHash *h_contract_terms,
struct GNUNET_TIME_Absolute exchange_timestamp,
struct GNUNET_TIME_Absolute refund_deadline,
struct GNUNET_TIME_Absolute wire_deadline,
const struct TALER_MerchantPublicKeyP *merchant,
const struct TALER_Amount *amount_without_fee)
{
struct TALER_ExchangePublicKeyP pub;
struct TALER_ExchangeSignatureP sig;
struct TALER_DepositConfirmationPS dc = {
.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT),
.purpose.size = htonl (sizeof (dc)),
.h_contract_terms = *h_contract_terms,
.h_wire = *h_wire,
.exchange_timestamp = GNUNET_TIME_absolute_hton (exchange_timestamp),
.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline),
.wire_deadline = GNUNET_TIME_absolute_hton (wire_deadline),
.coin_pub = *coin_pub,
.merchant_pub = *merchant
};
enum TALER_ErrorCode ec;
if (NULL != h_extensions)
dc.h_extensions = *h_extensions;
TALER_amount_hton (&dc.amount_without_fee,
amount_without_fee);
if (TALER_EC_NONE !=
(ec = TEH_keys_exchange_sign (&dc,
&pub,
&sig)))
{
return TALER_MHD_reply_with_ec (connection,
ec,
NULL);
}
return TALER_MHD_REPLY_JSON_PACK (
connection,
MHD_HTTP_OK,
GNUNET_JSON_pack_time_abs ("exchange_timestamp",
exchange_timestamp),
GNUNET_JSON_pack_data_auto ("exchange_sig",
&sig),
GNUNET_JSON_pack_data_auto ("exchange_pub",
&pub));
}
/**
* Closure for #deposit_transaction.
*/
struct DepositContext
{
/**
* Information about the deposit request.
*/
const struct TALER_EXCHANGEDB_Deposit *deposit;
/**
* Our timestamp (when we received the request).
*/
struct GNUNET_TIME_Absolute exchange_timestamp;
/**
* Calculated hash over the wire details.
*/
struct TALER_MerchantWireHash h_wire;
/**
* Value of the coin.
*/
struct TALER_Amount value;
/**
* payto:// URI of the credited account.
*/
const char *payto_uri;
};
/**
* Execute database transaction for /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 DepositContext`
* @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 DepositContext *dc = cls;
const struct TALER_EXCHANGEDB_Deposit *deposit = dc->deposit;
struct TALER_Amount spent;
enum GNUNET_DB_QueryStatus qs;
struct TALER_Amount deposit_fee;
/* make sure coin is 'known' in database */
qs = TEH_make_coin_known (&deposit->coin,
connection,
mhd_ret);
if (qs < 0)
return qs;
/* Check for idempotency: did we get this request before? */
qs = TEH_plugin->have_deposit (TEH_plugin->cls,
deposit,
&deposit_fee,
&dc->exchange_timestamp);
if (qs < 0)
{
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
{
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_FETCH_FAILED,
"have_deposit");
return GNUNET_DB_STATUS_HARD_ERROR;
}
return qs;
}
if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
{
struct TALER_Amount amount_without_fee;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"/deposit replay, accepting again!\n");
GNUNET_assert (0 <=
TALER_amount_subtract (&amount_without_fee,
&deposit->amount_with_fee,
&deposit_fee));
*mhd_ret = reply_deposit_success (connection,
&deposit->coin.coin_pub,
&dc->h_wire,
NULL /* h_extensions! */,
&deposit->h_contract_terms,
dc->exchange_timestamp,
deposit->refund_deadline,
deposit->wire_deadline,
&deposit->merchant_pub,
&amount_without_fee);
return GNUNET_DB_STATUS_HARD_ERROR;
}
/* Start with fee for THIS transaction */
spent = deposit->amount_with_fee;
/* add cost of all previous transactions; skip RECOUP as revoked
denominations are not eligible for deposit, and if we are the old coin
pub of a revoked coin (aka a zombie), then ONLY refresh is allowed. */
{
struct TALER_EXCHANGEDB_TransactionList *tl;
qs = TEH_plugin->get_coin_transactions (TEH_plugin->cls,
&deposit->coin.coin_pub,
GNUNET_NO,
&tl);
if (0 > qs)
{
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
*mhd_ret = TALER_MHD_reply_with_error (
connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_FETCH_FAILED,
NULL);
return qs;
}
if (GNUNET_OK !=
TALER_EXCHANGEDB_calculate_transaction_list_totals (tl,
&spent, /* starting offset */
&spent /* result */))
{
TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
tl);
*mhd_ret = TALER_MHD_reply_with_error (
connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_INVARIANT_FAILURE,
NULL);
return GNUNET_DB_STATUS_HARD_ERROR;
}
/* Check that cost of all transactions (including the current one) is
smaller (or equal) than the value of the coin. */
if (0 < TALER_amount_cmp (&spent,
&dc->value))
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Deposited coin has insufficient funds left!\n");
*mhd_ret = TEH_RESPONSE_reply_coin_insufficient_funds (connection,
TALER_EC_EXCHANGE_DEPOSIT_INSUFFICIENT_FUNDS,
&deposit->coin.
coin_pub,
tl);
TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
tl);
return GNUNET_DB_STATUS_HARD_ERROR;
}
TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
tl);
}
qs = TEH_plugin->insert_deposit (TEH_plugin->cls,
dc->exchange_timestamp,
deposit);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
{
TALER_LOG_WARNING ("Failed to store /deposit information in database\n");
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_STORE_FAILED,
NULL);
}
return qs;
}
/**
* Handle a "/coins/$COIN_PUB/deposit" request. Parses the JSON, and, if
* successful, passes the JSON data to #deposit_transaction() to
* further check the details of the operation specified. If everything checks
* out, this will ultimately lead to the "/deposit" being executed, or
* rejected.
*
* @param connection the MHD connection to handle
* @param coin_pub public key of the coin
* @param root uploaded JSON data
* @return MHD result code
*/
MHD_RESULT
TEH_handler_deposit (struct MHD_Connection *connection,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const json_t *root)
{
struct DepositContext dc;
struct TALER_EXCHANGEDB_Deposit deposit;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_string ("merchant_payto_uri",
&dc.payto_uri),
GNUNET_JSON_spec_fixed_auto ("wire_salt",
&deposit.wire_salt),
TALER_JSON_spec_amount ("contribution",
TEH_currency,
&deposit.amount_with_fee),
GNUNET_JSON_spec_fixed_auto ("denom_pub_hash",
&deposit.coin.denom_pub_hash),
TALER_JSON_spec_denom_sig ("ub_sig",
&deposit.coin.denom_sig),
GNUNET_JSON_spec_fixed_auto ("merchant_pub",
&deposit.merchant_pub),
GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
&deposit.h_contract_terms),
GNUNET_JSON_spec_fixed_auto ("coin_sig",
&deposit.csig),
TALER_JSON_spec_absolute_time ("timestamp",
&deposit.timestamp),
GNUNET_JSON_spec_mark_optional (
TALER_JSON_spec_absolute_time ("refund_deadline",
&deposit.refund_deadline)),
TALER_JSON_spec_absolute_time ("wire_transfer_deadline",
&deposit.wire_deadline),
GNUNET_JSON_spec_end ()
};
memset (&deposit,
0,
sizeof (deposit));
deposit.coin.coin_pub = *coin_pub;
{
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 */
}
}
/* validate merchant's wire details (as far as we can) */
{
char *emsg;
emsg = TALER_payto_validate (dc.payto_uri);
if (NULL != emsg)
{
MHD_RESULT ret;
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
emsg);
GNUNET_free (emsg);
return ret;
}
}
deposit.receiver_wire_account = (char *) dc.payto_uri;
if (deposit.refund_deadline.abs_value_us > deposit.wire_deadline.abs_value_us)
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_EXCHANGE_DEPOSIT_REFUND_DEADLINE_AFTER_WIRE_DEADLINE,
NULL);
}
TALER_merchant_wire_signature_hash (dc.payto_uri,
&deposit.wire_salt,
&dc.h_wire);
dc.deposit = &deposit;
/* new deposit */
dc.exchange_timestamp = GNUNET_TIME_absolute_get ();
(void) GNUNET_TIME_round_abs (&dc.exchange_timestamp);
/* check denomination exists and is valid */
{
struct TEH_DenominationKey *dk;
MHD_RESULT mret;
dk = TEH_keys_denomination_by_hash (&deposit.coin.denom_pub_hash,
connection,
&mret);
if (NULL == dk)
{
GNUNET_JSON_parse_free (spec);
return mret;
}
if (GNUNET_TIME_absolute_is_past (dk->meta.expire_deposit))
{
/* This denomination is past the expiration time for deposits */
struct GNUNET_TIME_Absolute now;
now = GNUNET_TIME_absolute_get ();
(void) GNUNET_TIME_round_abs (&now);
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
connection,
&deposit.coin.denom_pub_hash,
now,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_EXPIRED,
"DEPOSIT");
}
if (GNUNET_TIME_absolute_is_future (dk->meta.start))
{
/* This denomination is not yet valid */
struct GNUNET_TIME_Absolute now;
now = GNUNET_TIME_absolute_get ();
(void) GNUNET_TIME_round_abs (&now);
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
connection,
&deposit.coin.denom_pub_hash,
now,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_VALIDITY_IN_FUTURE,
"DEPOSIT");
}
if (dk->recoup_possible)
{
struct GNUNET_TIME_Absolute now;
now = GNUNET_TIME_absolute_get ();
(void) GNUNET_TIME_round_abs (&now);
/* This denomination has been revoked */
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
connection,
&deposit.coin.denom_pub_hash,
now,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_REVOKED,
"DEPOSIT");
}
deposit.deposit_fee = dk->meta.fee_deposit;
/* check coin signature */
if (GNUNET_YES !=
TALER_test_coin_valid (&deposit.coin,
&dk->denom_pub))
{
TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_UNAUTHORIZED,
TALER_EC_EXCHANGE_DENOMINATION_SIGNATURE_INVALID,
NULL);
}
dc.value = dk->meta.value;
}
if (0 < TALER_amount_cmp (&deposit.deposit_fee,
&deposit.amount_with_fee))
{
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);
}
if (GNUNET_OK !=
TALER_wallet_deposit_verify (&deposit.amount_with_fee,
&deposit.deposit_fee,
&dc.h_wire,
&deposit.h_contract_terms,
NULL /* h_extensions! */,
&deposit.coin.denom_pub_hash,
deposit.timestamp,
&deposit.merchant_pub,
deposit.refund_deadline,
&deposit.coin.coin_pub,
&deposit.csig))
{
TALER_LOG_WARNING ("Invalid signature on /deposit request\n");
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_UNAUTHORIZED,
TALER_EC_EXCHANGE_DEPOSIT_COIN_SIGNATURE_INVALID,
NULL);
}
/* execute transaction */
{
MHD_RESULT mhd_ret;
if (GNUNET_OK !=
TEH_DB_run_transaction (connection,
"execute deposit",
&mhd_ret,
&deposit_transaction,
&dc))
{
GNUNET_JSON_parse_free (spec);
return mhd_ret;
}
}
/* generate regular response */
{
struct TALER_Amount amount_without_fee;
MHD_RESULT res;
GNUNET_assert (0 <=
TALER_amount_subtract (&amount_without_fee,
&deposit.amount_with_fee,
&deposit.deposit_fee));
res = reply_deposit_success (connection,
&deposit.coin.coin_pub,
&dc.h_wire,
NULL /* h_extensions! */,
&deposit.h_contract_terms,
dc.exchange_timestamp,
deposit.refund_deadline,
deposit.wire_deadline,
&deposit.merchant_pub,
&amount_without_fee);
GNUNET_JSON_parse_free (spec);
return res;
}
}
/* end of taler-exchange-httpd_deposit.c */
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