/*
This file is part of TALER
Copyright (C) 2014-2022 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
*/
/**
* @file taler-exchange-httpd_withdraw.c
* @brief Handle /reserves/$RESERVE_PUB/withdraw requests
* @author Florian Dold
* @author Benedikt Mueller
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include
#include "taler_json_lib.h"
#include "taler_kyclogic_lib.h"
#include "taler_mhd_lib.h"
#include "taler-exchange-httpd_withdraw.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keys.h"
/**
* Context for #withdraw_transaction.
*/
struct WithdrawContext
{
/**
* Hash of the (blinded) message to be signed by the Exchange.
*/
struct TALER_BlindedCoinHashP h_coin_envelope;
/**
* Blinded planchet.
*/
struct TALER_BlindedPlanchet blinded_planchet;
/**
* Set to the resulting signed coin data to be returned to the client.
*/
struct TALER_EXCHANGEDB_CollectableBlindcoin collectable;
/**
* KYC status for the operation.
*/
struct TALER_EXCHANGEDB_KycStatus kyc;
/**
* Hash of the payto-URI representing the reserve
* from which we are withdrawing.
*/
struct TALER_PaytoHashP h_payto;
/**
* Current time for the DB transaction.
*/
struct GNUNET_TIME_Timestamp now;
};
/**
* Function called to iterate over KYC-relevant
* transaction amounts for a particular time range.
* Called within a database transaction, so must
* not start a new one.
*
* @param cls closure, identifies the event type and
* account to iterate over events for
* @param limit maximum time-range for which events
* should be fetched (timestamp in the past)
* @param cb function to call on each event found,
* events must be returned in reverse chronological
* order
* @param cb_cls closure for @a cb
*/
static void
withdraw_amount_cb (void *cls,
struct GNUNET_TIME_Absolute limit,
TALER_EXCHANGEDB_KycAmountCallback cb,
void *cb_cls)
{
struct WithdrawContext *wc = cls;
enum GNUNET_DB_QueryStatus qs;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Signaling amount %s for KYC check\n",
TALER_amount2s (&wc->collectable.amount_with_fee));
if (GNUNET_OK !=
cb (cb_cls,
&wc->collectable.amount_with_fee,
wc->now.abs_time))
return;
qs = TEH_plugin->select_withdraw_amounts_for_kyc_check (
TEH_plugin->cls,
&wc->h_payto,
limit,
cb,
cb_cls);
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Got %d additional transactions for this withdrawal and limit %llu\n",
qs,
(unsigned long long) limit.abs_value_us);
GNUNET_break (qs >= 0);
}
/**
* Function implementing withdraw transaction. 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.
*
* Note that "wc->collectable.sig" is set before entering this function as we
* signed before entering the transaction.
*
* @param cls a `struct WithdrawContext *`
* @param connection MHD request which triggered the transaction
* @param[out] mhd_ret set to MHD response status for @a connection,
* if transaction failed (!)
* @return transaction status
*/
static enum GNUNET_DB_QueryStatus
withdraw_transaction (void *cls,
struct MHD_Connection *connection,
MHD_RESULT *mhd_ret)
{
struct WithdrawContext *wc = cls;
enum GNUNET_DB_QueryStatus qs;
bool found = false;
bool balance_ok = false;
bool nonce_ok = false;
uint64_t ruuid;
const struct TALER_CsNonce *nonce;
const struct TALER_BlindedPlanchet *bp;
wc->now = GNUNET_TIME_timestamp_get ();
qs = TEH_plugin->reserves_get_origin (TEH_plugin->cls,
&wc->collectable.reserve_pub,
&wc->h_payto);
if (qs < 0)
return qs;
/* If no results, reserve was created by merge,
in which case no KYC check is required as the
merge already did that. */
if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
{
const char *kyc_required;
kyc_required = TALER_KYCLOGIC_kyc_test_required (
TALER_KYCLOGIC_KYC_TRIGGER_WITHDRAW,
&wc->h_payto,
TEH_plugin->select_satisfied_kyc_processes,
TEH_plugin->cls,
&withdraw_amount_cb,
wc);
if (NULL != kyc_required)
{
/* insert KYC requirement into DB! */
wc->kyc.ok = false;
return TEH_plugin->insert_kyc_requirement_for_account (
TEH_plugin->cls,
kyc_required,
&wc->h_payto,
&wc->kyc.requirement_row);
}
}
wc->kyc.ok = true;
bp = &wc->blinded_planchet;
nonce = (TALER_DENOMINATION_CS == bp->cipher)
? &bp->details.cs_blinded_planchet.nonce
: NULL;
qs = TEH_plugin->do_withdraw (TEH_plugin->cls,
nonce,
&wc->collectable,
wc->now,
&found,
&balance_ok,
&nonce_ok,
&ruuid);
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,
"do_withdraw");
return qs;
}
if (! found)
{
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_NOT_FOUND,
TALER_EC_EXCHANGE_GENERIC_RESERVE_UNKNOWN,
NULL);
return GNUNET_DB_STATUS_HARD_ERROR;
}
if (! balance_ok)
{
TEH_plugin->rollback (TEH_plugin->cls);
*mhd_ret = TEH_RESPONSE_reply_reserve_insufficient_balance (
connection,
TALER_EC_EXCHANGE_WITHDRAW_INSUFFICIENT_FUNDS,
&wc->collectable.amount_with_fee,
&wc->collectable.reserve_pub);
return GNUNET_DB_STATUS_HARD_ERROR;
}
if (! nonce_ok)
{
TEH_plugin->rollback (TEH_plugin->cls);
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_CONFLICT,
TALER_EC_EXCHANGE_WITHDRAW_NONCE_REUSE,
NULL);
return GNUNET_DB_STATUS_HARD_ERROR;
}
if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
TEH_METRICS_num_success[TEH_MT_SUCCESS_WITHDRAW]++;
return qs;
}
/**
* Check if the @a rc is replayed and we already have an
* answer. If so, replay the existing answer and return the
* HTTP response.
*
* @param rc request context
* @param[in,out] wc parsed request data
* @param[out] mret HTTP status, set if we return true
* @return true if the request is idempotent with an existing request
* false if we did not find the request in the DB and did not set @a mret
*/
static bool
check_request_idempotent (struct TEH_RequestContext *rc,
struct WithdrawContext *wc,
MHD_RESULT *mret)
{
enum GNUNET_DB_QueryStatus qs;
qs = TEH_plugin->get_withdraw_info (TEH_plugin->cls,
&wc->h_coin_envelope,
&wc->collectable);
if (0 > qs)
{
GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
*mret = TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_FETCH_FAILED,
"get_withdraw_info");
return true; /* well, kind-of */
}
if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
return false;
/* generate idempotent reply */
TEH_METRICS_num_requests[TEH_MT_REQUEST_IDEMPOTENT_WITHDRAW]++;
*mret = TALER_MHD_REPLY_JSON_PACK (
rc->connection,
MHD_HTTP_OK,
TALER_JSON_pack_blinded_denom_sig ("ev_sig",
&wc->collectable.sig));
TALER_blinded_denom_sig_free (&wc->collectable.sig);
return true;
}
MHD_RESULT
TEH_handler_withdraw (struct TEH_RequestContext *rc,
const struct TALER_ReservePublicKeyP *reserve_pub,
const json_t *root)
{
struct WithdrawContext wc;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("reserve_sig",
&wc.collectable.reserve_sig),
GNUNET_JSON_spec_fixed_auto ("denom_pub_hash",
&wc.collectable.denom_pub_hash),
TALER_JSON_spec_blinded_planchet ("coin_ev",
&wc.blinded_planchet),
GNUNET_JSON_spec_end ()
};
enum TALER_ErrorCode ec;
struct TEH_DenominationKey *dk;
memset (&wc,
0,
sizeof (wc));
wc.collectable.reserve_pub = *reserve_pub;
{
enum GNUNET_GenericReturnValue res;
res = TALER_MHD_parse_json_data (rc->connection,
root,
spec);
if (GNUNET_OK != res)
return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
}
{
MHD_RESULT mret;
struct TEH_KeyStateHandle *ksh;
ksh = TEH_keys_get_state ();
if (NULL == ksh)
{
if (! check_request_idempotent (rc,
&wc,
&mret))
{
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING,
NULL);
}
GNUNET_JSON_parse_free (spec);
return mret;
}
dk = TEH_keys_denomination_by_hash2 (ksh,
&wc.collectable.denom_pub_hash,
NULL,
NULL);
if (NULL == dk)
{
if (! check_request_idempotent (rc,
&wc,
&mret))
{
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_unknown_denom_pub_hash (
rc->connection,
&wc.collectable.denom_pub_hash);
}
GNUNET_JSON_parse_free (spec);
return mret;
}
if (GNUNET_TIME_absolute_is_past (dk->meta.expire_withdraw.abs_time))
{
/* This denomination is past the expiration time for withdraws */
if (! check_request_idempotent (rc,
&wc,
&mret))
{
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
rc->connection,
&wc.collectable.denom_pub_hash,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_EXPIRED,
"WITHDRAW");
}
GNUNET_JSON_parse_free (spec);
return mret;
}
if (GNUNET_TIME_absolute_is_future (dk->meta.start.abs_time))
{
/* This denomination is not yet valid, no need to check
for idempotency! */
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
rc->connection,
&wc.collectable.denom_pub_hash,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_VALIDITY_IN_FUTURE,
"WITHDRAW");
}
if (dk->recoup_possible)
{
/* This denomination has been revoked */
if (! check_request_idempotent (rc,
&wc,
&mret))
{
GNUNET_JSON_parse_free (spec);
return TEH_RESPONSE_reply_expired_denom_pub_hash (
rc->connection,
&wc.collectable.denom_pub_hash,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_REVOKED,
"WITHDRAW");
}
GNUNET_JSON_parse_free (spec);
return mret;
}
if (dk->denom_pub.cipher != wc.blinded_planchet.cipher)
{
/* denomination cipher and blinded planchet cipher not the same */
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_EXCHANGE_GENERIC_CIPHER_MISMATCH,
NULL);
}
}
if (0 >
TALER_amount_add (&wc.collectable.amount_with_fee,
&dk->meta.value,
&dk->meta.fees.withdraw))
{
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_EXCHANGE_WITHDRAW_AMOUNT_FEE_OVERFLOW,
NULL);
}
if (GNUNET_OK !=
TALER_coin_ev_hash (&wc.blinded_planchet,
&wc.collectable.denom_pub_hash,
&wc.collectable.h_coin_envelope))
{
GNUNET_break (0);
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE,
NULL);
}
TEH_METRICS_num_verifications[TEH_MT_SIGNATURE_EDDSA]++;
if (GNUNET_OK !=
TALER_wallet_withdraw_verify (&wc.collectable.denom_pub_hash,
&wc.collectable.amount_with_fee,
&wc.collectable.h_coin_envelope,
&wc.collectable.reserve_pub,
&wc.collectable.reserve_sig))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_error (rc->connection,
MHD_HTTP_FORBIDDEN,
TALER_EC_EXCHANGE_WITHDRAW_RESERVE_SIGNATURE_INVALID,
NULL);
}
{
struct TEH_CoinSignData csd = {
.h_denom_pub = &wc.collectable.denom_pub_hash,
.bp = &wc.blinded_planchet
};
/* Sign before transaction! */
ec = TEH_keys_denomination_sign_withdraw (
&csd,
&wc.collectable.sig);
}
if (TALER_EC_NONE != ec)
{
GNUNET_break (0);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Failed to sign coin: %d\n",
ec);
GNUNET_JSON_parse_free (spec);
return TALER_MHD_reply_with_ec (rc->connection,
ec,
NULL);
}
/* run transaction */
{
MHD_RESULT mhd_ret;
if (GNUNET_OK !=
TEH_DB_run_transaction (rc->connection,
"run withdraw",
TEH_MT_REQUEST_WITHDRAW,
&mhd_ret,
&withdraw_transaction,
&wc))
{
/* Even if #withdraw_transaction() failed, it may have created a signature
(or we might have done it optimistically above). */
TALER_blinded_denom_sig_free (&wc.collectable.sig);
GNUNET_JSON_parse_free (spec);
return mhd_ret;
}
}
/* Clean up and send back final response */
GNUNET_JSON_parse_free (spec);
if (! wc.kyc.ok)
return TEH_RESPONSE_reply_kyc_required (rc->connection,
&wc.h_payto,
&wc.kyc);
{
MHD_RESULT ret;
ret = TALER_MHD_REPLY_JSON_PACK (
rc->connection,
MHD_HTTP_OK,
TALER_JSON_pack_blinded_denom_sig ("ev_sig",
&wc.collectable.sig));
TALER_blinded_denom_sig_free (&wc.collectable.sig);
return ret;
}
}
/* end of taler-exchange-httpd_withdraw.c */