/*
This file is part of TALER
Copyright (C) 2014-2017 GNUnet e.V.
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_reserve_withdraw.c
* @brief Handle /reserve/withdraw requests
* @author Florian Dold
* @author Benedikt Mueller
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include
#include "taler-exchange-httpd_reserve_withdraw.h"
#include "taler-exchange-httpd_parsing.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keystate.h"
/**
* Send reserve status information to client with the
* message that we have insufficient funds for the
* requested /reserve/withdraw operation.
*
* @param connection connection to the client
* @param rh reserve history to return
* @return MHD result code
*/
static int
reply_reserve_withdraw_insufficient_funds (struct MHD_Connection *connection,
const struct TALER_EXCHANGEDB_ReserveHistory *rh)
{
json_t *json_balance;
json_t *json_history;
struct TALER_Amount balance;
json_history = TEH_RESPONSE_compile_reserve_history (rh,
&balance);
if (NULL == json_history)
return TEH_RESPONSE_reply_internal_error (connection,
TALER_EC_WITHDRAW_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
"balance calculation failure");
json_balance = TALER_JSON_from_amount (&balance);
return TEH_RESPONSE_reply_json_pack (connection,
MHD_HTTP_FORBIDDEN,
"{s:s, s:I, s:o, s:o}",
"error", "Insufficient funds",
"code", (json_int_t) TALER_EC_WITHDRAW_INSUFFICIENT_FUNDS,
"balance", json_balance,
"history", json_history);
}
/**
* Send blinded coin information to client.
*
* @param connection connection to the client
* @param collectable blinded coin to return
* @return MHD result code
*/
static int
reply_reserve_withdraw_success (struct MHD_Connection *connection,
const struct TALER_EXCHANGEDB_CollectableBlindcoin *collectable)
{
json_t *sig_json;
sig_json = GNUNET_JSON_from_rsa_signature (collectable->sig.rsa_signature);
return TEH_RESPONSE_reply_json_pack (connection,
MHD_HTTP_OK,
"{s:o}",
"ev_sig", sig_json);
}
/**
* Context for #withdraw_transaction.
*/
struct WithdrawContext
{
/**
* Details about the withdrawal request.
*/
struct TALER_WithdrawRequestPS wsrd;
/**
* Value of the coin plus withdraw fee.
*/
struct TALER_Amount amount_required;
/**
* Denomination public key.
*/
struct TALER_DenominationPublicKey denomination_pub;
/**
* Signature over the request.
*/
struct TALER_ReserveSignatureP signature;
/**
* Blinded planchet.
*/
char *blinded_msg;
/**
* Key state to use to inspect previous withdrawal values.
*/
struct TEH_KS_StateHandle *key_state;
/**
* Number of bytes in @e blinded_msg.
*/
size_t blinded_msg_len;
/**
* Details about denomination we are about to withdraw.
*/
struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki;
/**
* Set to the resulting signed coin data to be returned to the client.
*/
struct TALER_EXCHANGEDB_CollectableBlindcoin collectable;
};
/**
* Function implementing /reserve/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.
*
* @param cls a `struct WithdrawContext *`
* @param connection MHD request which triggered the transaction
* @param session database session to use
* @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,
struct TALER_EXCHANGEDB_Session *session,
int *mhd_ret)
{
struct WithdrawContext *wc = cls;
struct TALER_EXCHANGEDB_ReserveHistory *rh;
struct TALER_Amount deposit_total;
struct TALER_Amount withdraw_total;
struct TALER_Amount balance;
struct TALER_Amount value;
struct TALER_Amount fee_withdraw;
int res;
enum GNUNET_DB_QueryStatus qs;
struct TALER_DenominationSignature denom_sig;
struct GNUNET_HashCode h_blind;
GNUNET_CRYPTO_hash (wc->blinded_msg,
wc->blinded_msg_len,
&h_blind);
qs = TEH_plugin->get_withdraw_info (TEH_plugin->cls,
session,
&h_blind,
&wc->collectable);
if (0 > qs)
{
GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_DB_FETCH_ERROR);
return qs;
}
/* Don't sign again if we have already signed the coin */
if (1 == qs)
return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
GNUNET_assert (0 == qs);
/* Check if balance is sufficient */
qs = TEH_plugin->get_reserve_history (TEH_plugin->cls,
session,
&wc->wsrd.reserve_pub,
&rh);
if (0 > qs)
{
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_DB_FETCH_ERROR);
return qs;
}
if (NULL == rh)
{
*mhd_ret = TEH_RESPONSE_reply_arg_unknown (connection,
TALER_EC_WITHDRAW_RESERVE_UNKNOWN,
"reserve_pub");
return GNUNET_DB_STATUS_HARD_ERROR;
}
/* calculate balance of the reserve */
res = 0;
for (const struct TALER_EXCHANGEDB_ReserveHistory *pos = rh;
NULL != pos;
pos = pos->next)
{
switch (pos->type)
{
case TALER_EXCHANGEDB_RO_BANK_TO_EXCHANGE:
if (0 == (res & 1))
deposit_total = pos->details.bank->amount;
else
if (GNUNET_OK !=
TALER_amount_add (&deposit_total,
&deposit_total,
&pos->details.bank->amount))
{
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_AMOUNT_DEPOSITS_OVERFLOW);
return GNUNET_DB_STATUS_HARD_ERROR;
}
res |= 1;
break;
case TALER_EXCHANGEDB_RO_WITHDRAW_COIN:
{
struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *tdki;
tdki = TEH_KS_denomination_key_lookup (wc->key_state,
&pos->details.withdraw->denom_pub,
TEH_KS_DKU_WITHDRAW);
if (NULL == tdki)
{
GNUNET_break (0);
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_HISTORIC_DENOMINATION_KEY_NOT_FOUND);
return GNUNET_DB_STATUS_HARD_ERROR;
}
TALER_amount_ntoh (&value,
&tdki->issue.properties.value);
if (0 == (res & 2))
withdraw_total = value;
else
if (GNUNET_OK !=
TALER_amount_add (&withdraw_total,
&withdraw_total,
&value))
{
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_AMOUNT_WITHDRAWALS_OVERFLOW);
return GNUNET_DB_STATUS_HARD_ERROR;
}
res |= 2;
break;
}
case TALER_EXCHANGEDB_RO_PAYBACK_COIN:
if (0 == (res & 1))
deposit_total = pos->details.payback->value;
else
if (GNUNET_OK !=
TALER_amount_add (&deposit_total,
&deposit_total,
&pos->details.payback->value))
{
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_AMOUNT_DEPOSITS_OVERFLOW);
return GNUNET_DB_STATUS_HARD_ERROR;
}
res |= 1;
break;
case TALER_EXCHANGEDB_RO_EXCHANGE_TO_BANK:
if (0 == (res & 2))
withdraw_total = pos->details.bank->amount;
else
if (GNUNET_OK !=
TALER_amount_add (&withdraw_total,
&withdraw_total,
&pos->details.bank->amount))
{
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_AMOUNT_WITHDRAWALS_OVERFLOW);
return GNUNET_DB_STATUS_HARD_ERROR;
}
res |= 2;
break;
}
}
if (0 == (res & 1))
{
/* did not encounter any wire transfer operations, how can we have a reserve? */
GNUNET_break (0);
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_RESERVE_WITHOUT_WIRE_TRANSFER);
return GNUNET_DB_STATUS_HARD_ERROR;
}
if (0 == (res & 2))
{
/* did not encounter any withdraw operations, set to zero */
TALER_amount_get_zero (deposit_total.currency,
&withdraw_total);
}
/* All reserve balances should be non-negative */
if (GNUNET_SYSERR ==
TALER_amount_subtract (&balance,
&deposit_total,
&withdraw_total))
{
GNUNET_break (0); /* database inconsistent */
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_RESERVE_HISTORY_IMPOSSIBLE);
return GNUNET_DB_STATUS_HARD_ERROR;
}
if (0 < TALER_amount_cmp (&wc->amount_required,
&balance))
{
*mhd_ret = reply_reserve_withdraw_insufficient_funds (connection,
rh);
TEH_plugin->free_reserve_history (TEH_plugin->cls,
rh);
return GNUNET_DB_STATUS_HARD_ERROR;
}
TEH_plugin->free_reserve_history (TEH_plugin->cls,
rh);
/* Balance is good, sign the coin! */
denom_sig.rsa_signature
= GNUNET_CRYPTO_rsa_sign_blinded (wc->dki->denom_priv.rsa_private_key,
wc->blinded_msg,
wc->blinded_msg_len);
if (NULL == denom_sig.rsa_signature)
{
GNUNET_break (0);
*mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
TALER_EC_WITHDRAW_SIGNATURE_FAILED,
"Internal error");
return GNUNET_DB_STATUS_HARD_ERROR;
}
TALER_amount_ntoh (&fee_withdraw,
&wc->dki->issue.properties.fee_withdraw);
wc->collectable.sig = denom_sig;
wc->collectable.denom_pub = wc->denomination_pub;
wc->collectable.amount_with_fee = wc->amount_required;
wc->collectable.withdraw_fee = fee_withdraw;
wc->collectable.reserve_pub = wc->wsrd.reserve_pub;
wc->collectable.h_coin_envelope = h_blind;
wc->collectable.reserve_sig = wc->signature;
qs = TEH_plugin->insert_withdraw_info (TEH_plugin->cls,
session,
&wc->collectable);
if (0 > qs)
{
GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
GNUNET_CRYPTO_rsa_signature_free (denom_sig.rsa_signature);
if (GNUNET_DB_STATUS_HARD_ERROR == qs)
*mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
TALER_EC_WITHDRAW_DB_STORE_ERROR);
return qs;
}
return qs;
}
/**
* Handle a "/reserve/withdraw" request. Parses the "reserve_pub"
* EdDSA key of the reserve and the requested "denom_pub" which
* specifies the key/value of the coin to be withdrawn, and checks
* that the signature "reserve_sig" makes this a valid withdrawal
* request from the specified reserve. If so, the envelope
* with the blinded coin "coin_ev" is passed down to execute the
* withdrawl operation.
*
* @param rh context of the handler
* @param connection the MHD connection to handle
* @param[in,out] connection_cls the connection's closure (can be updated)
* @param upload_data upload data
* @param[in,out] upload_data_size number of bytes (left) in @a upload_data
* @return MHD result code
*/
int
TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
struct MHD_Connection *connection,
void **connection_cls,
const char *upload_data,
size_t *upload_data_size)
{
struct WithdrawContext wc;
json_t *root;
int res;
int mhd_ret;
struct TALER_Amount amount;
struct TALER_Amount fee_withdraw;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_varsize ("coin_ev",
(void **) &wc.blinded_msg,
&wc.blinded_msg_len),
GNUNET_JSON_spec_fixed_auto ("reserve_pub",
&wc.wsrd.reserve_pub),
GNUNET_JSON_spec_fixed_auto ("reserve_sig",
&wc.signature),
TALER_JSON_spec_denomination_public_key ("denom_pub",
&wc.denomination_pub),
GNUNET_JSON_spec_end ()
};
res = TEH_PARSE_post_json (connection,
connection_cls,
upload_data,
upload_data_size,
&root);
if (GNUNET_SYSERR == res)
return MHD_NO;
if ( (GNUNET_NO == res) || (NULL == root) )
return MHD_YES;
res = TEH_PARSE_json_data (connection,
root,
spec);
json_decref (root);
if (GNUNET_OK != res)
return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
wc.key_state = TEH_KS_acquire ();
wc.dki = TEH_KS_denomination_key_lookup (wc.key_state,
&wc.denomination_pub,
TEH_KS_DKU_WITHDRAW);
if (NULL == wc.dki)
{
GNUNET_JSON_parse_free (spec);
TEH_KS_release (wc.key_state);
return TEH_RESPONSE_reply_arg_unknown (connection,
TALER_EC_WITHDRAW_DENOMINATION_KEY_NOT_FOUND,
"denom_pub");
}
TALER_amount_ntoh (&amount,
&wc.dki->issue.properties.value);
TALER_amount_ntoh (&fee_withdraw,
&wc.dki->issue.properties.fee_withdraw);
if (GNUNET_OK !=
TALER_amount_add (&wc.amount_required,
&amount,
&fee_withdraw))
{
GNUNET_JSON_parse_free (spec);
TEH_KS_release (wc.key_state);
return TEH_RESPONSE_reply_internal_error (connection,
TALER_EC_WITHDRAW_AMOUNT_FEE_OVERFLOW,
"amount overflow for value plus withdraw fee");
}
TALER_amount_hton (&wc.wsrd.amount_with_fee,
&wc.amount_required);
TALER_amount_hton (&wc.wsrd.withdraw_fee,
&fee_withdraw);
/* verify signature! */
wc.wsrd.purpose.size
= htonl (sizeof (struct TALER_WithdrawRequestPS));
wc.wsrd.purpose.purpose
= htonl (TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW);
GNUNET_CRYPTO_rsa_public_key_hash (wc.denomination_pub.rsa_public_key,
&wc.wsrd.h_denomination_pub);
GNUNET_CRYPTO_hash (wc.blinded_msg,
wc.blinded_msg_len,
&wc.wsrd.h_coin_envelope);
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW,
&wc.wsrd.purpose,
&wc.signature.eddsa_signature,
&wc.wsrd.reserve_pub.eddsa_pub))
{
TALER_LOG_WARNING ("Client supplied invalid signature for /reserve/withdraw request\n");
GNUNET_JSON_parse_free (spec);
TEH_KS_release (wc.key_state);
return TEH_RESPONSE_reply_signature_invalid (connection,
TALER_EC_WITHDRAW_RESERVE_SIGNATURE_INVALID,
"reserve_sig");
}
if (GNUNET_OK !=
TEH_DB_run_transaction (connection,
&mhd_ret,
&withdraw_transaction,
&wc))
{
TEH_KS_release (wc.key_state);
GNUNET_JSON_parse_free (spec);
return mhd_ret;
}
TEH_KS_release (wc.key_state);
GNUNET_JSON_parse_free (spec);
mhd_ret = reply_reserve_withdraw_success (connection,
&wc.collectable);
GNUNET_CRYPTO_rsa_signature_free (wc.collectable.sig.rsa_signature);
return mhd_ret;
}
/* end of taler-exchange-httpd_reserve_withdraw.c */