/*
This file is part of TALER
Copyright (C) 2014, 2015, 2018, 2019 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see
*/
/**
* @file exchange-lib/exchange_api_deposit.c
* @brief Implementation of the /deposit request of the exchange's HTTP API
* @author Sree Harsha Totakura
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include /* just for HTTP status codes */
#include
#include
#include
#include "taler_json_lib.h"
#include "taler_auditor_service.h"
#include "taler_exchange_service.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* 1:#AUDITOR_CHANCE is the probability that we report deposits
* to the auditor.
*
* 2==50% of going to auditor. This is way too high, but set
* deliberately this high for testing
*/
#define AUDITOR_CHANCE 2
/**
* @brief A Deposit Handle
*/
struct TALER_EXCHANGE_DepositHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
*/
char *url;
/**
* Context for #TEH_curl_easy_post(). Keeps the data that must
* persist for Curl to make the upload.
*/
struct TEAH_PostContext ctx;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_DepositResultCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Information the exchange should sign in response.
*/
struct TALER_DepositConfirmationPS depconf;
/**
* Exchange signature, set for #auditor_cb.
*/
struct TALER_ExchangeSignatureP exchange_sig;
/**
* Exchange signing public key, set for #auditor_cb.
*/
struct TALER_ExchangePublicKeyP exchange_pub;
/**
* Value of the /deposit transaction, including fee.
*/
struct TALER_Amount amount_with_fee;
/**
* Total value of the coin being transacted with.
*/
struct TALER_Amount coin_value;
};
/**
* Function called for each auditor to give us a chance to possibly
* launch a deposit confirmation interaction.
*
* @param cls closure
* @param ah handle to the auditor
* @param auditor_pub public key of the auditor
* @return NULL if no deposit confirmation interaction was launched
*/
static struct TEAH_AuditorInteractionEntry *
auditor_cb (void *cls,
struct TALER_AUDITOR_Handle *ah,
const struct TALER_AuditorPublicKeyP *auditor_pub)
{
struct TALER_EXCHANGE_DepositHandle *dh = cls;
const struct TALER_EXCHANGE_Keys *key_state;
const struct TALER_EXCHANGE_SigningPublicKey *spk;
struct TALER_Amount amount_without_fee;
struct TEAH_AuditorInteractionEntry *aie;
if (0 != GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
AUDITOR_CHANCE))
return NULL;
key_state = TALER_EXCHANGE_get_keys (dh->exchange);
spk = TALER_EXCHANGE_get_signing_key_details (key_state,
&dh->exchange_pub);
GNUNET_assert (NULL != spk);
TALER_amount_ntoh (&amount_without_fee,
&dh->depconf.amount_without_fee);
aie = GNUNET_new (struct TEAH_AuditorInteractionEntry);
aie->dch = TALER_AUDITOR_deposit_confirmation (ah,
&dh->depconf.h_wire,
&dh->depconf.h_contract_terms,
GNUNET_TIME_absolute_ntoh (dh->depconf.timestamp),
GNUNET_TIME_absolute_ntoh (dh->depconf.refund_deadline),
&amount_without_fee,
&dh->depconf.coin_pub,
&dh->depconf.merchant,
&dh->exchange_pub,
&dh->exchange_sig,
&key_state->master_pub,
spk->valid_from,
spk->valid_until,
spk->valid_legal,
&spk->master_sig,
&TEAH_acc_confirmation_cb,
aie);
return aie;
}
/**
* Verify that the signature on the "200 OK" response
* from the exchange is valid.
*
* @param dh deposit handle
* @param json json reply with the signature
* @param exchange_sig[out] set to the exchange's signature
* @param exchange_pub[out] set to the exchange's public key
* @return #GNUNET_OK if the signature is valid, #GNUNET_SYSERR if not
*/
static int
verify_deposit_signature_ok (struct TALER_EXCHANGE_DepositHandle *dh,
const json_t *json,
struct TALER_ExchangeSignatureP *exchange_sig,
struct TALER_ExchangePublicKeyP *exchange_pub)
{
const struct TALER_EXCHANGE_Keys *key_state;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("sig", exchange_sig),
GNUNET_JSON_spec_fixed_auto ("pub", exchange_pub),
GNUNET_JSON_spec_end()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
key_state = TALER_EXCHANGE_get_keys (dh->exchange);
if (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (key_state,
exchange_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT,
&dh->depconf.purpose,
&exchange_sig->eddsa_signature,
&exchange_pub->eddsa_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
dh->exchange_sig = *exchange_sig;
dh->exchange_pub = *exchange_pub;
TEAH_get_auditors_for_dc (dh->exchange,
&auditor_cb,
dh);
return GNUNET_OK;
}
/**
* Verify that the signatures on the "403 FORBIDDEN" response from the
* exchange demonstrating customer double-spending are valid.
*
* @param dh deposit handle
* @param json json reply with the signature(s) and transaction history
* @return #GNUNET_OK if the signature(s) is valid, #GNUNET_SYSERR if not
*/
static int
verify_deposit_signature_forbidden (const struct TALER_EXCHANGE_DepositHandle *dh,
const json_t *json)
{
json_t *history;
struct TALER_Amount total;
history = json_object_get (json,
"history");
if (GNUNET_OK !=
TALER_EXCHANGE_verify_coin_history (dh->coin_value.currency,
&dh->depconf.coin_pub,
history,
&total))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_amount_add (&total,
&total,
&dh->amount_with_fee))
{
/* clearly not OK if our transaction would have caused
the overflow... */
return GNUNET_OK;
}
if (0 >= TALER_amount_cmp (&total,
&dh->coin_value))
{
/* transaction should have still fit */
GNUNET_break (0);
return GNUNET_SYSERR;
}
/* everything OK, proof of double-spending was provided */
return GNUNET_OK;
}
/**
* Function called when we're done processing the
* HTTP /deposit request.
*
* @param cls the `struct TALER_EXCHANGE_DepositHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_deposit_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_DepositHandle *dh = cls;
struct TALER_ExchangeSignatureP exchange_sig;
struct TALER_ExchangePublicKeyP exchange_pub;
struct TALER_ExchangeSignatureP *es = NULL;
struct TALER_ExchangePublicKeyP *ep = NULL;
const json_t *j = response;
dh->job = NULL;
switch (response_code)
{
case 0:
break;
case MHD_HTTP_OK:
if (GNUNET_OK !=
verify_deposit_signature_ok (dh,
j,
&exchange_sig,
&exchange_pub))
{
GNUNET_break_op (0);
response_code = 0;
}
else
{
es = &exchange_sig;
ep = &exchange_pub;
}
break;
case MHD_HTTP_BAD_REQUEST:
/* This should never happen, either us or the exchange is buggy
(or API version conflict); just pass JSON reply to the application */
break;
case MHD_HTTP_FORBIDDEN:
/* Double spending; check signatures on transaction history */
if (GNUNET_OK !=
verify_deposit_signature_forbidden (dh,
j))
{
GNUNET_break_op (0);
response_code = 0;
}
break;
case MHD_HTTP_UNAUTHORIZED:
/* Nothing really to verify, exchange says one of the signatures is
invalid; as we checked them, this should never happen, we
should pass the JSON reply to the application */
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify, this should never
happen, we should pass the JSON reply to the application */
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
break;
default:
/* unexpected response code */
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u\n",
(unsigned int) response_code);
GNUNET_break (0);
response_code = 0;
break;
}
dh->cb (dh->cb_cls,
response_code,
TALER_JSON_get_error_code (j),
es,
ep,
j);
TALER_EXCHANGE_deposit_cancel (dh);
}
/**
* Verify signature information about the deposit.
*
* @param dki public key information
* @param amount the amount to be deposited
* @param h_wire hash of the merchant’s account details
* @param h_contract_terms hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
* @param coin_pub coin’s public key
* @param denom_pub denomination key with which the coin is signed
* @param denom_pub_hash hash of @a denom_pub
* @param denom_sig exchange’s unblinded signature of the coin
* @param timestamp timestamp when the deposit was finalized
* @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
* @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed)
* @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
* @return #GNUNET_OK if signatures are OK, #GNUNET_SYSERR if not
*/
static int
verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
const struct TALER_Amount *amount,
const struct GNUNET_HashCode *h_wire,
const struct GNUNET_HashCode *h_contract_terms,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_DenominationSignature *denom_sig,
const struct TALER_DenominationPublicKey *denom_pub,
const struct GNUNET_HashCode *denom_pub_hash,
struct GNUNET_TIME_Absolute timestamp,
const struct TALER_MerchantPublicKeyP *merchant_pub,
struct GNUNET_TIME_Absolute refund_deadline,
const struct TALER_CoinSpendSignatureP *coin_sig)
{
struct TALER_DepositRequestPS dr;
struct TALER_CoinPublicInfo coin_info;
dr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_DEPOSIT);
dr.purpose.size = htonl (sizeof (struct TALER_DepositRequestPS));
dr.h_contract_terms = *h_contract_terms;
dr.h_wire = *h_wire;
dr.timestamp = GNUNET_TIME_absolute_hton (timestamp);
dr.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
TALER_amount_hton (&dr.amount_with_fee,
amount);
TALER_amount_hton (&dr.deposit_fee,
&dki->fee_deposit);
dr.merchant = *merchant_pub;
dr.coin_pub = *coin_pub;
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT,
&dr.purpose,
&coin_sig->eddsa_signature,
&coin_pub->eddsa_pub))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Invalid coin signature on /deposit request!\n");
{
TALER_LOG_DEBUG ("... amount_with_fee was %s\n",
TALER_amount2s (amount));
TALER_LOG_DEBUG ("... deposit_fee was %s\n",
TALER_amount2s (&dki->fee_deposit));
}
return GNUNET_SYSERR;
}
/* check coin signature */
coin_info.coin_pub = *coin_pub;
coin_info.denom_pub_hash = *denom_pub_hash;
coin_info.denom_sig = *denom_sig;
if (GNUNET_YES !=
TALER_test_coin_valid (&coin_info,
denom_pub))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
return GNUNET_SYSERR;
}
if (0 < TALER_amount_cmp (&dki->fee_deposit,
amount))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Deposit amount smaller than fee\n");
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
/**
* Submit a deposit permission to the exchange and get the exchange's response.
* Note that while we return the response verbatim to the caller for
* further processing, we do already verify that the response is
* well-formed (i.e. that signatures included in the response are all
* valid). If the exchange's reply is not well-formed, we return an
* HTTP status code of zero to @a cb.
*
* We also verify that the @a coin_sig is valid for this deposit
* request, and that the @a ub_sig is a valid signature for @a
* coin_pub. Also, the @a exchange must be ready to operate (i.e. have
* finished processing the /keys reply). If either check fails, we do
* NOT initiate the transaction with the exchange and instead return NULL.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param amount the amount to be deposited
* @param wire_deadline date until which the merchant would like the exchange to settle the balance (advisory, the exchange cannot be
* forced to settle in the past or upon very short notice, but of course a well-behaved exchange will limit aggregation based on the advice received)
* @param wire_details the merchant’s account details, in a format supported by the exchange
* @param h_contract_terms hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
* @param coin_pub coin’s public key
* @param denom_pub denomination key with which the coin is signed
* @param denom_sig exchange’s unblinded signature of the coin
* @param timestamp timestamp when the contract was finalized, must not be too far in the future
* @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
* @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed); must not be after the @a wire_deadline
* @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
* @param cb the callback to call when a reply for this request is available
* @param cb_cls closure for the above callback
* @return a handle for this request; NULL if the inputs are invalid (i.e.
* signatures fail to verify). In this case, the callback is not called.
*/
struct TALER_EXCHANGE_DepositHandle *
TALER_EXCHANGE_deposit (struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_Amount *amount,
struct GNUNET_TIME_Absolute wire_deadline,
json_t *wire_details,
const struct GNUNET_HashCode *h_contract_terms,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_DenominationSignature *denom_sig,
const struct TALER_DenominationPublicKey *denom_pub,
struct GNUNET_TIME_Absolute timestamp,
const struct TALER_MerchantPublicKeyP *merchant_pub,
struct GNUNET_TIME_Absolute refund_deadline,
const struct TALER_CoinSpendSignatureP *coin_sig,
TALER_EXCHANGE_DepositResultCallback cb,
void *cb_cls)
{
const struct TALER_EXCHANGE_Keys *key_state;
const struct TALER_EXCHANGE_DenomPublicKey *dki;
struct TALER_EXCHANGE_DepositHandle *dh;
struct GNUNET_CURL_Context *ctx;
json_t *deposit_obj;
CURL *eh;
struct GNUNET_HashCode h_wire;
struct GNUNET_HashCode denom_pub_hash;
struct TALER_Amount amount_without_fee;
(void) GNUNET_TIME_round_abs (&wire_deadline);
(void) GNUNET_TIME_round_abs (&refund_deadline);
GNUNET_assert (refund_deadline.abs_value_us <= wire_deadline.abs_value_us);
GNUNET_assert (GNUNET_YES ==
TEAH_handle_is_ready (exchange));
/* initialize h_wire */
if (GNUNET_OK !=
TALER_JSON_merchant_wire_signature_hash (wire_details,
&h_wire))
{
GNUNET_break (0);
return NULL;
}
key_state = TALER_EXCHANGE_get_keys (exchange);
dki = TALER_EXCHANGE_get_denomination_key (key_state,
denom_pub);
GNUNET_assert (NULL != dki);
GNUNET_assert (GNUNET_SYSERR !=
TALER_amount_subtract (&amount_without_fee,
amount,
&dki->fee_deposit));
GNUNET_CRYPTO_rsa_public_key_hash (denom_pub->rsa_public_key,
&denom_pub_hash);
if (GNUNET_OK !=
verify_signatures (dki,
amount,
&h_wire,
h_contract_terms,
coin_pub,
denom_sig,
denom_pub,
&denom_pub_hash,
timestamp,
merchant_pub,
refund_deadline,
coin_sig))
{
GNUNET_break_op (0);
return NULL;
}
deposit_obj = json_pack ("{s:o, s:O," /* f/wire */
" s:o, s:o," /* H_wire, h_contract_terms */
" s:o, s:o," /* coin_pub, denom_pub */
" s:o, s:o," /* ub_sig, timestamp */
" s:o," /* merchant_pub */
" s:o, s:o," /* refund_deadline, wire_deadline */
" s:o}", /* coin_sig */
"contribution", TALER_JSON_from_amount (amount),
"wire", wire_details,
"H_wire", GNUNET_JSON_from_data_auto (&h_wire),
"h_contract_terms", GNUNET_JSON_from_data_auto (h_contract_terms),
"coin_pub", GNUNET_JSON_from_data_auto (coin_pub),
"denom_pub_hash", GNUNET_JSON_from_data_auto (&denom_pub_hash),
"ub_sig", GNUNET_JSON_from_rsa_signature (denom_sig->rsa_signature),
"timestamp", GNUNET_JSON_from_time_abs (timestamp),
"merchant_pub", GNUNET_JSON_from_data_auto (merchant_pub),
"refund_deadline", GNUNET_JSON_from_time_abs (refund_deadline),
"wire_transfer_deadline", GNUNET_JSON_from_time_abs (wire_deadline),
"coin_sig", GNUNET_JSON_from_data_auto (coin_sig)
);
if (NULL == deposit_obj)
{
GNUNET_break (0);
return NULL;
}
dh = GNUNET_new (struct TALER_EXCHANGE_DepositHandle);
dh->exchange = exchange;
dh->cb = cb;
dh->cb_cls = cb_cls;
dh->url = TEAH_path_to_url (exchange, "/deposit");
dh->depconf.purpose.size = htonl (sizeof (struct TALER_DepositConfirmationPS));
dh->depconf.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT);
dh->depconf.h_contract_terms = *h_contract_terms;
dh->depconf.h_wire = h_wire;
dh->depconf.timestamp = GNUNET_TIME_absolute_hton (timestamp);
dh->depconf.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
TALER_amount_hton (&dh->depconf.amount_without_fee,
&amount_without_fee);
dh->depconf.coin_pub = *coin_pub;
dh->depconf.merchant = *merchant_pub;
dh->amount_with_fee = *amount;
dh->coin_value = dki->value;
eh = TEL_curl_easy_get (dh->url);
if (GNUNET_OK !=
TALER_curl_easy_post (&dh->ctx,
eh,
deposit_obj))
{
GNUNET_break (0);
curl_easy_cleanup (eh);
json_decref (deposit_obj);
GNUNET_free (dh->url);
GNUNET_free (dh);
return NULL;
}
json_decref (deposit_obj);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"URL for deposit: `%s'\n",
dh->url);
ctx = TEAH_handle_to_context (exchange);
dh->job = GNUNET_CURL_job_add2 (ctx,
eh,
dh->ctx.headers,
&handle_deposit_finished,
dh);
return dh;
}
/**
* Cancel a deposit permission request. This function cannot be used
* on a request handle if a response is already served for it.
*
* @param deposit the deposit permission request handle
*/
void
TALER_EXCHANGE_deposit_cancel (struct TALER_EXCHANGE_DepositHandle *deposit)
{
if (NULL != deposit->job)
{
GNUNET_CURL_job_cancel (deposit->job);
deposit->job = NULL;
}
GNUNET_free (deposit->url);
TALER_curl_easy_post_finished (&deposit->ctx);
GNUNET_free (deposit);
}
/* end of exchange_api_deposit.c */