taler/exchange
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
8a3f0e3f8d
exchange/src/lib/exchange_api_payback.c

425 lines
13 KiB
C
Raw Blame History

/*
This file is part of TALER
Copyright (C) 2017 GNUnet e.V. and Inria
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
<http://www.gnu.org/licenses/>
*/
/**
* @file exchange-lib/exchange_api_payback.c
* @brief Implementation of the /payback request of the exchange's HTTP API
* @author Christian Grothoff
*/
#include "platform.h"
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_json_lib.h"
#include "taler_exchange_service.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* @brief A Payback Handle
*/
struct TALER_EXCHANGE_PaybackHandle
{
/**
* 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;
/**
* Denomination key of the coin.
*/
struct TALER_EXCHANGE_DenomPublicKey pk;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_PaybackResultCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Public key of the coin we are trying to get paid back.
*/
struct TALER_CoinSpendPublicKeyP coin_pub;
/**
* #GNUNET_YES if the coin was refreshed
*/
int was_refreshed;
};
/**
* Verify that the signature on the "200 OK" response
* from the exchange is valid. If it is, call the
* callback.
*
* @param ph payback handle
* @param json json reply with the signature
* @return #GNUNET_OK if the signature is valid and we called the callback;
* #GNUNET_SYSERR if not (callback must still be called)
*/
static int
verify_payback_signature_ok (const struct TALER_EXCHANGE_PaybackHandle *ph,
const json_t *json)
{
struct TALER_PaybackConfirmationPS pc;
struct TALER_PaybackRefreshConfirmationPS pr;
struct TALER_ExchangePublicKeyP exchange_pub;
struct TALER_ExchangeSignatureP exchange_sig;
struct TALER_Amount amount;
struct GNUNET_TIME_Absolute timestamp;
const struct TALER_EXCHANGE_Keys *key_state;
struct GNUNET_JSON_Specification spec_withdraw[] = {
GNUNET_JSON_spec_fixed_auto ("exchange_sig", &exchange_sig),
GNUNET_JSON_spec_fixed_auto ("exchange_pub", &exchange_pub),
TALER_JSON_spec_amount ("amount", &amount),
GNUNET_JSON_spec_absolute_time ("timestamp", &timestamp),
GNUNET_JSON_spec_fixed_auto ("reserve_pub", &pc.reserve_pub),
GNUNET_JSON_spec_end ()
};
struct GNUNET_JSON_Specification spec_refresh[] = {
GNUNET_JSON_spec_fixed_auto ("exchange_sig", &exchange_sig),
GNUNET_JSON_spec_fixed_auto ("exchange_pub", &exchange_pub),
TALER_JSON_spec_amount ("amount", &amount),
GNUNET_JSON_spec_absolute_time ("timestamp", &timestamp),
GNUNET_JSON_spec_fixed_auto ("old_coin_pub", &pr.old_coin_pub),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
ph->was_refreshed ? spec_refresh : spec_withdraw,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
key_state = TALER_EXCHANGE_get_keys (ph->exchange);
if (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (key_state,
&exchange_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (ph->was_refreshed)
{
pr.purpose.purpose = htonl (
TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK_REFRESH);
pr.purpose.size = htonl (sizeof (pr));
pr.timestamp = GNUNET_TIME_absolute_hton (timestamp);
TALER_amount_hton (&pr.payback_amount,
&amount);
pr.coin_pub = ph->coin_pub;
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (
TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK_REFRESH,
&pr.purpose,
&exchange_sig.eddsa_signature,
&exchange_pub.eddsa_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
}
else
{
pc.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK);
pc.purpose.size = htonl (sizeof (pc));
pc.timestamp = GNUNET_TIME_absolute_hton (timestamp);
TALER_amount_hton (&pc.payback_amount,
&amount);
pc.coin_pub = ph->coin_pub;
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_PAYBACK,
&pc.purpose,
&exchange_sig.eddsa_signature,
&exchange_pub.eddsa_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
}
ph->cb (ph->cb_cls,
MHD_HTTP_OK,
TALER_EC_NONE,
&amount,
timestamp,
ph->was_refreshed ? NULL : &pc.reserve_pub,
ph->was_refreshed ? &pr.old_coin_pub : NULL,
json);
return GNUNET_OK;
}
/**
* Function called when we're done processing the
* HTTP /payback request.
*
* @param cls the `struct TALER_EXCHANGE_PaybackHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_payback_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_PaybackHandle *ph = cls;
const json_t *j = response;
ph->job = NULL;
switch (response_code)
{
case 0:
break;
case MHD_HTTP_OK:
if (GNUNET_OK !=
verify_payback_signature_ok (ph,
j))
{
GNUNET_break_op (0);
response_code = 0;
}
TALER_EXCHANGE_payback_cancel (ph);
return;
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_CONFLICT:
{
/* Insufficient funds, proof attached */
json_t *history;
struct TALER_Amount total;
const struct TALER_EXCHANGE_DenomPublicKey *dki;
dki = &ph->pk;
history = json_object_get (j,
"history");
if (GNUNET_OK !=
TALER_EXCHANGE_verify_coin_history (dki->fee_deposit.currency,
&ph->coin_pub,
history,
&total))
{
GNUNET_break_op (0);
response_code = 0;
}
ph->cb (ph->cb_cls,
response_code,
TALER_JSON_get_error_code (j),
&total,
GNUNET_TIME_UNIT_FOREVER_ABS,
NULL,
NULL,
j);
TALER_EXCHANGE_payback_cancel (ph);
return;
}
case MHD_HTTP_FORBIDDEN:
/* 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_GONE:
/* Kind of normal: the money was already sent to the merchant
(it was too late for the refund). */
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;
}
ph->cb (ph->cb_cls,
response_code,
TALER_JSON_get_error_code (j),
NULL,
GNUNET_TIME_UNIT_FOREVER_ABS,
NULL,
NULL,
j);
TALER_EXCHANGE_payback_cancel (ph);
}
/**
* Ask the exchange to pay back a coin due to the exchange triggering
* the emergency payback protocol for a given denomination. The value
* of the coin will be refunded to the original customer (without fees).
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to pay back
* @param denom_sig signature over the coin by the exchange using @a pk
* @param ps secret internals of the original planchet
* @param was_refreshed #GNUNET_YES if the coin in @a ps was refreshed
* @param payback_cb the callback to call when the final result for this request is available
* @param payback_cb_cls closure for @a payback_cb
* @return NULL
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_PaybackHandle *
TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_DenominationSignature *denom_sig,
const struct TALER_PlanchetSecretsP *ps,
int was_refreshed,
TALER_EXCHANGE_PaybackResultCallback payback_cb,
void *payback_cb_cls)
{
struct TALER_EXCHANGE_PaybackHandle *ph;
struct GNUNET_CURL_Context *ctx;
struct TALER_PaybackRequestPS pr;
struct TALER_CoinSpendSignatureP coin_sig;
struct GNUNET_HashCode h_denom_pub;
json_t *payback_obj;
CURL *eh;
GNUNET_assert (GNUNET_YES ==
TEAH_handle_is_ready (exchange));
pr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_PAYBACK);
pr.purpose.size = htonl (sizeof (struct TALER_PaybackRequestPS));
GNUNET_CRYPTO_eddsa_key_get_public (&ps->coin_priv.eddsa_priv,
&pr.coin_pub.eddsa_pub);
GNUNET_CRYPTO_rsa_public_key_hash (pk->key.rsa_public_key,
&h_denom_pub);
pr.h_denom_pub = pk->h_key;
pr.coin_blind = ps->blinding_key;
GNUNET_assert (GNUNET_OK ==
GNUNET_CRYPTO_eddsa_sign (&ps->coin_priv.eddsa_priv,
&pr.purpose,
&coin_sig.eddsa_signature));
payback_obj = json_pack ("{s:o, s:o," /* denom pub/sig */
" s:o, s:o," /* coin pub/sig */
" s:o, s:o}", /* coin_bks */
"denom_pub_hash", GNUNET_JSON_from_data_auto (
&h_denom_pub),
"denom_sig", GNUNET_JSON_from_rsa_signature (
denom_sig->rsa_signature),
"coin_pub", GNUNET_JSON_from_data_auto (
&pr.coin_pub),
"coin_sig", GNUNET_JSON_from_data_auto (&coin_sig),
"coin_blind_key_secret", GNUNET_JSON_from_data_auto (
&ps->blinding_key),
"refreshed", json_boolean (was_refreshed)
);
if (NULL == payback_obj)
{
GNUNET_break (0);
return NULL;
}
ph = GNUNET_new (struct TALER_EXCHANGE_PaybackHandle);
ph->coin_pub = pr.coin_pub;
ph->exchange = exchange;
ph->pk = *pk;
ph->pk.key.rsa_public_key = GNUNET_CRYPTO_rsa_public_key_dup (
pk->key.rsa_public_key);
ph->cb = payback_cb;
ph->cb_cls = payback_cb_cls;
ph->url = TEAH_path_to_url (exchange, "/payback");
ph->was_refreshed = was_refreshed;
eh = TEL_curl_easy_get (ph->url);
if (GNUNET_OK !=
TALER_curl_easy_post (&ph->ctx,
eh,
payback_obj))
{
GNUNET_break (0);
curl_easy_cleanup (eh);
json_decref (payback_obj);
GNUNET_free (ph->url);
GNUNET_CRYPTO_rsa_public_key_free (ph->pk.key.rsa_public_key);
GNUNET_free (ph);
return NULL;
}
json_decref (payback_obj);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"URL for payback: `%s'\n",
ph->url);
ctx = TEAH_handle_to_context (exchange);
ph->job = GNUNET_CURL_job_add2 (ctx,
eh,
ph->ctx.headers,
&handle_payback_finished,
ph);
return ph;
}
/**
* Cancel a payback request. This function cannot be used on a
* request handle if the callback was already invoked.
*
* @param ph the payback handle
*/
void
TALER_EXCHANGE_payback_cancel (struct TALER_EXCHANGE_PaybackHandle *ph)
{
if (NULL != ph->job)
{
GNUNET_CURL_job_cancel (ph->job);
ph->job = NULL;
}
GNUNET_free (ph->url);
TALER_curl_easy_post_finished (&ph->ctx);
GNUNET_CRYPTO_rsa_public_key_free (ph->pk.key.rsa_public_key);
GNUNET_free (ph);
}
/* end of exchange_api_payback.c */
Reference in New Issue View Git Blame Copy Permalink