421 lines
13 KiB
C
421 lines
13 KiB
C
/*
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This file is part of TALER
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Copyright (C) 2017-2021 Taler Systems SA
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TALER is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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TALER is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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TALER; see the file COPYING. If not, see
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<http://www.gnu.org/licenses/>
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*/
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/**
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* @file lib/exchange_api_recoup.c
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* @brief Implementation of the /recoup request of the exchange's HTTP API
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* @author Christian Grothoff
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*/
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#include "platform.h"
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#include <jansson.h>
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#include <microhttpd.h> /* just for HTTP status codes */
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#include <gnunet/gnunet_util_lib.h>
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#include <gnunet/gnunet_json_lib.h>
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#include <gnunet/gnunet_curl_lib.h>
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#include "taler_json_lib.h"
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#include "taler_exchange_service.h"
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#include "exchange_api_handle.h"
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#include "taler_signatures.h"
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#include "exchange_api_curl_defaults.h"
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/**
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* @brief A Recoup Handle
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*/
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struct TALER_EXCHANGE_RecoupHandle
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{
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/**
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* The connection to exchange this request handle will use
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*/
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struct TALER_EXCHANGE_Handle *exchange;
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/**
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* The url for this request.
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*/
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char *url;
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/**
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* Context for #TEH_curl_easy_post(). Keeps the data that must
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* persist for Curl to make the upload.
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*/
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struct TALER_CURL_PostContext ctx;
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/**
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* Denomination key of the coin.
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*/
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struct TALER_EXCHANGE_DenomPublicKey pk;
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/**
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* Handle for the request.
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*/
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struct GNUNET_CURL_Job *job;
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/**
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* Function to call with the result.
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*/
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TALER_EXCHANGE_RecoupResultCallback cb;
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/**
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* Closure for @a cb.
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*/
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void *cb_cls;
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/**
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* Public key of the coin we are trying to get paid back.
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*/
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struct TALER_CoinSpendPublicKeyP coin_pub;
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/**
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* #GNUNET_YES if the coin was refreshed
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*/
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int was_refreshed;
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};
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/**
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* Parse a recoup response. If it is valid, call the callback.
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*
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* @param ph recoup handle
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* @param json json reply with the signature
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* @return #GNUNET_OK if the signature is valid and we called the callback;
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* #GNUNET_SYSERR if not (callback must still be called)
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*/
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static int
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process_recoup_response (const struct TALER_EXCHANGE_RecoupHandle *ph,
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const json_t *json)
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{
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int refreshed;
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struct TALER_ReservePublicKeyP reserve_pub;
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struct TALER_CoinSpendPublicKeyP old_coin_pub;
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struct GNUNET_JSON_Specification spec_withdraw[] = {
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GNUNET_JSON_spec_boolean ("refreshed", &refreshed),
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GNUNET_JSON_spec_fixed_auto ("reserve_pub", &reserve_pub),
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GNUNET_JSON_spec_end ()
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};
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struct GNUNET_JSON_Specification spec_refresh[] = {
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GNUNET_JSON_spec_boolean ("refreshed", &refreshed),
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GNUNET_JSON_spec_fixed_auto ("old_coin_pub", &old_coin_pub),
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GNUNET_JSON_spec_end ()
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};
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struct TALER_EXCHANGE_HttpResponse hr = {
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.reply = json,
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.http_status = MHD_HTTP_OK
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};
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if (GNUNET_OK !=
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GNUNET_JSON_parse (json,
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ph->was_refreshed ? spec_refresh : spec_withdraw,
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NULL, NULL))
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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if (ph->was_refreshed != refreshed)
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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ph->cb (ph->cb_cls,
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&hr,
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ph->was_refreshed ? NULL : &reserve_pub,
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ph->was_refreshed ? &old_coin_pub : NULL);
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return GNUNET_OK;
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}
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/**
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* Function called when we're done processing the
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* HTTP /recoup request.
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*
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* @param cls the `struct TALER_EXCHANGE_RecoupHandle`
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* @param response_code HTTP response code, 0 on error
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* @param response parsed JSON result, NULL on error
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*/
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static void
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handle_recoup_finished (void *cls,
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long response_code,
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const void *response)
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{
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struct TALER_EXCHANGE_RecoupHandle *ph = cls;
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const json_t *j = response;
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struct TALER_EXCHANGE_HttpResponse hr = {
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.reply = j,
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.http_status = (unsigned int) response_code
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};
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ph->job = NULL;
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switch (response_code)
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{
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case 0:
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hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
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break;
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case MHD_HTTP_OK:
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if (GNUNET_OK !=
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process_recoup_response (ph,
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j))
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{
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GNUNET_break_op (0);
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hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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hr.http_status = 0;
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break;
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}
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TALER_EXCHANGE_recoup_cancel (ph);
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return;
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case MHD_HTTP_BAD_REQUEST:
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/* This should never happen, either us or the exchange is buggy
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(or API version conflict); just pass JSON reply to the application */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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break;
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case MHD_HTTP_CONFLICT:
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{
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/* Insufficient funds, proof attached */
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json_t *history;
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struct TALER_Amount total;
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struct GNUNET_HashCode h_denom_pub;
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const struct TALER_EXCHANGE_DenomPublicKey *dki;
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enum TALER_ErrorCode ec;
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dki = &ph->pk;
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history = json_object_get (j,
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"history");
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if (GNUNET_OK !=
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TALER_EXCHANGE_verify_coin_history (dki,
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dki->fee_deposit.currency,
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&ph->coin_pub,
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history,
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&h_denom_pub,
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&total))
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{
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GNUNET_break_op (0);
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hr.http_status = 0;
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hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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}
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else
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{
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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}
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ec = TALER_JSON_get_error_code (j);
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switch (ec)
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{
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case TALER_EC_EXCHANGE_RECOUP_COIN_BALANCE_ZERO:
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if (0 > TALER_amount_cmp (&total,
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&dki->value))
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{
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/* recoup MAY have still been possible */
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/* FIXME: This code may falsely complain, as we do not
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know that the smallest denomination offered by the
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exchange is here. We should look at the key
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structure of ph->exchange, and find the smallest
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_currently withdrawable_ denomination and check
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if the value remaining would suffice... *///
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GNUNET_break_op (0);
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hr.http_status = 0;
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hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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break;
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}
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break;
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case TALER_EC_EXCHANGE_GENERIC_COIN_CONFLICTING_DENOMINATION_KEY:
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if (0 == GNUNET_memcmp (&ph->pk.h_key,
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&h_denom_pub))
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{
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/* invalid proof provided */
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GNUNET_break_op (0);
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hr.http_status = 0;
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hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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break;
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}
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/* valid error from exchange */
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break;
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default:
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GNUNET_break_op (0);
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hr.http_status = 0;
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hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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break;
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}
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ph->cb (ph->cb_cls,
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&hr,
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NULL,
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NULL);
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TALER_EXCHANGE_recoup_cancel (ph);
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return;
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}
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case MHD_HTTP_FORBIDDEN:
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/* Nothing really to verify, exchange says one of the signatures is
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invalid; as we checked them, this should never happen, we
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should pass the JSON reply to the application */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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break;
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case MHD_HTTP_NOT_FOUND:
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/* Nothing really to verify, this should never
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happen, we should pass the JSON reply to the application */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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break;
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case MHD_HTTP_GONE:
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/* Kind of normal: the money was already sent to the merchant
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(it was too late for the refund). */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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break;
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case MHD_HTTP_INTERNAL_SERVER_ERROR:
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/* Server had an internal issue; we should retry, but this API
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leaves this to the application */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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break;
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default:
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/* unexpected response code */
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hr.ec = TALER_JSON_get_error_code (j);
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hr.hint = TALER_JSON_get_error_hint (j);
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GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
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"Unexpected response code %u/%d for exchange recoup\n",
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(unsigned int) response_code,
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(int) hr.ec);
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GNUNET_break (0);
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break;
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}
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ph->cb (ph->cb_cls,
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&hr,
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NULL,
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NULL);
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TALER_EXCHANGE_recoup_cancel (ph);
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}
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struct TALER_EXCHANGE_RecoupHandle *
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TALER_EXCHANGE_recoup (struct TALER_EXCHANGE_Handle *exchange,
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const struct TALER_EXCHANGE_DenomPublicKey *pk,
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const struct TALER_DenominationSignature *denom_sig,
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const struct TALER_PlanchetSecretsP *ps,
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bool was_refreshed,
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TALER_EXCHANGE_RecoupResultCallback recoup_cb,
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void *recoup_cb_cls)
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{
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struct TALER_EXCHANGE_RecoupHandle *ph;
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struct GNUNET_CURL_Context *ctx;
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struct TALER_RecoupRequestPS pr;
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struct TALER_CoinSpendSignatureP coin_sig;
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struct GNUNET_HashCode h_denom_pub;
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json_t *recoup_obj;
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CURL *eh;
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char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
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GNUNET_assert (GNUNET_YES ==
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TEAH_handle_is_ready (exchange));
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pr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_RECOUP);
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pr.purpose.size = htonl (sizeof (struct TALER_RecoupRequestPS));
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GNUNET_CRYPTO_eddsa_key_get_public (&ps->coin_priv.eddsa_priv,
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&pr.coin_pub.eddsa_pub);
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GNUNET_CRYPTO_rsa_public_key_hash (pk->key.rsa_public_key,
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&h_denom_pub);
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pr.h_denom_pub = pk->h_key;
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pr.coin_blind = ps->blinding_key;
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GNUNET_CRYPTO_eddsa_sign (&ps->coin_priv.eddsa_priv,
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&pr,
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&coin_sig.eddsa_signature);
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recoup_obj = GNUNET_JSON_PACK (
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GNUNET_JSON_pack_data_auto ("denom_pub_hash",
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&h_denom_pub),
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TALER_JSON_pack_denomination_signature ("denom_sig",
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denom_sig),
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GNUNET_JSON_pack_data_auto ("coin_sig",
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&coin_sig),
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GNUNET_JSON_pack_data_auto ("coin_blind_key_secret",
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&ps->blinding_key),
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GNUNET_JSON_pack_bool ("refreshed",
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was_refreshed));
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{
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char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
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char *end;
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end = GNUNET_STRINGS_data_to_string (&pr.coin_pub,
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sizeof (struct
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TALER_CoinSpendPublicKeyP),
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pub_str,
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sizeof (pub_str));
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*end = '\0';
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GNUNET_snprintf (arg_str,
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sizeof (arg_str),
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"/coins/%s/recoup",
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pub_str);
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}
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ph = GNUNET_new (struct TALER_EXCHANGE_RecoupHandle);
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ph->coin_pub = pr.coin_pub;
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ph->exchange = exchange;
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ph->pk = *pk;
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ph->pk.key.rsa_public_key = NULL; /* zero out, as lifetime cannot be warranted */
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ph->cb = recoup_cb;
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ph->cb_cls = recoup_cb_cls;
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ph->url = TEAH_path_to_url (exchange,
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arg_str);
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if (NULL == ph->url)
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{
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json_decref (recoup_obj);
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GNUNET_free (ph);
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return NULL;
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}
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ph->was_refreshed = was_refreshed;
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eh = TALER_EXCHANGE_curl_easy_get_ (ph->url);
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if ( (NULL == eh) ||
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(GNUNET_OK !=
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TALER_curl_easy_post (&ph->ctx,
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eh,
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recoup_obj)) )
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{
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GNUNET_break (0);
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if (NULL != eh)
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curl_easy_cleanup (eh);
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json_decref (recoup_obj);
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GNUNET_free (ph->url);
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GNUNET_free (ph);
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return NULL;
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}
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json_decref (recoup_obj);
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GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
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"URL for recoup: `%s'\n",
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ph->url);
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ctx = TEAH_handle_to_context (exchange);
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ph->job = GNUNET_CURL_job_add2 (ctx,
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eh,
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ph->ctx.headers,
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&handle_recoup_finished,
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ph);
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return ph;
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}
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void
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TALER_EXCHANGE_recoup_cancel (struct TALER_EXCHANGE_RecoupHandle *ph)
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{
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if (NULL != ph->job)
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{
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GNUNET_CURL_job_cancel (ph->job);
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ph->job = NULL;
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}
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GNUNET_free (ph->url);
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TALER_curl_easy_post_finished (&ph->ctx);
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GNUNET_free (ph);
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}
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/* end of exchange_api_recoup.c */
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