LCOV - code coverage report
Current view: top level - lib - exchange_api_recoup.c (source / functions) Hit Total Coverage
Test: GNU Taler exchange coverage report Lines: 0 127 0.0 %
Date: 2022-08-25 06:15:09 Functions: 0 4 0.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*
       2             :   This file is part of TALER
       3             :   Copyright (C) 2017-2022 Taler Systems SA
       4             : 
       5             :   TALER is free software; you can redistribute it and/or modify it under the
       6             :   terms of the GNU General Public License as published by the Free Software
       7             :   Foundation; either version 3, or (at your option) any later version.
       8             : 
       9             :   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
      10             :   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
      11             :   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
      12             : 
      13             :   You should have received a copy of the GNU General Public License along with
      14             :   TALER; see the file COPYING.  If not, see
      15             :   <http://www.gnu.org/licenses/>
      16             : */
      17             : /**
      18             :  * @file lib/exchange_api_recoup.c
      19             :  * @brief Implementation of the /recoup request of the exchange's HTTP API
      20             :  * @author Christian Grothoff
      21             :  */
      22             : #include "platform.h"
      23             : #include <jansson.h>
      24             : #include <microhttpd.h> /* just for HTTP status codes */
      25             : #include <gnunet/gnunet_util_lib.h>
      26             : #include <gnunet/gnunet_json_lib.h>
      27             : #include <gnunet/gnunet_curl_lib.h>
      28             : #include "taler_json_lib.h"
      29             : #include "taler_exchange_service.h"
      30             : #include "exchange_api_common.h"
      31             : #include "exchange_api_handle.h"
      32             : #include "taler_signatures.h"
      33             : #include "exchange_api_curl_defaults.h"
      34             : 
      35             : 
      36             : /**
      37             :  * @brief A Recoup Handle
      38             :  */
      39             : struct TALER_EXCHANGE_RecoupHandle
      40             : {
      41             : 
      42             :   /**
      43             :    * The connection to exchange this request handle will use
      44             :    */
      45             :   struct TALER_EXCHANGE_Handle *exchange;
      46             : 
      47             :   /**
      48             :    * The url for this request.
      49             :    */
      50             :   char *url;
      51             : 
      52             :   /**
      53             :    * Context for #TEH_curl_easy_post(). Keeps the data that must
      54             :    * persist for Curl to make the upload.
      55             :    */
      56             :   struct TALER_CURL_PostContext ctx;
      57             : 
      58             :   /**
      59             :    * Denomination key of the coin.
      60             :    */
      61             :   struct TALER_EXCHANGE_DenomPublicKey pk;
      62             : 
      63             :   /**
      64             :    * Our signature requesting the recoup.
      65             :    */
      66             :   struct TALER_CoinSpendSignatureP coin_sig;
      67             : 
      68             :   /**
      69             :    * Handle for the request.
      70             :    */
      71             :   struct GNUNET_CURL_Job *job;
      72             : 
      73             :   /**
      74             :    * Function to call with the result.
      75             :    */
      76             :   TALER_EXCHANGE_RecoupResultCallback cb;
      77             : 
      78             :   /**
      79             :    * Closure for @a cb.
      80             :    */
      81             :   void *cb_cls;
      82             : 
      83             :   /**
      84             :    * Public key of the coin we are trying to get paid back.
      85             :    */
      86             :   struct TALER_CoinSpendPublicKeyP coin_pub;
      87             : 
      88             : };
      89             : 
      90             : 
      91             : /**
      92             :  * Parse a recoup response.  If it is valid, call the callback.
      93             :  *
      94             :  * @param ph recoup handle
      95             :  * @param json json reply with the signature
      96             :  * @return #GNUNET_OK if the signature is valid and we called the callback;
      97             :  *         #GNUNET_SYSERR if not (callback must still be called)
      98             :  */
      99             : static enum GNUNET_GenericReturnValue
     100           0 : process_recoup_response (const struct TALER_EXCHANGE_RecoupHandle *ph,
     101             :                          const json_t *json)
     102             : {
     103             :   struct TALER_ReservePublicKeyP reserve_pub;
     104             :   struct GNUNET_JSON_Specification spec_withdraw[] = {
     105           0 :     GNUNET_JSON_spec_fixed_auto ("reserve_pub",
     106             :                                  &reserve_pub),
     107           0 :     GNUNET_JSON_spec_end ()
     108             :   };
     109           0 :   struct TALER_EXCHANGE_HttpResponse hr = {
     110             :     .reply = json,
     111             :     .http_status = MHD_HTTP_OK
     112             :   };
     113             : 
     114           0 :   if (GNUNET_OK !=
     115           0 :       GNUNET_JSON_parse (json,
     116             :                          spec_withdraw,
     117             :                          NULL, NULL))
     118             :   {
     119           0 :     GNUNET_break_op (0);
     120           0 :     return GNUNET_SYSERR;
     121             :   }
     122           0 :   ph->cb (ph->cb_cls,
     123             :           &hr,
     124             :           &reserve_pub);
     125           0 :   return GNUNET_OK;
     126             : }
     127             : 
     128             : 
     129             : /**
     130             :  * Function called when we're done processing the
     131             :  * HTTP /recoup request.
     132             :  *
     133             :  * @param cls the `struct TALER_EXCHANGE_RecoupHandle`
     134             :  * @param response_code HTTP response code, 0 on error
     135             :  * @param response parsed JSON result, NULL on error
     136             :  */
     137             : static void
     138           0 : handle_recoup_finished (void *cls,
     139             :                         long response_code,
     140             :                         const void *response)
     141             : {
     142           0 :   struct TALER_EXCHANGE_RecoupHandle *ph = cls;
     143           0 :   const json_t *j = response;
     144           0 :   struct TALER_EXCHANGE_HttpResponse hr = {
     145             :     .reply = j,
     146           0 :     .http_status = (unsigned int) response_code
     147             :   };
     148             :   const struct TALER_EXCHANGE_Keys *keys;
     149             : 
     150           0 :   ph->job = NULL;
     151           0 :   keys = TALER_EXCHANGE_get_keys (ph->exchange);
     152           0 :   switch (response_code)
     153             :   {
     154           0 :   case 0:
     155           0 :     hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
     156           0 :     break;
     157           0 :   case MHD_HTTP_OK:
     158           0 :     if (GNUNET_OK !=
     159           0 :         process_recoup_response (ph,
     160             :                                  j))
     161             :     {
     162           0 :       GNUNET_break_op (0);
     163           0 :       hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
     164           0 :       hr.http_status = 0;
     165           0 :       break;
     166             :     }
     167           0 :     TALER_EXCHANGE_recoup_cancel (ph);
     168           0 :     return;
     169           0 :   case MHD_HTTP_BAD_REQUEST:
     170             :     /* This should never happen, either us or the exchange is buggy
     171             :        (or API version conflict); just pass JSON reply to the application */
     172           0 :     hr.ec = TALER_JSON_get_error_code (j);
     173           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     174           0 :     break;
     175           0 :   case MHD_HTTP_CONFLICT:
     176             :     {
     177             :       struct TALER_Amount min_key;
     178             : 
     179           0 :       hr.ec = TALER_JSON_get_error_code (j);
     180           0 :       hr.hint = TALER_JSON_get_error_hint (j);
     181           0 :       if (GNUNET_OK !=
     182           0 :           TALER_EXCHANGE_get_min_denomination_ (keys,
     183             :                                                 &min_key))
     184             :       {
     185           0 :         GNUNET_break (0);
     186           0 :         hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
     187           0 :         hr.http_status = 0;
     188           0 :         break;
     189             :       }
     190           0 :       if (GNUNET_OK !=
     191           0 :           TALER_EXCHANGE_check_coin_conflict_ (
     192             :             keys,
     193             :             j,
     194           0 :             &ph->pk,
     195           0 :             &ph->coin_pub,
     196           0 :             &ph->coin_sig,
     197             :             &min_key))
     198             :       {
     199           0 :         GNUNET_break (0);
     200           0 :         hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
     201           0 :         hr.http_status = 0;
     202           0 :         break;
     203             :       }
     204           0 :       break;
     205             :     }
     206           0 :   case MHD_HTTP_FORBIDDEN:
     207             :     /* Nothing really to verify, exchange says one of the signatures is
     208             :        invalid; as we checked them, this should never happen, we
     209             :        should pass the JSON reply to the application */
     210           0 :     hr.ec = TALER_JSON_get_error_code (j);
     211           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     212           0 :     break;
     213           0 :   case MHD_HTTP_NOT_FOUND:
     214             :     /* Nothing really to verify, this should never
     215             :        happen, we should pass the JSON reply to the application */
     216           0 :     hr.ec = TALER_JSON_get_error_code (j);
     217           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     218           0 :     break;
     219           0 :   case MHD_HTTP_GONE:
     220             :     /* Kind of normal: the money was already sent to the merchant
     221             :        (it was too late for the refund). */
     222           0 :     hr.ec = TALER_JSON_get_error_code (j);
     223           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     224           0 :     break;
     225           0 :   case MHD_HTTP_INTERNAL_SERVER_ERROR:
     226             :     /* Server had an internal issue; we should retry, but this API
     227             :        leaves this to the application */
     228           0 :     hr.ec = TALER_JSON_get_error_code (j);
     229           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     230           0 :     break;
     231           0 :   default:
     232             :     /* unexpected response code */
     233           0 :     hr.ec = TALER_JSON_get_error_code (j);
     234           0 :     hr.hint = TALER_JSON_get_error_hint (j);
     235           0 :     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
     236             :                 "Unexpected response code %u/%d for exchange recoup\n",
     237             :                 (unsigned int) response_code,
     238             :                 (int) hr.ec);
     239           0 :     GNUNET_break (0);
     240           0 :     break;
     241             :   }
     242           0 :   ph->cb (ph->cb_cls,
     243             :           &hr,
     244             :           NULL);
     245           0 :   TALER_EXCHANGE_recoup_cancel (ph);
     246             : }
     247             : 
     248             : 
     249             : struct TALER_EXCHANGE_RecoupHandle *
     250           0 : TALER_EXCHANGE_recoup (struct TALER_EXCHANGE_Handle *exchange,
     251             :                        const struct TALER_EXCHANGE_DenomPublicKey *pk,
     252             :                        const struct TALER_DenominationSignature *denom_sig,
     253             :                        const struct TALER_ExchangeWithdrawValues *exchange_vals,
     254             :                        const struct TALER_PlanchetMasterSecretP *ps,
     255             :                        TALER_EXCHANGE_RecoupResultCallback recoup_cb,
     256             :                        void *recoup_cb_cls)
     257             : {
     258             :   struct TALER_EXCHANGE_RecoupHandle *ph;
     259             :   struct GNUNET_CURL_Context *ctx;
     260             :   struct TALER_DenominationHashP h_denom_pub;
     261             :   json_t *recoup_obj;
     262             :   CURL *eh;
     263             :   char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
     264             :   struct TALER_CoinSpendPrivateKeyP coin_priv;
     265             :   union TALER_DenominationBlindingKeyP bks;
     266             : 
     267           0 :   GNUNET_assert (GNUNET_YES ==
     268             :                  TEAH_handle_is_ready (exchange));
     269           0 :   ph = GNUNET_new (struct TALER_EXCHANGE_RecoupHandle);
     270           0 :   TALER_planchet_setup_coin_priv (ps,
     271             :                                   exchange_vals,
     272             :                                   &coin_priv);
     273           0 :   TALER_planchet_blinding_secret_create (ps,
     274             :                                          exchange_vals,
     275             :                                          &bks);
     276           0 :   GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv.eddsa_priv,
     277             :                                       &ph->coin_pub.eddsa_pub);
     278           0 :   TALER_denom_pub_hash (&pk->key,
     279             :                         &h_denom_pub);
     280           0 :   TALER_wallet_recoup_sign (&h_denom_pub,
     281             :                             &bks,
     282             :                             &coin_priv,
     283             :                             &ph->coin_sig);
     284           0 :   recoup_obj = GNUNET_JSON_PACK (
     285             :     GNUNET_JSON_pack_data_auto ("denom_pub_hash",
     286             :                                 &h_denom_pub),
     287             :     TALER_JSON_pack_denom_sig ("denom_sig",
     288             :                                denom_sig),
     289             :     TALER_JSON_pack_exchange_withdraw_values ("ewv",
     290             :                                               exchange_vals),
     291             :     GNUNET_JSON_pack_data_auto ("coin_sig",
     292             :                                 &ph->coin_sig),
     293             :     GNUNET_JSON_pack_data_auto ("coin_blind_key_secret",
     294             :                                 &bks));
     295           0 :   if (TALER_DENOMINATION_CS == denom_sig->cipher)
     296             :   {
     297             :     struct TALER_CsNonce nonce;
     298             : 
     299             :     /* NOTE: this is not elegant, and as per the note in TALER_coin_ev_hash()
     300             :        it is not strictly clear that the nonce is needed. Best case would be
     301             :        to find a way to include it more 'naturally' somehow, for example with
     302             :        the variant union version of bks! */
     303           0 :     TALER_cs_withdraw_nonce_derive (ps,
     304             :                                     &nonce);
     305           0 :     GNUNET_assert (
     306             :       0 ==
     307             :       json_object_set_new (recoup_obj,
     308             :                            "cs_nonce",
     309             :                            GNUNET_JSON_from_data_auto (
     310             :                              &nonce)));
     311             :   }
     312             : 
     313             :   {
     314             :     char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
     315             :     char *end;
     316             : 
     317           0 :     end = GNUNET_STRINGS_data_to_string (
     318           0 :       &ph->coin_pub,
     319             :       sizeof (struct TALER_CoinSpendPublicKeyP),
     320             :       pub_str,
     321             :       sizeof (pub_str));
     322           0 :     *end = '\0';
     323           0 :     GNUNET_snprintf (arg_str,
     324             :                      sizeof (arg_str),
     325             :                      "/coins/%s/recoup",
     326             :                      pub_str);
     327             :   }
     328             : 
     329           0 :   ph->exchange = exchange;
     330           0 :   ph->pk = *pk;
     331           0 :   memset (&ph->pk.key,
     332             :           0,
     333             :           sizeof (ph->pk.key)); /* zero out, as lifetime cannot be warranted */
     334           0 :   ph->cb = recoup_cb;
     335           0 :   ph->cb_cls = recoup_cb_cls;
     336           0 :   ph->url = TEAH_path_to_url (exchange,
     337             :                               arg_str);
     338           0 :   if (NULL == ph->url)
     339             :   {
     340           0 :     json_decref (recoup_obj);
     341           0 :     GNUNET_free (ph);
     342           0 :     return NULL;
     343             :   }
     344           0 :   eh = TALER_EXCHANGE_curl_easy_get_ (ph->url);
     345           0 :   if ( (NULL == eh) ||
     346             :        (GNUNET_OK !=
     347           0 :         TALER_curl_easy_post (&ph->ctx,
     348             :                               eh,
     349             :                               recoup_obj)) )
     350             :   {
     351           0 :     GNUNET_break (0);
     352           0 :     if (NULL != eh)
     353           0 :       curl_easy_cleanup (eh);
     354           0 :     json_decref (recoup_obj);
     355           0 :     GNUNET_free (ph->url);
     356           0 :     GNUNET_free (ph);
     357           0 :     return NULL;
     358             :   }
     359           0 :   json_decref (recoup_obj);
     360           0 :   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
     361             :               "URL for recoup: `%s'\n",
     362             :               ph->url);
     363           0 :   ctx = TEAH_handle_to_context (exchange);
     364           0 :   ph->job = GNUNET_CURL_job_add2 (ctx,
     365             :                                   eh,
     366           0 :                                   ph->ctx.headers,
     367             :                                   &handle_recoup_finished,
     368             :                                   ph);
     369           0 :   return ph;
     370             : }
     371             : 
     372             : 
     373             : void
     374           0 : TALER_EXCHANGE_recoup_cancel (struct TALER_EXCHANGE_RecoupHandle *ph)
     375             : {
     376           0 :   if (NULL != ph->job)
     377             :   {
     378           0 :     GNUNET_CURL_job_cancel (ph->job);
     379           0 :     ph->job = NULL;
     380             :   }
     381           0 :   GNUNET_free (ph->url);
     382           0 :   TALER_curl_easy_post_finished (&ph->ctx);
     383           0 :   GNUNET_free (ph);
     384           0 : }
     385             : 
     386             : 
     387             : /* end of exchange_api_recoup.c */

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