LCOV - code coverage report
Current view: top level - lib - exchange_api_recoup.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 0 124 0.0 %
Date: 2025-06-05 21:03:14 Functions: 0 4 0.0 %

          Line data    Source code
       1             : /*
       2             :   This file is part of TALER
       3             :   Copyright (C) 2017-2023 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 keys of the exchange this request handle will use
      44             :    */
      45             :   struct TALER_EXCHANGE_Keys *keys;
      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           0 :   struct TALER_EXCHANGE_RecoupResponse rr = {
     104             :     .hr.reply = json,
     105             :     .hr.http_status = MHD_HTTP_OK
     106             :   };
     107             :   struct GNUNET_JSON_Specification spec_withdraw[] = {
     108           0 :     GNUNET_JSON_spec_fixed_auto ("reserve_pub",
     109             :                                  &rr.details.ok.reserve_pub),
     110           0 :     GNUNET_JSON_spec_end ()
     111             :   };
     112             : 
     113           0 :   if (GNUNET_OK !=
     114           0 :       GNUNET_JSON_parse (json,
     115             :                          spec_withdraw,
     116             :                          NULL, NULL))
     117             :   {
     118           0 :     GNUNET_break_op (0);
     119           0 :     return GNUNET_SYSERR;
     120             :   }
     121           0 :   ph->cb (ph->cb_cls,
     122             :           &rr);
     123           0 :   return GNUNET_OK;
     124             : }
     125             : 
     126             : 
     127             : /**
     128             :  * Function called when we're done processing the
     129             :  * HTTP /recoup request.
     130             :  *
     131             :  * @param cls the `struct TALER_EXCHANGE_RecoupHandle`
     132             :  * @param response_code HTTP response code, 0 on error
     133             :  * @param response parsed JSON result, NULL on error
     134             :  */
     135             : static void
     136           0 : handle_recoup_finished (void *cls,
     137             :                         long response_code,
     138             :                         const void *response)
     139             : {
     140           0 :   struct TALER_EXCHANGE_RecoupHandle *ph = cls;
     141           0 :   const json_t *j = response;
     142           0 :   struct TALER_EXCHANGE_RecoupResponse rr = {
     143             :     .hr.reply = j,
     144           0 :     .hr.http_status = (unsigned int) response_code
     145             :   };
     146             : 
     147           0 :   ph->job = NULL;
     148           0 :   switch (response_code)
     149             :   {
     150           0 :   case 0:
     151           0 :     rr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
     152           0 :     break;
     153           0 :   case MHD_HTTP_OK:
     154           0 :     if (GNUNET_OK !=
     155           0 :         process_recoup_response (ph,
     156             :                                  j))
     157             :     {
     158           0 :       GNUNET_break_op (0);
     159           0 :       rr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
     160           0 :       rr.hr.http_status = 0;
     161           0 :       break;
     162             :     }
     163           0 :     TALER_EXCHANGE_recoup_cancel (ph);
     164           0 :     return;
     165           0 :   case MHD_HTTP_BAD_REQUEST:
     166             :     /* This should never happen, either us or the exchange is buggy
     167             :        (or API version conflict); just pass JSON reply to the application */
     168           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     169           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     170           0 :     break;
     171           0 :   case MHD_HTTP_CONFLICT:
     172             :     {
     173             :       struct TALER_Amount min_key;
     174             : 
     175           0 :       rr.hr.ec = TALER_JSON_get_error_code (j);
     176           0 :       rr.hr.hint = TALER_JSON_get_error_hint (j);
     177           0 :       if (GNUNET_OK !=
     178           0 :           TALER_EXCHANGE_get_min_denomination_ (ph->keys,
     179             :                                                 &min_key))
     180             :       {
     181           0 :         GNUNET_break (0);
     182           0 :         rr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
     183           0 :         rr.hr.http_status = 0;
     184           0 :         break;
     185             :       }
     186           0 :       break;
     187             :     }
     188           0 :   case MHD_HTTP_FORBIDDEN:
     189             :     /* Nothing really to verify, exchange says one of the signatures is
     190             :        invalid; as we checked them, this should never happen, we
     191             :        should pass the JSON reply to the application */
     192           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     193           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     194           0 :     break;
     195           0 :   case MHD_HTTP_NOT_FOUND:
     196             :     /* Nothing really to verify, this should never
     197             :        happen, we should pass the JSON reply to the application */
     198           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     199           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     200           0 :     break;
     201           0 :   case MHD_HTTP_GONE:
     202             :     /* Kind of normal: the money was already sent to the merchant
     203             :        (it was too late for the refund). */
     204           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     205           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     206           0 :     break;
     207           0 :   case MHD_HTTP_INTERNAL_SERVER_ERROR:
     208             :     /* Server had an internal issue; we should retry, but this API
     209             :        leaves this to the application */
     210           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     211           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     212           0 :     break;
     213           0 :   default:
     214             :     /* unexpected response code */
     215           0 :     rr.hr.ec = TALER_JSON_get_error_code (j);
     216           0 :     rr.hr.hint = TALER_JSON_get_error_hint (j);
     217           0 :     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
     218             :                 "Unexpected response code %u/%d for exchange recoup\n",
     219             :                 (unsigned int) response_code,
     220             :                 (int) rr.hr.ec);
     221           0 :     GNUNET_break (0);
     222           0 :     break;
     223             :   }
     224           0 :   ph->cb (ph->cb_cls,
     225             :           &rr);
     226           0 :   TALER_EXCHANGE_recoup_cancel (ph);
     227             : }
     228             : 
     229             : 
     230             : struct TALER_EXCHANGE_RecoupHandle *
     231           0 : TALER_EXCHANGE_recoup (
     232             :   struct GNUNET_CURL_Context *ctx,
     233             :   const char *url,
     234             :   struct TALER_EXCHANGE_Keys *keys,
     235             :   const struct TALER_EXCHANGE_DenomPublicKey *pk,
     236             :   const struct TALER_DenominationSignature *denom_sig,
     237             :   const struct TALER_ExchangeBlindingValues *blinding_values,
     238             :   const struct TALER_PlanchetMasterSecretP *ps,
     239             :   const struct TALER_HashBlindedPlanchetsP *h_planchets,
     240             :   TALER_EXCHANGE_RecoupResultCallback recoup_cb,
     241             :   void *recoup_cb_cls)
     242             : {
     243             :   struct TALER_EXCHANGE_RecoupHandle *ph;
     244             :   struct TALER_DenominationHashP h_denom_pub;
     245             :   json_t *recoup_obj;
     246             :   CURL *eh;
     247             :   char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
     248             :   struct TALER_CoinSpendPrivateKeyP coin_priv;
     249             :   union GNUNET_CRYPTO_BlindingSecretP bks;
     250             : 
     251           0 :   ph = GNUNET_new (struct TALER_EXCHANGE_RecoupHandle);
     252           0 :   TALER_planchet_setup_coin_priv (ps,
     253             :                                   blinding_values,
     254             :                                   &coin_priv);
     255           0 :   TALER_planchet_blinding_secret_create (ps,
     256             :                                          blinding_values,
     257             :                                          &bks);
     258           0 :   GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv.eddsa_priv,
     259             :                                       &ph->coin_pub.eddsa_pub);
     260           0 :   TALER_denom_pub_hash (&pk->key,
     261             :                         &h_denom_pub);
     262           0 :   TALER_wallet_recoup_sign (&h_denom_pub,
     263             :                             &bks,
     264             :                             &coin_priv,
     265             :                             &ph->coin_sig);
     266           0 :   recoup_obj = GNUNET_JSON_PACK (
     267             :     GNUNET_JSON_pack_data_auto ("denom_pub_hash",
     268             :                                 &h_denom_pub),
     269             :     TALER_JSON_pack_denom_sig ("denom_sig",
     270             :                                denom_sig),
     271             :     TALER_JSON_pack_exchange_blinding_values ("ewv",
     272             :                                               blinding_values),
     273             :     GNUNET_JSON_pack_data_auto ("coin_sig",
     274             :                                 &ph->coin_sig),
     275             :     GNUNET_JSON_pack_data_auto ("h_planchets",
     276             :                                 h_planchets),
     277             :     GNUNET_JSON_pack_data_auto ("coin_blind_key_secret",
     278             :                                 &bks));
     279           0 :   switch (denom_sig->unblinded_sig->cipher)
     280             :   {
     281           0 :   case GNUNET_CRYPTO_BSA_INVALID:
     282           0 :     json_decref (recoup_obj);
     283           0 :     GNUNET_break (0);
     284           0 :     GNUNET_free (ph);
     285           0 :     return NULL;
     286           0 :   case GNUNET_CRYPTO_BSA_RSA:
     287           0 :     break;
     288           0 :   case GNUNET_CRYPTO_BSA_CS:
     289             :     {
     290             :       union GNUNET_CRYPTO_BlindSessionNonce nonce;
     291             : 
     292             :       /* NOTE: this is not elegant, and as per the note in TALER_coin_ev_hash()
     293             :          it is not strictly clear that the nonce is needed. Best case would be
     294             :          to find a way to include it more 'naturally' somehow, for example with
     295             :          the variant union version of bks! */
     296           0 :       TALER_cs_withdraw_nonce_derive (ps,
     297             :                                       &nonce.cs_nonce);
     298           0 :       GNUNET_assert (
     299             :         0 ==
     300             :         json_object_set_new (recoup_obj,
     301             :                              "nonce",
     302             :                              GNUNET_JSON_from_data_auto (
     303             :                                &nonce)));
     304             :     }
     305             :   }
     306             : 
     307             :   {
     308             :     char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
     309             :     char *end;
     310             : 
     311           0 :     end = GNUNET_STRINGS_data_to_string (
     312           0 :       &ph->coin_pub,
     313             :       sizeof (struct TALER_CoinSpendPublicKeyP),
     314             :       pub_str,
     315             :       sizeof (pub_str));
     316           0 :     *end = '\0';
     317           0 :     GNUNET_snprintf (arg_str,
     318             :                      sizeof (arg_str),
     319             :                      "coins/%s/recoup",
     320             :                      pub_str);
     321             :   }
     322             : 
     323           0 :   ph->pk = *pk;
     324           0 :   memset (&ph->pk.key,
     325             :           0,
     326             :           sizeof (ph->pk.key)); /* zero out, as lifetime cannot be warranted */
     327           0 :   ph->cb = recoup_cb;
     328           0 :   ph->cb_cls = recoup_cb_cls;
     329           0 :   ph->url = TALER_url_join (url,
     330             :                             arg_str,
     331             :                             NULL);
     332           0 :   if (NULL == ph->url)
     333             :   {
     334           0 :     json_decref (recoup_obj);
     335           0 :     GNUNET_free (ph);
     336           0 :     return NULL;
     337             :   }
     338           0 :   eh = TALER_EXCHANGE_curl_easy_get_ (ph->url);
     339           0 :   if ( (NULL == eh) ||
     340             :        (GNUNET_OK !=
     341           0 :         TALER_curl_easy_post (&ph->ctx,
     342             :                               eh,
     343             :                               recoup_obj)) )
     344             :   {
     345           0 :     GNUNET_break (0);
     346           0 :     if (NULL != eh)
     347           0 :       curl_easy_cleanup (eh);
     348           0 :     json_decref (recoup_obj);
     349           0 :     GNUNET_free (ph->url);
     350           0 :     GNUNET_free (ph);
     351           0 :     return NULL;
     352             :   }
     353           0 :   json_decref (recoup_obj);
     354           0 :   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
     355             :               "URL for recoup: `%s'\n",
     356             :               ph->url);
     357           0 :   ph->keys = TALER_EXCHANGE_keys_incref (keys);
     358           0 :   ph->job = GNUNET_CURL_job_add2 (ctx,
     359             :                                   eh,
     360           0 :                                   ph->ctx.headers,
     361             :                                   &handle_recoup_finished,
     362             :                                   ph);
     363           0 :   return ph;
     364             : }
     365             : 
     366             : 
     367             : void
     368           0 : TALER_EXCHANGE_recoup_cancel (struct TALER_EXCHANGE_RecoupHandle *ph)
     369             : {
     370           0 :   if (NULL != ph->job)
     371             :   {
     372           0 :     GNUNET_CURL_job_cancel (ph->job);
     373           0 :     ph->job = NULL;
     374             :   }
     375           0 :   GNUNET_free (ph->url);
     376           0 :   TALER_curl_easy_post_finished (&ph->ctx);
     377           0 :   TALER_EXCHANGE_keys_decref (ph->keys);
     378           0 :   GNUNET_free (ph);
     379           0 : }
     380             : 
     381             : 
     382             : /* end of exchange_api_recoup.c */

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