diff options
Diffstat (limited to 'src/lib/exchange_api_csr_melt.c')
-rw-r--r-- | src/lib/exchange_api_csr_melt.c | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/src/lib/exchange_api_csr_melt.c b/src/lib/exchange_api_csr_melt.c new file mode 100644 index 000000000..f59995af3 --- /dev/null +++ b/src/lib/exchange_api_csr_melt.c @@ -0,0 +1,317 @@ +/* + This file is part of TALER + Copyright (C) 2014-2022 Taler Systems SA + + 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 lib/exchange_api_csr_melt.c + * @brief Implementation of /csr-melt requests (get R in exchange used for Clause Schnorr refresh) + * @author Lucien Heuzeveldt + * @author Gian Demarmels + */ +#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_exchange_service.h" +#include "taler_json_lib.h" +#include "exchange_api_handle.h" +#include "taler_signatures.h" +#include "exchange_api_curl_defaults.h" + + +/** + * @brief A Clause Schnorr R Handle + */ +struct TALER_EXCHANGE_CsRMeltHandle +{ + + /** + * Function to call with the result. + */ + TALER_EXCHANGE_CsRMeltCallback cb; + + /** + * Closure for @a cb. + */ + void *cb_cls; + + /** + * The url for this request. + */ + char *url; + + /** + * Handle for the request. + */ + struct GNUNET_CURL_Job *job; + + /** + * Context for #TEH_curl_easy_post(). Keeps the data that must + * persist for Curl to make the upload. + */ + struct TALER_CURL_PostContext post_ctx; +}; + + +/** + * We got a 200 OK response for the /reserves/$RESERVE_PUB/withdraw operation. + * Extract the coin's signature and return it to the caller. The signature we + * get from the exchange is for the blinded value. Thus, we first must + * unblind it and then should verify its validity against our coin's hash. + * + * If everything checks out, we return the unblinded signature + * to the application via the callback. + * + * @param csrh operation handle + * @param arr reply from the exchange + * @param hr http response details + * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors + */ +static enum GNUNET_GenericReturnValue +csr_ok (struct TALER_EXCHANGE_CsRMeltHandle *csrh, + const json_t *arr, + struct TALER_EXCHANGE_HttpResponse *hr) +{ + unsigned int alen = json_array_size (arr); + struct TALER_ExchangeWithdrawValues alg_values[GNUNET_NZL (alen)]; + struct TALER_EXCHANGE_CsRMeltResponse csrr = { + .hr = *hr, + .details.ok.alg_values_len = alen, + .details.ok.alg_values = alg_values + }; + + for (unsigned int i = 0; i<alen; i++) + { + json_t *av = json_array_get (arr, + i); + struct GNUNET_JSON_Specification spec[] = { + TALER_JSON_spec_exchange_withdraw_values ( + "ewv", + &alg_values[i]), + GNUNET_JSON_spec_end () + }; + + if (GNUNET_OK != + GNUNET_JSON_parse (av, + spec, + NULL, NULL)) + { + GNUNET_break_op (0); + return GNUNET_SYSERR; + } + } + csrh->cb (csrh->cb_cls, + &csrr); + return GNUNET_OK; +} + + +/** + * Function called when we're done processing the HTTP /csr request. + * + * @param cls the `struct TALER_EXCHANGE_CsRMeltHandle` + * @param response_code HTTP response code, 0 on error + * @param response parsed JSON result, NULL on error + */ +static void +handle_csr_finished (void *cls, + long response_code, + const void *response) +{ + struct TALER_EXCHANGE_CsRMeltHandle *csrh = cls; + const json_t *j = response; + struct TALER_EXCHANGE_HttpResponse hr = { + .reply = j, + .http_status = (unsigned int) response_code + }; + struct TALER_EXCHANGE_CsRMeltResponse csrr = { + .hr = hr + }; + + csrh->job = NULL; + switch (response_code) + { + case 0: + csrr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE; + break; + case MHD_HTTP_OK: + { + json_t *arr; + + arr = json_object_get (j, + "ewvs"); + if ( (NULL == arr) || + (0 == json_array_size (arr)) || + (GNUNET_OK != + csr_ok (csrh, + arr, + &hr)) ) + { + GNUNET_break_op (0); + csrr.hr.http_status = 0; + csrr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED; + break; + } + } + TALER_EXCHANGE_csr_melt_cancel (csrh); + 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 */ + csrr.hr.ec = TALER_JSON_get_error_code (j); + csrr.hr.hint = TALER_JSON_get_error_hint (j); + break; + case MHD_HTTP_NOT_FOUND: + /* Nothing really to verify, the exchange basically just says + that it doesn't know the /csr endpoint or denomination. + Can happen if the exchange doesn't support Clause Schnorr. + We should simply pass the JSON reply to the application. */ + csrr.hr.ec = TALER_JSON_get_error_code (j); + csrr.hr.hint = TALER_JSON_get_error_hint (j); + break; + case MHD_HTTP_GONE: + /* could happen if denomination was revoked */ + /* Note: one might want to check /keys for revocation + signature here, alas tricky in case our /keys + is outdated => left to clients */ + csrr.hr.ec = TALER_JSON_get_error_code (j); + csrr.hr.hint = TALER_JSON_get_error_hint (j); + break; + case MHD_HTTP_INTERNAL_SERVER_ERROR: + /* Server had an internal issue; we should retry, but this API + leaves this to the application */ + csrr.hr.ec = TALER_JSON_get_error_code (j); + csrr.hr.hint = TALER_JSON_get_error_hint (j); + break; + default: + /* unexpected response code */ + GNUNET_break_op (0); + csrr.hr.ec = TALER_JSON_get_error_code (j); + csrr.hr.hint = TALER_JSON_get_error_hint (j); + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "Unexpected response code %u/%d for CS R request\n", + (unsigned int) response_code, + (int) hr.ec); + break; + } + csrh->cb (csrh->cb_cls, + &csrr); + csrh->cb = NULL; + TALER_EXCHANGE_csr_melt_cancel (csrh); +} + + +struct TALER_EXCHANGE_CsRMeltHandle * +TALER_EXCHANGE_csr_melt ( + struct GNUNET_CURL_Context *ctx, + const char *url, + const struct TALER_RefreshMasterSecretP *rms, + unsigned int nks_len, + struct TALER_EXCHANGE_NonceKey nks[static nks_len], + TALER_EXCHANGE_CsRMeltCallback res_cb, + void *res_cb_cls) +{ + struct TALER_EXCHANGE_CsRMeltHandle *csrh; + json_t *csr_arr; + + if (0 == nks_len) + { + GNUNET_break (0); + return NULL; + } + for (unsigned int i = 0; i<nks_len; i++) + if (TALER_DENOMINATION_CS != nks[i].pk->key.cipher) + { + GNUNET_break (0); + return NULL; + } + csrh = GNUNET_new (struct TALER_EXCHANGE_CsRMeltHandle); + csrh->cb = res_cb; + csrh->cb_cls = res_cb_cls; + csr_arr = json_array (); + GNUNET_assert (NULL != csr_arr); + for (unsigned int i = 0; i<nks_len; i++) + { + const struct TALER_EXCHANGE_NonceKey *nk = &nks[i]; + json_t *csr_obj; + + csr_obj = GNUNET_JSON_PACK ( + GNUNET_JSON_pack_uint64 ("coin_offset", + nk->cnc_num), + GNUNET_JSON_pack_data_auto ("denom_pub_hash", + &nk->pk->h_key)); + GNUNET_assert (NULL != csr_obj); + GNUNET_assert (0 == + json_array_append_new (csr_arr, + csr_obj)); + } + csrh->url = TALER_url_join (url, + "csr-melt", + NULL); + if (NULL == csrh->url) + { + json_decref (csr_arr); + GNUNET_free (csrh); + return NULL; + } + { + CURL *eh; + json_t *req; + + req = GNUNET_JSON_PACK ( + GNUNET_JSON_pack_data_auto ("rms", + rms), + GNUNET_JSON_pack_array_steal ("nks", + csr_arr)); + eh = TALER_EXCHANGE_curl_easy_get_ (csrh->url); + if ( (NULL == eh) || + (GNUNET_OK != + TALER_curl_easy_post (&csrh->post_ctx, + eh, + req)) ) + { + GNUNET_break (0); + if (NULL != eh) + curl_easy_cleanup (eh); + json_decref (req); + GNUNET_free (csrh->url); + GNUNET_free (csrh); + return NULL; + } + json_decref (req); + csrh->job = GNUNET_CURL_job_add2 (ctx, + eh, + csrh->post_ctx.headers, + &handle_csr_finished, + csrh); + } + return csrh; +} + + +void +TALER_EXCHANGE_csr_melt_cancel (struct TALER_EXCHANGE_CsRMeltHandle *csrh) +{ + if (NULL != csrh->job) + { + GNUNET_CURL_job_cancel (csrh->job); + csrh->job = NULL; + } + GNUNET_free (csrh->url); + TALER_curl_easy_post_finished (&csrh->post_ctx); + GNUNET_free (csrh); +} |