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_refresh.c
19 : * @brief Implementation of the /recoup-refresh 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_RecoupRefreshHandle
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 : * Handle for the request.
65 : */
66 : struct GNUNET_CURL_Job *job;
67 :
68 : /**
69 : * Function to call with the result.
70 : */
71 : TALER_EXCHANGE_RecoupRefreshResultCallback cb;
72 :
73 : /**
74 : * Closure for @a cb.
75 : */
76 : void *cb_cls;
77 :
78 : /**
79 : * Public key of the coin we are trying to get paid back.
80 : */
81 : struct TALER_CoinSpendPublicKeyP coin_pub;
82 :
83 : /**
84 : * Signature affirming the recoup-refresh operation.
85 : */
86 : struct TALER_CoinSpendSignatureP coin_sig;
87 :
88 : };
89 :
90 :
91 : /**
92 : * Parse a recoup-refresh 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 (
101 : const struct TALER_EXCHANGE_RecoupRefreshHandle *ph,
102 : const json_t *json)
103 : {
104 0 : struct TALER_EXCHANGE_RecoupRefreshResponse rrr = {
105 : .hr.reply = json,
106 : .hr.http_status = MHD_HTTP_OK
107 : };
108 : struct GNUNET_JSON_Specification spec_refresh[] = {
109 0 : GNUNET_JSON_spec_fixed_auto ("old_coin_pub",
110 : &rrr.details.ok.old_coin_pub),
111 0 : GNUNET_JSON_spec_end ()
112 : };
113 :
114 0 : if (GNUNET_OK !=
115 0 : GNUNET_JSON_parse (json,
116 : spec_refresh,
117 : NULL, NULL))
118 : {
119 0 : GNUNET_break_op (0);
120 0 : return GNUNET_SYSERR;
121 : }
122 0 : ph->cb (ph->cb_cls,
123 : &rrr);
124 0 : return GNUNET_OK;
125 : }
126 :
127 :
128 : /**
129 : * Function called when we're done processing the
130 : * HTTP /recoup-refresh request.
131 : *
132 : * @param cls the `struct TALER_EXCHANGE_RecoupRefreshHandle`
133 : * @param response_code HTTP response code, 0 on error
134 : * @param response parsed JSON result, NULL on error
135 : */
136 : static void
137 0 : handle_recoup_refresh_finished (void *cls,
138 : long response_code,
139 : const void *response)
140 : {
141 0 : struct TALER_EXCHANGE_RecoupRefreshHandle *ph = cls;
142 0 : const json_t *j = response;
143 0 : struct TALER_EXCHANGE_RecoupRefreshResponse rrr = {
144 : .hr.reply = j,
145 0 : .hr.http_status = (unsigned int) response_code
146 : };
147 :
148 0 : ph->job = NULL;
149 0 : switch (response_code)
150 : {
151 0 : case 0:
152 0 : rrr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
153 0 : break;
154 0 : case MHD_HTTP_OK:
155 0 : if (GNUNET_OK !=
156 0 : process_recoup_response (ph,
157 : j))
158 : {
159 0 : GNUNET_break_op (0);
160 0 : rrr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
161 0 : rrr.hr.http_status = 0;
162 0 : break;
163 : }
164 0 : TALER_EXCHANGE_recoup_refresh_cancel (ph);
165 0 : return;
166 0 : case MHD_HTTP_BAD_REQUEST:
167 : /* This should never happen, either us or the exchange is buggy
168 : (or API version conflict); just pass JSON reply to the application */
169 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
170 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
171 0 : break;
172 0 : case MHD_HTTP_FORBIDDEN:
173 : /* Nothing really to verify, exchange says one of the signatures is
174 : invalid; as we checked them, this should never happen, we
175 : should pass the JSON reply to the application */
176 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
177 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
178 0 : break;
179 0 : case MHD_HTTP_NOT_FOUND:
180 : /* Nothing really to verify, this should never
181 : happen, we should pass the JSON reply to the application */
182 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
183 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
184 0 : break;
185 0 : case MHD_HTTP_CONFLICT:
186 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
187 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
188 0 : break;
189 0 : case MHD_HTTP_GONE:
190 : /* Kind of normal: the money was already sent to the merchant
191 : (it was too late for the refund). */
192 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
193 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
194 0 : break;
195 0 : case MHD_HTTP_INTERNAL_SERVER_ERROR:
196 : /* Server had an internal issue; we should retry, but this API
197 : leaves this to the application */
198 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
199 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
200 0 : break;
201 0 : default:
202 : /* unexpected response code */
203 0 : rrr.hr.ec = TALER_JSON_get_error_code (j);
204 0 : rrr.hr.hint = TALER_JSON_get_error_hint (j);
205 0 : GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
206 : "Unexpected response code %u/%d for exchange recoup\n",
207 : (unsigned int) response_code,
208 : (int) rrr.hr.ec);
209 0 : GNUNET_break (0);
210 0 : break;
211 : }
212 0 : ph->cb (ph->cb_cls,
213 : &rrr);
214 0 : TALER_EXCHANGE_recoup_refresh_cancel (ph);
215 : }
216 :
217 :
218 : struct TALER_EXCHANGE_RecoupRefreshHandle *
219 0 : TALER_EXCHANGE_recoup_refresh (
220 : struct GNUNET_CURL_Context *ctx,
221 : const char *url,
222 : struct TALER_EXCHANGE_Keys *keys,
223 : const struct TALER_EXCHANGE_DenomPublicKey *pk,
224 : const struct TALER_DenominationSignature *denom_sig,
225 : const struct TALER_ExchangeBlindingValues *blinding_values,
226 : const struct TALER_RefreshMasterSecretP *rms,
227 : const struct TALER_PlanchetMasterSecretP *ps,
228 : unsigned int idx,
229 : TALER_EXCHANGE_RecoupRefreshResultCallback recoup_cb,
230 : void *recoup_cb_cls)
231 : {
232 : struct TALER_EXCHANGE_RecoupRefreshHandle *ph;
233 : struct TALER_DenominationHashP h_denom_pub;
234 : json_t *recoup_obj;
235 : CURL *eh;
236 : char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
237 : struct TALER_CoinSpendPrivateKeyP coin_priv;
238 : union GNUNET_CRYPTO_BlindingSecretP bks;
239 :
240 0 : GNUNET_assert (NULL != recoup_cb);
241 0 : ph = GNUNET_new (struct TALER_EXCHANGE_RecoupRefreshHandle);
242 0 : ph->pk = *pk;
243 0 : memset (&ph->pk.key,
244 : 0,
245 : sizeof (ph->pk.key)); /* zero out, as lifetime cannot be warranted */
246 0 : ph->cb = recoup_cb;
247 0 : ph->cb_cls = recoup_cb_cls;
248 0 : TALER_planchet_setup_coin_priv (ps,
249 : blinding_values,
250 : &coin_priv);
251 0 : TALER_planchet_blinding_secret_create (ps,
252 : blinding_values,
253 : &bks);
254 0 : GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv.eddsa_priv,
255 : &ph->coin_pub.eddsa_pub);
256 0 : TALER_denom_pub_hash (&pk->key,
257 : &h_denom_pub);
258 0 : TALER_wallet_recoup_refresh_sign (&h_denom_pub,
259 : &bks,
260 : &coin_priv,
261 : &ph->coin_sig);
262 0 : recoup_obj = GNUNET_JSON_PACK (
263 : GNUNET_JSON_pack_data_auto ("denom_pub_hash",
264 : &h_denom_pub),
265 : TALER_JSON_pack_denom_sig ("denom_sig",
266 : denom_sig),
267 : TALER_JSON_pack_exchange_blinding_values ("ewv",
268 : blinding_values),
269 : GNUNET_JSON_pack_data_auto ("coin_sig",
270 : &ph->coin_sig),
271 : GNUNET_JSON_pack_data_auto ("coin_blind_key_secret",
272 : &bks));
273 :
274 0 : switch (denom_sig->unblinded_sig->cipher)
275 : {
276 0 : case GNUNET_CRYPTO_BSA_INVALID:
277 0 : json_decref (recoup_obj);
278 0 : GNUNET_break (0);
279 0 : GNUNET_free (ph);
280 0 : return NULL;
281 0 : case GNUNET_CRYPTO_BSA_RSA:
282 0 : break;
283 0 : case GNUNET_CRYPTO_BSA_CS:
284 : {
285 : union GNUNET_CRYPTO_BlindSessionNonce nonce;
286 :
287 : /* NOTE: this is not elegant, and as per the note in TALER_coin_ev_hash()
288 : it is not strictly clear that the nonce is needed. Best case would be
289 : to find a way to include it more 'naturally' somehow, for example with
290 : the variant union version of bks! */
291 0 : TALER_cs_refresh_nonce_derive (rms,
292 : idx,
293 : &nonce.cs_nonce);
294 0 : GNUNET_assert (
295 : 0 ==
296 : json_object_set_new (recoup_obj,
297 : "nonce",
298 : GNUNET_JSON_from_data_auto (
299 : &nonce)));
300 : }
301 0 : break;
302 : }
303 :
304 : {
305 : char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
306 : char *end;
307 :
308 0 : end = GNUNET_STRINGS_data_to_string (
309 0 : &ph->coin_pub,
310 : sizeof (struct TALER_CoinSpendPublicKeyP),
311 : pub_str,
312 : sizeof (pub_str));
313 0 : *end = '\0';
314 0 : GNUNET_snprintf (arg_str,
315 : sizeof (arg_str),
316 : "coins/%s/recoup-refresh",
317 : pub_str);
318 : }
319 :
320 0 : ph->url = TALER_url_join (url,
321 : arg_str,
322 : NULL);
323 0 : if (NULL == ph->url)
324 : {
325 0 : json_decref (recoup_obj);
326 0 : GNUNET_free (ph);
327 0 : return NULL;
328 : }
329 0 : eh = TALER_EXCHANGE_curl_easy_get_ (ph->url);
330 0 : if ( (NULL == eh) ||
331 : (GNUNET_OK !=
332 0 : TALER_curl_easy_post (&ph->ctx,
333 : eh,
334 : recoup_obj)) )
335 : {
336 0 : GNUNET_break (0);
337 0 : if (NULL != eh)
338 0 : curl_easy_cleanup (eh);
339 0 : json_decref (recoup_obj);
340 0 : GNUNET_free (ph->url);
341 0 : GNUNET_free (ph);
342 0 : return NULL;
343 : }
344 0 : json_decref (recoup_obj);
345 0 : GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
346 : "URL for recoup-refresh: `%s'\n",
347 : ph->url);
348 0 : ph->keys = TALER_EXCHANGE_keys_incref (keys);
349 0 : ph->job = GNUNET_CURL_job_add2 (ctx,
350 : eh,
351 0 : ph->ctx.headers,
352 : &handle_recoup_refresh_finished,
353 : ph);
354 0 : return ph;
355 : }
356 :
357 :
358 : void
359 0 : TALER_EXCHANGE_recoup_refresh_cancel (
360 : struct TALER_EXCHANGE_RecoupRefreshHandle *ph)
361 : {
362 0 : if (NULL != ph->job)
363 : {
364 0 : GNUNET_CURL_job_cancel (ph->job);
365 0 : ph->job = NULL;
366 : }
367 0 : GNUNET_free (ph->url);
368 0 : TALER_curl_easy_post_finished (&ph->ctx);
369 0 : TALER_EXCHANGE_keys_decref (ph->keys);
370 0 : GNUNET_free (ph);
371 0 : }
372 :
373 :
374 : /* end of exchange_api_recoup_refresh.c */
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