Line data Source code
1 : /*
2 : This file is part of TALER
3 : Copyright (C) 2023-2025 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_reveal_withdraw.c
19 : * @brief Implementation of /reveal-withdraw requests
20 : * @author Özgür Kesim
21 : */
22 :
23 : #include "platform.h"
24 : #include <gnunet/gnunet_common.h>
25 : #include <jansson.h>
26 : #include <microhttpd.h> /* just for HTTP status codes */
27 : #include <gnunet/gnunet_util_lib.h>
28 : #include <gnunet/gnunet_json_lib.h>
29 : #include <gnunet/gnunet_curl_lib.h>
30 : #include "taler_curl_lib.h"
31 : #include "taler_json_lib.h"
32 : #include "taler_exchange_service.h"
33 : #include "exchange_api_common.h"
34 : #include "exchange_api_handle.h"
35 : #include "taler_signatures.h"
36 : #include "exchange_api_curl_defaults.h"
37 :
38 : /**
39 : * Handler for a running reveal-withdraw request
40 : */
41 : struct TALER_EXCHANGE_RevealWithdrawHandle
42 : {
43 : /**
44 : * The commitment from the previous call withdraw
45 : */
46 : const struct TALER_HashBlindedPlanchetsP *planchets_h;
47 :
48 : /**
49 : * Number of coins for which to reveal tuples of seeds
50 : */
51 : size_t num_coins;
52 :
53 : /**
54 : * The TALER_CNC_KAPPA-1 tuple of seeds to reveal
55 : */
56 : struct TALER_RevealWithdrawMasterSeedsP seeds;
57 :
58 : /**
59 : * The url for the reveal request
60 : */
61 : char *request_url;
62 :
63 : /**
64 : * CURL handle for the request job.
65 : */
66 : struct GNUNET_CURL_Job *job;
67 :
68 : /**
69 : * Post Context
70 : */
71 : struct TALER_CURL_PostContext post_ctx;
72 :
73 : /**
74 : * Callback
75 : */
76 : TALER_EXCHANGE_RevealWithdrawCallback callback;
77 :
78 : /**
79 : * Reveal
80 : */
81 : void *callback_cls;
82 : };
83 :
84 :
85 : /**
86 : * We got a 200 OK response for the /reveal-withdraw operation.
87 : * Extract the signed blindedcoins and return it to the caller.
88 : *
89 : * @param wrh operation handle
90 : * @param j_response reply from the exchange
91 : * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
92 : */
93 : static enum GNUNET_GenericReturnValue
94 3 : reveal_withdraw_ok (
95 : struct TALER_EXCHANGE_RevealWithdrawHandle *wrh,
96 : const json_t *j_response)
97 : {
98 3 : struct TALER_EXCHANGE_RevealWithdrawResponse response = {
99 : .hr.reply = j_response,
100 : .hr.http_status = MHD_HTTP_OK,
101 : };
102 : const json_t *j_sigs;
103 : struct GNUNET_JSON_Specification spec[] = {
104 3 : GNUNET_JSON_spec_array_const ("ev_sigs",
105 : &j_sigs),
106 3 : GNUNET_JSON_spec_end ()
107 : };
108 :
109 3 : if (GNUNET_OK !=
110 3 : GNUNET_JSON_parse (j_response,
111 : spec,
112 : NULL, NULL))
113 : {
114 0 : GNUNET_break_op (0);
115 0 : return GNUNET_SYSERR;
116 : }
117 :
118 3 : if (wrh->num_coins != json_array_size (j_sigs))
119 : {
120 : /* Number of coins generated does not match our expectation */
121 0 : GNUNET_break_op (0);
122 0 : return GNUNET_SYSERR;
123 : }
124 :
125 3 : {
126 3 : struct TALER_BlindedDenominationSignature denom_sigs[wrh->num_coins];
127 : json_t *j_sig;
128 : size_t n;
129 :
130 : /* Reconstruct the coins and unblind the signatures */
131 10 : json_array_foreach (j_sigs, n, j_sig)
132 : {
133 : struct GNUNET_JSON_Specification ispec[] = {
134 7 : TALER_JSON_spec_blinded_denom_sig (NULL,
135 : &denom_sigs[n]),
136 7 : GNUNET_JSON_spec_end ()
137 : };
138 :
139 7 : if (GNUNET_OK !=
140 7 : GNUNET_JSON_parse (j_sig,
141 : ispec,
142 : NULL, NULL))
143 : {
144 0 : GNUNET_break_op (0);
145 0 : return GNUNET_SYSERR;
146 : }
147 : }
148 :
149 3 : response.details.ok.num_sigs = wrh->num_coins;
150 3 : response.details.ok.blinded_denom_sigs = denom_sigs;
151 3 : wrh->callback (wrh->callback_cls,
152 : &response);
153 : /* Make sure the callback isn't called again */
154 3 : wrh->callback = NULL;
155 : /* Free resources */
156 10 : for (size_t i = 0; i < wrh->num_coins; i++)
157 7 : TALER_blinded_denom_sig_free (&denom_sigs[i]);
158 : }
159 :
160 3 : return GNUNET_OK;
161 : }
162 :
163 :
164 : /**
165 : * Function called when we're done processing the
166 : * HTTP /reveal-withdraw request.
167 : *
168 : * @param cls the `struct TALER_EXCHANGE_RevealWithdrawHandle`
169 : * @param response_code The HTTP response code
170 : * @param response response data
171 : */
172 : static void
173 3 : handle_reveal_withdraw_finished (
174 : void *cls,
175 : long response_code,
176 : const void *response)
177 : {
178 3 : struct TALER_EXCHANGE_RevealWithdrawHandle *wrh = cls;
179 3 : const json_t *j_response = response;
180 3 : struct TALER_EXCHANGE_RevealWithdrawResponse awr = {
181 : .hr.reply = j_response,
182 3 : .hr.http_status = (unsigned int) response_code
183 : };
184 :
185 3 : wrh->job = NULL;
186 3 : switch (response_code)
187 : {
188 0 : case 0:
189 0 : awr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
190 0 : break;
191 3 : case MHD_HTTP_OK:
192 : {
193 : enum GNUNET_GenericReturnValue ret;
194 :
195 3 : ret = reveal_withdraw_ok (wrh,
196 : j_response);
197 3 : if (GNUNET_OK != ret)
198 : {
199 0 : GNUNET_break_op (0);
200 0 : awr.hr.http_status = 0;
201 0 : awr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
202 0 : break;
203 : }
204 3 : GNUNET_assert (NULL == wrh->callback);
205 3 : TALER_EXCHANGE_reveal_withdraw_cancel (wrh);
206 3 : return;
207 : }
208 0 : case MHD_HTTP_BAD_REQUEST:
209 : /* This should never happen, either us or the exchange is buggy
210 : (or API version conflict); just pass JSON reply to the application */
211 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
212 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
213 0 : break;
214 0 : case MHD_HTTP_NOT_FOUND:
215 : /* Nothing really to verify, the exchange basically just says
216 : that it doesn't know this age-withdraw commitment. */
217 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
218 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
219 0 : break;
220 0 : case MHD_HTTP_CONFLICT:
221 : /* An age commitment for one of the coins did not fulfill
222 : * the required maximum age requirement of the corresponding
223 : * reserve.
224 : * Error code: TALER_EC_EXCHANGE_GENERIC_COIN_AGE_REQUIREMENT_FAILURE
225 : * or TALER_EC_EXCHANGE_AGE_WITHDRAW_REVEAL_INVALID_HASH.
226 : */
227 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
228 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
229 0 : break;
230 0 : case MHD_HTTP_INTERNAL_SERVER_ERROR:
231 : /* Server had an internal issue; we should retry, but this API
232 : leaves this to the application */
233 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
234 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
235 0 : break;
236 0 : default:
237 : /* unexpected response code */
238 0 : GNUNET_break_op (0);
239 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
240 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
241 0 : GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
242 : "Unexpected response code %u/%d for exchange age-withdraw\n",
243 : (unsigned int) response_code,
244 : (int) awr.hr.ec);
245 0 : break;
246 : }
247 0 : wrh->callback (wrh->callback_cls,
248 : &awr);
249 0 : TALER_EXCHANGE_reveal_withdraw_cancel (wrh);
250 : }
251 :
252 :
253 : /**
254 : * Call /reveal-withdraw
255 : *
256 : * @param curl_ctx The context for CURL
257 : * @param wrh The handler
258 : */
259 : static void
260 3 : perform_protocol (
261 : struct GNUNET_CURL_Context *curl_ctx,
262 : struct TALER_EXCHANGE_RevealWithdrawHandle *wrh)
263 : {
264 : CURL *curlh;
265 : json_t *j_array_of_secrets;
266 :
267 3 : j_array_of_secrets = json_array ();
268 3 : GNUNET_assert (NULL != j_array_of_secrets);
269 :
270 9 : for (uint8_t k = 0; k < TALER_CNC_KAPPA - 1; k++)
271 : {
272 6 : json_t *j_sec = GNUNET_JSON_from_data_auto (&wrh->seeds.tuple[k]);
273 6 : GNUNET_assert (NULL != j_sec);
274 6 : GNUNET_assert (0 == json_array_append_new (j_array_of_secrets,
275 : j_sec));
276 : }
277 : {
278 : json_t *j_request_body;
279 :
280 3 : j_request_body = GNUNET_JSON_PACK (
281 : GNUNET_JSON_pack_data_auto ("planchets_h",
282 : wrh->planchets_h),
283 : GNUNET_JSON_pack_array_steal ("disclosed_batch_seeds",
284 : j_array_of_secrets));
285 3 : GNUNET_assert (NULL != j_request_body);
286 :
287 3 : curlh = TALER_EXCHANGE_curl_easy_get_ (wrh->request_url);
288 3 : GNUNET_assert (NULL != curlh);
289 3 : GNUNET_assert (GNUNET_OK ==
290 : TALER_curl_easy_post (&wrh->post_ctx,
291 : curlh,
292 : j_request_body));
293 :
294 3 : json_decref (j_request_body);
295 : }
296 :
297 6 : wrh->job = GNUNET_CURL_job_add2 (
298 : curl_ctx,
299 : curlh,
300 3 : wrh->post_ctx.headers,
301 : &handle_reveal_withdraw_finished,
302 : wrh);
303 3 : if (NULL == wrh->job)
304 : {
305 0 : GNUNET_break (0);
306 0 : if (NULL != curlh)
307 0 : curl_easy_cleanup (curlh);
308 0 : TALER_EXCHANGE_reveal_withdraw_cancel (wrh);
309 : }
310 :
311 3 : return;
312 : }
313 :
314 :
315 : struct TALER_EXCHANGE_RevealWithdrawHandle *
316 3 : TALER_EXCHANGE_reveal_withdraw (
317 : struct GNUNET_CURL_Context *curl_ctx,
318 : const char *exchange_url,
319 : size_t num_coins,
320 : const struct TALER_HashBlindedPlanchetsP *planchets_h,
321 : const struct TALER_RevealWithdrawMasterSeedsP *seeds,
322 : TALER_EXCHANGE_RevealWithdrawCallback reveal_cb,
323 : void *reveal_cb_cls)
324 : {
325 : struct TALER_EXCHANGE_RevealWithdrawHandle *wrh =
326 3 : GNUNET_new (struct TALER_EXCHANGE_RevealWithdrawHandle);
327 3 : wrh->planchets_h = planchets_h;
328 3 : wrh->num_coins = num_coins;
329 3 : wrh->seeds = *seeds;
330 3 : wrh->callback = reveal_cb;
331 3 : wrh->callback_cls = reveal_cb_cls;
332 3 : wrh->request_url = TALER_url_join (exchange_url,
333 : "reveal-withdraw",
334 : NULL);
335 3 : if (NULL == wrh->request_url)
336 : {
337 0 : GNUNET_break (0);
338 0 : GNUNET_free (wrh);
339 0 : return NULL;
340 : }
341 :
342 3 : perform_protocol (curl_ctx, wrh);
343 :
344 3 : return wrh;
345 : }
346 :
347 :
348 : void
349 3 : TALER_EXCHANGE_reveal_withdraw_cancel (
350 : struct TALER_EXCHANGE_RevealWithdrawHandle *wrh)
351 : {
352 3 : if (NULL != wrh->job)
353 : {
354 0 : GNUNET_CURL_job_cancel (wrh->job);
355 0 : wrh->job = NULL;
356 : }
357 3 : TALER_curl_easy_post_finished (&wrh->post_ctx);
358 :
359 3 : if (NULL != wrh->request_url)
360 3 : GNUNET_free (wrh->request_url);
361 :
362 3 : GNUNET_free (wrh);
363 3 : }
364 :
365 :
366 : /* exchange_api_reveal_withdraw.c */
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