Line data Source code
1 : /*
2 : This file is part of TALER
3 : Copyright (C) 2023-2026 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_post-reveal-withdraw.c
19 : * @brief Implementation of POST /reveal-withdraw requests
20 : * @author Özgür Kesim
21 : */
22 :
23 : #include "taler/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/taler_curl_lib.h"
31 : #include "taler/taler_json_lib.h"
32 : #include "taler/taler_exchange_service.h"
33 : #include "exchange_api_common.h"
34 : #include "exchange_api_handle.h"
35 : #include "taler/taler_signatures.h"
36 : #include "exchange_api_curl_defaults.h"
37 :
38 :
39 : /**
40 : * Handler for a running POST /reveal-withdraw request
41 : */
42 : struct TALER_EXCHANGE_PostRevealWithdrawHandle
43 : {
44 : /**
45 : * The commitment from the previous call to withdraw
46 : */
47 : struct TALER_HashBlindedPlanchetsP planchets_h;
48 :
49 : /**
50 : * Number of coins for which to reveal tuples of seeds
51 : */
52 : size_t num_coins;
53 :
54 : /**
55 : * The TALER_CNC_KAPPA-1 tuple of seeds to reveal
56 : */
57 : struct TALER_RevealWithdrawMasterSeedsP seeds;
58 :
59 : /**
60 : * The exchange base URL.
61 : */
62 : char *exchange_url;
63 :
64 : /**
65 : * The url for the reveal request
66 : */
67 : char *request_url;
68 :
69 : /**
70 : * The curl context
71 : */
72 : struct GNUNET_CURL_Context *curl_ctx;
73 :
74 : /**
75 : * CURL handle for the request job.
76 : */
77 : struct GNUNET_CURL_Job *job;
78 :
79 : /**
80 : * Post Context
81 : */
82 : struct TALER_CURL_PostContext post_ctx;
83 :
84 : /**
85 : * Callback to pass the result to
86 : */
87 : TALER_EXCHANGE_PostRevealWithdrawCallback callback;
88 :
89 : /**
90 : * Closure for @e callback
91 : */
92 : void *callback_cls;
93 : };
94 :
95 :
96 : /**
97 : * We got a 200 OK response for the /reveal-withdraw operation.
98 : * Extract the signed blinded coins and return it to the caller.
99 : *
100 : * @param wrh operation handle
101 : * @param j_response reply from the exchange
102 : * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
103 : */
104 : static enum GNUNET_GenericReturnValue
105 3 : reveal_withdraw_ok (
106 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh,
107 : const json_t *j_response)
108 : {
109 3 : struct TALER_EXCHANGE_PostRevealWithdrawResponse response = {
110 : .hr.reply = j_response,
111 : .hr.http_status = MHD_HTTP_OK,
112 : };
113 : const json_t *j_sigs;
114 : struct GNUNET_JSON_Specification spec[] = {
115 3 : GNUNET_JSON_spec_array_const ("ev_sigs",
116 : &j_sigs),
117 3 : GNUNET_JSON_spec_end ()
118 : };
119 :
120 3 : if (GNUNET_OK !=
121 3 : GNUNET_JSON_parse (j_response,
122 : spec,
123 : NULL, NULL))
124 : {
125 0 : GNUNET_break_op (0);
126 0 : return GNUNET_SYSERR;
127 : }
128 :
129 3 : if (wrh->num_coins != json_array_size (j_sigs))
130 : {
131 : /* Number of coins generated does not match our expectation */
132 0 : GNUNET_break_op (0);
133 0 : return GNUNET_SYSERR;
134 : }
135 :
136 3 : {
137 3 : struct TALER_BlindedDenominationSignature denom_sigs[wrh->num_coins];
138 : json_t *j_sig;
139 : size_t n;
140 :
141 : /* Reconstruct the coins and unblind the signatures */
142 10 : json_array_foreach (j_sigs, n, j_sig)
143 : {
144 : struct GNUNET_JSON_Specification ispec[] = {
145 7 : TALER_JSON_spec_blinded_denom_sig (NULL,
146 : &denom_sigs[n]),
147 7 : GNUNET_JSON_spec_end ()
148 : };
149 :
150 7 : if (GNUNET_OK !=
151 7 : GNUNET_JSON_parse (j_sig,
152 : ispec,
153 : NULL, NULL))
154 : {
155 0 : GNUNET_break_op (0);
156 0 : return GNUNET_SYSERR;
157 : }
158 : }
159 :
160 3 : response.details.ok.num_sigs = wrh->num_coins;
161 3 : response.details.ok.blinded_denom_sigs = denom_sigs;
162 3 : wrh->callback (wrh->callback_cls,
163 : &response);
164 : /* Make sure the callback isn't called again */
165 3 : wrh->callback = NULL;
166 : /* Free resources */
167 10 : for (size_t i = 0; i < wrh->num_coins; i++)
168 7 : TALER_blinded_denom_sig_free (&denom_sigs[i]);
169 : }
170 :
171 3 : return GNUNET_OK;
172 : }
173 :
174 :
175 : /**
176 : * Function called when we're done processing the
177 : * HTTP /reveal-withdraw request.
178 : *
179 : * @param cls the `struct TALER_EXCHANGE_PostRevealWithdrawHandle`
180 : * @param response_code The HTTP response code
181 : * @param response response data
182 : */
183 : static void
184 3 : handle_reveal_withdraw_finished (
185 : void *cls,
186 : long response_code,
187 : const void *response)
188 : {
189 3 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh = cls;
190 3 : const json_t *j_response = response;
191 3 : struct TALER_EXCHANGE_PostRevealWithdrawResponse awr = {
192 : .hr.reply = j_response,
193 3 : .hr.http_status = (unsigned int) response_code
194 : };
195 :
196 3 : wrh->job = NULL;
197 3 : switch (response_code)
198 : {
199 0 : case 0:
200 0 : awr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
201 0 : break;
202 3 : case MHD_HTTP_OK:
203 : {
204 : enum GNUNET_GenericReturnValue ret;
205 :
206 3 : ret = reveal_withdraw_ok (wrh,
207 : j_response);
208 3 : if (GNUNET_OK != ret)
209 : {
210 0 : GNUNET_break_op (0);
211 0 : awr.hr.http_status = 0;
212 0 : awr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
213 0 : break;
214 : }
215 3 : GNUNET_assert (NULL == wrh->callback);
216 3 : TALER_EXCHANGE_post_reveal_withdraw_cancel (wrh);
217 3 : return;
218 : }
219 0 : case MHD_HTTP_BAD_REQUEST:
220 : /* This should never happen, either us or the exchange is buggy
221 : (or API version conflict); just pass JSON reply to the application */
222 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
223 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
224 0 : break;
225 0 : case MHD_HTTP_NOT_FOUND:
226 : /* Nothing really to verify, the exchange basically just says
227 : that it doesn't know this age-withdraw commitment. */
228 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
229 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
230 0 : break;
231 0 : case MHD_HTTP_CONFLICT:
232 : /* An age commitment for one of the coins did not fulfill
233 : * the required maximum age requirement of the corresponding
234 : * reserve.
235 : * Error code: TALER_EC_EXCHANGE_GENERIC_COIN_AGE_REQUIREMENT_FAILURE
236 : * or TALER_EC_EXCHANGE_AGE_WITHDRAW_REVEAL_INVALID_HASH.
237 : */
238 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
239 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
240 0 : break;
241 0 : case MHD_HTTP_INTERNAL_SERVER_ERROR:
242 : /* Server had an internal issue; we should retry, but this API
243 : leaves this to the application */
244 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
245 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
246 0 : break;
247 0 : default:
248 : /* unexpected response code */
249 0 : GNUNET_break_op (0);
250 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
251 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
252 0 : GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
253 : "Unexpected response code %u/%d for exchange age-withdraw\n",
254 : (unsigned int) response_code,
255 : (int) awr.hr.ec);
256 0 : break;
257 : }
258 0 : wrh->callback (wrh->callback_cls,
259 : &awr);
260 0 : TALER_EXCHANGE_post_reveal_withdraw_cancel (wrh);
261 : }
262 :
263 :
264 : /**
265 : * Call /reveal-withdraw
266 : *
267 : * @param wrh The handler
268 : */
269 : static void
270 3 : perform_protocol (
271 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh)
272 : {
273 : CURL *curlh;
274 : json_t *j_array_of_secrets;
275 :
276 3 : j_array_of_secrets = json_array ();
277 3 : GNUNET_assert (NULL != j_array_of_secrets);
278 :
279 9 : for (uint8_t k = 0; k < TALER_CNC_KAPPA - 1; k++)
280 : {
281 6 : json_t *j_sec = GNUNET_JSON_from_data_auto (&wrh->seeds.tuple[k]);
282 6 : GNUNET_assert (NULL != j_sec);
283 6 : GNUNET_assert (0 == json_array_append_new (j_array_of_secrets,
284 : j_sec));
285 : }
286 : {
287 : json_t *j_request_body;
288 :
289 3 : j_request_body = GNUNET_JSON_PACK (
290 : GNUNET_JSON_pack_data_auto ("planchets_h",
291 : &wrh->planchets_h),
292 : GNUNET_JSON_pack_array_steal ("disclosed_batch_seeds",
293 : j_array_of_secrets));
294 3 : GNUNET_assert (NULL != j_request_body);
295 :
296 3 : curlh = TALER_EXCHANGE_curl_easy_get_ (wrh->request_url);
297 3 : GNUNET_assert (NULL != curlh);
298 3 : GNUNET_assert (GNUNET_OK ==
299 : TALER_curl_easy_post (&wrh->post_ctx,
300 : curlh,
301 : j_request_body));
302 :
303 3 : json_decref (j_request_body);
304 : }
305 :
306 6 : wrh->job = GNUNET_CURL_job_add2 (
307 : wrh->curl_ctx,
308 : curlh,
309 3 : wrh->post_ctx.headers,
310 : &handle_reveal_withdraw_finished,
311 : wrh);
312 3 : if (NULL == wrh->job)
313 : {
314 0 : GNUNET_break (0);
315 0 : if (NULL != curlh)
316 0 : curl_easy_cleanup (curlh);
317 : /* caller must call _cancel to free wrh */
318 : }
319 3 : }
320 :
321 :
322 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *
323 3 : TALER_EXCHANGE_post_reveal_withdraw_create (
324 : struct GNUNET_CURL_Context *curl_ctx,
325 : const char *exchange_url,
326 : size_t num_coins,
327 : const struct TALER_HashBlindedPlanchetsP *h_planchets,
328 : const struct TALER_RevealWithdrawMasterSeedsP *seeds)
329 : {
330 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh;
331 :
332 3 : wrh = GNUNET_new (struct TALER_EXCHANGE_PostRevealWithdrawHandle);
333 3 : wrh->curl_ctx = curl_ctx;
334 3 : wrh->exchange_url = GNUNET_strdup (exchange_url);
335 3 : wrh->num_coins = num_coins;
336 3 : wrh->planchets_h = *h_planchets;
337 3 : wrh->seeds = *seeds;
338 3 : return wrh;
339 : }
340 :
341 :
342 : enum TALER_ErrorCode
343 3 : TALER_EXCHANGE_post_reveal_withdraw_start (
344 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *prwh,
345 : TALER_EXCHANGE_PostRevealWithdrawCallback cb,
346 : TALER_EXCHANGE_POST_REVEAL_WITHDRAW_RESULT_CLOSURE *cb_cls)
347 : {
348 3 : prwh->callback = cb;
349 3 : prwh->callback_cls = cb_cls;
350 3 : prwh->request_url = TALER_url_join (prwh->exchange_url,
351 : "reveal-withdraw",
352 : NULL);
353 3 : if (NULL == prwh->request_url)
354 : {
355 0 : GNUNET_break (0);
356 0 : return TALER_EC_GENERIC_CONFIGURATION_INVALID;
357 : }
358 3 : perform_protocol (prwh);
359 3 : if (NULL == prwh->job)
360 : {
361 0 : GNUNET_break (0);
362 0 : return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
363 : }
364 3 : return TALER_EC_NONE;
365 : }
366 :
367 :
368 : void
369 3 : TALER_EXCHANGE_post_reveal_withdraw_cancel (
370 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *prwh)
371 : {
372 3 : if (NULL != prwh->job)
373 : {
374 0 : GNUNET_CURL_job_cancel (prwh->job);
375 0 : prwh->job = NULL;
376 : }
377 3 : TALER_curl_easy_post_finished (&prwh->post_ctx);
378 3 : GNUNET_free (prwh->request_url);
379 3 : GNUNET_free (prwh->exchange_url);
380 3 : GNUNET_free (prwh);
381 3 : }
382 :
383 :
384 : /* exchange_api_post-reveal-withdraw.c */
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