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