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 reserve the previous call to withdraw was made from
44 : */
45 : struct TALER_ReservePublicKeyP reserve_pub;
46 :
47 : /**
48 : * The commitment from the previous call to withdraw
49 : */
50 : struct TALER_HashBlindedPlanchetsP planchets_h;
51 :
52 : /**
53 : * Number of coins for which to reveal tuples of seeds
54 : */
55 : size_t num_coins;
56 :
57 : /**
58 : * The TALER_CNC_KAPPA-1 tuple of seeds to reveal
59 : */
60 : struct TALER_RevealWithdrawMasterSeedsP seeds;
61 :
62 : /**
63 : * The exchange base URL.
64 : */
65 : char *exchange_url;
66 :
67 : /**
68 : * The url for the reveal request
69 : */
70 : char *request_url;
71 :
72 : /**
73 : * The curl context
74 : */
75 : struct GNUNET_CURL_Context *curl_ctx;
76 :
77 : /**
78 : * CURL handle for the request job.
79 : */
80 : struct GNUNET_CURL_Job *job;
81 :
82 : /**
83 : * Post Context
84 : */
85 : struct TALER_CURL_PostContext post_ctx;
86 :
87 : /**
88 : * Callback to pass the result to
89 : */
90 : TALER_EXCHANGE_PostRevealWithdrawCallback callback;
91 :
92 : /**
93 : * Closure for @e callback
94 : */
95 : void *callback_cls;
96 : };
97 :
98 :
99 : /**
100 : * We got a 200 OK response for the /reveal-withdraw operation.
101 : * Extract the signed blinded coins and return it to the caller.
102 : *
103 : * @param wrh operation handle
104 : * @param j_response reply from the exchange
105 : * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
106 : */
107 : static enum GNUNET_GenericReturnValue
108 3 : reveal_withdraw_ok (
109 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh,
110 : const json_t *j_response)
111 : {
112 3 : struct TALER_EXCHANGE_PostRevealWithdrawResponse response = {
113 : .hr.reply = j_response,
114 : .hr.http_status = MHD_HTTP_OK,
115 : };
116 : const json_t *j_sigs;
117 : struct GNUNET_JSON_Specification spec[] = {
118 3 : GNUNET_JSON_spec_array_const ("ev_sigs",
119 : &j_sigs),
120 3 : GNUNET_JSON_spec_end ()
121 : };
122 :
123 3 : if (GNUNET_OK !=
124 3 : GNUNET_JSON_parse (j_response,
125 : spec,
126 : NULL, NULL))
127 : {
128 0 : GNUNET_break_op (0);
129 0 : return GNUNET_SYSERR;
130 : }
131 :
132 3 : if (wrh->num_coins != json_array_size (j_sigs))
133 : {
134 : /* Number of coins generated does not match our expectation */
135 0 : GNUNET_break_op (0);
136 0 : return GNUNET_SYSERR;
137 : }
138 :
139 3 : {
140 3 : struct TALER_BlindedDenominationSignature denom_sigs[wrh->num_coins];
141 : json_t *j_sig;
142 : size_t n;
143 :
144 : /* Reconstruct the coins and unblind the signatures */
145 10 : json_array_foreach (j_sigs, n, j_sig)
146 : {
147 : struct GNUNET_JSON_Specification ispec[] = {
148 7 : TALER_JSON_spec_blinded_denom_sig (NULL,
149 : &denom_sigs[n]),
150 7 : GNUNET_JSON_spec_end ()
151 : };
152 :
153 7 : if (GNUNET_OK !=
154 7 : GNUNET_JSON_parse (j_sig,
155 : ispec,
156 : NULL, NULL))
157 : {
158 0 : GNUNET_break_op (0);
159 0 : for (size_t k = 0; k < n; k++)
160 0 : TALER_blinded_denom_sig_free (&denom_sigs[k]);
161 0 : return GNUNET_SYSERR;
162 : }
163 : }
164 :
165 3 : response.details.ok.num_sigs = wrh->num_coins;
166 3 : response.details.ok.blinded_denom_sigs = denom_sigs;
167 3 : wrh->callback (wrh->callback_cls,
168 : &response);
169 : /* Make sure the callback isn't called again */
170 3 : wrh->callback = NULL;
171 : /* Free resources */
172 10 : for (size_t i = 0; i < wrh->num_coins; i++)
173 7 : TALER_blinded_denom_sig_free (&denom_sigs[i]);
174 : }
175 :
176 3 : return GNUNET_OK;
177 : }
178 :
179 :
180 : /**
181 : * Function called when we're done processing the
182 : * HTTP /reveal-withdraw request.
183 : *
184 : * @param cls the `struct TALER_EXCHANGE_PostRevealWithdrawHandle`
185 : * @param response_code The HTTP response code
186 : * @param response response data
187 : */
188 : static void
189 3 : handle_reveal_withdraw_finished (
190 : void *cls,
191 : long response_code,
192 : const void *response)
193 : {
194 3 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh = cls;
195 3 : const json_t *j_response = response;
196 3 : struct TALER_EXCHANGE_PostRevealWithdrawResponse awr = {
197 : .hr.reply = j_response,
198 3 : .hr.http_status = (unsigned int) response_code
199 : };
200 :
201 3 : wrh->job = NULL;
202 3 : switch (response_code)
203 : {
204 0 : case 0:
205 0 : awr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
206 0 : break;
207 3 : case MHD_HTTP_OK:
208 : {
209 : enum GNUNET_GenericReturnValue ret;
210 :
211 3 : ret = reveal_withdraw_ok (wrh,
212 : j_response);
213 3 : if (GNUNET_OK != ret)
214 : {
215 0 : GNUNET_break_op (0);
216 0 : awr.hr.http_status = 0;
217 0 : awr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
218 0 : break;
219 : }
220 3 : GNUNET_assert (NULL == wrh->callback);
221 3 : TALER_EXCHANGE_post_reveal_withdraw_cancel (wrh);
222 3 : return;
223 : }
224 0 : case MHD_HTTP_BAD_REQUEST:
225 : /* This should never happen, either us or the exchange is buggy
226 : (or API version conflict); just pass JSON reply to the application */
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_NOT_FOUND:
231 : /* Nothing really to verify, the exchange basically just says
232 : that it doesn't know this age-withdraw commitment. */
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 : case MHD_HTTP_CONFLICT:
237 : /* An age commitment for one of the coins did not fulfill
238 : * the required maximum age requirement of the corresponding
239 : * reserve.
240 : * Error code: TALER_EC_EXCHANGE_GENERIC_COIN_AGE_REQUIREMENT_FAILURE
241 : * or TALER_EC_EXCHANGE_AGE_WITHDRAW_REVEAL_INVALID_HASH.
242 : */
243 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
244 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
245 0 : break;
246 0 : case MHD_HTTP_INTERNAL_SERVER_ERROR:
247 : /* Server had an internal issue; we should retry, but this API
248 : leaves this to the application */
249 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
250 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
251 0 : break;
252 0 : default:
253 : /* unexpected response code */
254 0 : GNUNET_break_op (0);
255 0 : awr.hr.ec = TALER_JSON_get_error_code (j_response);
256 0 : awr.hr.hint = TALER_JSON_get_error_hint (j_response);
257 0 : GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
258 : "Unexpected response code %u/%d for exchange age-withdraw\n",
259 : (unsigned int) response_code,
260 : (int) awr.hr.ec);
261 0 : break;
262 : }
263 0 : wrh->callback (wrh->callback_cls,
264 : &awr);
265 0 : TALER_EXCHANGE_post_reveal_withdraw_cancel (wrh);
266 : }
267 :
268 :
269 : /**
270 : * Call /reveal-withdraw
271 : *
272 : * @param wrh The handler
273 : */
274 : static void
275 3 : perform_protocol (
276 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh)
277 : {
278 : CURL *curlh;
279 : json_t *j_array_of_secrets;
280 :
281 3 : j_array_of_secrets = json_array ();
282 3 : GNUNET_assert (NULL != j_array_of_secrets);
283 :
284 9 : for (uint8_t k = 0; k < TALER_CNC_KAPPA - 1; k++)
285 : {
286 6 : json_t *j_sec = GNUNET_JSON_from_data_auto (&wrh->seeds.tuple[k]);
287 6 : GNUNET_assert (NULL != j_sec);
288 6 : GNUNET_assert (0 == json_array_append_new (j_array_of_secrets,
289 : j_sec));
290 : }
291 : {
292 : json_t *j_request_body;
293 :
294 3 : j_request_body = GNUNET_JSON_PACK (
295 : GNUNET_JSON_pack_data_auto ("reserve_pub",
296 : &wrh->reserve_pub),
297 : GNUNET_JSON_pack_data_auto ("planchets_h",
298 : &wrh->planchets_h),
299 : GNUNET_JSON_pack_array_steal ("disclosed_batch_seeds",
300 : j_array_of_secrets));
301 3 : GNUNET_assert (NULL != j_request_body);
302 :
303 3 : curlh = TALER_EXCHANGE_curl_easy_get_ (wrh->request_url);
304 3 : GNUNET_assert (NULL != curlh);
305 3 : GNUNET_assert (GNUNET_OK ==
306 : TALER_curl_easy_post (&wrh->post_ctx,
307 : curlh,
308 : j_request_body));
309 :
310 3 : json_decref (j_request_body);
311 : }
312 :
313 6 : wrh->job = GNUNET_CURL_job_add2 (
314 : wrh->curl_ctx,
315 : curlh,
316 3 : wrh->post_ctx.headers,
317 : &handle_reveal_withdraw_finished,
318 : wrh);
319 3 : if (NULL == wrh->job)
320 : {
321 0 : GNUNET_break (0);
322 0 : if (NULL != curlh)
323 0 : curl_easy_cleanup (curlh);
324 : /* caller must call _cancel to free wrh */
325 : }
326 3 : }
327 :
328 :
329 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *
330 3 : TALER_EXCHANGE_post_reveal_withdraw_create (
331 : struct GNUNET_CURL_Context *curl_ctx,
332 : const char *exchange_url,
333 : size_t num_coins,
334 : const struct TALER_ReservePublicKeyP *reserve_pub,
335 : const struct TALER_HashBlindedPlanchetsP *h_planchets,
336 : const struct TALER_RevealWithdrawMasterSeedsP *seeds)
337 : {
338 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *wrh;
339 :
340 3 : wrh = GNUNET_new (struct TALER_EXCHANGE_PostRevealWithdrawHandle);
341 3 : wrh->curl_ctx = curl_ctx;
342 3 : wrh->exchange_url = GNUNET_strdup (exchange_url);
343 3 : wrh->num_coins = num_coins;
344 3 : wrh->reserve_pub = *reserve_pub;
345 3 : wrh->planchets_h = *h_planchets;
346 3 : wrh->seeds = *seeds;
347 3 : return wrh;
348 : }
349 :
350 :
351 : enum TALER_ErrorCode
352 3 : TALER_EXCHANGE_post_reveal_withdraw_start (
353 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *prwh,
354 : TALER_EXCHANGE_PostRevealWithdrawCallback cb,
355 : TALER_EXCHANGE_POST_REVEAL_WITHDRAW_RESULT_CLOSURE *cb_cls)
356 : {
357 3 : prwh->callback = cb;
358 3 : prwh->callback_cls = cb_cls;
359 3 : prwh->request_url = TALER_url_join (prwh->exchange_url,
360 : "reveal-withdraw",
361 : NULL);
362 3 : if (NULL == prwh->request_url)
363 : {
364 0 : GNUNET_break (0);
365 0 : return TALER_EC_GENERIC_CONFIGURATION_INVALID;
366 : }
367 3 : perform_protocol (prwh);
368 3 : if (NULL == prwh->job)
369 : {
370 0 : GNUNET_break (0);
371 0 : return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
372 : }
373 3 : return TALER_EC_NONE;
374 : }
375 :
376 :
377 : void
378 3 : TALER_EXCHANGE_post_reveal_withdraw_cancel (
379 : struct TALER_EXCHANGE_PostRevealWithdrawHandle *prwh)
380 : {
381 3 : if (NULL != prwh->job)
382 : {
383 0 : GNUNET_CURL_job_cancel (prwh->job);
384 0 : prwh->job = NULL;
385 : }
386 3 : TALER_curl_easy_post_finished (&prwh->post_ctx);
387 3 : GNUNET_free (prwh->request_url);
388 3 : GNUNET_free (prwh->exchange_url);
389 3 : GNUNET_free (prwh);
390 3 : }
391 :
392 :
393 : /* exchange_api_post-reveal-withdraw.c */
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