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.c
19 : * @brief Implementation of the /recoup request of the exchange's HTTP API
20 : * @author Christian Grothoff
21 : */
22 : #include "taler/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/taler_json_lib.h"
29 : #include "taler/taler_exchange_service.h"
30 : #include "exchange_api_common.h"
31 : #include "exchange_api_handle.h"
32 : #include "taler/taler_signatures.h"
33 : #include "exchange_api_curl_defaults.h"
34 :
35 :
36 : /**
37 : * @brief A Recoup Handle
38 : */
39 : struct TALER_EXCHANGE_RecoupHandle
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 : * Our signature requesting the recoup.
65 : */
66 : struct TALER_CoinSpendSignatureP coin_sig;
67 :
68 : /**
69 : * Handle for the request.
70 : */
71 : struct GNUNET_CURL_Job *job;
72 :
73 : /**
74 : * Function to call with the result.
75 : */
76 : TALER_EXCHANGE_RecoupResultCallback cb;
77 :
78 : /**
79 : * Closure for @a cb.
80 : */
81 : void *cb_cls;
82 :
83 : /**
84 : * Public key of the coin we are trying to get paid back.
85 : */
86 : struct TALER_CoinSpendPublicKeyP coin_pub;
87 :
88 : };
89 :
90 :
91 : /**
92 : * Parse a recoup 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 (const struct TALER_EXCHANGE_RecoupHandle *ph,
101 : const json_t *json)
102 : {
103 0 : struct TALER_EXCHANGE_RecoupResponse rr = {
104 : .hr.reply = json,
105 : .hr.http_status = MHD_HTTP_OK
106 : };
107 : struct GNUNET_JSON_Specification spec_withdraw[] = {
108 0 : GNUNET_JSON_spec_fixed_auto ("reserve_pub",
109 : &rr.details.ok.reserve_pub),
110 0 : GNUNET_JSON_spec_end ()
111 : };
112 :
113 0 : if (GNUNET_OK !=
114 0 : GNUNET_JSON_parse (json,
115 : spec_withdraw,
116 : NULL, NULL))
117 : {
118 0 : GNUNET_break_op (0);
119 0 : return GNUNET_SYSERR;
120 : }
121 0 : ph->cb (ph->cb_cls,
122 : &rr);
123 0 : return GNUNET_OK;
124 : }
125 :
126 :
127 : /**
128 : * Function called when we're done processing the
129 : * HTTP /recoup request.
130 : *
131 : * @param cls the `struct TALER_EXCHANGE_RecoupHandle`
132 : * @param response_code HTTP response code, 0 on error
133 : * @param response parsed JSON result, NULL on error
134 : */
135 : static void
136 0 : handle_recoup_finished (void *cls,
137 : long response_code,
138 : const void *response)
139 : {
140 0 : struct TALER_EXCHANGE_RecoupHandle *ph = cls;
141 0 : const json_t *j = response;
142 0 : struct TALER_EXCHANGE_RecoupResponse rr = {
143 : .hr.reply = j,
144 0 : .hr.http_status = (unsigned int) response_code
145 : };
146 :
147 0 : ph->job = NULL;
148 0 : switch (response_code)
149 : {
150 0 : case 0:
151 0 : rr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
152 0 : break;
153 0 : case MHD_HTTP_OK:
154 0 : if (GNUNET_OK !=
155 0 : process_recoup_response (ph,
156 : j))
157 : {
158 0 : GNUNET_break_op (0);
159 0 : rr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
160 0 : rr.hr.http_status = 0;
161 0 : break;
162 : }
163 0 : TALER_EXCHANGE_recoup_cancel (ph);
164 0 : return;
165 0 : case MHD_HTTP_BAD_REQUEST:
166 : /* This should never happen, either us or the exchange is buggy
167 : (or API version conflict); just pass JSON reply to the application */
168 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
169 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
170 0 : break;
171 0 : case MHD_HTTP_CONFLICT:
172 : {
173 : struct TALER_Amount min_key;
174 :
175 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
176 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
177 0 : if (GNUNET_OK !=
178 0 : TALER_EXCHANGE_get_min_denomination_ (ph->keys,
179 : &min_key))
180 : {
181 0 : GNUNET_break (0);
182 0 : rr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
183 0 : rr.hr.http_status = 0;
184 0 : break;
185 : }
186 0 : break;
187 : }
188 0 : case MHD_HTTP_FORBIDDEN:
189 : /* Nothing really to verify, exchange says one of the signatures is
190 : invalid; as we checked them, this should never happen, we
191 : should pass the JSON reply to the application */
192 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
193 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
194 0 : break;
195 0 : case MHD_HTTP_NOT_FOUND:
196 : /* Nothing really to verify, this should never
197 : happen, we should pass the JSON reply to the application */
198 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
199 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
200 0 : break;
201 0 : case MHD_HTTP_GONE:
202 : /* Kind of normal: the money was already sent to the merchant
203 : (it was too late for the refund). */
204 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
205 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
206 0 : break;
207 0 : case MHD_HTTP_INTERNAL_SERVER_ERROR:
208 : /* Server had an internal issue; we should retry, but this API
209 : leaves this to the application */
210 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
211 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
212 0 : break;
213 0 : default:
214 : /* unexpected response code */
215 0 : rr.hr.ec = TALER_JSON_get_error_code (j);
216 0 : rr.hr.hint = TALER_JSON_get_error_hint (j);
217 0 : GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
218 : "Unexpected response code %u/%d for exchange recoup\n",
219 : (unsigned int) response_code,
220 : (int) rr.hr.ec);
221 0 : GNUNET_break (0);
222 0 : break;
223 : }
224 0 : ph->cb (ph->cb_cls,
225 : &rr);
226 0 : TALER_EXCHANGE_recoup_cancel (ph);
227 : }
228 :
229 :
230 : struct TALER_EXCHANGE_RecoupHandle *
231 0 : TALER_EXCHANGE_recoup (
232 : struct GNUNET_CURL_Context *ctx,
233 : const char *url,
234 : struct TALER_EXCHANGE_Keys *keys,
235 : const struct TALER_EXCHANGE_DenomPublicKey *pk,
236 : const struct TALER_DenominationSignature *denom_sig,
237 : const struct TALER_ExchangeBlindingValues *blinding_values,
238 : const struct TALER_PlanchetMasterSecretP *ps,
239 : const struct TALER_HashBlindedPlanchetsP *h_planchets,
240 : TALER_EXCHANGE_RecoupResultCallback recoup_cb,
241 : void *recoup_cb_cls)
242 : {
243 : struct TALER_EXCHANGE_RecoupHandle *ph;
244 : struct TALER_DenominationHashP h_denom_pub;
245 : json_t *recoup_obj;
246 : CURL *eh;
247 : char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
248 : struct TALER_CoinSpendPrivateKeyP coin_priv;
249 : union GNUNET_CRYPTO_BlindingSecretP bks;
250 :
251 0 : ph = GNUNET_new (struct TALER_EXCHANGE_RecoupHandle);
252 0 : TALER_planchet_setup_coin_priv (ps,
253 : blinding_values,
254 : &coin_priv);
255 0 : TALER_planchet_blinding_secret_create (ps,
256 : blinding_values,
257 : &bks);
258 0 : GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv.eddsa_priv,
259 : &ph->coin_pub.eddsa_pub);
260 0 : TALER_denom_pub_hash (&pk->key,
261 : &h_denom_pub);
262 0 : TALER_wallet_recoup_sign (&h_denom_pub,
263 : &bks,
264 : &coin_priv,
265 : &ph->coin_sig);
266 0 : recoup_obj = GNUNET_JSON_PACK (
267 : GNUNET_JSON_pack_data_auto ("denom_pub_hash",
268 : &h_denom_pub),
269 : TALER_JSON_pack_denom_sig ("denom_sig",
270 : denom_sig),
271 : TALER_JSON_pack_exchange_blinding_values ("ewv",
272 : blinding_values),
273 : GNUNET_JSON_pack_data_auto ("coin_sig",
274 : &ph->coin_sig),
275 : GNUNET_JSON_pack_data_auto ("h_planchets",
276 : h_planchets),
277 : GNUNET_JSON_pack_data_auto ("coin_blind_key_secret",
278 : &bks));
279 0 : switch (denom_sig->unblinded_sig->cipher)
280 : {
281 0 : case GNUNET_CRYPTO_BSA_INVALID:
282 0 : json_decref (recoup_obj);
283 0 : GNUNET_break (0);
284 0 : GNUNET_free (ph);
285 0 : return NULL;
286 0 : case GNUNET_CRYPTO_BSA_RSA:
287 0 : break;
288 0 : case GNUNET_CRYPTO_BSA_CS:
289 : {
290 : union GNUNET_CRYPTO_BlindSessionNonce nonce;
291 :
292 : /* NOTE: this is not elegant, and as per the note in TALER_coin_ev_hash()
293 : it is not strictly clear that the nonce is needed. Best case would be
294 : to find a way to include it more 'naturally' somehow, for example with
295 : the variant union version of bks! */
296 0 : TALER_cs_withdraw_nonce_derive (ps,
297 : &nonce.cs_nonce);
298 0 : GNUNET_assert (
299 : 0 ==
300 : json_object_set_new (recoup_obj,
301 : "nonce",
302 : GNUNET_JSON_from_data_auto (
303 : &nonce)));
304 : }
305 : }
306 :
307 : {
308 : char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
309 : char *end;
310 :
311 0 : end = GNUNET_STRINGS_data_to_string (
312 0 : &ph->coin_pub,
313 : sizeof (struct TALER_CoinSpendPublicKeyP),
314 : pub_str,
315 : sizeof (pub_str));
316 0 : *end = '\0';
317 0 : GNUNET_snprintf (arg_str,
318 : sizeof (arg_str),
319 : "coins/%s/recoup",
320 : pub_str);
321 : }
322 :
323 0 : ph->pk = *pk;
324 0 : memset (&ph->pk.key,
325 : 0,
326 : sizeof (ph->pk.key)); /* zero out, as lifetime cannot be warranted */
327 0 : ph->cb = recoup_cb;
328 0 : ph->cb_cls = recoup_cb_cls;
329 0 : ph->url = TALER_url_join (url,
330 : arg_str,
331 : NULL);
332 0 : if (NULL == ph->url)
333 : {
334 0 : json_decref (recoup_obj);
335 0 : GNUNET_free (ph);
336 0 : return NULL;
337 : }
338 0 : eh = TALER_EXCHANGE_curl_easy_get_ (ph->url);
339 0 : if ( (NULL == eh) ||
340 : (GNUNET_OK !=
341 0 : TALER_curl_easy_post (&ph->ctx,
342 : eh,
343 : recoup_obj)) )
344 : {
345 0 : GNUNET_break (0);
346 0 : if (NULL != eh)
347 0 : curl_easy_cleanup (eh);
348 0 : json_decref (recoup_obj);
349 0 : GNUNET_free (ph->url);
350 0 : GNUNET_free (ph);
351 0 : return NULL;
352 : }
353 0 : json_decref (recoup_obj);
354 0 : GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
355 : "URL for recoup: `%s'\n",
356 : ph->url);
357 0 : ph->keys = TALER_EXCHANGE_keys_incref (keys);
358 0 : ph->job = GNUNET_CURL_job_add2 (ctx,
359 : eh,
360 0 : ph->ctx.headers,
361 : &handle_recoup_finished,
362 : ph);
363 0 : return ph;
364 : }
365 :
366 :
367 : void
368 0 : TALER_EXCHANGE_recoup_cancel (struct TALER_EXCHANGE_RecoupHandle *ph)
369 : {
370 0 : if (NULL != ph->job)
371 : {
372 0 : GNUNET_CURL_job_cancel (ph->job);
373 0 : ph->job = NULL;
374 : }
375 0 : GNUNET_free (ph->url);
376 0 : TALER_curl_easy_post_finished (&ph->ctx);
377 0 : TALER_EXCHANGE_keys_decref (ph->keys);
378 0 : GNUNET_free (ph);
379 0 : }
380 :
381 :
382 : /* end of exchange_api_recoup.c */
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