summaryrefslogtreecommitdiff
path: root/src/exchange/taler-exchange-httpd_deposit.c
blob: ac854de68372a13f1633b3d4eb4f97b8bbff3ffb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
/*
  This file is part of TALER
  Copyright (C) 2014-2020 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file taler-exchange-httpd_deposit.c
 * @brief Handle /deposit requests; parses the POST and JSON and
 *        verifies the coin signature before handing things off
 *        to the database.
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <jansson.h>
#include <microhttpd.h>
#include <pthread.h>
#include "taler_json_lib.h"
#include "taler_mhd_lib.h"
#include "taler-exchange-httpd_deposit.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keystate.h"


/**
 * Send confirmation of deposit success to client.  This function
 * will create a signed message affirming the given information
 * and return it to the client.  By this, the exchange affirms that
 * the coin had sufficient (residual) value for the specified
 * transaction and that it will execute the requested deposit
 * operation with the given wiring details.
 *
 * @param connection connection to the client
 * @param coin_pub public key of the coin
 * @param h_wire hash of wire details
 * @param h_contract_terms hash of contract details
 * @param timestamp client's timestamp
 * @param refund_deadline until when this deposit be refunded
 * @param merchant merchant public key
 * @param amount_without_fee fraction of coin value to deposit, without the fee
 * @return MHD result code
 */
static int
reply_deposit_success (struct MHD_Connection *connection,
                       const struct TALER_CoinSpendPublicKeyP *coin_pub,
                       const struct GNUNET_HashCode *h_wire,
                       const struct GNUNET_HashCode *h_contract_terms,
                       struct GNUNET_TIME_Absolute timestamp,
                       struct GNUNET_TIME_Absolute refund_deadline,
                       const struct TALER_MerchantPublicKeyP *merchant,
                       const struct TALER_Amount *amount_without_fee)
{
  struct TALER_ExchangePublicKeyP pub;
  struct TALER_ExchangeSignatureP sig;
  struct TALER_DepositConfirmationPS dc = {
    .purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT),
    .purpose.size = htonl (sizeof (dc)),
    .h_contract_terms = *h_contract_terms,
    .h_wire = *h_wire,
    .timestamp = GNUNET_TIME_absolute_hton (timestamp),
    .refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline),
    .coin_pub = *coin_pub,
    .merchant = *merchant
  };

  TALER_amount_hton (&dc.amount_without_fee,
                     amount_without_fee);
  if (GNUNET_OK !=
      TEH_KS_sign (&dc,
                   &pub,
                   &sig))
  {
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
                                       "no keys");
  }
  return TALER_MHD_reply_json_pack (connection,
                                    MHD_HTTP_OK,
                                    "{s:s, s:o, s:o}",
                                    "status", "DEPOSIT_OK",
                                    "sig", GNUNET_JSON_from_data_auto (&sig),
                                    "pub", GNUNET_JSON_from_data_auto (&pub));
}


/**
 * Closure for #deposit_transaction.
 */
struct DepositContext
{
  /**
   * Information about the deposit request.
   */
  const struct TALER_EXCHANGEDB_Deposit *deposit;

  /**
   * Value of the coin.
   */
  struct TALER_Amount value;

};


/**
 * Execute database transaction for /deposit.  Runs the transaction
 * logic; IF it returns a non-error code, the transaction logic MUST
 * NOT queue a MHD response.  IF it returns an hard error, the
 * transaction logic MUST queue a MHD response and set @a mhd_ret.  IF
 * it returns the soft error code, the function MAY be called again to
 * retry and MUST not queue a MHD response.
 *
 * @param cls a `struct DepositContext`
 * @param connection MHD request context
 * @param session database session and transaction to use
 * @param[out] mhd_ret set to MHD status on error
 * @return transaction status
 */
static enum GNUNET_DB_QueryStatus
deposit_transaction (void *cls,
                     struct MHD_Connection *connection,
                     struct TALER_EXCHANGEDB_Session *session,
                     int *mhd_ret)
{
  struct DepositContext *dc = cls;
  const struct TALER_EXCHANGEDB_Deposit *deposit = dc->deposit;
  struct TALER_Amount spent;
  enum GNUNET_DB_QueryStatus qs;

  qs = TEH_plugin->have_deposit (TEH_plugin->cls,
                                 session,
                                 deposit,
                                 GNUNET_YES /* check refund deadline */);
  if (qs < 0)
  {
    if (GNUNET_DB_STATUS_HARD_ERROR == qs)
    {
      *mhd_ret = TALER_MHD_reply_with_error (connection,
                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
                                             TALER_EC_DEPOSIT_HISTORY_DB_ERROR,
                                             "Could not check for existing identical deposit");
      return GNUNET_DB_STATUS_HARD_ERROR;
    }
    return qs;
  }
  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
  {
    struct TALER_Amount amount_without_fee;

    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "/deposit replay, accepting again!\n");
    GNUNET_assert (GNUNET_OK ==
                   TALER_amount_subtract (&amount_without_fee,
                                          &deposit->amount_with_fee,
                                          &deposit->deposit_fee));
    *mhd_ret = reply_deposit_success (connection,
                                      &deposit->coin.coin_pub,
                                      &deposit->h_wire,
                                      &deposit->h_contract_terms,
                                      deposit->timestamp,
                                      deposit->refund_deadline,
                                      &deposit->merchant_pub,
                                      &amount_without_fee);
    /* Treat as 'hard' DB error as we want to rollback and
       never try again. */
    return GNUNET_DB_STATUS_HARD_ERROR;
  }

  /* Start with fee for THIS transaction */
  spent = deposit->amount_with_fee;
  /* add cost of all previous transactions; skip RECOUP as revoked
     denominations are not eligible for deposit, and if we are the old coin
     pub of a revoked coin (aka a zombie), then ONLY refresh is allowed. */
  {
    struct TALER_EXCHANGEDB_TransactionList *tl;

    qs = TEH_plugin->get_coin_transactions (TEH_plugin->cls,
                                            session,
                                            &deposit->coin.coin_pub,
                                            GNUNET_NO,
                                            &tl);
    if (0 > qs)
    {
      if (GNUNET_DB_STATUS_HARD_ERROR == qs)
        *mhd_ret = TALER_MHD_reply_with_error (
          connection,
          MHD_HTTP_INTERNAL_SERVER_ERROR,
          TALER_EC_DEPOSIT_HISTORY_DB_ERROR,
          "could not fetch coin transaction history");
      return qs;
    }
    if (GNUNET_OK !=
        TALER_EXCHANGEDB_calculate_transaction_list_totals (tl,
                                                            &spent, /* starting offset */
                                                            &spent /* result */))
    {
      TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                              tl);
      *mhd_ret = TALER_MHD_reply_with_error (
        connection,
        MHD_HTTP_INTERNAL_SERVER_ERROR,
        TALER_EC_DEPOSIT_HISTORY_DB_ERROR,
        "could not calculate historic coin amount total");
      return GNUNET_DB_STATUS_HARD_ERROR;
    }
    /* Check that cost of all transactions (including the current one) is
       smaller (or equal) than the value of the coin. */
    if (0 < TALER_amount_cmp (&spent,
                              &dc->value))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Deposited coin has insufficient funds left!\n");
      *mhd_ret = TEH_RESPONSE_reply_coin_insufficient_funds (connection,
                                                             TALER_EC_DEPOSIT_INSUFFICIENT_FUNDS,
                                                             &deposit->coin.
                                                             coin_pub,
                                                             tl);
      TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                              tl);
      return GNUNET_DB_STATUS_HARD_ERROR;
    }
    TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                            tl);
  }
  qs = TEH_plugin->insert_deposit (TEH_plugin->cls,
                                   session,
                                   deposit);
  if (GNUNET_DB_STATUS_HARD_ERROR == qs)
  {
    TALER_LOG_WARNING ("Failed to store /deposit information in database\n");
    *mhd_ret = TALER_MHD_reply_with_error (connection,
                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
                                           TALER_EC_DEPOSIT_STORE_DB_ERROR,
                                           "Could not persist /deposit data");
  }
  return qs;
}


/**
 * Check that @a ts is reasonably close to our own RTC.
 *
 * @param ts timestamp to check
 * @return #GNUNET_OK if @a ts is reasonable
 */
static int
check_timestamp_current (struct GNUNET_TIME_Absolute ts)
{
  struct GNUNET_TIME_Relative r;
  struct GNUNET_TIME_Relative tolerance;

  /* Let's be VERY generous (after all, this is basically about
     which year the deposit counts for in terms of tax purposes) */
  tolerance = GNUNET_TIME_UNIT_MONTHS;
  r = GNUNET_TIME_absolute_get_duration (ts);
  if (r.rel_value_us > tolerance.rel_value_us)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Deposit timestamp too old: %llu vs %llu > %llu\n",
                (unsigned long long) ts.abs_value_us,
                (unsigned long long) GNUNET_TIME_absolute_get ().abs_value_us,
                (unsigned long long) tolerance.rel_value_us);
    return GNUNET_SYSERR;
  }
  r = GNUNET_TIME_absolute_get_remaining (ts);
  if (r.rel_value_us > tolerance.rel_value_us)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Deposit timestamp too new: %llu vs %llu < - %llu\n",
                (unsigned long long) ts.abs_value_us,
                (unsigned long long) GNUNET_TIME_absolute_get ().abs_value_us,
                (unsigned long long) tolerance.rel_value_us);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Handle a "/coins/$COIN_PUB/deposit" request.  Parses the JSON, and, if
 * successful, passes the JSON data to #deposit_transaction() to
 * further check the details of the operation specified.  If everything checks
 * out, this will ultimately lead to the "/deposit" being executed, or
 * rejected.
 *
 * @param connection the MHD connection to handle
 * @param coin_pub public key of the coin
 * @param root uploaded JSON data
 * @return MHD result code
  */
int
TEH_handler_deposit (struct MHD_Connection *connection,
                     const struct TALER_CoinSpendPublicKeyP *coin_pub,
                     const json_t *root)
{
  json_t *wire;
  struct DepositContext dc;
  struct TALER_EXCHANGEDB_Deposit deposit;
  struct GNUNET_HashCode my_h_wire;
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_json ("wire", &wire),
    TALER_JSON_spec_amount ("contribution", &deposit.amount_with_fee),
    GNUNET_JSON_spec_fixed_auto ("denom_pub_hash",
                                 &deposit.coin.denom_pub_hash),
    TALER_JSON_spec_denomination_signature ("ub_sig", &deposit.coin.denom_sig),
    GNUNET_JSON_spec_fixed_auto ("merchant_pub", &deposit.merchant_pub),
    GNUNET_JSON_spec_fixed_auto ("h_contract_terms", &deposit.h_contract_terms),
    GNUNET_JSON_spec_fixed_auto ("h_wire", &deposit.h_wire),
    GNUNET_JSON_spec_fixed_auto ("coin_sig",  &deposit.csig),
    GNUNET_JSON_spec_absolute_time ("timestamp", &deposit.timestamp),
    GNUNET_JSON_spec_absolute_time ("refund_deadline",
                                    &deposit.refund_deadline),
    GNUNET_JSON_spec_absolute_time ("wire_transfer_deadline",
                                    &deposit.wire_deadline),
    GNUNET_JSON_spec_end ()
  };

  memset (&deposit,
          0,
          sizeof (deposit));
  deposit.coin.coin_pub = *coin_pub;
  {
    int res;

    res = TALER_MHD_parse_json_data (connection,
                                     root,
                                     spec);
    if (GNUNET_SYSERR == res)
    {
      GNUNET_break (0);
      return MHD_NO; /* hard failure */
    }
    if (GNUNET_NO == res)
    {
      GNUNET_break_op (0);
      return MHD_YES; /* failure */
    }
  }
  deposit.receiver_wire_account = wire;
  if (deposit.refund_deadline.abs_value_us > deposit.wire_deadline.abs_value_us)
  {
    GNUNET_break_op (0);
    GNUNET_JSON_parse_free (spec);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_DEPOSIT_REFUND_DEADLINE_AFTER_WIRE_DEADLINE,
                                       "refund_deadline");
  }

  if (GNUNET_OK !=
      check_timestamp_current (deposit.timestamp))
  {
    GNUNET_break_op (0);
    GNUNET_JSON_parse_free (spec);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_DEPOSIT_INVALID_TIMESTAMP,
                                       "timestamp");
  }
  if (GNUNET_OK !=
      TALER_JSON_merchant_wire_signature_hash (wire,
                                               &my_h_wire))
  {
    TALER_LOG_WARNING (
      "Failed to parse JSON wire format specification for /deposit request\n");
    GNUNET_JSON_parse_free (spec);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON,
                                       "wire");
  }
  if (0 != GNUNET_memcmp (&deposit.h_wire,
                          &my_h_wire))
  {
    /* Client hashed wire details differently than we did, reject */
    GNUNET_JSON_parse_free (spec);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_CONTRACT_HASH_CONFLICT,
                                       "h_wire");
  }

  /* check denomination exists and is valid */
  {
    struct TEH_KS_StateHandle *key_state;
    struct TALER_EXCHANGEDB_DenominationKey *dki;
    enum TALER_ErrorCode ec;
    unsigned int hc;

    key_state = TEH_KS_acquire (GNUNET_TIME_absolute_get ());
    if (NULL == key_state)
    {
      TALER_LOG_ERROR ("Lacking keys to operate\n");
      GNUNET_JSON_parse_free (spec);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
                                         TALER_EC_EXCHANGE_BAD_CONFIGURATION,
                                         "no keys");
    }
    dki = TEH_KS_denomination_key_lookup_by_hash (key_state,
                                                  &deposit.coin.denom_pub_hash,
                                                  TEH_KS_DKU_DEPOSIT,
                                                  &ec,
                                                  &hc);
    if (NULL == dki)
    {
      TALER_LOG_DEBUG ("Unknown denomination key in /deposit request\n");
      TEH_KS_release (key_state);
      GNUNET_JSON_parse_free (spec);
      return TALER_MHD_reply_with_error (connection,
                                         hc,
                                         ec,
                                         "Could not find denomination key used in deposit");
    }
    TALER_amount_ntoh (&deposit.deposit_fee,
                       &dki->issue.properties.fee_deposit);
    if (GNUNET_YES !=
        TALER_amount_cmp_currency (&deposit.amount_with_fee,
                                   &deposit.deposit_fee) )
    {
      GNUNET_break_op (0);
      TEH_KS_release (key_state);
      GNUNET_JSON_parse_free (spec);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_BAD_REQUEST,
                                         TALER_EC_DEPOSIT_CURRENCY_MISMATCH,
                                         "contribution");
    }
    /* check coin signature */
    if (GNUNET_YES !=
        TALER_test_coin_valid (&deposit.coin,
                               &dki->denom_pub))
    {
      TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
      TEH_KS_release (key_state);
      GNUNET_JSON_parse_free (spec);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_UNAUTHORIZED,
                                         TALER_EC_DEPOSIT_DENOMINATION_SIGNATURE_INVALID,
                                         "ub_sig");
    }
    TALER_amount_ntoh (&deposit.deposit_fee,
                       &dki->issue.properties.fee_deposit);
    TALER_amount_ntoh (&dc.value,
                       &dki->issue.properties.value);
    TEH_KS_release (key_state);
  }
  if (0 < TALER_amount_cmp (&deposit.deposit_fee,
                            &deposit.amount_with_fee))
  {
    GNUNET_break_op (0);
    GNUNET_JSON_parse_free (spec);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_DEPOSIT_NEGATIVE_VALUE_AFTER_FEE,
                                       "deposited amount smaller than depositing fee");
  }

  /* make sure coin is 'known' in database */
  {
    int mhd_ret;
    struct TEH_DB_KnowCoinContext kcc = {
      .coin = &deposit.coin,
      .connection = connection
    };

    if (GNUNET_OK !=
        TEH_DB_run_transaction (connection,
                                "know coin for deposit",
                                &mhd_ret,
                                &TEH_DB_know_coin_transaction,
                                &kcc))
    {
      GNUNET_JSON_parse_free (spec);
      return mhd_ret;
    }
  }

  /* check deposit signature */
  {
    struct TALER_DepositRequestPS dr = {
      .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_DEPOSIT),
      .purpose.size = htonl (sizeof (dr)),
      .h_contract_terms = deposit.h_contract_terms,
      .h_wire = deposit.h_wire,
      .timestamp = GNUNET_TIME_absolute_hton (deposit.timestamp),
      .refund_deadline = GNUNET_TIME_absolute_hton (deposit.refund_deadline),
      .merchant = deposit.merchant_pub,
      .coin_pub = deposit.coin.coin_pub
    };

    TALER_amount_hton (&dr.amount_with_fee,
                       &deposit.amount_with_fee);
    TALER_amount_hton (&dr.deposit_fee,
                       &deposit.deposit_fee);
    if (GNUNET_OK !=
        GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT,
                                    &dr,
                                    &deposit.csig.eddsa_signature,
                                    &deposit.coin.coin_pub.eddsa_pub))
    {
      TALER_LOG_WARNING ("Invalid signature on /deposit request\n");
      GNUNET_JSON_parse_free (spec);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_UNAUTHORIZED,
                                         TALER_EC_DEPOSIT_COIN_SIGNATURE_INVALID,
                                         "coin_sig");
    }
  }

  /* execute transaction */
  dc.deposit = &deposit;
  {
    int mhd_ret;

    if (GNUNET_OK !=
        TEH_DB_run_transaction (connection,
                                "execute deposit",
                                &mhd_ret,
                                &deposit_transaction,
                                &dc))
    {
      GNUNET_JSON_parse_free (spec);
      return mhd_ret;
    }
  }

  /* generate regular response */
  {
    struct TALER_Amount amount_without_fee;
    int res;

    GNUNET_assert (GNUNET_SYSERR !=
                   TALER_amount_subtract (&amount_without_fee,
                                          &deposit.amount_with_fee,
                                          &deposit.deposit_fee));
    res = reply_deposit_success (connection,
                                 &deposit.coin.coin_pub,
                                 &deposit.h_wire,
                                 &deposit.h_contract_terms,
                                 deposit.timestamp,
                                 deposit.refund_deadline,
                                 &deposit.merchant_pub,
                                 &amount_without_fee);
    GNUNET_JSON_parse_free (spec);
    return res;
  }
}


/* end of taler-exchange-httpd_deposit.c */