aboutsummaryrefslogtreecommitdiff
path: root/src/exchangedb/exchangedb_denomkeys.c
blob: 58d9519c6f4bb7f1b3e0759ff6ac6fca79a84d0a (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
/*
  This file is part of TALER
  Copyright (C) 2014-2019 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU 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 General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file exchangedb/exchangedb_denomkeys.c
 * @brief I/O operations for the Exchange's denomination private keys
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Sree Harsha Totakura
 * @author Christian Grothoff
 */
#include "platform.h"
#include "taler_exchangedb_lib.h"


GNUNET_NETWORK_STRUCT_BEGIN

/**
 * Contents of a file with a revocation certificate.
 */
struct RevocationFileP
{

  /**
   * Hash of the denomination public key being revoked.
   */
  struct GNUNET_HashCode denom_hash;

  /**
   * Master signature over the revocation, must match purpose
   * #TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED.
   */
  struct TALER_MasterSignatureP msig;
};

GNUNET_NETWORK_STRUCT_END


/**
 * Mark the given denomination key as revoked and request the wallets
 * to initiate /recoup.
 *
 * @param revocation_dir where to write the revocation certificate
 * @param denom_hash hash of the denomination key to revoke
 * @param mpriv master private key to sign with
 * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure.
 */
int
TALER_EXCHANGEDB_denomination_key_revoke (const char *revocation_dir,
                                          const struct
                                          GNUNET_HashCode *denom_hash,
                                          const struct
                                          TALER_MasterPrivateKeyP *mpriv)
{
  struct TALER_MasterDenominationKeyRevocationPS rm;
  char *fn;
  int ret;
  struct RevocationFileP rd;

  GNUNET_asprintf (&fn,
                   "%s" DIR_SEPARATOR_STR
                   "%s.rev",
                   revocation_dir,
                   GNUNET_h2s_full (denom_hash));
  rm.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED);
  rm.purpose.size = htonl (sizeof (rm));
  rm.h_denom_pub = *denom_hash;
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_CRYPTO_eddsa_sign (&mpriv->eddsa_priv,
                                           &rm.purpose,
                                           &rd.msig.eddsa_signature));
  rd.denom_hash = *denom_hash;
  if (sizeof (rd) !=
      GNUNET_DISK_fn_write (fn,
                            &rd,
                            sizeof (rd),
                            GNUNET_DISK_PERM_USER_READ
                            | GNUNET_DISK_PERM_USER_WRITE))
    ret = GNUNET_SYSERR;
  else
    ret = GNUNET_OK;
  GNUNET_free (fn);
  return ret;
}


/**
 * Import a denomination key from the given file.
 *
 * @param filename the file to import the key from
 * @param[out] dki set to the imported denomination key
 * @return #GNUNET_OK upon success;
 *         #GNUNET_SYSERR upon failure
 */
int
TALER_EXCHANGEDB_denomination_key_read (const char *filename,
                                        struct
                                        TALER_EXCHANGEDB_DenominationKeyIssueInformation
                                        *dki)
{
  uint64_t size;
  size_t offset;
  void *data;
  struct GNUNET_CRYPTO_RsaPrivateKey *priv;

  if (GNUNET_OK !=
      GNUNET_DISK_file_size (filename,
                             &size,
                             GNUNET_YES,
                             GNUNET_YES))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Skipping inaccessable denomination key file `%s'\n",
                filename);
    return GNUNET_SYSERR;
  }
  offset = sizeof (struct TALER_EXCHANGEDB_DenominationKeyInformationP);
  if (size <= offset)
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  data = GNUNET_malloc (size);
  if (((ssize_t) size) !=
      GNUNET_DISK_fn_read (filename,
                           data,
                           size))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
                              "read",
                              filename);
    GNUNET_free (data);
    return GNUNET_SYSERR;
  }
  if (NULL ==
      (priv = GNUNET_CRYPTO_rsa_private_key_decode (data + offset,
                                                    size - offset)))
  {
    GNUNET_free (data);
    return GNUNET_SYSERR;
  }
  GNUNET_assert (NULL == dki->denom_priv.rsa_private_key);
  dki->denom_priv.rsa_private_key = priv;
  dki->denom_pub.rsa_public_key
    = GNUNET_CRYPTO_rsa_private_key_get_public (priv);
  memcpy (&dki->issue,
          data,
          offset);
  GNUNET_free (data);
  if (0 == GNUNET_TIME_absolute_get_remaining
        (GNUNET_TIME_absolute_ntoh (
          dki->issue.properties.expire_withdraw)).rel_value_us)
  {
    if (0 != unlink (filename))
    {
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                                "unlink",
                                filename);
      return GNUNET_OK; /* yes, we had an error, but the file content
                           was fine and is being returned */
    }
  }
  return GNUNET_OK;
}


/**
 * Exports a denomination key to the given file.
 *
 * @param filename the file where to write the denomination key
 * @param dki the denomination key
 * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure.
 */
int
TALER_EXCHANGEDB_denomination_key_write (const char *filename,
                                         const struct
                                         TALER_EXCHANGEDB_DenominationKeyIssueInformation
                                         *dki)
{
  char *priv_enc;
  size_t priv_enc_size;
  struct GNUNET_DISK_FileHandle *fh;
  ssize_t wrote;
  size_t wsize;
  int ret;

  fh = NULL;
  priv_enc_size
    = GNUNET_CRYPTO_rsa_private_key_encode (dki->denom_priv.rsa_private_key,
                                            &priv_enc);
  ret = GNUNET_SYSERR;
  if (GNUNET_OK !=
      GNUNET_DISK_directory_create_for_file (filename))
    return GNUNET_SYSERR;
  if (NULL == (fh = GNUNET_DISK_file_open
                      (filename,
                      GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_CREATE
                      | GNUNET_DISK_OPEN_TRUNCATE,
                      GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE
                      | GNUNET_DISK_OPEN_FAILIFEXISTS)))
    goto cleanup;
  wsize = sizeof (struct TALER_EXCHANGEDB_DenominationKeyInformationP);
  if (GNUNET_SYSERR == (wrote = GNUNET_DISK_file_write (fh,
                                                        &dki->issue,
                                                        wsize)))
    goto cleanup;
  if (wrote != (ssize_t) wsize)
    goto cleanup;
  if (GNUNET_SYSERR ==
      (wrote = GNUNET_DISK_file_write (fh,
                                       priv_enc,
                                       priv_enc_size)))
    goto cleanup;
  if (wrote != (ssize_t) priv_enc_size)
    goto cleanup;
  ret = GNUNET_OK;
cleanup:
  GNUNET_free_non_null (priv_enc);
  if (NULL != fh)
    (void) GNUNET_DISK_file_close (fh);
  return ret;
}


/**
 * Closure for #denomkeys_iterate_keydir_iter() and
 * #denomkeys_iterate_topdir_iter().
 */
struct DenomkeysIterateContext
{

  /**
   * Set to the name of the directory below the top-level directory
   * during the call to #denomkeys_iterate_keydir_iter().
   */
  const char *alias;

  /**
   * Function to call on each denomination key.
   */
  TALER_EXCHANGEDB_DenominationKeyIterator it;

  /**
   * Closure for @e it.
   */
  void *it_cls;
};


/**
 * Decode the denomination key in the given file @a filename and call
 * the callback in @a cls with the information.
 *
 * @param cls the `struct DenomkeysIterateContext *`
 * @param filename name of a file that should contain
 *                 a denomination key
 * @return #GNUNET_OK to continue to iterate
 *         #GNUNET_NO to abort iteration with success
 *         #GNUNET_SYSERR to abort iteration with failure
 */
static int
denomkeys_iterate_keydir_iter (void *cls,
                               const char *filename)
{
  struct DenomkeysIterateContext *dic = cls;
  struct TALER_EXCHANGEDB_DenominationKeyIssueInformation issue;
  int ret;

  memset (&issue, 0, sizeof (issue));
  if (GNUNET_OK !=
      TALER_EXCHANGEDB_denomination_key_read (filename,
                                              &issue))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Invalid denomkey file: '%s'\n",
                filename);
    return GNUNET_OK;
  }
  ret = dic->it (dic->it_cls,
                 dic->alias,
                 &issue);
  GNUNET_CRYPTO_rsa_private_key_free (issue.denom_priv.rsa_private_key);
  GNUNET_CRYPTO_rsa_public_key_free (issue.denom_pub.rsa_public_key);
  return ret;
}


/**
 * Function called on each subdirectory in the #TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS.  Will
 * call the #denomkeys_iterate_keydir_iter() on each file in the
 * subdirectory.
 *
 * @param cls the `struct DenomkeysIterateContext *`
 * @param filename name of the subdirectory to scan
 * @return #GNUNET_OK on success,
 *         #GNUNET_SYSERR if we need to abort
 */
static int
denomkeys_iterate_topdir_iter (void *cls,
                               const char *filename)
{
  struct DenomkeysIterateContext *dic = cls;

  dic->alias = GNUNET_STRINGS_get_short_name (filename);
  if (0 > GNUNET_DISK_directory_scan (filename,
                                      &denomkeys_iterate_keydir_iter,
                                      dic))
    return GNUNET_SYSERR;
  return GNUNET_OK;
}


/**
 * Call @a it for each denomination key found in the @a exchange_base_dir.
 *
 * @param exchange_base_dir base directory for the exchange,
 *                      the signing keys must be in the #TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS
 *                      subdirectory
 * @param it function to call on each denomination key found
 * @param it_cls closure for @a it
 * @return -1 on error, 0 if no files were found, otherwise
 *         a positive number (however, even with a positive
 *         number it is possible that @a it was never called
 *         as maybe none of the files were well-formed)
 */
int
TALER_EXCHANGEDB_denomination_keys_iterate (const char *exchange_base_dir,
                                            TALER_EXCHANGEDB_DenominationKeyIterator
                                            it,
                                            void *it_cls)
{
  char *dir;
  struct DenomkeysIterateContext dic;
  int ret;

  GNUNET_asprintf (&dir,
                   "%s" DIR_SEPARATOR_STR
                   TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS,
                   exchange_base_dir);
  dic.it = it;
  dic.it_cls = it_cls;
  ret = GNUNET_DISK_directory_scan (dir,
                                    &denomkeys_iterate_topdir_iter,
                                    &dic);
  GNUNET_free (dir);
  return ret;
}


/**
 * Closure for #revocations_iterate_cb().
 */
struct RevocationsIterateContext
{

  /**
   * Function to call on each revoked denomination key.
   */
  TALER_EXCHANGEDB_RevocationIterator it;

  /**
   * Closure for @e it.
   */
  void *it_cls;

  /**
   * Master public key to use to validate revocations.
   */
  const struct TALER_MasterPublicKeyP *master_pub;

};


/**
 * Decode the revocation certificate in the given file @a filename and call
 * the callback in @a cls with the information.
 *
 * @param cls the `struct RevocationsIterateContext *`
 * @param filename name of a file that should contain
 *                 a denomination key
 * @return #GNUNET_OK to continue to iterate
 *         #GNUNET_NO to abort iteration with success
 *         #GNUNET_SYSERR to abort iteration with failure
 */
static int
revocations_iterate_cb (void *cls,
                        const char *filename)
{
  struct RevocationsIterateContext *ric = cls;
  struct RevocationFileP rf;
  struct TALER_MasterDenominationKeyRevocationPS rm;

  /* Check if revocation is valid... */
  if (sizeof (rf) !=
      GNUNET_DISK_fn_read (filename,
                           &rf,
                           sizeof (rf)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ (
                  "Invalid revocation file `%s' found and ignored (bad size)\n"),
                filename);
    return GNUNET_OK;
  }
  rm.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED);
  rm.purpose.size = htonl (sizeof (rm));
  rm.h_denom_pub = rf.denom_hash;
  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify (
        TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED,
        &rm.purpose,
        &rf.msig.eddsa_signature,
        &ric->master_pub->eddsa_pub))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ (
                  "Invalid revocation file `%s' found and ignored (bad signature)\n"),
                filename);
    return GNUNET_OK;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Denomination key `%s' was revoked!\n",
              GNUNET_h2s (&rm.h_denom_pub));
  return ric->it (ric->it_cls,
                  &rm.h_denom_pub,
                  &rf.msig);
}


/**
 * Call @a it for each revoked denomination key found in the @a revocation_dir.
 *
 * @param revocation_dir base directory where revocations are stored
 * @param master_pub master public key (used to check revocations)
 * @param it function to call on each revoked denomination key found
 * @param it_cls closure for @a it
 * @return -1 on error, 0 if no files were found, otherwise
 *         a positive number (however, even with a positive
 *         number it is possible that @a it was never called
 *         as maybe none of the files were well-formed)
 */
int
TALER_EXCHANGEDB_revocations_iterate (const char *revocation_dir,
                                      const struct
                                      TALER_MasterPublicKeyP *master_pub,
                                      TALER_EXCHANGEDB_RevocationIterator it,
                                      void *it_cls)
{
  struct RevocationsIterateContext ric = {
    .it = it,
    .it_cls = it_cls,
    .master_pub = master_pub
  };

  if (GNUNET_OK !=
      GNUNET_DISK_directory_create (revocation_dir))
    return 0; /* directory doesn't exist and we couldn't even create it,
     clearly means there are no revocations there */
  return GNUNET_DISK_directory_scan (revocation_dir,
                                     &revocations_iterate_cb,
                                     &ric);
}


/* end of exchangedb_denomkeys.c */