GNUnet  0.10.x
crypto_rsa.c
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1 /*
2  This file is part of GNUnet
3  Copyright (C) 2014,2016 GNUnet e.V.
4 
5  GNUnet is free software: you can redistribute it and/or modify it
6  under the terms of the GNU Affero General Public License as published
7  by the Free Software Foundation, either version 3 of the License,
8  or (at your option) any later version.
9 
10  GNUnet is distributed in the hope that it will be useful, but
11  WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  Affero General Public License for more details.
14 
15  You should have received a copy of the GNU Affero General Public License
16  along with this program. If not, see <http://www.gnu.org/licenses/>.
17 
18  SPDX-License-Identifier: AGPL3.0-or-later
19 */
20 
28 #include "platform.h"
29 #include <gcrypt.h>
30 #include "gnunet_crypto_lib.h"
31 #include "benchmark.h"
32 
33 #define LOG(kind,...) GNUNET_log_from (kind, "util-crypto-rsa", __VA_ARGS__)
34 
35 
40 {
44  gcry_sexp_t sexp;
45 };
46 
47 
52 {
56  gcry_sexp_t sexp;
57 };
58 
59 
64 {
68  gcry_sexp_t sexp;
69 };
70 
71 
76 {
80  gcry_mpi_t r;
81 };
82 
83 
93 static int
94 key_from_sexp (gcry_mpi_t *array,
95  gcry_sexp_t sexp,
96  const char *topname,
97  const char *elems)
98 {
99  gcry_sexp_t list;
100  gcry_sexp_t l2;
101  const char *s;
102  unsigned int idx;
103 
104  if (! (list = gcry_sexp_find_token (sexp, topname, 0)))
105  return 1;
106  l2 = gcry_sexp_cadr (list);
107  gcry_sexp_release (list);
108  list = l2;
109  if (! list)
110  return 2;
111  idx = 0;
112  for (s = elems; *s; s++, idx++)
113  {
114  if (! (l2 = gcry_sexp_find_token (list, s, 1)))
115  {
116  for (unsigned int i = 0; i < idx; i++)
117  {
118  gcry_free (array[i]);
119  array[i] = NULL;
120  }
121  gcry_sexp_release (list);
122  return 3; /* required parameter not found */
123  }
124  array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
125  gcry_sexp_release (l2);
126  if (! array[idx])
127  {
128  for (unsigned int i = 0; i < idx; i++)
129  {
130  gcry_free (array[i]);
131  array[i] = NULL;
132  }
133  gcry_sexp_release (list);
134  return 4; /* required parameter is invalid */
135  }
136  }
137  gcry_sexp_release (list);
138  return 0;
139 }
140 
141 
150 {
152  gcry_sexp_t s_key;
153  gcry_sexp_t s_keyparam;
154 
155  BENCHMARK_START (rsa_private_key_create);
156 
157  GNUNET_assert (0 ==
158  gcry_sexp_build (&s_keyparam,
159  NULL,
160  "(genkey(rsa(nbits %d)))",
161  len));
162  GNUNET_assert (0 ==
163  gcry_pk_genkey (&s_key,
164  s_keyparam));
165  gcry_sexp_release (s_keyparam);
166 #if EXTRA_CHECKS
167  GNUNET_assert (0 ==
168  gcry_pk_testkey (s_key));
169 #endif
171  ret->sexp = s_key;
172  BENCHMARK_END (rsa_private_key_create);
173  return ret;
174 }
175 
176 
182 void
184 {
185  gcry_sexp_release (key->sexp);
186  GNUNET_free (key);
187 }
188 
189 
198 size_t
200  char **buffer)
201 {
202  size_t n;
203  char *b;
204 
205  n = gcry_sexp_sprint (key->sexp,
206  GCRYSEXP_FMT_DEFAULT,
207  NULL,
208  0);
209  b = GNUNET_malloc (n);
210  GNUNET_assert ((n - 1) == /* since the last byte is \0 */
211  gcry_sexp_sprint (key->sexp,
212  GCRYSEXP_FMT_DEFAULT,
213  b,
214  n));
215  *buffer = b;
216  return n;
217 }
218 
219 
230  size_t len)
231 {
234  if (0 !=
235  gcry_sexp_new (&key->sexp,
236  buf,
237  len,
238  0))
239  {
241  "Decoded private key is not valid\n");
242  GNUNET_free (key);
243  return NULL;
244  }
245  if (0 != gcry_pk_testkey (key->sexp))
246  {
248  "Decoded private key is not valid\n");
250  return NULL;
251  }
252  return key;
253 }
254 
255 
264 {
266  gcry_mpi_t ne[2];
267  int rc;
268  gcry_sexp_t result;
269 
270  BENCHMARK_START (rsa_private_key_get_public);
271 
272  rc = key_from_sexp (ne, priv->sexp, "public-key", "ne");
273  if (0 != rc)
274  rc = key_from_sexp (ne, priv->sexp, "private-key", "ne");
275  if (0 != rc)
276  rc = key_from_sexp (ne, priv->sexp, "rsa", "ne");
277  if (0 != rc)
278  {
279  GNUNET_break_op (0);
280  return NULL;
281  }
282  rc = gcry_sexp_build (&result,
283  NULL,
284  "(public-key(rsa(n %m)(e %m)))",
285  ne[0],
286  ne[1]);
287  gcry_mpi_release (ne[0]);
288  gcry_mpi_release (ne[1]);
289  pub = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
290  pub->sexp = result;
291  BENCHMARK_END (rsa_private_key_get_public);
292  return pub;
293 }
294 
295 
301 void
303 {
304  gcry_sexp_release (key->sexp);
305  GNUNET_free (key);
306 }
307 
308 
317 size_t
319  char **buffer)
320 {
321  size_t n;
322  char *b;
323 
324  n = gcry_sexp_sprint (key->sexp,
325  GCRYSEXP_FMT_ADVANCED,
326  NULL,
327  0);
328  b = GNUNET_malloc (n);
329  GNUNET_assert ((n -1) == /* since the last byte is \0 */
330  gcry_sexp_sprint (key->sexp,
331  GCRYSEXP_FMT_ADVANCED,
332  b,
333  n));
334  *buffer = b;
335  return n;
336 }
337 
338 
345 void
347  struct GNUNET_HashCode *hc)
348 {
349  char *buf;
350  size_t buf_size;
351 
352  buf_size = GNUNET_CRYPTO_rsa_public_key_encode (key,
353  &buf);
354  GNUNET_CRYPTO_hash (buf,
355  buf_size,
356  hc);
357  GNUNET_free (buf);
358 }
359 
360 
371  size_t len)
372 {
374  gcry_mpi_t n;
375  int ret;
376 
377  key = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
378  if (0 !=
379  gcry_sexp_new (&key->sexp,
380  buf,
381  len,
382  0))
383  {
384  GNUNET_break_op (0);
385  GNUNET_free (key);
386  return NULL;
387  }
388  /* verify that this is an RSA public key */
389  ret = key_from_sexp (&n, key->sexp, "public-key", "n");
390  if (0 != ret)
391  ret = key_from_sexp (&n, key->sexp, "rsa", "n");
392  if (0 != ret)
393  {
394  /* this is no public RSA key */
395  GNUNET_break (0);
396  gcry_sexp_release (key->sexp);
397  GNUNET_free (key);
398  return NULL;
399  }
400  gcry_mpi_release (n);
401  return key;
402 }
403 
404 
416 static int
417 rsa_gcd_validate(gcry_mpi_t r, gcry_mpi_t n)
418 {
419  gcry_mpi_t g;
420  int t;
421 
422  g = gcry_mpi_new (0);
423  t = gcry_mpi_gcd(g,r,n);
424  gcry_mpi_release (g);
425  return t;
426 }
427 
428 
436 static struct RsaBlindingKey *
438  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks)
439 {
440  char *xts = "Blinding KDF extrator HMAC key"; /* Trusts bks' randomness more */
441  struct RsaBlindingKey *blind;
442  gcry_mpi_t n;
443 
444  blind = GNUNET_new (struct RsaBlindingKey);
445  GNUNET_assert( NULL != blind );
446 
447  /* Extract the composite n from the RSA public key */
448  GNUNET_assert( 0 == key_from_sexp (&n, pkey->sexp, "rsa", "n") );
449  /* Assert that it at least looks like an RSA key */
450  GNUNET_assert( 0 == gcry_mpi_get_flag(n, GCRYMPI_FLAG_OPAQUE) );
451 
452  GNUNET_CRYPTO_kdf_mod_mpi (&blind->r,
453  n,
454  xts, strlen(xts),
455  bks, sizeof(*bks),
456  "Blinding KDF");
457  if (0 == rsa_gcd_validate(blind->r, n)) {
458  GNUNET_free (blind);
459  blind = NULL;
460  }
461 
462  gcry_mpi_release (n);
463  return blind;
464 }
465 
466 
467 /*
468 We originally added GNUNET_CRYPTO_kdf_mod_mpi for the benifit of the
469 previous routine.
470 
471 There was previously a call to GNUNET_CRYPTO_kdf in
472  bkey = rsa_blinding_key_derive (len, bks);
473 that gives exactly len bits where
474  len = GNUNET_CRYPTO_rsa_public_key_len (pkey);
475 
476 Now r = 2^(len-1)/pkey.n is the probability that a set high bit being
477 okay, meaning bkey < pkey.n. It follows that (1-r)/2 of the time bkey >
478 pkey.n making the effective bkey be
479  bkey mod pkey.n = bkey - pkey.n
480 so the effective bkey has its high bit set with probability r/2.
481 
482 We expect r to be close to 1/2 if the exchange is honest, but the
483 exchange can choose r otherwise.
484 
485 In blind signing, the exchange sees
486  B = bkey * S mod pkey.n
487 On deposit, the exchange sees S so they can compute bkey' = B/S mod
488 pkey.n for all B they recorded to see if bkey' has it's high bit set.
489 Also, note the exchange can compute 1/S efficiently since they know the
490 factors of pkey.n.
491 
492 I suppose that happens with probability r/(1+r) if its the wrong B, not
493 completely sure. If otoh we've the right B, then we've the probability
494 r/2 of a set high bit in the effective bkey.
495 
496 Interestingly, r^2-r has a maximum at the default r=1/2 anyways, giving
497 the wrong and right probabilities 1/3 and 1/4, respectively.
498 
499 I feared this gives the exchange a meaningful fraction of a bit of
500 information per coin involved in the transaction. It sounds damaging if
501 numerous coins were involved. And it could run across transactions in
502 some scenarios.
503 
504 We fixed this by using a more uniform deterministic pseudo-random number
505 generator for blinding factors. I do not believe this to be a problem
506 for the rsa_full_domain_hash routine, but better safe than sorry.
507 */
508 
509 
517 int
519  struct GNUNET_CRYPTO_RsaSignature *s2)
520 {
521  char *b1;
522  char *b2;
523  size_t z1;
524  size_t z2;
525  int ret;
526 
528  &b1);
530  &b2);
531  if (z1 != z2)
532  ret = 1;
533  else
534  ret = memcmp (b1,
535  b2,
536  z1);
537  GNUNET_free (b1);
538  GNUNET_free (b2);
539  return ret;
540 }
541 
542 
550 int
552  struct GNUNET_CRYPTO_RsaPublicKey *p2)
553 {
554  char *b1;
555  char *b2;
556  size_t z1;
557  size_t z2;
558  int ret;
559 
561  &b1);
563  &b2);
564  if (z1 != z2)
565  ret = 1;
566  else
567  ret = memcmp (b1,
568  b2,
569  z1);
570  GNUNET_free (b1);
571  GNUNET_free (b2);
572  return ret;
573 }
574 
575 
583 int
585  struct GNUNET_CRYPTO_RsaPrivateKey *p2)
586 {
587  char *b1;
588  char *b2;
589  size_t z1;
590  size_t z2;
591  int ret;
592 
594  &b1);
596  &b2);
597  if (z1 != z2)
598  ret = 1;
599  else
600  ret = memcmp (b1,
601  b2,
602  z1);
603  GNUNET_free (b1);
604  GNUNET_free (b2);
605  return ret;
606 }
607 
608 
615 unsigned int
617 {
618  gcry_mpi_t n;
619  unsigned int rval;
620 
621  if (0 != key_from_sexp (&n, key->sexp, "rsa", "n"))
622  { /* Not an RSA public key */
623  GNUNET_break (0);
624  return 0;
625  }
626  rval = gcry_mpi_get_nbits (n);
627  gcry_mpi_release (n);
628  return rval;
629 }
630 
631 
637 static void
639 {
640  gcry_mpi_release (bkey->r);
641  GNUNET_free (bkey);
642 }
643 
644 
652 static size_t
654  char **buffer)
655 {
656  size_t n;
657  char *b;
658  size_t rsize;
659 
660  gcry_mpi_print (GCRYMPI_FMT_USG,
661  NULL,
662  0,
663  &n,
664  v);
665  b = GNUNET_malloc (n);
666  GNUNET_assert (0 ==
667  gcry_mpi_print (GCRYMPI_FMT_USG,
668  (unsigned char *) b,
669  n,
670  &rsize,
671  v));
672  *buffer = b;
673  return n;
674 }
675 
676 
689 static gcry_mpi_t
691  const struct GNUNET_HashCode *hash)
692 {
693  gcry_mpi_t r,n;
694  char *xts;
695  size_t xts_len;
696  int ok;
697 
698  /* Extract the composite n from the RSA public key */
699  GNUNET_assert( 0 == key_from_sexp (&n, pkey->sexp, "rsa", "n") );
700  /* Assert that it at least looks like an RSA key */
701  GNUNET_assert( 0 == gcry_mpi_get_flag(n, GCRYMPI_FLAG_OPAQUE) );
702 
703  /* We key with the public denomination key as a homage to RSA-PSS by *
704  * Mihir Bellare and Phillip Rogaway. Doing this lowers the degree *
705  * of the hypothetical polyomial-time attack on RSA-KTI created by a *
706  * polynomial-time one-more forgary attack. Yey seeding! */
707  xts_len = GNUNET_CRYPTO_rsa_public_key_encode (pkey, &xts);
708 
710  n,
711  xts, xts_len,
712  hash, sizeof(*hash),
713  "RSA-FDA FTpsW!");
714  GNUNET_free (xts);
715 
716  ok = rsa_gcd_validate(r,n);
717  gcry_mpi_release (n);
718  if (ok)
719  return r;
720  gcry_mpi_release (r);
721  return NULL;
722 }
723 
724 
735 int
737  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
739  char **buf, size_t *buf_size)
740 {
741  struct RsaBlindingKey *bkey;
742  gcry_mpi_t data;
743  gcry_mpi_t ne[2];
744  gcry_mpi_t r_e;
745  gcry_mpi_t data_r_e;
746  int ret;
747 
748  BENCHMARK_START (rsa_blind);
749 
750  GNUNET_assert (buf != NULL && buf_size != NULL);
751  ret = key_from_sexp (ne, pkey->sexp, "public-key", "ne");
752  if (0 != ret)
753  ret = key_from_sexp (ne, pkey->sexp, "rsa", "ne");
754  if (0 != ret)
755  {
756  GNUNET_break (0);
757  *buf = NULL;
758  *buf_size = 0;
759  return 0;
760  }
761 
762  data = rsa_full_domain_hash (pkey, hash);
763  if (NULL == data)
764  goto rsa_gcd_validate_failure;
765 
766  bkey = rsa_blinding_key_derive (pkey, bks);
767  if (NULL == bkey) {
768  gcry_mpi_release (data);
769  goto rsa_gcd_validate_failure;
770  }
771 
772  r_e = gcry_mpi_new (0);
773  gcry_mpi_powm (r_e,
774  bkey->r,
775  ne[1],
776  ne[0]);
777  data_r_e = gcry_mpi_new (0);
778  gcry_mpi_mulm (data_r_e,
779  data,
780  r_e,
781  ne[0]);
782  gcry_mpi_release (data);
783  gcry_mpi_release (ne[0]);
784  gcry_mpi_release (ne[1]);
785  gcry_mpi_release (r_e);
786  rsa_blinding_key_free (bkey);
787 
788  *buf_size = numeric_mpi_alloc_n_print (data_r_e, buf);
789  gcry_mpi_release (data_r_e);
790 
791  BENCHMARK_END (rsa_blind);
792 
793  return GNUNET_YES;
794 
795 rsa_gcd_validate_failure:
796  /* We know the RSA key is malicious here, so warn the wallet. */
797  /* GNUNET_break_op (0); */
798  gcry_mpi_release (ne[0]);
799  gcry_mpi_release (ne[1]);
800  *buf = NULL;
801  *buf_size = 0;
802  return GNUNET_NO;
803 }
804 
805 
812 static gcry_sexp_t
813 mpi_to_sexp (gcry_mpi_t value)
814 {
815  gcry_sexp_t data = NULL;
816 
817  GNUNET_assert (0 ==
818  gcry_sexp_build (&data,
819  NULL,
820  "(data (flags raw) (value %M))",
821  value));
822  return data;
823 }
824 
825 
833 static struct GNUNET_CRYPTO_RsaSignature *
835  gcry_mpi_t value)
836 {
837  struct GNUNET_CRYPTO_RsaSignature *sig;
838  gcry_sexp_t data;
839  gcry_sexp_t result;
840  int rc;
841 
842  data = mpi_to_sexp (value);
843 
844  if (0 !=
845  (rc = gcry_pk_sign (&result,
846  data,
847  key->sexp)))
848  {
850  _("RSA signing failed at %s:%d: %s\n"),
851  __FILE__,
852  __LINE__,
853  gcry_strerror (rc));
854  GNUNET_break (0);
855  return NULL;
856  }
857 
858  /* Lenstra protection was first added to libgcrypt 1.6.4
859  * with commit c17f84bd02d7ee93845e92e20f6ddba814961588.
860  */
861 #if GCRYPT_VERSION_NUMBER < 0x010604
862  /* verify signature (guards against Lenstra's attack with fault injection...) */
864  if (0 !=
865  gcry_pk_verify (result,
866  data,
867  public_key->sexp))
868  {
869  GNUNET_break (0);
871  gcry_sexp_release (data);
872  gcry_sexp_release (result);
873  return NULL;
874  }
876 #endif
877 
878  /* return signature */
879  gcry_sexp_release (data);
880  sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
881  sig->sexp = result;
882  return sig;
883 }
884 
885 
896  const void *msg,
897  size_t msg_len)
898 {
899  gcry_mpi_t v = NULL;
900  struct GNUNET_CRYPTO_RsaSignature *sig;
901 
902  BENCHMARK_START (rsa_sign_blinded);
903 
904  GNUNET_assert (0 ==
905  gcry_mpi_scan (&v,
906  GCRYMPI_FMT_USG,
907  msg,
908  msg_len,
909  NULL));
910 
911  sig = rsa_sign_mpi (key, v);
912  gcry_mpi_release (v);
913  BENCHMARK_END (rsa_sign_blinded);
914  return sig;
915 }
916 
917 
927  const struct GNUNET_HashCode *hash)
928 {
930  gcry_mpi_t v = NULL;
931  struct GNUNET_CRYPTO_RsaSignature *sig;
932 
934  v = rsa_full_domain_hash (pkey, hash);
936  if (NULL == v) /* rsa_gcd_validate failed meaning */
937  return NULL; /* our *own* RSA key is malicious. */
938 
939  sig = rsa_sign_mpi (key, v);
940  gcry_mpi_release (v);
941  return sig;
942 }
943 
944 
950 void
952 {
953  gcry_sexp_release (sig->sexp);
954  GNUNET_free (sig);
955 }
956 
957 
965 size_t
967  char **buffer)
968 {
969  size_t n;
970  char *b;
971 
972  n = gcry_sexp_sprint (sig->sexp,
973  GCRYSEXP_FMT_ADVANCED,
974  NULL,
975  0);
976  b = GNUNET_malloc (n);
977  GNUNET_assert ((n - 1) == /* since the last byte is \0 */
978  gcry_sexp_sprint (sig->sexp,
979  GCRYSEXP_FMT_ADVANCED,
980  b,
981  n));
982  *buffer = b;
983  return n;
984 }
985 
986 
997  size_t len)
998 {
999  struct GNUNET_CRYPTO_RsaSignature *sig;
1000  int ret;
1001  gcry_mpi_t s;
1002 
1003  sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1004  if (0 !=
1005  gcry_sexp_new (&sig->sexp,
1006  buf,
1007  len,
1008  0))
1009  {
1010  GNUNET_break_op (0);
1011  GNUNET_free (sig);
1012  return NULL;
1013  }
1014  /* verify that this is an RSA signature */
1015  ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1016  if (0 != ret)
1017  ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1018  if (0 != ret)
1019  {
1020  /* this is no RSA Signature */
1021  GNUNET_break_op (0);
1022  gcry_sexp_release (sig->sexp);
1023  GNUNET_free (sig);
1024  return NULL;
1025  }
1026  gcry_mpi_release (s);
1027  return sig;
1028 }
1029 
1030 
1039 {
1040  struct GNUNET_CRYPTO_RsaPublicKey *dup;
1041  gcry_sexp_t dup_sexp;
1042  size_t erroff;
1043 
1044  /* check if we really are exporting a public key */
1045  dup_sexp = gcry_sexp_find_token (key->sexp, "public-key", 0);
1046  GNUNET_assert (NULL != dup_sexp);
1047  gcry_sexp_release (dup_sexp);
1048  /* copy the sexp */
1049  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
1050  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
1051  dup->sexp = dup_sexp;
1052  return dup;
1053 }
1054 
1055 
1068  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
1070 {
1071  struct RsaBlindingKey *bkey;
1072  gcry_mpi_t n;
1073  gcry_mpi_t s;
1074  gcry_mpi_t r_inv;
1075  gcry_mpi_t ubsig;
1076  int ret;
1077  struct GNUNET_CRYPTO_RsaSignature *sret;
1078 
1079  BENCHMARK_START (rsa_unblind);
1080 
1081  ret = key_from_sexp (&n, pkey->sexp, "public-key", "n");
1082  if (0 != ret)
1083  ret = key_from_sexp (&n, pkey->sexp, "rsa", "n");
1084  if (0 != ret)
1085  {
1086  GNUNET_break_op (0);
1087  return NULL;
1088  }
1089  ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1090  if (0 != ret)
1091  ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1092  if (0 != ret)
1093  {
1094  gcry_mpi_release (n);
1095  GNUNET_break_op (0);
1096  return NULL;
1097  }
1098 
1099  bkey = rsa_blinding_key_derive (pkey, bks);
1100  if (NULL == bkey)
1101  {
1102  /* RSA key is malicious since rsa_gcd_validate failed here.
1103  * It should have failed during GNUNET_CRYPTO_rsa_blind too though,
1104  * so the exchange is being malicious in an unfamilair way, maybe
1105  * just trying to crash us. */
1106  GNUNET_break_op (0);
1107  gcry_mpi_release (n);
1108  gcry_mpi_release (s);
1109  return NULL;
1110  }
1111 
1112  r_inv = gcry_mpi_new (0);
1113  if (1 !=
1114  gcry_mpi_invm (r_inv,
1115  bkey->r,
1116  n))
1117  {
1118  /* We cannot find r mod n, so gcd(r,n) != 1, which should get *
1119  * caught above, but we handle it the same here. */
1120  GNUNET_break_op (0);
1121  gcry_mpi_release (r_inv);
1122  rsa_blinding_key_free (bkey);
1123  gcry_mpi_release (n);
1124  gcry_mpi_release (s);
1125  return NULL;
1126  }
1127 
1128  ubsig = gcry_mpi_new (0);
1129  gcry_mpi_mulm (ubsig, s, r_inv, n);
1130  gcry_mpi_release (n);
1131  gcry_mpi_release (r_inv);
1132  gcry_mpi_release (s);
1133  rsa_blinding_key_free (bkey);
1134 
1135  sret = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1136  GNUNET_assert (0 ==
1137  gcry_sexp_build (&sret->sexp,
1138  NULL,
1139  "(sig-val (rsa (s %M)))",
1140  ubsig));
1141  gcry_mpi_release (ubsig);
1142  BENCHMARK_END (rsa_unblind);
1143  return sret;
1144 }
1145 
1146 
1156 int
1158  const struct GNUNET_CRYPTO_RsaSignature *sig,
1159  const struct GNUNET_CRYPTO_RsaPublicKey *pkey)
1160 {
1161  gcry_sexp_t data;
1162  gcry_mpi_t r;
1163  int rc;
1164 
1165  BENCHMARK_START (rsa_verify);
1166 
1167  r = rsa_full_domain_hash (pkey, hash);
1168  if (NULL == r) {
1169  GNUNET_break_op (0);
1170  /* RSA key is malicious since rsa_gcd_validate failed here.
1171  * It should have failed during GNUNET_CRYPTO_rsa_blind too though,
1172  * so the exchange is being malicious in an unfamilair way, maybe
1173  * just trying to crash us. Arguably, we've only an internal error
1174  * though because we should've detected this in our previous call
1175  * to GNUNET_CRYPTO_rsa_unblind. */
1176  return GNUNET_NO;
1177  }
1178 
1179  data = mpi_to_sexp(r);
1180  gcry_mpi_release (r);
1181 
1182  rc = gcry_pk_verify (sig->sexp,
1183  data,
1184  pkey->sexp);
1185  gcry_sexp_release (data);
1186  if (0 != rc)
1187  {
1189  _("RSA signature verification failed at %s:%d: %s\n"),
1190  __FILE__,
1191  __LINE__,
1192  gcry_strerror (rc));
1193  return GNUNET_SYSERR;
1194  BENCHMARK_END (rsa_verify);
1195  }
1196  BENCHMARK_END (rsa_verify);
1197  return GNUNET_OK;
1198 }
1199 
1200 
1209 {
1210  struct GNUNET_CRYPTO_RsaPrivateKey *dup;
1211  gcry_sexp_t dup_sexp;
1212  size_t erroff;
1213 
1214  /* check if we really are exporting a private key */
1215  dup_sexp = gcry_sexp_find_token (key->sexp, "private-key", 0);
1216  GNUNET_assert (NULL != dup_sexp);
1217  gcry_sexp_release (dup_sexp);
1218  /* copy the sexp */
1219  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
1220  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPrivateKey);
1221  dup->sexp = dup_sexp;
1222  return dup;
1223 }
1224 
1225 
1234 {
1235  struct GNUNET_CRYPTO_RsaSignature *dup;
1236  gcry_sexp_t dup_sexp;
1237  size_t erroff;
1238  gcry_mpi_t s;
1239  int ret;
1240 
1241  /* verify that this is an RSA signature */
1242  ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1243  if (0 != ret)
1244  ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1245  GNUNET_assert (0 == ret);
1246  gcry_mpi_release (s);
1247  /* copy the sexp */
1248  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", sig->sexp));
1249  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1250  dup->sexp = dup_sexp;
1251  return dup;
1252 }
1253 
1254 
1255 /* end of util/rsa.c */
int GNUNET_CRYPTO_rsa_blind(const struct GNUNET_HashCode *hash, const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks, struct GNUNET_CRYPTO_RsaPublicKey *pkey, char **buf, size_t *buf_size)
Blinds the given message with the given blinding key.
Definition: crypto_rsa.c:736
static int key_from_sexp(gcry_mpi_t *array, gcry_sexp_t sexp, const char *topname, const char *elems)
Extract values from an S-expression.
Definition: crypto_rsa.c:94
unsigned int GNUNET_CRYPTO_rsa_public_key_len(const struct GNUNET_CRYPTO_RsaPublicKey *key)
Obtain the length of the RSA key in bits.
Definition: crypto_rsa.c:616
static struct RsaBlindingKey * rsa_blinding_key_derive(const struct GNUNET_CRYPTO_RsaPublicKey *pkey, const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks)
Create a blinding key.
Definition: crypto_rsa.c:437
size_t GNUNET_CRYPTO_rsa_signature_encode(const struct GNUNET_CRYPTO_RsaSignature *sig, char **buffer)
Encode the given signature in a format suitable for storing it into a file.
Definition: crypto_rsa.c:966
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
static char * pkey
Public key of the zone to look in, in ASCII.
struct GNUNET_CRYPTO_RsaSignature * GNUNET_CRYPTO_rsa_signature_dup(const struct GNUNET_CRYPTO_RsaSignature *sig)
Duplicate the given private key.
Definition: crypto_rsa.c:1233
an RSA signature
Definition: crypto_rsa.c:63
static gcry_mpi_t rsa_full_domain_hash(const struct GNUNET_CRYPTO_RsaPublicKey *pkey, const struct GNUNET_HashCode *hash)
Computes a full domain hash seeded by the given public key.
Definition: crypto_rsa.c:690
#define BENCHMARK_START(opname)
Definition: benchmark.h:53
void GNUNET_CRYPTO_kdf_mod_mpi(gcry_mpi_t *r, gcry_mpi_t n, const void *xts, size_t xts_len, const void *skm, size_t skm_len, const char *ctx)
Deterministically generate a pseudo-random number uniformly from the integers modulo a libgcrypt mpi...
Definition: crypto_kdf.c:128
size_t GNUNET_CRYPTO_rsa_public_key_encode(const struct GNUNET_CRYPTO_RsaPublicKey *key, char **buffer)
Encode the public key in a format suitable for storing it into a file.
Definition: crypto_rsa.c:318
size_t GNUNET_CRYPTO_rsa_private_key_encode(const struct GNUNET_CRYPTO_RsaPrivateKey *key, char **buffer)
Encode the private key in a format suitable for storing it into a file.
Definition: crypto_rsa.c:199
int GNUNET_CRYPTO_rsa_public_key_cmp(struct GNUNET_CRYPTO_RsaPublicKey *p1, struct GNUNET_CRYPTO_RsaPublicKey *p2)
Compare the values of two public keys.
Definition: crypto_rsa.c:551
struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_private_key_decode(const char *buf, size_t len)
Decode the private key from the data-format back to the "normal", internal format.
Definition: crypto_rsa.c:229
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
gcry_mpi_t r
Random value used for blinding.
Definition: crypto_rsa.c:80
#define BENCHMARK_END(opname)
Definition: benchmark.h:54
void GNUNET_CRYPTO_rsa_public_key_free(struct GNUNET_CRYPTO_RsaPublicKey *key)
Free memory occupied by the public key.
Definition: crypto_rsa.c:302
struct GNUNET_CRYPTO_RsaPublicKey * GNUNET_CRYPTO_rsa_private_key_get_public(const struct GNUNET_CRYPTO_RsaPrivateKey *priv)
Extract the public key of the given private key.
Definition: crypto_rsa.c:263
static int ok
Return value from &#39;main&#39; (0 == success)
#define GNUNET_NO
Definition: gnunet_common.h:81
int GNUNET_CRYPTO_rsa_signature_cmp(struct GNUNET_CRYPTO_RsaSignature *s1, struct GNUNET_CRYPTO_RsaSignature *s2)
Compare the values of two signatures.
Definition: crypto_rsa.c:518
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:78
#define GNUNET_new(type)
Allocate a struct or union of the given type.
static struct GNUNET_SCHEDULER_Task * t
Main task.
static int ret
Final status code.
Definition: gnunet-arm.c:89
The public information of an RSA key pair.
Definition: crypto_rsa.c:51
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
struct GNUNET_CRYPTO_RsaSignature * GNUNET_CRYPTO_rsa_signature_decode(const char *buf, size_t len)
Decode the signature from the data-format back to the "normal", internal format.
Definition: crypto_rsa.c:996
static gcry_sexp_t mpi_to_sexp(gcry_mpi_t value)
Convert an MPI to an S-expression suitable for signature operations.
Definition: crypto_rsa.c:813
#define _(String)
GNU gettext support macro.
Definition: platform.h:208
cryptographic primitives for GNUnet
gcry_sexp_t sexp
Libgcrypt S-expression for the RSA private key.
Definition: crypto_rsa.c:44
static char * value
Value of the record to add/remove.
struct GNUNET_CRYPTO_RsaPublicKey * GNUNET_CRYPTO_rsa_public_key_decode(const char *buf, size_t len)
Decode the public key from the data-format back to the "normal", internal format. ...
Definition: crypto_rsa.c:370
int GNUNET_CRYPTO_rsa_verify(const struct GNUNET_HashCode *hash, const struct GNUNET_CRYPTO_RsaSignature *sig, const struct GNUNET_CRYPTO_RsaPublicKey *pkey)
Verify whether the given hash corresponds to the given signature and the signature is valid with resp...
Definition: crypto_rsa.c:1157
int GNUNET_CRYPTO_rsa_private_key_cmp(struct GNUNET_CRYPTO_RsaPrivateKey *p1, struct GNUNET_CRYPTO_RsaPrivateKey *p2)
Compare the values of two private keys.
Definition: crypto_rsa.c:584
static size_t numeric_mpi_alloc_n_print(gcry_mpi_t v, char **buffer)
Print an MPI to a newly created buffer.
Definition: crypto_rsa.c:653
#define GNUNET_break_op(cond)
Use this for assertion violations caused by other peers (i.e.
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:44
struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_private_key_create(unsigned int len)
Create a new private key.
Definition: crypto_rsa.c:149
static char buf[2048]
#define LOG(kind,...)
Definition: crypto_rsa.c:33
static int rsa_gcd_validate(gcry_mpi_t r, gcry_mpi_t n)
Test for malicious RSA key.
Definition: crypto_rsa.c:417
static int result
Global testing status.
A 512-bit hashcode.
RSA blinding key.
Definition: crypto_rsa.c:75
static struct GNUNET_CRYPTO_RsaSignature * rsa_sign_mpi(const struct GNUNET_CRYPTO_RsaPrivateKey *key, gcry_mpi_t value)
Sign the given MPI.
Definition: crypto_rsa.c:834
void GNUNET_CRYPTO_rsa_public_key_hash(const struct GNUNET_CRYPTO_RsaPublicKey *key, struct GNUNET_HashCode *hc)
Compute hash over the public key.
Definition: crypto_rsa.c:346
struct GNUNET_HashCode key
The key used in the DHT.
#define GNUNET_SYSERR
Definition: gnunet_common.h:79
static void rsa_blinding_key_free(struct RsaBlindingKey *bkey)
Destroy a blinding key.
Definition: crypto_rsa.c:638
gcry_sexp_t sexp
Libgcrypt S-expression for the RSA signature.
Definition: crypto_rsa.c:68
void GNUNET_CRYPTO_rsa_signature_free(struct GNUNET_CRYPTO_RsaSignature *sig)
Free memory occupied by signature.
Definition: crypto_rsa.c:951
void GNUNET_CRYPTO_rsa_private_key_free(struct GNUNET_CRYPTO_RsaPrivateKey *key)
Free memory occupied by the private key.
Definition: crypto_rsa.c:183
gcry_sexp_t sexp
Libgcrypt S-expression for the RSA public key.
Definition: crypto_rsa.c:56
static struct GNUNET_CRYPTO_EddsaPublicKey pub
Definition: gnunet-scrypt.c:39
The private information of an RSA key pair.
Definition: crypto_rsa.c:39
struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_private_key_dup(const struct GNUNET_CRYPTO_RsaPrivateKey *key)
Duplicate the given private key.
Definition: crypto_rsa.c:1208
struct GNUNET_CRYPTO_RsaPublicKey * GNUNET_CRYPTO_rsa_public_key_dup(const struct GNUNET_CRYPTO_RsaPublicKey *key)
Duplicate the given public key.
Definition: crypto_rsa.c:1038
struct GNUNET_CRYPTO_RsaSignature * GNUNET_CRYPTO_rsa_unblind(const struct GNUNET_CRYPTO_RsaSignature *sig, const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks, struct GNUNET_CRYPTO_RsaPublicKey *pkey)
Unblind a blind-signed signature.
Definition: crypto_rsa.c:1067
Constant-size pre-secret for blinding key generation.
#define GNUNET_YES
Definition: gnunet_common.h:80
benchmarking for various operations
uint32_t data
The data value.
struct GNUNET_CRYPTO_RsaSignature * GNUNET_CRYPTO_rsa_sign_fdh(const struct GNUNET_CRYPTO_RsaPrivateKey *key, const struct GNUNET_HashCode *hash)
Create and sign a full domain hash of a message.
Definition: crypto_rsa.c:926
static int list
Set if we should print a list of currently running services.
Definition: gnunet-arm.c:64
#define GNUNET_malloc(size)
Wrapper around malloc.
#define GNUNET_free(ptr)
Wrapper around free.
struct GNUNET_CRYPTO_RsaSignature * GNUNET_CRYPTO_rsa_sign_blinded(const struct GNUNET_CRYPTO_RsaPrivateKey *key, const void *msg, size_t msg_len)
Sign a blinded value, which must be a full domain hash of a message.
Definition: crypto_rsa.c:895
uint16_t len
length of data (which is always a uint32_t, but presumably this can be used to specify that fewer byt...