GNUnet  0.11.x
crypto_rsa.c
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1 /*
2  This file is part of GNUnet
3  Copyright (C) 2014,2016,2019 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
201  char **buffer)
202 {
203  size_t n;
204  char *b;
205 
206  n = gcry_sexp_sprint (key->sexp,
207  GCRYSEXP_FMT_DEFAULT,
208  NULL,
209  0);
210  b = GNUNET_malloc (n);
211  GNUNET_assert ((n - 1) == /* since the last byte is \0 */
212  gcry_sexp_sprint (key->sexp,
213  GCRYSEXP_FMT_DEFAULT,
214  b,
215  n));
216  *buffer = b;
217  return n;
218 }
219 
220 
231  size_t len)
232 {
234 
236  if (0 !=
237  gcry_sexp_new (&key->sexp,
238  buf,
239  len,
240  0))
241  {
243  "Decoded private key is not valid\n");
244  GNUNET_free (key);
245  return NULL;
246  }
247  if (0 != gcry_pk_testkey (key->sexp))
248  {
250  "Decoded private key is not valid\n");
252  return NULL;
253  }
254  return key;
255 }
256 
257 
267 {
269  gcry_mpi_t ne[2];
270  int rc;
271  gcry_sexp_t result;
272 
273  BENCHMARK_START (rsa_private_key_get_public);
274 
275  rc = key_from_sexp (ne, priv->sexp, "public-key", "ne");
276  if (0 != rc)
277  rc = key_from_sexp (ne, priv->sexp, "private-key", "ne");
278  if (0 != rc)
279  rc = key_from_sexp (ne, priv->sexp, "rsa", "ne");
280  if (0 != rc)
281  {
282  GNUNET_break_op (0);
283  return NULL;
284  }
285  rc = gcry_sexp_build (&result,
286  NULL,
287  "(public-key(rsa(n %m)(e %m)))",
288  ne[0],
289  ne[1]);
290  gcry_mpi_release (ne[0]);
291  gcry_mpi_release (ne[1]);
292  pub = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
293  pub->sexp = result;
294  BENCHMARK_END (rsa_private_key_get_public);
295  return pub;
296 }
297 
298 
304 void
306 {
307  gcry_sexp_release (key->sexp);
308  GNUNET_free (key);
309 }
310 
311 
313 
318 {
322  uint16_t modulus_length GNUNET_PACKED;
323 
327  uint16_t public_exponent_length GNUNET_PACKED;
328 
329  /* followed by variable-size modulus and
330  public exponent follows as big-endian encoded
331  integers */
332 };
333 
335 
336 
345 size_t
348  char **buffer)
349 {
350  gcry_mpi_t ne[2];
351  size_t n_size;
352  size_t e_size;
353  size_t rsize;
354  size_t buf_size;
355  char *buf;
357  int ret;
358 
359  ret = key_from_sexp (ne, key->sexp, "public-key", "ne");
360  if (0 != ret)
361  ret = key_from_sexp (ne, key->sexp, "rsa", "ne");
362  if (0 != ret)
363  {
364  GNUNET_break (0);
365  *buffer = NULL;
366  return 0;
367  }
368  gcry_mpi_print (GCRYMPI_FMT_USG,
369  NULL,
370  0,
371  &n_size,
372  ne[0]);
373  gcry_mpi_print (GCRYMPI_FMT_USG,
374  NULL,
375  0,
376  &e_size,
377  ne[1]);
378  if ( (e_size > UINT16_MAX) ||
379  (n_size > UINT16_MAX) )
380  {
381  GNUNET_break (0);
382  *buffer = NULL;
383  gcry_mpi_release (ne[0]);
384  gcry_mpi_release (ne[1]);
385  return 0;
386  }
387  buf_size = n_size + e_size + sizeof (hdr);
388  buf = GNUNET_malloc (buf_size);
389  hdr.modulus_length = htons ((uint16_t) n_size);
390  hdr.public_exponent_length = htons ((uint16_t) e_size);
391  memcpy (buf, &hdr, sizeof (hdr));
392  GNUNET_assert (0 ==
393  gcry_mpi_print (GCRYMPI_FMT_USG,
394  (unsigned char *) &buf[sizeof (hdr)],
395  n_size,
396  &rsize,
397  ne[0]));
398 
399  GNUNET_assert (0 ==
400  gcry_mpi_print (GCRYMPI_FMT_USG,
401  (unsigned char *) &buf[sizeof (hdr) + n_size],
402  e_size,
403  &rsize,
404  ne[1]));
405  *buffer = buf;
406  gcry_mpi_release (ne[0]);
407  gcry_mpi_release (ne[1]);
408  return buf_size;
409 }
410 
411 
418 void
420  struct GNUNET_HashCode *hc)
421 {
422  char *buf;
423  size_t buf_size;
424 
425  buf_size = GNUNET_CRYPTO_rsa_public_key_encode (key,
426  &buf);
427  GNUNET_CRYPTO_hash (buf,
428  buf_size,
429  hc);
430  GNUNET_free (buf);
431 }
432 
433 
444  size_t len)
445 {
448  size_t e_size;
449  size_t n_size;
450  gcry_mpi_t n;
451  gcry_mpi_t e;
452  gcry_sexp_t data;
453 
454  if (len < sizeof (hdr))
455  {
456  GNUNET_break_op (0);
457  return NULL;
458  }
459  memcpy (&hdr, buf, sizeof (hdr));
460  n_size = ntohs (hdr.modulus_length);
461  e_size = ntohs (hdr.public_exponent_length);
462  if (len != sizeof (hdr) + e_size + n_size)
463  {
464  GNUNET_break_op (0);
465  return NULL;
466  }
467  if (0 !=
468  gcry_mpi_scan (&n,
469  GCRYMPI_FMT_USG,
470  &buf[sizeof (hdr)],
471  n_size,
472  NULL))
473  {
474  GNUNET_break_op (0);
475  return NULL;
476  }
477  if (0 !=
478  gcry_mpi_scan (&e,
479  GCRYMPI_FMT_USG,
480  &buf[sizeof (hdr) + n_size],
481  e_size,
482  NULL))
483  {
484  GNUNET_break_op (0);
485  gcry_mpi_release (n);
486  return NULL;
487  }
488 
489  if (0 !=
490  gcry_sexp_build (&data,
491  NULL,
492  "(public-key(rsa(n %m)(e %m)))",
493  n,
494  e))
495  {
496  GNUNET_break (0);
497  gcry_mpi_release (n);
498  gcry_mpi_release (e);
499  return NULL;
500  }
501  gcry_mpi_release (n);
502  gcry_mpi_release (e);
503  key = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
504  key->sexp = data;
505  return key;
506 }
507 
508 
520 static int
521 rsa_gcd_validate (gcry_mpi_t r, gcry_mpi_t n)
522 {
523  gcry_mpi_t g;
524  int t;
525 
526  g = gcry_mpi_new (0);
527  t = gcry_mpi_gcd (g, r, n);
528  gcry_mpi_release (g);
529  return t;
530 }
531 
532 
540 static struct RsaBlindingKey *
542  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks)
543 {
544  char *xts = "Blinding KDF extrator HMAC key"; /* Trusts bks' randomness more */
545  struct RsaBlindingKey *blind;
546  gcry_mpi_t n;
547 
548  blind = GNUNET_new (struct RsaBlindingKey);
549  GNUNET_assert (NULL != blind);
550 
551  /* Extract the composite n from the RSA public key */
552  GNUNET_assert (0 == key_from_sexp (&n, pkey->sexp, "rsa", "n"));
553  /* Assert that it at least looks like an RSA key */
554  GNUNET_assert (0 == gcry_mpi_get_flag (n, GCRYMPI_FLAG_OPAQUE));
555 
556  GNUNET_CRYPTO_kdf_mod_mpi (&blind->r,
557  n,
558  xts, strlen (xts),
559  bks, sizeof(*bks),
560  "Blinding KDF");
561  if (0 == rsa_gcd_validate (blind->r, n))
562  {
563  GNUNET_free (blind);
564  blind = NULL;
565  }
566 
567  gcry_mpi_release (n);
568  return blind;
569 }
570 
571 
572 /*
573  We originally added GNUNET_CRYPTO_kdf_mod_mpi for the benifit of the
574  previous routine.
575 
576  There was previously a call to GNUNET_CRYPTO_kdf in
577  bkey = rsa_blinding_key_derive (len, bks);
578  that gives exactly len bits where
579  len = GNUNET_CRYPTO_rsa_public_key_len (pkey);
580 
581  Now r = 2^(len-1)/pkey.n is the probability that a set high bit being
582  okay, meaning bkey < pkey.n. It follows that (1-r)/2 of the time bkey >
583  pkey.n making the effective bkey be
584  bkey mod pkey.n = bkey - pkey.n
585  so the effective bkey has its high bit set with probability r/2.
586 
587  We expect r to be close to 1/2 if the exchange is honest, but the
588  exchange can choose r otherwise.
589 
590  In blind signing, the exchange sees
591  B = bkey * S mod pkey.n
592  On deposit, the exchange sees S so they can compute bkey' = B/S mod
593  pkey.n for all B they recorded to see if bkey' has it's high bit set.
594  Also, note the exchange can compute 1/S efficiently since they know the
595  factors of pkey.n.
596 
597  I suppose that happens with probability r/(1+r) if its the wrong B, not
598  completely sure. If otoh we've the right B, then we've the probability
599  r/2 of a set high bit in the effective bkey.
600 
601  Interestingly, r^2-r has a maximum at the default r=1/2 anyways, giving
602  the wrong and right probabilities 1/3 and 1/4, respectively.
603 
604  I feared this gives the exchange a meaningful fraction of a bit of
605  information per coin involved in the transaction. It sounds damaging if
606  numerous coins were involved. And it could run across transactions in
607  some scenarios.
608 
609  We fixed this by using a more uniform deterministic pseudo-random number
610  generator for blinding factors. I do not believe this to be a problem
611  for the rsa_full_domain_hash routine, but better safe than sorry.
612  */
613 
614 
622 int
624  struct GNUNET_CRYPTO_RsaSignature *s2)
625 {
626  char *b1;
627  char *b2;
628  size_t z1;
629  size_t z2;
630  int ret;
631 
633  &b1);
635  &b2);
636  if (z1 != z2)
637  ret = 1;
638  else
639  ret = memcmp (b1,
640  b2,
641  z1);
642  GNUNET_free (b1);
643  GNUNET_free (b2);
644  return ret;
645 }
646 
647 
655 int
657  struct GNUNET_CRYPTO_RsaPublicKey *p2)
658 {
659  char *b1;
660  char *b2;
661  size_t z1;
662  size_t z2;
663  int ret;
664 
666  &b1);
668  &b2);
669  if (z1 != z2)
670  ret = 1;
671  else
672  ret = memcmp (b1,
673  b2,
674  z1);
675  GNUNET_free (b1);
676  GNUNET_free (b2);
677  return ret;
678 }
679 
680 
688 int
690  struct GNUNET_CRYPTO_RsaPrivateKey *p2)
691 {
692  char *b1;
693  char *b2;
694  size_t z1;
695  size_t z2;
696  int ret;
697 
699  &b1);
701  &b2);
702  if (z1 != z2)
703  ret = 1;
704  else
705  ret = memcmp (b1,
706  b2,
707  z1);
708  GNUNET_free (b1);
709  GNUNET_free (b2);
710  return ret;
711 }
712 
713 
720 unsigned int
722 {
723  gcry_mpi_t n;
724  unsigned int rval;
725 
726  if (0 != key_from_sexp (&n, key->sexp, "rsa", "n"))
727  { /* Not an RSA public key */
728  GNUNET_break (0);
729  return 0;
730  }
731  rval = gcry_mpi_get_nbits (n);
732  gcry_mpi_release (n);
733  return rval;
734 }
735 
736 
742 static void
744 {
745  gcry_mpi_release (bkey->r);
746  GNUNET_free (bkey);
747 }
748 
749 
757 static size_t
759  char **buffer)
760 {
761  size_t n;
762  char *b;
763  size_t rsize;
764 
765  gcry_mpi_print (GCRYMPI_FMT_USG,
766  NULL,
767  0,
768  &n,
769  v);
770  b = GNUNET_malloc (n);
771  GNUNET_assert (0 ==
772  gcry_mpi_print (GCRYMPI_FMT_USG,
773  (unsigned char *) b,
774  n,
775  &rsize,
776  v));
777  *buffer = b;
778  return n;
779 }
780 
781 
794 static gcry_mpi_t
796  const struct GNUNET_HashCode *hash)
797 {
798  gcry_mpi_t r, n;
799  char *xts;
800  size_t xts_len;
801  int ok;
802 
803  /* Extract the composite n from the RSA public key */
804  GNUNET_assert (0 == key_from_sexp (&n, pkey->sexp, "rsa", "n"));
805  /* Assert that it at least looks like an RSA key */
806  GNUNET_assert (0 == gcry_mpi_get_flag (n, GCRYMPI_FLAG_OPAQUE));
807 
808  /* We key with the public denomination key as a homage to RSA-PSS by *
809  * Mihir Bellare and Phillip Rogaway. Doing this lowers the degree *
810  * of the hypothetical polyomial-time attack on RSA-KTI created by a *
811  * polynomial-time one-more forgary attack. Yey seeding! */
812  xts_len = GNUNET_CRYPTO_rsa_public_key_encode (pkey, &xts);
813 
815  n,
816  xts, xts_len,
817  hash, sizeof(*hash),
818  "RSA-FDA FTpsW!");
819  GNUNET_free (xts);
820 
821  ok = rsa_gcd_validate (r, n);
822  gcry_mpi_release (n);
823  if (ok)
824  return r;
825  gcry_mpi_release (r);
826  return NULL;
827 }
828 
829 
840 int
842  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
844  char **buf, size_t *buf_size)
845 {
846  struct RsaBlindingKey *bkey;
847  gcry_mpi_t data;
848  gcry_mpi_t ne[2];
849  gcry_mpi_t r_e;
850  gcry_mpi_t data_r_e;
851  int ret;
852 
853  BENCHMARK_START (rsa_blind);
854 
855  GNUNET_assert (buf != NULL && buf_size != NULL);
856  ret = key_from_sexp (ne, pkey->sexp, "public-key", "ne");
857  if (0 != ret)
858  ret = key_from_sexp (ne, pkey->sexp, "rsa", "ne");
859  if (0 != ret)
860  {
861  GNUNET_break (0);
862  *buf = NULL;
863  *buf_size = 0;
864  return 0;
865  }
866 
867  data = rsa_full_domain_hash (pkey, hash);
868  if (NULL == data)
869  goto rsa_gcd_validate_failure;
870 
871  bkey = rsa_blinding_key_derive (pkey, bks);
872  if (NULL == bkey)
873  {
874  gcry_mpi_release (data);
875  goto rsa_gcd_validate_failure;
876  }
877 
878  r_e = gcry_mpi_new (0);
879  gcry_mpi_powm (r_e,
880  bkey->r,
881  ne[1],
882  ne[0]);
883  data_r_e = gcry_mpi_new (0);
884  gcry_mpi_mulm (data_r_e,
885  data,
886  r_e,
887  ne[0]);
888  gcry_mpi_release (data);
889  gcry_mpi_release (ne[0]);
890  gcry_mpi_release (ne[1]);
891  gcry_mpi_release (r_e);
892  rsa_blinding_key_free (bkey);
893 
894  *buf_size = numeric_mpi_alloc_n_print (data_r_e, buf);
895  gcry_mpi_release (data_r_e);
896 
897  BENCHMARK_END (rsa_blind);
898 
899  return GNUNET_YES;
900 
901 rsa_gcd_validate_failure:
902  /* We know the RSA key is malicious here, so warn the wallet. */
903  /* GNUNET_break_op (0); */
904  gcry_mpi_release (ne[0]);
905  gcry_mpi_release (ne[1]);
906  *buf = NULL;
907  *buf_size = 0;
908  return GNUNET_NO;
909 }
910 
911 
918 static gcry_sexp_t
919 mpi_to_sexp (gcry_mpi_t value)
920 {
921  gcry_sexp_t data = NULL;
922 
923  GNUNET_assert (0 ==
924  gcry_sexp_build (&data,
925  NULL,
926  "(data (flags raw) (value %M))",
927  value));
928  return data;
929 }
930 
931 
939 static struct GNUNET_CRYPTO_RsaSignature *
941  gcry_mpi_t value)
942 {
943  struct GNUNET_CRYPTO_RsaSignature *sig;
944  gcry_sexp_t data;
945  gcry_sexp_t result;
946  int rc;
947 
948  data = mpi_to_sexp (value);
949 
950  if (0 !=
951  (rc = gcry_pk_sign (&result,
952  data,
953  key->sexp)))
954  {
956  _ ("RSA signing failed at %s:%d: %s\n"),
957  __FILE__,
958  __LINE__,
959  gcry_strerror (rc));
960  GNUNET_break (0);
961  return NULL;
962  }
963 
964  /* Lenstra protection was first added to libgcrypt 1.6.4
965  * with commit c17f84bd02d7ee93845e92e20f6ddba814961588.
966  */
967 #if GCRYPT_VERSION_NUMBER < 0x010604
968  /* verify signature (guards against Lenstra's attack with fault injection...) */
969  struct GNUNET_CRYPTO_RsaPublicKey *public_key =
971  if (0 !=
972  gcry_pk_verify (result,
973  data,
974  public_key->sexp))
975  {
976  GNUNET_break (0);
978  gcry_sexp_release (data);
979  gcry_sexp_release (result);
980  return NULL;
981  }
983 #endif
984 
985  /* return signature */
986  gcry_sexp_release (data);
987  sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
988  sig->sexp = result;
989  return sig;
990 }
991 
992 
1003  const void *msg,
1004  size_t msg_len)
1005 {
1006  gcry_mpi_t v = NULL;
1007  struct GNUNET_CRYPTO_RsaSignature *sig;
1008 
1009  BENCHMARK_START (rsa_sign_blinded);
1010 
1011  GNUNET_assert (0 ==
1012  gcry_mpi_scan (&v,
1013  GCRYMPI_FMT_USG,
1014  msg,
1015  msg_len,
1016  NULL));
1017 
1018  sig = rsa_sign_mpi (key, v);
1019  gcry_mpi_release (v);
1020  BENCHMARK_END (rsa_sign_blinded);
1021  return sig;
1022 }
1023 
1024 
1034  const struct GNUNET_HashCode *hash)
1035 {
1037  gcry_mpi_t v = NULL;
1038  struct GNUNET_CRYPTO_RsaSignature *sig;
1039 
1041  v = rsa_full_domain_hash (pkey, hash);
1043  if (NULL == v) /* rsa_gcd_validate failed meaning */
1044  return NULL; /* our *own* RSA key is malicious. */
1045 
1046  sig = rsa_sign_mpi (key, v);
1047  gcry_mpi_release (v);
1048  return sig;
1049 }
1050 
1051 
1057 void
1059 {
1060  gcry_sexp_release (sig->sexp);
1061  GNUNET_free (sig);
1062 }
1063 
1064 
1072 size_t
1075  char **buffer)
1076 {
1077  gcry_mpi_t s;
1078  size_t buf_size;
1079  size_t rsize;
1080  unsigned char *buf;
1081  int ret;
1082 
1083  ret = key_from_sexp (&s,
1084  sig->sexp,
1085  "sig-val",
1086  "s");
1087  if (0 != ret)
1088  ret = key_from_sexp (&s,
1089  sig->sexp,
1090  "rsa",
1091  "s");
1092  GNUNET_assert (0 == ret);
1093  gcry_mpi_print (GCRYMPI_FMT_USG,
1094  NULL,
1095  0,
1096  &buf_size,
1097  s);
1098  buf = GNUNET_malloc (buf_size);
1099  GNUNET_assert (0 ==
1100  gcry_mpi_print (GCRYMPI_FMT_USG,
1101  buf,
1102  buf_size,
1103  &rsize,
1104  s));
1105  GNUNET_assert (rsize == buf_size);
1106  *buffer = (char *) buf;
1107  gcry_mpi_release (s);
1108  return buf_size;
1109 }
1110 
1111 
1122  size_t len)
1123 {
1124  struct GNUNET_CRYPTO_RsaSignature *sig;
1125  gcry_mpi_t s;
1126  gcry_sexp_t data;
1127 
1128  if (0 !=
1129  gcry_mpi_scan (&s,
1130  GCRYMPI_FMT_USG,
1131  buf,
1132  len,
1133  NULL))
1134  {
1135  GNUNET_break_op (0);
1136  return NULL;
1137  }
1138 
1139  if (0 !=
1140  gcry_sexp_build (&data,
1141  NULL,
1142  "(sig-val(rsa(s %M)))",
1143  s))
1144  {
1145  GNUNET_break (0);
1146  gcry_mpi_release (s);
1147  return NULL;
1148  }
1149  gcry_mpi_release (s);
1150  sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1151  sig->sexp = data;
1152  return sig;
1153 }
1154 
1155 
1164 {
1165  struct GNUNET_CRYPTO_RsaPublicKey *dup;
1166  gcry_sexp_t dup_sexp;
1167  size_t erroff;
1168 
1169  /* check if we really are exporting a public key */
1170  dup_sexp = gcry_sexp_find_token (key->sexp, "public-key", 0);
1171  GNUNET_assert (NULL != dup_sexp);
1172  gcry_sexp_release (dup_sexp);
1173  /* copy the sexp */
1174  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
1175  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
1176  dup->sexp = dup_sexp;
1177  return dup;
1178 }
1179 
1180 
1193  const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
1195 {
1196  struct RsaBlindingKey *bkey;
1197  gcry_mpi_t n;
1198  gcry_mpi_t s;
1199  gcry_mpi_t r_inv;
1200  gcry_mpi_t ubsig;
1201  int ret;
1202  struct GNUNET_CRYPTO_RsaSignature *sret;
1203 
1204  BENCHMARK_START (rsa_unblind);
1205 
1206  ret = key_from_sexp (&n, pkey->sexp, "public-key", "n");
1207  if (0 != ret)
1208  ret = key_from_sexp (&n, pkey->sexp, "rsa", "n");
1209  if (0 != ret)
1210  {
1211  GNUNET_break_op (0);
1212  return NULL;
1213  }
1214  ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1215  if (0 != ret)
1216  ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1217  if (0 != ret)
1218  {
1219  gcry_mpi_release (n);
1220  GNUNET_break_op (0);
1221  return NULL;
1222  }
1223 
1224  bkey = rsa_blinding_key_derive (pkey, bks);
1225  if (NULL == bkey)
1226  {
1227  /* RSA key is malicious since rsa_gcd_validate failed here.
1228  * It should have failed during GNUNET_CRYPTO_rsa_blind too though,
1229  * so the exchange is being malicious in an unfamilair way, maybe
1230  * just trying to crash us. */
1231  GNUNET_break_op (0);
1232  gcry_mpi_release (n);
1233  gcry_mpi_release (s);
1234  return NULL;
1235  }
1236 
1237  r_inv = gcry_mpi_new (0);
1238  if (1 !=
1239  gcry_mpi_invm (r_inv,
1240  bkey->r,
1241  n))
1242  {
1243  /* We cannot find r mod n, so gcd(r,n) != 1, which should get *
1244  * caught above, but we handle it the same here. */
1245  GNUNET_break_op (0);
1246  gcry_mpi_release (r_inv);
1247  rsa_blinding_key_free (bkey);
1248  gcry_mpi_release (n);
1249  gcry_mpi_release (s);
1250  return NULL;
1251  }
1252 
1253  ubsig = gcry_mpi_new (0);
1254  gcry_mpi_mulm (ubsig, s, r_inv, n);
1255  gcry_mpi_release (n);
1256  gcry_mpi_release (r_inv);
1257  gcry_mpi_release (s);
1258  rsa_blinding_key_free (bkey);
1259 
1260  sret = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1261  GNUNET_assert (0 ==
1262  gcry_sexp_build (&sret->sexp,
1263  NULL,
1264  "(sig-val (rsa (s %M)))",
1265  ubsig));
1266  gcry_mpi_release (ubsig);
1267  BENCHMARK_END (rsa_unblind);
1268  return sret;
1269 }
1270 
1271 
1281 int
1283  const struct GNUNET_CRYPTO_RsaSignature *sig,
1284  const struct GNUNET_CRYPTO_RsaPublicKey *pkey)
1285 {
1286  gcry_sexp_t data;
1287  gcry_mpi_t r;
1288  int rc;
1289 
1290  BENCHMARK_START (rsa_verify);
1291 
1292  r = rsa_full_domain_hash (pkey, hash);
1293  if (NULL == r)
1294  {
1295  GNUNET_break_op (0);
1296  /* RSA key is malicious since rsa_gcd_validate failed here.
1297  * It should have failed during GNUNET_CRYPTO_rsa_blind too though,
1298  * so the exchange is being malicious in an unfamilair way, maybe
1299  * just trying to crash us. Arguably, we've only an internal error
1300  * though because we should've detected this in our previous call
1301  * to GNUNET_CRYPTO_rsa_unblind. */return GNUNET_NO;
1302  }
1303 
1304  data = mpi_to_sexp (r);
1305  gcry_mpi_release (r);
1306 
1307  rc = gcry_pk_verify (sig->sexp,
1308  data,
1309  pkey->sexp);
1310  gcry_sexp_release (data);
1311  if (0 != rc)
1312  {
1314  _ ("RSA signature verification failed at %s:%d: %s\n"),
1315  __FILE__,
1316  __LINE__,
1317  gcry_strerror (rc));
1318  return GNUNET_SYSERR;
1319  BENCHMARK_END (rsa_verify);
1320  }
1321  BENCHMARK_END (rsa_verify);
1322  return GNUNET_OK;
1323 }
1324 
1325 
1335 {
1336  struct GNUNET_CRYPTO_RsaPrivateKey *dup;
1337  gcry_sexp_t dup_sexp;
1338  size_t erroff;
1339 
1340  /* check if we really are exporting a private key */
1341  dup_sexp = gcry_sexp_find_token (key->sexp, "private-key", 0);
1342  GNUNET_assert (NULL != dup_sexp);
1343  gcry_sexp_release (dup_sexp);
1344  /* copy the sexp */
1345  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
1346  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPrivateKey);
1347  dup->sexp = dup_sexp;
1348  return dup;
1349 }
1350 
1351 
1360 {
1361  struct GNUNET_CRYPTO_RsaSignature *dup;
1362  gcry_sexp_t dup_sexp;
1363  size_t erroff;
1364  gcry_mpi_t s;
1365  int ret;
1366 
1367  /* verify that this is an RSA signature */
1368  ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1369  if (0 != ret)
1370  ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1371  GNUNET_assert (0 == ret);
1372  gcry_mpi_release (s);
1373  /* copy the sexp */
1374  GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", sig->sexp));
1375  dup = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1376  dup->sexp = dup_sexp;
1377  return dup;
1378 }
1379 
1380 
1381 /* 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:841
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:721
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:541
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:1073
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:1359
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:795
#define BENCHMARK_START(opname)
Definition: benchmark.h:57
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:126
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:656
uint16_t modulus_length
length of modulus &#39;n&#39; in bytes, in NBO
Definition: crypto_rsa.c:322
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:230
#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:58
void GNUNET_CRYPTO_rsa_public_key_free(struct GNUNET_CRYPTO_RsaPublicKey *key)
Free memory occupied by the public key.
Definition: crypto_rsa.c:305
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:265
static int ok
Return value from &#39;main&#39; (0 == success)
static int ret
Return value of the commandline.
Definition: gnunet-abd.c:81
static struct Experiment * e
#define GNUNET_NO
Definition: gnunet_common.h:86
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:623
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:83
#define GNUNET_new(type)
Allocate a struct or union of the given type.
static struct GNUNET_SCHEDULER_Task * t
Main task.
uint16_t public_exponent_length
length of exponent in bytes, in NBO
Definition: crypto_rsa.c:327
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:1121
#define GNUNET_NETWORK_STRUCT_BEGIN
Define as empty, GNUNET_PACKED should suffice, but this won&#39;t work on W32.
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:919
#define _(String)
GNU gettext support macro.
Definition: platform.h:180
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:443
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:1282
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:689
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:758
#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:48
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:521
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:940
Format of the header of a serialized RSA public key.
Definition: crypto_rsa.c:317
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:419
struct GNUNET_HashCode key
The key used in the DHT.
#define GNUNET_SYSERR
Definition: gnunet_common.h:84
static void rsa_blinding_key_free(struct RsaBlindingKey *bkey)
Destroy a blinding key.
Definition: crypto_rsa.c:743
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:1058
#define GNUNET_NETWORK_STRUCT_END
Define as empty, GNUNET_PACKED should suffice, but this won&#39;t work on W32;.
#define GNUNET_PACKED
gcc-ism to get packed structs.
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
GNUNET_NETWORK_STRUCT_END 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:346
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:1333
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:1163
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:1192
Constant-size pre-secret for blinding key generation.
#define GNUNET_YES
Definition: gnunet_common.h:85
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:1033
static int list
Set if we should print a list of currently running services.
Definition: gnunet-arm.c:69
#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:1002
uint16_t len
length of data (which is always a uint32_t, but presumably this can be used to specify that fewer byt...