2 * Copyright (C) 2001, 2002, 2003, 2004, 2005, 2008, 2010 Free Software
5 * Author: Nikos Mavrogiannopoulos
7 * This file is part of GnuTLS.
9 * The GnuTLS is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public License
11 * as published by the Free Software Foundation; either version 2.1 of
12 * the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
26 /* Here lie everything that has to do with large numbers, libgcrypt and
27 * other stuff that didn't fit anywhere else.
30 #include <gnutls_int.h>
32 #include <gnutls_errors.h>
33 #include <gnutls_num.h>
34 #include <gnutls_mpi.h>
37 /* Functions that refer to the mpi library.
40 #define clearbit(v,n) ((unsigned char)(v) & ~( (unsigned char)(1) << (unsigned)(n)))
43 _gnutls_mpi_randomize (bigint_t r, unsigned int bits,
44 gnutls_rnd_level_t level)
46 size_t size = 1 + (bits / 8);
54 if (size < sizeof (tmpbuf))
60 buf = gnutls_malloc (size);
70 ret = _gnutls_rnd (level, buf, size);
77 /* mask the bits that weren't requested */
86 for (i = 8; i >= rem; i--)
87 buf[0] = clearbit (buf[0], i);
90 ret = _gnutls_mpi_scan (&tmp, buf, size);
105 _gnutls_mpi_set (r, tmp);
106 _gnutls_mpi_release (&tmp);
113 if (buf_release != 0)
119 _gnutls_mpi_release (bigint_t * x)
124 _gnutls_mpi_ops.bigint_release (*x);
128 /* returns zero on success
131 _gnutls_mpi_scan (bigint_t * ret_mpi, const void *buffer, size_t nbytes)
134 _gnutls_mpi_ops.bigint_scan (buffer, nbytes, GNUTLS_MPI_FORMAT_USG);
135 if (*ret_mpi == NULL)
138 return GNUTLS_E_MPI_SCAN_FAILED;
144 /* returns zero on success. Fails if the number is zero.
147 _gnutls_mpi_scan_nz (bigint_t * ret_mpi, const void *buffer, size_t nbytes)
151 ret = _gnutls_mpi_scan (ret_mpi, buffer, nbytes);
155 /* MPIs with 0 bits are illegal
157 if (_gnutls_mpi_cmp_ui (*ret_mpi, 0) == 0)
159 _gnutls_mpi_release (ret_mpi);
160 return GNUTLS_E_MPI_SCAN_FAILED;
167 _gnutls_mpi_scan_pgp (bigint_t * ret_mpi, const void *buffer, size_t nbytes)
170 _gnutls_mpi_ops.bigint_scan (buffer, nbytes, GNUTLS_MPI_FORMAT_PGP);
171 if (*ret_mpi == NULL)
174 return GNUTLS_E_MPI_SCAN_FAILED;
180 /* Always has the first bit zero */
182 _gnutls_mpi_dprint_lz (const bigint_t a, gnutls_datum_t * dest)
188 if (dest == NULL || a == NULL)
189 return GNUTLS_E_INVALID_REQUEST;
191 _gnutls_mpi_print_lz (a, NULL, &bytes);
194 buf = gnutls_malloc (bytes);
196 return GNUTLS_E_MEMORY_ERROR;
198 ret = _gnutls_mpi_print_lz (a, buf, &bytes);
211 _gnutls_mpi_dprint (const bigint_t a, gnutls_datum_t * dest)
217 if (dest == NULL || a == NULL)
218 return GNUTLS_E_INVALID_REQUEST;
220 _gnutls_mpi_print (a, NULL, &bytes);
222 buf = gnutls_malloc (bytes);
224 return GNUTLS_E_MEMORY_ERROR;
226 ret = _gnutls_mpi_print (a, buf, &bytes);
238 /* This function will copy the mpi data into a datum,
239 * but will set minimum size to 'size'. That means that
240 * the output value is left padded with zeros.
243 _gnutls_mpi_dprint_size (const bigint_t a, gnutls_datum_t * dest, size_t size)
250 if (dest == NULL || a == NULL)
251 return GNUTLS_E_INVALID_REQUEST;
253 _gnutls_mpi_print (a, NULL, &bytes);
255 buf = gnutls_malloc (MAX (size, bytes));
257 return GNUTLS_E_MEMORY_ERROR;
261 size_t diff = size - bytes;
262 for (i = 0; i < diff; i++)
264 ret = _gnutls_mpi_print (a, &buf[diff], &bytes);
268 ret = _gnutls_mpi_print (a, buf, &bytes);
278 dest->size = MAX (size, bytes);
282 /* this function reads an integer
283 * from asn1 structs. Combines the read and mpi_scan
287 _gnutls_x509_read_int (ASN1_TYPE node, const char *value, bigint_t * ret_mpi)
290 opaque *tmpstr = NULL;
294 result = asn1_read_value (node, value, NULL, &tmpstr_size);
295 if (result != ASN1_MEM_ERROR)
298 return _gnutls_asn2err (result);
301 tmpstr = gnutls_malloc (tmpstr_size);
305 return GNUTLS_E_MEMORY_ERROR;
308 result = asn1_read_value (node, value, tmpstr, &tmpstr_size);
309 if (result != ASN1_SUCCESS)
312 gnutls_free (tmpstr);
313 return _gnutls_asn2err (result);
316 result = _gnutls_mpi_scan (ret_mpi, tmpstr, tmpstr_size);
317 gnutls_free (tmpstr);
328 /* Writes the specified integer into the specified node.
331 _gnutls_x509_write_int (ASN1_TYPE node, const char *value, bigint_t mpi,
340 result = _gnutls_mpi_print_lz (mpi, NULL, &s_len);
342 result = _gnutls_mpi_print (mpi, NULL, &s_len);
344 if (result != GNUTLS_E_SHORT_MEMORY_BUFFER)
350 tmpstr = gnutls_malloc (s_len);
354 return GNUTLS_E_MEMORY_ERROR;
358 result = _gnutls_mpi_print_lz (mpi, tmpstr, &s_len);
360 result = _gnutls_mpi_print (mpi, tmpstr, &s_len);
365 gnutls_free (tmpstr);
366 return GNUTLS_E_MPI_PRINT_FAILED;
369 result = asn1_write_value (node, value, tmpstr, s_len);
371 gnutls_free (tmpstr);
373 if (result != ASN1_SUCCESS)
376 return _gnutls_asn2err (result);