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t-mpi-bit.c
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/* t-mpi-bit.c - Tests for bit level functions
* Copyright (C) 2006 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdarg.h>
#include "../src/gcrypt.h"
#define PGM "t-mpi-bit"
static const char *wherestr;
static int verbose;
static int error_count;
#define xmalloc(a) gcry_xmalloc ((a))
#define xcalloc(a,b) gcry_xcalloc ((a),(b))
#define xfree(a) gcry_free ((a))
#define pass() do { ; } while (0)
static void
show (const char *format, ...)
{
va_list arg_ptr;
if (!verbose)
return;
fprintf (stderr, "%s: ", PGM);
va_start (arg_ptr, format);
vfprintf (stderr, format, arg_ptr);
va_end (arg_ptr);
}
static void
fail (const char *format, ...)
{
va_list arg_ptr;
fflush (stdout);
fprintf (stderr, "%s: ", PGM);
if (wherestr)
fprintf (stderr, "%s: ", wherestr);
va_start (arg_ptr, format);
vfprintf (stderr, format, arg_ptr);
va_end (arg_ptr);
error_count++;
}
static void
die (const char *format, ...)
{
va_list arg_ptr;
fflush (stdout);
fprintf (stderr, "%s: ", PGM);
if (wherestr)
fprintf (stderr, "%s: ", wherestr);
va_start (arg_ptr, format);
vfprintf (stderr, format, arg_ptr);
va_end (arg_ptr);
exit (1);
}
/* Allocate a bit string consisting of '0' and '1' from the MPI
A. Return the LENGTH least significant bits. Caller needs to xfree
the result. */
static char *
mpi2bitstr (gcry_mpi_t a, size_t length)
{
char *p, *buf;
buf = p = xmalloc (length+1);
while (length--)
*p++ = gcry_mpi_test_bit (a, length) ? '1':'0';
*p = 0;
return buf;
}
/* Allocate a bit string consisting of '0' and '1' from the MPI A. Do
not return any leading zero bits. Caller needs to xfree the
result. */
static char *
mpi2bitstr_nlz (gcry_mpi_t a)
{
char *p, *buf;
size_t length = gcry_mpi_get_nbits (a);
if (!length)
{
buf = p = xmalloc (2);
*p++ = '0';
}
else
{
buf = p = xmalloc (length + 1);
while (length-- > 1)
*p++ = gcry_mpi_test_bit (a, length) ? '1':'0';
*p++ = gcry_mpi_test_bit (a, 0) ? '1':'0';
}
*p = 0;
return buf;
}
/* Shift a bit string to the right. */
static void
rshiftbitstring (char *string, size_t n)
{
size_t len = strlen (string);
if (n > len)
n = len;
memmove (string+n, string, len-n);
memset (string, '0', n);
}
/* Shift a bit string to the left. Caller needs to free the result. */
static char *
lshiftbitstring (const char *string, size_t n)
{
size_t len = strlen (string);
char *result;
if (len+n+1 < len)
die ("internal overflow\n");
/* Allocate enough space. */
result = xmalloc (len+n+1);
for (; *string == '0' && string[1]; string++, len--)
;
memcpy (result, string, len);
if (*string == '0' && !string[1])
n = 0; /* Avoid extra nulls for an only 0 string. */
else
memset (result+len, '0', n);
result[len+n] = 0;
return result;
}
/* This is to check a bug reported by bpgcrypt at itaparica.org on
2006-07-31 against libgcrypt 1.2.2. */
static void
one_bit_only (int highbit)
{
gcry_mpi_t a;
char *result;
int i;
wherestr = "one_bit_only";
show ("checking that set_%sbit does only set one bit\n", highbit?"high":"");
a = gcry_mpi_new (0);
gcry_mpi_randomize (a, 70, GCRY_WEAK_RANDOM);
gcry_mpi_set_ui (a, 0);
if (highbit)
gcry_mpi_set_highbit (a, 42);
else
gcry_mpi_set_bit (a, 42);
if (!gcry_mpi_test_bit (a, 42))
fail ("failed to set a bit\n");
gcry_mpi_clear_bit (a, 42);
if (gcry_mpi_test_bit (a, 42))
fail ("failed to clear a bit\n");
result = mpi2bitstr (a, 70);
assert (strlen (result) == 70);
for (i=0; result[i]; i++)
if ( result[i] != '0' )
break;
if (result[i])
fail ("spurious bits detected\n");
xfree (result);
gcry_mpi_release (a);
}
/* Check that right shifting actually works for an amount larger than
the number of bits per limb. */
static void
test_rshift (int pass)
{
gcry_mpi_t a, b;
char *result, *result2;
int i;
wherestr = "test_rshift";
show ("checking that rshift works as expected (pass %d)\n", pass);
a = gcry_mpi_new (0);
b = gcry_mpi_new (0);
gcry_mpi_randomize (a, 70, GCRY_WEAK_RANDOM);
for (i=0; i < 75; i++)
{
gcry_mpi_rshift (b, a, i);
result = mpi2bitstr (b, 72);
result2 = mpi2bitstr (a, 72);
rshiftbitstring (result2, i);
if (strcmp (result, result2))
{
show ("got =%s\n", result);
show ("want=%s\n", result2);
fail ("rshift by %d failed\n", i);
}
xfree (result);
xfree (result2);
}
/* Again. This time using in-place operation. */
gcry_mpi_randomize (a, 70, GCRY_WEAK_RANDOM);
for (i=0; i < 75; i++)
{
gcry_mpi_release (b);
b = gcry_mpi_copy (a);
gcry_mpi_rshift (b, b, i);
result = mpi2bitstr (b, 72);
result2 = mpi2bitstr (a, 72);
rshiftbitstring (result2, i);
if (strcmp (result, result2))
{
show ("got =%s\n", result);
show ("want=%s\n", result2);
fail ("in-place rshift by %d failed\n", i);
}
xfree (result2);
xfree (result);
}
gcry_mpi_release (b);
gcry_mpi_release (a);
}
/* Check that left shifting works correctly. */
static void
test_lshift (int pass)
{
static int size_list[] = {1, 31, 32, 63, 64, 65, 70, 0};
int size_idx;
gcry_mpi_t a, b;
char *tmpstr, *result, *result2;
int i;
wherestr = "test_lshift";
show ("checking that lshift works as expected (pass %d)\n", pass);
for (size_idx=0; size_list[size_idx]; size_idx++)
{
a = gcry_mpi_new (0);
b = gcry_mpi_new (0);
/* gcry_mpi_randomize rounds up to full bytes, thus we need to
use gcry_mpi_clear_highbit to fix that. */
gcry_mpi_randomize (a, size_list[size_idx], GCRY_WEAK_RANDOM);
gcry_mpi_clear_highbit (a, size_list[size_idx]);
for (i=0; i < 75; i++)
{
gcry_mpi_lshift (b, a, i);
result = mpi2bitstr_nlz (b);
tmpstr = mpi2bitstr_nlz (a);
result2 = lshiftbitstring (tmpstr, i);
xfree (tmpstr);
if (strcmp (result, result2))
{
show ("got =%s\n", result);
show ("want=%s\n", result2);
fail ("lshift by %d failed\n", i);
}
xfree (result);
xfree (result2);
}
/* Again. This time using in-place operation. */
gcry_mpi_randomize (a, size_list[size_idx], GCRY_WEAK_RANDOM);
gcry_mpi_clear_highbit (a, size_list[size_idx]);
for (i=0; i < 75; i++)
{
gcry_mpi_release (b);
b = gcry_mpi_copy (a);
gcry_mpi_lshift (b, b, i);
result = mpi2bitstr_nlz (b);
tmpstr = mpi2bitstr_nlz (a);
result2 = lshiftbitstring (tmpstr, i);
xfree (tmpstr);
if (strcmp (result, result2))
{
show ("got =%s\n", result);
show ("want=%s\n", result2);
fail ("in-place lshift by %d failed\n", i);
}
xfree (result2);
xfree (result);
}
gcry_mpi_release (b);
gcry_mpi_release (a);
}
}
/* Bug fixed on 2014-05-09:
a = gcry_mpi_new (1523);
gcry_mpi_set_bit (a, 1536);
didn't initialized all limbs in A. */
static void
set_bit_with_resize (void)
{
gcry_mpi_t a;
int i;
wherestr = "set_bit_with_resize";
show ("checking that set_bit initializes all limbs\n");
a = gcry_mpi_new (1536);
gcry_mpi_set_bit (a, 1536);
if (!gcry_mpi_test_bit (a, 1536))
fail ("failed to set a bit\n");
for (i=0; i < 1536; i++)
{
if (gcry_mpi_test_bit (a, i))
{
fail ("spurious bit detected\n");
break;
}
}
if (gcry_mpi_test_bit (a, 1537))
fail ("more bits set than expected\n");
gcry_mpi_release (a);
wherestr = "set_highbit_with_resize";
show ("checking that set_highbit initializes all limbs\n");
a = gcry_mpi_new (1536);
gcry_mpi_set_highbit (a, 1536);
if (!gcry_mpi_test_bit (a, 1536))
fail ("failed to set a bit\n");
for (i=0; i < 1536; i++)
{
if (gcry_mpi_test_bit (a, i))
{
fail ("spurious bit detected\n");
break;
}
}
if (gcry_mpi_test_bit (a, 1537))
fail ("more bits set than expected\n");
gcry_mpi_release (a);
}
int
main (int argc, char **argv)
{
int debug = 0;
int i;
if (argc > 1 && !strcmp (argv[1], "--verbose"))
verbose = 1;
else if (argc > 1 && !strcmp (argv[1], "--debug"))
verbose = debug = 1;
if (!gcry_check_version (GCRYPT_VERSION))
die ("version mismatch\n");
gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
if (debug)
gcry_control (GCRYCTL_SET_DEBUG_FLAGS, 1u, 0);
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
one_bit_only (0);
one_bit_only (1);
for (i=0; i < 5; i++)
test_rshift (i); /* Run several times due to random initializations. */
for (i=0; i < 5; i++)
test_lshift (i); /* Run several times due to random initializations. */
set_bit_with_resize ();
show ("All tests completed. Errors: %d\n", error_count);
return error_count ? 1 : 0;
}

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