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mpiutil.c
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/* mpiutil.ac - Utility functions for MPI
* Copyright (C) 1998, 2000, 2001, 2002, 2003,
* 2007 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, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "g10lib.h"
#include "mpi-internal.h"
#include "memory.h"
#include "mod-source-info.h"
const char *
_gcry_mpi_get_hw_config (void)
{
return mod_source_info + 1;
}
/****************
* Note: It was a bad idea to use the number of limbs to allocate
* because on a alpha the limbs are large but we normally need
* integers of n bits - So we should change this to bits (or bytes).
*
* But mpi_alloc is used in a lot of places :-(. New code
* should use mpi_new.
*/
gcry_mpi_t
_gcry_mpi_alloc( unsigned nlimbs )
{
gcry_mpi_t a;
a = gcry_xmalloc( sizeof *a );
a->d = nlimbs? mpi_alloc_limb_space( nlimbs, 0 ) : NULL;
a->alloced = nlimbs;
a->nlimbs = 0;
a->sign = 0;
a->flags = 0;
return a;
}
void
_gcry_mpi_m_check( gcry_mpi_t a )
{
_gcry_check_heap(a);
_gcry_check_heap(a->d);
}
gcry_mpi_t
_gcry_mpi_alloc_secure( unsigned nlimbs )
{
gcry_mpi_t a;
a = gcry_xmalloc( sizeof *a );
a->d = nlimbs? mpi_alloc_limb_space( nlimbs, 1 ) : NULL;
a->alloced = nlimbs;
a->flags = 1;
a->nlimbs = 0;
a->sign = 0;
return a;
}
mpi_ptr_t
_gcry_mpi_alloc_limb_space( unsigned int nlimbs, int secure )
{
mpi_ptr_t p;
size_t len;
len = (nlimbs ? nlimbs : 1) * sizeof (mpi_limb_t);
p = secure ? gcry_xmalloc_secure (len) : gcry_xmalloc (len);
if (! nlimbs)
*p = 0;
return p;
}
void
_gcry_mpi_free_limb_space( mpi_ptr_t a, unsigned int nlimbs)
{
if (a)
{
size_t len = nlimbs * sizeof(mpi_limb_t);
/* If we have information on the number of allocated limbs, we
better wipe that space out. This is a failsafe feature if
secure memory has been disabled or was not properly
implemented in user provided allocation functions. */
if (len)
wipememory (a, len);
gcry_free(a);
}
}
void
_gcry_mpi_assign_limb_space( gcry_mpi_t a, mpi_ptr_t ap, unsigned int nlimbs )
{
_gcry_mpi_free_limb_space (a->d, a->alloced);
a->d = ap;
a->alloced = nlimbs;
}
/****************
* Resize the array of A to NLIMBS. The additional space is cleared
* (set to 0).
*/
void
_gcry_mpi_resize (gcry_mpi_t a, unsigned nlimbs)
{
size_t i;
if (nlimbs <= a->alloced)
{
/* We only need to clear the new space (this is a nop if the
limb space is already of the correct size. */
for (i=a->nlimbs; i < a->alloced; i++)
a->d[i] = 0;
return;
}
/* Actually resize the limb space. */
if (a->d)
{
a->d = gcry_xrealloc (a->d, nlimbs * sizeof (mpi_limb_t));
for (i=a->alloced; i < nlimbs; i++)
a->d[i] = 0;
}
else
{
if (a->flags & 1)
/* Secure memory is wanted. */
a->d = gcry_xcalloc_secure (nlimbs , sizeof (mpi_limb_t));
else
/* Standard memory. */
a->d = gcry_xcalloc (nlimbs , sizeof (mpi_limb_t));
}
a->alloced = nlimbs;
}
void
_gcry_mpi_clear( gcry_mpi_t a )
{
a->nlimbs = 0;
a->flags = 0;
}
void
_gcry_mpi_free( gcry_mpi_t a )
{
if (!a )
return;
if ((a->flags & 4))
gcry_free( a->d );
else
{
_gcry_mpi_free_limb_space(a->d, a->alloced);
}
if ((a->flags & ~7))
log_bug("invalid flag value in mpi\n");
gcry_free(a);
}
static void
mpi_set_secure( gcry_mpi_t a )
{
mpi_ptr_t ap, bp;
if ( (a->flags & 1) )
return;
a->flags |= 1;
ap = a->d;
if (!a->nlimbs)
{
assert(!ap);
return;
}
bp = mpi_alloc_limb_space (a->nlimbs, 1);
MPN_COPY( bp, ap, a->nlimbs );
a->d = bp;
_gcry_mpi_free_limb_space (ap, a->alloced);
}
gcry_mpi_t
gcry_mpi_set_opaque( gcry_mpi_t a, void *p, unsigned int nbits )
{
if (!a)
a = mpi_alloc(0);
if( a->flags & 4 )
gcry_free( a->d );
else
_gcry_mpi_free_limb_space (a->d, a->alloced);
a->d = p;
a->alloced = 0;
a->nlimbs = 0;
a->sign = nbits;
a->flags = 4;
return a;
}
void *
gcry_mpi_get_opaque( gcry_mpi_t a, unsigned int *nbits )
{
if( !(a->flags & 4) )
log_bug("mpi_get_opaque on normal mpi\n");
if( nbits )
*nbits = a->sign;
return a->d;
}
/****************
* Note: This copy function should not interpret the MPI
* but copy it transparently.
*/
gcry_mpi_t
gcry_mpi_copy( gcry_mpi_t a )
{
int i;
gcry_mpi_t b;
if( a && (a->flags & 4) ) {
void *p = gcry_is_secure(a->d)? gcry_xmalloc_secure( (a->sign+7)/8 )
: gcry_xmalloc( (a->sign+7)/8 );
memcpy( p, a->d, (a->sign+7)/8 );
b = gcry_mpi_set_opaque( NULL, p, a->sign );
}
else if( a ) {
b = mpi_is_secure(a)? mpi_alloc_secure( a->nlimbs )
: mpi_alloc( a->nlimbs );
b->nlimbs = a->nlimbs;
b->sign = a->sign;
b->flags = a->flags;
for(i=0; i < b->nlimbs; i++ )
b->d[i] = a->d[i];
}
else
b = NULL;
return b;
}
/****************
* This function allocates an MPI which is optimized to hold
* a value as large as the one given in the argument and allocates it
* with the same flags as A.
*/
gcry_mpi_t
_gcry_mpi_alloc_like( gcry_mpi_t a )
{
gcry_mpi_t b;
if( a && (a->flags & 4) ) {
int n = (a->sign+7)/8;
void *p = gcry_is_secure(a->d)? gcry_malloc_secure( n )
: gcry_malloc( n );
memcpy( p, a->d, n );
b = gcry_mpi_set_opaque( NULL, p, a->sign );
}
else if( a ) {
b = mpi_is_secure(a)? mpi_alloc_secure( a->nlimbs )
: mpi_alloc( a->nlimbs );
b->nlimbs = 0;
b->sign = 0;
b->flags = a->flags;
}
else
b = NULL;
return b;
}
gcry_mpi_t
gcry_mpi_set( gcry_mpi_t w, gcry_mpi_t u)
{
mpi_ptr_t wp, up;
mpi_size_t usize = u->nlimbs;
int usign = u->sign;
if (!w)
w = _gcry_mpi_alloc( mpi_get_nlimbs(u) );
RESIZE_IF_NEEDED(w, usize);
wp = w->d;
up = u->d;
MPN_COPY( wp, up, usize );
w->nlimbs = usize;
w->flags = u->flags;
w->sign = usign;
return w;
}
gcry_mpi_t
gcry_mpi_set_ui( gcry_mpi_t w, unsigned long u)
{
if (!w)
w = _gcry_mpi_alloc (1);
/* FIXME: If U is 0 we have no need to resize and thus possible
allocating the the limbs. */
RESIZE_IF_NEEDED(w, 1);
w->d[0] = u;
w->nlimbs = u? 1:0;
w->sign = 0;
w->flags = 0;
return w;
}
gcry_err_code_t
_gcry_mpi_get_ui (gcry_mpi_t w, unsigned long *u)
{
gcry_err_code_t err = GPG_ERR_NO_ERROR;
unsigned long x = 0;
if (w->nlimbs > 1)
err = GPG_ERR_TOO_LARGE;
else if (w->nlimbs == 1)
x = w->d[0];
else
x = 0;
if (! err)
*u = x;
return err;
}
gcry_error_t
gcry_mpi_get_ui (gcry_mpi_t w, unsigned long *u)
{
gcry_err_code_t err = GPG_ERR_NO_ERROR;
err = _gcry_mpi_get_ui (w, u);
return gcry_error (err);
}
gcry_mpi_t
_gcry_mpi_alloc_set_ui( unsigned long u)
{
gcry_mpi_t w = mpi_alloc(1);
w->d[0] = u;
w->nlimbs = u? 1:0;
w->sign = 0;
return w;
}
void
gcry_mpi_swap( gcry_mpi_t a, gcry_mpi_t b)
{
struct gcry_mpi tmp;
tmp = *a; *a = *b; *b = tmp;
}
gcry_mpi_t
gcry_mpi_new( unsigned int nbits )
{
return _gcry_mpi_alloc ( (nbits+BITS_PER_MPI_LIMB-1)
/ BITS_PER_MPI_LIMB );
}
gcry_mpi_t
gcry_mpi_snew( unsigned int nbits )
{
return _gcry_mpi_alloc_secure ( (nbits+BITS_PER_MPI_LIMB-1)
/ BITS_PER_MPI_LIMB );
}
void
gcry_mpi_release( gcry_mpi_t a )
{
_gcry_mpi_free( a );
}
void
gcry_mpi_randomize( gcry_mpi_t w,
unsigned int nbits, enum gcry_random_level level )
{
unsigned char *p;
size_t nbytes = (nbits+7)/8;
if (level == GCRY_WEAK_RANDOM)
{
p = mpi_is_secure(w) ? gcry_xmalloc_secure (nbytes)
: gcry_xmalloc (nbytes);
gcry_create_nonce (p, nbytes);
}
else
{
p = mpi_is_secure(w) ? gcry_random_bytes_secure (nbytes, level)
: gcry_random_bytes (nbytes, level);
}
_gcry_mpi_set_buffer( w, p, nbytes, 0 );
gcry_free (p);
}
void
gcry_mpi_set_flag( gcry_mpi_t a, enum gcry_mpi_flag flag )
{
switch( flag ) {
case GCRYMPI_FLAG_SECURE: mpi_set_secure(a); break;
case GCRYMPI_FLAG_OPAQUE:
default: log_bug("invalid flag value\n");
}
}
void
gcry_mpi_clear_flag( gcry_mpi_t a, enum gcry_mpi_flag flag )
{
(void)a; /* Not yet used. */
switch (flag)
{
case GCRYMPI_FLAG_SECURE:
case GCRYMPI_FLAG_OPAQUE:
default: log_bug("invalid flag value\n");
}
}
int
gcry_mpi_get_flag( gcry_mpi_t a, enum gcry_mpi_flag flag )
{
switch (flag)
{
case GCRYMPI_FLAG_SECURE: return (a->flags & 1);
case GCRYMPI_FLAG_OPAQUE: return (a->flags & 4);
default: log_bug("invalid flag value\n");
}
/*NOTREACHED*/
return 0;
}

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