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/* mpiapi.a - MPI function interface
* Copyright (C) 1998 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GnuPG 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>
#define GCRYPT_NO_MPI_MACROS 1
#include "g10lib.h"
#include "mpi.h"
int
gcry_mpi_api( enum gcry_mpi_opcode opcode, int n_args, ... )
{
switch( opcode ) {
case GCRYMPI_NOOP:
return 0;
default:
return GCRYERR_INV_OP;
}
}
struct gcry_mpi *
gcry_mpi_new( enum gcry_mpi_opcode opcode,
unsigned int nbits, struct gcry_mpi *val)
{
switch( opcode ) {
case GCRYMPI_NEW:
return mpi_alloc( (nbits+BITS_PER_MPI_LIMB-1) / BITS_PER_MPI_LIMB );
case GCRYMPI_SNEW:
return mpi_alloc_secure( (nbits+BITS_PER_MPI_LIMB-1)
/ BITS_PER_MPI_LIMB );
case GCRYMPI_COPY:
return mpi_copy( val );
default:
return NULL;
}
}
int
gcry_mpi_scan( struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,
const char *buffer, size_t *nbytes )
{
struct gcry_mpi *a = NULL;
unsigned int len;
len = nbytes? *nbytes : strlen(buffer);
/* TODO: add formats to allocate the MPI in secure memory */
if( format == GCRYMPI_FMT_STD ) {
a = mpi_read_from_buffer( (char*)buffer, &len, 0 );
if( nbytes )
*nbytes = len;
if( ret_mpi )
*ret_mpi = a;
else
mpi_free(a);
return a? 0 : GCRYERR_INV_OBJ;
}
else if( format == GCRYMPI_FMT_SSH ) {
const byte *s = buffer;
size_t n;
if( len < 4 )
return GCRYERR_TOO_SHORT;
n = s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3];
s += 4; len -= 4;
if( n > len )
return GCRYERR_TOO_LARGE; /* or should it be too_short */
a = mpi_alloc( (n+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB );
if( len ) { /* not zero */
a->sign = *s & 0x80;
if( a->sign ) {
/* FIXME: we have to convert from 2compl to magnitude format */
mpi_free(a);
return GCRYERR_INTERNAL;
}
else
mpi_set_buffer( a, s, n, 0 );
}
if( nbytes )
*nbytes = n+4;
if( ret_mpi )
*ret_mpi = a;
else
mpi_free(a);
return 0;
}
else
return GCRYERR_INV_ARG;
}
/****************
* Write a in format into buffer which has a length of *NBYTES.
* Return the number of bytes actually written in nbytes.
* TODO: Move this stuff to mpicoder.c or replace mpicoder.c
*/
int
gcry_mpi_print( enum gcry_mpi_format format, char *buffer, size_t *nbytes,
struct gcry_mpi *a )
{
unsigned int nbits = mpi_get_nbits(a);
size_t len;
if( !nbytes )
return GCRYERR_INV_ARG;
len = *nbytes;
if( format == GCRYMPI_FMT_STD ) {
unsigned int n = (nbits + 7)/8;
byte *s = buffer;
char *tmp;
if( a->sign )
return GCRYERR_INV_ARG; /* pgp format can only handle unsigned */
if( n+2 > len )
return GCRYERR_TOO_SHORT; /* the provided buffer is too short */
s[0] = nbits >> 8;
s[1] = nbits;
tmp = mpi_get_buffer( a, &n, NULL );
memcpy( s+2, tmp, n );
m_free(tmp);
*nbytes = n+2;
return 0;
}
else if( format == GCRYMPI_FMT_SSH ) {
byte *s = buffer;
char *tmp;
int extra = 0;
unsigned int n;
if( a->sign )
return GCRYERR_INTERNAL; /* can't handle it yet */
tmp = mpi_get_buffer( a, &n, NULL );
if( n && (*tmp & 0x80) ) {
n++;
extra=1;
}
if( n+4 > len ) {
m_free(tmp);
return GCRYERR_TOO_SHORT; /* the provided buffer is too short */
}
*s++ = n >> 24;
*s++ = n >> 16;
*s++ = n >> 8;
*s++ = n;
if( extra )
*s++ = 0;
memcpy( s, tmp, n-extra );
m_free(tmp);
*nbytes = 4+n;
return 0;
}
else if( format == GCRYMPI_FMT_HEX ) {
byte *s = buffer;
byte *tmp;
int i;
int extra = 0;
unsigned int n=0;
if( a->sign )
return GCRYERR_INTERNAL; /* can't handle it yet */
tmp = mpi_get_buffer( a, &n, NULL );
if( n && (*tmp & 0x80) ) {
n++;
extra=1;
}
if( 2*n+2+1 > len ) {
m_free(tmp);
return GCRYERR_TOO_SHORT; /* the provided buffer is too short */
}
if( extra || !n ) {
*s++ = '0';
*s++ = '0';
n += 2;
}
#if BYTES_PER_MPI_LIMB == 2
#define X "4"
#elif BYTES_PER_MPI_LIMB == 4
#define X "8"
#elif BYTES_PER_MPI_LIMB == 8
#define X "16"
#else
#error please define the format here
#endif
for(i=0; i < n; i++ ) {
unsigned int c = tmp[i];
*s++ = (c >> 4) < 10? '0'+(c>>4) : 'A'+(c>>4)-10 ;
c &= 15;
*s++ = c < 10? '0'+c : 'A'+c-10 ;
}
*s++ = 0;
*nbytes = (char*)s - buffer;
#undef X
return 0;
}
else
return GCRYERR_INV_ARG;
}
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