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/* symapi.c - symmetric cipher 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
*/
/* fixme: merge this function with ../cipher/cipher.c */
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>
#include "g10lib.h"
#define G10_MPI_H /* fake mpi.h header */
#include "cipher.h"
/* FIXME: We should really have the m_lib functions to allow
* overriding of the default malloc functions
* For now use this kludge: */
#define m_lib_alloc m_alloc
#define m_lib_alloc_clear m_alloc_clear
#define m_lib_free m_free
#define CONTEXT_MAGIC 0x12569afe
struct gcry_cipher_context {
u32 magic;
int mode;
unsigned flags;
CIPHER_HANDLE hd;
};
GCRY_CIPHER_HD
gcry_cipher_open( int algo, int mode, unsigned flags )
{
GCRY_CIPHER_HD h;
/* check whether the algo is available */
if( check_cipher_algo( algo ) ) {
set_lasterr( GCRYERR_INV_ALGO );
return NULL;
}
/* check flags */
if( (flags & ~(GCRY_CIPHER_SECURE|GCRY_CIPHER_ENABLE_SYNC)) ) {
set_lasterr( GCRYERR_INV_ARG );
return NULL;
}
/* map mode to internal mode */
switch( mode ) {
case GCRY_CIPHER_MODE_NONE:
mode = CIPHER_MODE_DUMMY;
break;
case GCRY_CIPHER_MODE_ECB:
mode = CIPHER_MODE_ECB;
break;
case GCRY_CIPHER_MODE_CFB:
mode = (flags & GCRY_CIPHER_ENABLE_SYNC) ? CIPHER_MODE_PHILS_CFB
: CIPHER_MODE_CFB;
break;
case GCRY_CIPHER_MODE_CBC: mode = CIPHER_MODE_CBC;
break;
default:
set_lasterr( GCRYERR_INV_ALGO );
return NULL;
}
/* FIXME: issue a warning when CIPHER_MODE_NONE is used */
/* allocate the handle */
h = m_lib_alloc_clear( sizeof *h );
if( !h ) {
set_lasterr( GCRYERR_NOMEM );
return NULL;
}
h->magic = CONTEXT_MAGIC;
h->mode = mode;
h->hd = cipher_open( algo, mode, (flags & GCRY_CIPHER_SECURE) );
if( !h ) {
m_lib_free( h );
set_lasterr( GCRYERR_INTERNAL );
return NULL;
}
return h;
}
void
gcry_cipher_close( GCRY_CIPHER_HD h )
{
if( !h )
return;
if( h->magic != CONTEXT_MAGIC ) {
fatal_invalid_arg("gcry_cipher_close: already closed/invalid handle");
return;
}
cipher_close( h->hd );
h->magic = 0;
m_lib_free(h);
}
int gcry_cipher_ctl( GCRY_CIPHER_HD h, int cmd, byte *buffer, size_t buflen)
{
switch( cmd ) {
case GCRYCTL_SET_KEY:
cipher_setkey( h->hd, buffer, buflen );
break;
case GCRYCTL_SET_IV:
cipher_setiv( h->hd, buffer, buflen );
break;
case GCRYCTL_CFB_SYNC:
cipher_sync( h->hd );
default:
return set_lasterr( GCRYERR_INV_OP );
}
return 0;
}
/****************
* Return information about the cipher handle.
* -1 is returned on error and gcry_errno() may be used to get more information
* about the error.
*/
int
gcry_cipher_info( GCRY_CIPHER_HD h, int cmd, byte *buffer, size_t *nbytes)
{
switch( cmd ) {
default:
set_lasterr( GCRYERR_INV_OP );
return -1;
}
return 0;
}
/****************
* Return information about the given cipher algorithm
* WHAT select the kind of information returned:
* GCRYCTL_GET_KEYLEN:
* Return the length of the key, if the algorithm
* supports multiple key length, the maximum supported value
* is returnd. The length is return as number of octets.
* buffer and nbytes must be zero.
* GCRYCTL_GET_BLKLEN:
* Return the blocklength of the algorithm counted in octets.
* buffer and nbytes must be zero.
* GCRYCTL_TEST_ALGO:
* Returns 0 when the specified algorithm is available for use.
* buffer and nbytes must be zero.
*
* On error the value -1 is returned and the error reason may be
* retrieved by gcry_errno().
* Note: Because this function is in most caes used to return an
* integer value, we can make it easier for the caller to just look at
* the return value. The caller will in all cases consult the value
* and thereby detecting whether a error occured or not (i.e. while checking
* the block size)
*/
int
gcry_cipher_algo_info( int algo, int what, void *buffer, size_t *nbytes)
{
switch( what ) {
case GCRYCTL_GET_KEYLEN:
if( buffer || nbytes ) {
set_lasterr( GCRYERR_INV_ARG );
return -1;
}
BUG(); /* FIXME: implement this */
break;
case GCRYCTL_GET_BLKLEN:
if( buffer || nbytes ) {
set_lasterr( GCRYERR_INV_ARG );
return -1;
}
ui = cipher_get_blocksize( algo );
if( ui > 0 && ui < 10000 )
return (int)ui;
/* the only reason is an invalid algo or a strange blocksize */
set_lasterr( GCRYERR_INV_ALGO );
return -1;
case GCRYCTL_TEST_ALGO:
if( buffer || nbytes ) {
set_lasterr( GCRYERR_INV_ARG );
return -1;
}
if( check_cipher_algo( algo ) ) {
set_lasterr( GCRYERR_INV_ALGO );
return -1;
}
return 0;
default:
set_lasterr( GCRYERR_INV_OP );
return -1;
}
return 0;
}
/****************
* This function simply returns the name of the algorithm or soem constant
* string when there is no algo. It will never return NULL.
*/
const char *
gcry_cipher_algo_name( int algo )
{
return cipher_algo_to_string( algo );
}
/****************
* Encrypt IN and write it to OUT. If IN is NULL, in-place encryption has
* been requested,
*/
int
gcry_cipher_encrypt( GCRY_CIPHER_HD h, byte *out, size_t outsize,
const byte *in, size_t inlen )
{
if( !in ) {
/* caller requested in-place encryption */
/* actullay cipher_encrypt() does not need to know about it, but
* we may chnage this to get better performace */
cipher_encrypt( h->hd, out, out, outsize );
}
else {
if( outsize < inlen )
return set_lasterr( GCRYERR_TOO_SHORT );
/* fixme: check that the inlength is a multipe of the blocksize
* if a blockoriented mode is used, or modify cipher_encrypt to
* return an error in this case */
cipher_encrypt( h->hd, out, in, inlen );
}
return 0;
}
int
gcry_cipher_decrypt( GCRY_CIPHER_HD h, byte *out, size_t outsize,
const byte *in, size_t inlen )
{
if( !in ) {
/* caller requested in-place encryption */
/* actullay cipher_encrypt() does not need to know about it, but
* we may chnage this to get better performace */
cipher_decrypt( h->hd, out, out, outsize );
}
else {
if( outsize < inlen )
return set_lasterr( GCRYERR_TOO_SHORT );
/* fixme: check that the inlength is a multipe of the blocksize
* if a blockoriented mode is used, or modify cipher_encrypt to
* return an error in this case */
cipher_decrypt( h->hd, out, in, inlen );
}
return 0;
}

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Mime Type
text/x-c
Expires
Mon, Feb 2, 8:06 AM (2 h, 14 m)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
9f/98/52cf5d500ca8565831da775c8474

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