mbedtls/library/pk.c

/*
 *  Public Key abstraction layer
 *
 *  Copyright (C) 2006-2013, Brainspark B.V.
 *
 *  This file is part of PolarSSL (http://www.polarssl.org)
 *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
 *
 *  All rights reserved.
 *
 *  This program 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.
 *
 *  This program 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.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "polarssl/config.h"

#include "polarssl/pk.h"
#include "polarssl/pk_wrap.h"

#if defined(POLARSSL_RSA_C)
#include "polarssl/rsa.h"
#endif
#if defined(POLARSSL_ECP_C)
#include "polarssl/ecp.h"
#endif
#if defined(POLARSSL_ECDSA_C)
#include "polarssl/ecdsa.h"
#endif

#if defined(POLARSSL_MEMORY_C)
#include "polarssl/memory.h"
#else
#define polarssl_malloc     malloc
#define polarssl_free       free
#endif

#include <stdlib.h>

/*
 * Initialise a pk_context
 */
void pk_init( pk_context *ctx )
{
    if( ctx == NULL )
        return;

    ctx->info = NULL;
    ctx->type = POLARSSL_PK_NONE;
    ctx->data = NULL;
    ctx->dont_free = 0;
}

/*
 * Free (the components of) a pk_context
 */
void pk_free( pk_context *ctx )
{
    if( ctx == NULL )
        return;

#if defined(POLARSSL_RSA_C)
    if( ctx->type == POLARSSL_PK_RSA )
        rsa_free( ctx->data );
    else
#endif
#if defined(POLARSSL_ECP_C)
    if( ctx->type == POLARSSL_PK_ECKEY || ctx->type == POLARSSL_PK_ECKEY_DH )
        ecp_keypair_free( ctx->data );
    else
#endif
#if defined(POLARSSL_ECDSA_C)
    if( ctx->type == POLARSSL_PK_ECDSA )
        ecdsa_free( ctx->data );
    else
#endif
    {
        ; /* guard for the else's above */
    }

    if( ! ctx->dont_free )
        polarssl_free( ctx->data );

    ctx->info = NULL;
    ctx->type = POLARSSL_PK_NONE;
    ctx->data = NULL;
}

/*
 * Set a pk_context to a given type
 */
int pk_set_type( pk_context *ctx, pk_type_t type )
{
    size_t size;
    const pk_info_t *info;

    if( ctx->type == type )
        return( 0 );

    if( ctx->type != POLARSSL_PK_NONE )
        return( POLARSSL_ERR_PK_TYPE_MISMATCH );

#if defined(POLARSSL_RSA_C)
    if( type == POLARSSL_PK_RSA )
    {
        size = sizeof( rsa_context );
        info = &rsa_info;
    }
    else
#endif
#if defined(POLARSSL_ECP_C)
    if( type == POLARSSL_PK_ECKEY || type == POLARSSL_PK_ECKEY_DH )
    {
        size = sizeof( ecp_keypair );
        info = &eckey_info;
    }
    else
#endif
#if defined(POLARSSL_ECDSA_C)
    if( type == POLARSSL_PK_ECDSA )
    {
        size = sizeof( ecdsa_context );
        info = &ecdsa_info;
    }
    else
#endif
        return( POLARSSL_ERR_PK_TYPE_MISMATCH );

    if( ( ctx->data = polarssl_malloc( size ) ) == NULL )
        return( POLARSSL_ERR_PK_MALLOC_FAILED );

    memset( ctx->data, 0, size );
    ctx->type = type;
    ctx->info = info;

    return( 0 );
}

#if defined(POLARSSL_ECDSA_C)
/*
 * Convert generic EC context to ECDSA
 */
int pk_ec_to_ecdsa( pk_context *ctx )
{
    ecp_keypair *eckey;
    ecdsa_context *ecdsa;

    if( ctx->type == POLARSSL_PK_ECDSA )
        return( 0 );

    if( ctx->type != POLARSSL_PK_ECKEY )
        return( POLARSSL_ERR_PK_TYPE_MISMATCH );

    eckey = (ecp_keypair *) ctx->data;

    if( ( ecdsa = polarssl_malloc( sizeof( ecdsa_context ) ) ) == NULL )
        return( POLARSSL_ERR_PK_MALLOC_FAILED );

    ecdsa_init( ecdsa );

    /* struct ecdsa_context begins the same as struct ecp_keypair */
    memcpy( ecdsa, eckey, sizeof( ecp_keypair ) );

    if( ! ctx->dont_free )
        polarssl_free( eckey );

    ctx->dont_free = 0;
    ctx->type = POLARSSL_PK_ECDSA;
    ctx->data = ecdsa;

    return( 0 );
}
#endif /* POLARSSL_ECDSA_C */

#if defined(POLARSSL_RSA_C)
/*
 * Wrap an RSA context in a PK context
 */
int pk_wrap_rsa( pk_context *ctx, const rsa_context *rsa)
{
    if( ctx->type != POLARSSL_PK_NONE )
        return( POLARSSL_ERR_PK_TYPE_MISMATCH );

    ctx->type = POLARSSL_PK_RSA;
    ctx->data = (rsa_context *) rsa;
    ctx->dont_free = 1;

    return( 0 );
}
#endif