160 lines
4.4 KiB
C
160 lines
4.4 KiB
C
/*
|
|
* DTLS cookie callbacks implementation
|
|
*
|
|
* Copyright (C) 2014, 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.
|
|
*/
|
|
/*
|
|
* These session callbacks use a simple chained list
|
|
* to store and retrieve the session information.
|
|
*/
|
|
|
|
#if !defined(POLARSSL_CONFIG_FILE)
|
|
#include "polarssl/config.h"
|
|
#else
|
|
#include POLARSSL_CONFIG_FILE
|
|
#endif
|
|
|
|
#if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY)
|
|
|
|
#include "polarssl/ssl_cookie.h"
|
|
|
|
#if defined(POLARSSL_PLATFORM_C)
|
|
#include "polarssl/platform.h"
|
|
#else
|
|
#define polarssl_malloc malloc
|
|
#define polarssl_free free
|
|
#endif
|
|
|
|
/* Implementation that should never be optimized out by the compiler */
|
|
static void polarssl_zeroize( void *v, size_t n ) {
|
|
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
|
|
}
|
|
|
|
/*
|
|
* If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is
|
|
* available. Try SHA-256 first, 512 wastes resources since we need to stay
|
|
* with max 32 bytes of cookie for DTLS 1.0
|
|
*/
|
|
#if defined(POLARSSL_SHA256_C)
|
|
#define HVR_MD POLARSSL_MD_SHA256
|
|
#define HVR_MD_LEN 32
|
|
#define HVR_MD_USE 32
|
|
#elif defined(POLARSSL_SHA512_C)
|
|
#define HVR_MD POLARSSL_MD_SHA384
|
|
#define HVR_MD_LEN 48
|
|
#define HVR_MD_USE 32
|
|
#elif defined(POLARSSL_SHA1_C)
|
|
#define HVR_MD POLARSSL_MD_SHA1
|
|
#define HVR_MD_LEN 20
|
|
#define HVR_MD_USE 20
|
|
#else
|
|
#error "DTLS hello verify needs SHA-1 or SHA-2"
|
|
#endif
|
|
|
|
void ssl_cookie_init( ssl_cookie_ctx *ctx )
|
|
{
|
|
md_init( &ctx->hmac_ctx );
|
|
}
|
|
|
|
void ssl_cookie_free( ssl_cookie_ctx *ctx )
|
|
{
|
|
md_free( &ctx->hmac_ctx );
|
|
}
|
|
|
|
int ssl_cookie_setup( ssl_cookie_ctx *ctx,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
int ret;
|
|
unsigned char key[HVR_MD_LEN];
|
|
|
|
if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
|
|
return( ret );
|
|
|
|
ret = md_init_ctx( &ctx->hmac_ctx, md_info_from_type( HVR_MD ) );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
|
|
ret = md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
|
|
polarssl_zeroize( key, sizeof( key ) );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Generate cookie for DTLS ClientHello verification
|
|
*/
|
|
int ssl_cookie_write( void *p_ctx,
|
|
unsigned char **p, unsigned char *end,
|
|
const unsigned char *cli_id, size_t cli_id_len )
|
|
{
|
|
int ret;
|
|
unsigned char hmac_out[HVR_MD_LEN];
|
|
ssl_cookie_ctx *ctx = (ssl_cookie_ctx *) p_ctx;
|
|
|
|
if( ctx == NULL )
|
|
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
|
|
|
|
if( (size_t)( end - *p ) < HVR_MD_USE )
|
|
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = md_hmac_reset( &ctx->hmac_ctx ) ) != 0 ||
|
|
( ret = md_hmac_update( &ctx->hmac_ctx, cli_id, cli_id_len ) ) != 0 ||
|
|
( ret = md_hmac_finish( &ctx->hmac_ctx, hmac_out ) ) != 0 )
|
|
{
|
|
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
|
|
}
|
|
|
|
memcpy( *p, hmac_out, HVR_MD_USE );
|
|
*p += HVR_MD_USE;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Check a cookie
|
|
*/
|
|
int ssl_cookie_check( void *p_ctx,
|
|
const unsigned char *cookie, size_t cookie_len,
|
|
const unsigned char *cli_id, size_t cli_id_len )
|
|
{
|
|
unsigned char ref_cookie[HVR_MD_USE];
|
|
unsigned char *p = ref_cookie;
|
|
|
|
if( cookie_len != HVR_MD_USE )
|
|
return( -1 );
|
|
|
|
if( ssl_cookie_write( p_ctx,
|
|
&p, p + sizeof( ref_cookie ),
|
|
cli_id, cli_id_len ) != 0 )
|
|
return( -1 );
|
|
|
|
if( safer_memcmp( cookie, ref_cookie, sizeof( ref_cookie ) ) != 0 )
|
|
return( -1 );
|
|
|
|
return( 0 );
|
|
}
|
|
#endif /* POLARSSL_SSL_COOKIE_C */
|