mbedtls/library/ssl_cookie.c
Janos Follath 73c616bdc1 Put includes in alphabetical order
The library style is to start with the includes corresponding to the
current module and then the rest in alphabetical order. Some modules
have several header files (eg. ssl_internal.h).

The recently added error.h includes did not respect this convention and
this commit restores it. In some cases this is not possible just by
moving the error.h declarations. This commit fixes the pre-existing
order in these instances too.
2019-12-19 10:27:57 +00:00

258 lines
7.2 KiB
C

/*
* DTLS cookie callbacks implementation
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
/*
* These session callbacks use a simple chained list
* to store and retrieve the session information.
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_SSL_COOKIE_C)
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#include "mbedtls/ssl_cookie.h"
#include "mbedtls/ssl_internal.h"
#include "mbedtls/error.h"
#include "mbedtls/platform_util.h"
#include <string.h>
/*
* 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(MBEDTLS_SHA256_C)
#define COOKIE_MD MBEDTLS_MD_SHA224
#define COOKIE_MD_OUTLEN 32
#define COOKIE_HMAC_LEN 28
#elif defined(MBEDTLS_SHA512_C)
#define COOKIE_MD MBEDTLS_MD_SHA384
#define COOKIE_MD_OUTLEN 48
#define COOKIE_HMAC_LEN 28
#elif defined(MBEDTLS_SHA1_C)
#define COOKIE_MD MBEDTLS_MD_SHA1
#define COOKIE_MD_OUTLEN 20
#define COOKIE_HMAC_LEN 20
#else
#error "DTLS hello verify needs SHA-1 or SHA-2"
#endif
/*
* Cookies are formed of a 4-bytes timestamp (or serial number) and
* an HMAC of timestemp and client ID.
*/
#define COOKIE_LEN ( 4 + COOKIE_HMAC_LEN )
void mbedtls_ssl_cookie_init( mbedtls_ssl_cookie_ctx *ctx )
{
mbedtls_md_init( &ctx->hmac_ctx );
#if !defined(MBEDTLS_HAVE_TIME)
ctx->serial = 0;
#endif
ctx->timeout = MBEDTLS_SSL_COOKIE_TIMEOUT;
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &ctx->mutex );
#endif
}
void mbedtls_ssl_cookie_set_timeout( mbedtls_ssl_cookie_ctx *ctx, unsigned long delay )
{
ctx->timeout = delay;
}
void mbedtls_ssl_cookie_free( mbedtls_ssl_cookie_ctx *ctx )
{
mbedtls_md_free( &ctx->hmac_ctx );
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_free( &ctx->mutex );
#endif
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) );
}
int mbedtls_ssl_cookie_setup( mbedtls_ssl_cookie_ctx *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char key[COOKIE_MD_OUTLEN];
if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
return( ret );
ret = mbedtls_md_setup( &ctx->hmac_ctx, mbedtls_md_info_from_type( COOKIE_MD ), 1 );
if( ret != 0 )
return( ret );
ret = mbedtls_md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
if( ret != 0 )
return( ret );
mbedtls_platform_zeroize( key, sizeof( key ) );
return( 0 );
}
/*
* Generate the HMAC part of a cookie
*/
static int ssl_cookie_hmac( mbedtls_md_context_t *hmac_ctx,
const unsigned char time[4],
unsigned char **p, unsigned char *end,
const unsigned char *cli_id, size_t cli_id_len )
{
unsigned char hmac_out[COOKIE_MD_OUTLEN];
if( (size_t)( end - *p ) < COOKIE_HMAC_LEN )
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
if( mbedtls_md_hmac_reset( hmac_ctx ) != 0 ||
mbedtls_md_hmac_update( hmac_ctx, time, 4 ) != 0 ||
mbedtls_md_hmac_update( hmac_ctx, cli_id, cli_id_len ) != 0 ||
mbedtls_md_hmac_finish( hmac_ctx, hmac_out ) != 0 )
{
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
*p += COOKIE_HMAC_LEN;
return( 0 );
}
/*
* Generate cookie for DTLS ClientHello verification
*/
int mbedtls_ssl_cookie_write( void *p_ctx,
unsigned char **p, unsigned char *end,
const unsigned char *cli_id, size_t cli_id_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
unsigned long t;
if( ctx == NULL || cli_id == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
if( (size_t)( end - *p ) < COOKIE_LEN )
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
#if defined(MBEDTLS_HAVE_TIME)
t = (unsigned long) mbedtls_time( NULL );
#else
t = ctx->serial++;
#endif
(*p)[0] = (unsigned char)( t >> 24 );
(*p)[1] = (unsigned char)( t >> 16 );
(*p)[2] = (unsigned char)( t >> 8 );
(*p)[3] = (unsigned char)( t );
*p += 4;
#if defined(MBEDTLS_THREADING_C)
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
#endif
ret = ssl_cookie_hmac( &ctx->hmac_ctx, *p - 4,
p, end, cli_id, cli_id_len );
#if defined(MBEDTLS_THREADING_C)
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
MBEDTLS_ERR_THREADING_MUTEX_ERROR );
#endif
return( ret );
}
/*
* Check a cookie
*/
int mbedtls_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_hmac[COOKIE_HMAC_LEN];
int ret = 0;
unsigned char *p = ref_hmac;
mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
unsigned long cur_time, cookie_time;
if( ctx == NULL || cli_id == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
if( cookie_len != COOKIE_LEN )
return( -1 );
#if defined(MBEDTLS_THREADING_C)
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
#endif
if( ssl_cookie_hmac( &ctx->hmac_ctx, cookie,
&p, p + sizeof( ref_hmac ),
cli_id, cli_id_len ) != 0 )
ret = -1;
#if defined(MBEDTLS_THREADING_C)
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
MBEDTLS_ERR_THREADING_MUTEX_ERROR );
#endif
if( ret != 0 )
return( ret );
if( mbedtls_ssl_safer_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 )
return( -1 );
#if defined(MBEDTLS_HAVE_TIME)
cur_time = (unsigned long) mbedtls_time( NULL );
#else
cur_time = ctx->serial;
#endif
cookie_time = ( (unsigned long) cookie[0] << 24 ) |
( (unsigned long) cookie[1] << 16 ) |
( (unsigned long) cookie[2] << 8 ) |
( (unsigned long) cookie[3] );
if( ctx->timeout != 0 && cur_time - cookie_time > ctx->timeout )
return( -1 );
return( 0 );
}
#endif /* MBEDTLS_SSL_COOKIE_C */