mirror of
https://github.com/yuzu-emu/mbedtls.git
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0e8dc48cff
This commit uses the previously defined macro to uniformize bounds checks in several places. It also adds bounds checks to the ClientHello writing function that were previously missing. Also, the functions adding extensions to the ClientHello message can now fail if the buffer is too small or a different error condition occurs, and moreover they take an additional buffer end parameter to free them from the assumption that one is writing to the default output buffer. Signed-off-by: Ronald Cron <ronald.cron@arm.com>
259 lines
7.2 KiB
C
259 lines
7.2 KiB
C
/*
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* DTLS cookie callbacks implementation
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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/*
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* These session callbacks use a simple chained list
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* to store and retrieve the session information.
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_SSL_COOKIE_C)
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#define mbedtls_calloc calloc
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#define mbedtls_free free
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#endif
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#include "mbedtls/ssl_cookie.h"
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#include "mbedtls/ssl_internal.h"
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#include <string.h>
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/* Implementation that should never be optimized out by the compiler */
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static void mbedtls_zeroize( void *v, size_t n ) {
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volatile unsigned char *p = v; while( n-- ) *p++ = 0;
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}
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/*
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* If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is
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* available. Try SHA-256 first, 512 wastes resources since we need to stay
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* with max 32 bytes of cookie for DTLS 1.0
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*/
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#if defined(MBEDTLS_SHA256_C)
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#define COOKIE_MD MBEDTLS_MD_SHA224
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#define COOKIE_MD_OUTLEN 32
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#define COOKIE_HMAC_LEN 28
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#elif defined(MBEDTLS_SHA512_C)
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#define COOKIE_MD MBEDTLS_MD_SHA384
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#define COOKIE_MD_OUTLEN 48
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#define COOKIE_HMAC_LEN 28
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#elif defined(MBEDTLS_SHA1_C)
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#define COOKIE_MD MBEDTLS_MD_SHA1
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#define COOKIE_MD_OUTLEN 20
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#define COOKIE_HMAC_LEN 20
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#else
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#error "DTLS hello verify needs SHA-1 or SHA-2"
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#endif
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/*
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* Cookies are formed of a 4-bytes timestamp (or serial number) and
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* an HMAC of timestemp and client ID.
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*/
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#define COOKIE_LEN ( 4 + COOKIE_HMAC_LEN )
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void mbedtls_ssl_cookie_init( mbedtls_ssl_cookie_ctx *ctx )
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{
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mbedtls_md_init( &ctx->hmac_ctx );
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#if !defined(MBEDTLS_HAVE_TIME)
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ctx->serial = 0;
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#endif
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ctx->timeout = MBEDTLS_SSL_COOKIE_TIMEOUT;
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#if defined(MBEDTLS_THREADING_C)
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mbedtls_mutex_init( &ctx->mutex );
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#endif
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}
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void mbedtls_ssl_cookie_set_timeout( mbedtls_ssl_cookie_ctx *ctx, unsigned long delay )
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{
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ctx->timeout = delay;
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}
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void mbedtls_ssl_cookie_free( mbedtls_ssl_cookie_ctx *ctx )
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{
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mbedtls_md_free( &ctx->hmac_ctx );
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#if defined(MBEDTLS_THREADING_C)
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mbedtls_mutex_free( &ctx->mutex );
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#endif
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mbedtls_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) );
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}
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int mbedtls_ssl_cookie_setup( mbedtls_ssl_cookie_ctx *ctx,
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int (*f_rng)(void *, unsigned char *, size_t),
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void *p_rng )
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{
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int ret;
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unsigned char key[COOKIE_MD_OUTLEN];
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if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
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return( ret );
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ret = mbedtls_md_setup( &ctx->hmac_ctx, mbedtls_md_info_from_type( COOKIE_MD ), 1 );
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if( ret != 0 )
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return( ret );
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ret = mbedtls_md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
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if( ret != 0 )
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return( ret );
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mbedtls_zeroize( key, sizeof( key ) );
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return( 0 );
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}
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/*
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* Generate the HMAC part of a cookie
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*/
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static int ssl_cookie_hmac( mbedtls_md_context_t *hmac_ctx,
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const unsigned char time[4],
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unsigned char **p, unsigned char *end,
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const unsigned char *cli_id, size_t cli_id_len )
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{
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unsigned char hmac_out[COOKIE_MD_OUTLEN];
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MBEDTLS_SSL_CHK_BUF_PTR( *p, end, COOKIE_HMAC_LEN );
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if( mbedtls_md_hmac_reset( hmac_ctx ) != 0 ||
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mbedtls_md_hmac_update( hmac_ctx, time, 4 ) != 0 ||
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mbedtls_md_hmac_update( hmac_ctx, cli_id, cli_id_len ) != 0 ||
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mbedtls_md_hmac_finish( hmac_ctx, hmac_out ) != 0 )
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{
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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}
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memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
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*p += COOKIE_HMAC_LEN;
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return( 0 );
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}
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/*
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* Generate cookie for DTLS ClientHello verification
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*/
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int mbedtls_ssl_cookie_write( void *p_ctx,
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unsigned char **p, unsigned char *end,
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const unsigned char *cli_id, size_t cli_id_len )
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{
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int ret;
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mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
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unsigned long t;
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if( ctx == NULL || cli_id == NULL )
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return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
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MBEDTLS_SSL_CHK_BUF_PTR( *p, end, COOKIE_LEN );
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#if defined(MBEDTLS_HAVE_TIME)
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t = (unsigned long) mbedtls_time( NULL );
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#else
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t = ctx->serial++;
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#endif
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(*p)[0] = (unsigned char)( t >> 24 );
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(*p)[1] = (unsigned char)( t >> 16 );
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(*p)[2] = (unsigned char)( t >> 8 );
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(*p)[3] = (unsigned char)( t );
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*p += 4;
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#if defined(MBEDTLS_THREADING_C)
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if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
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#endif
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ret = ssl_cookie_hmac( &ctx->hmac_ctx, *p - 4,
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p, end, cli_id, cli_id_len );
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#if defined(MBEDTLS_THREADING_C)
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if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
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MBEDTLS_ERR_THREADING_MUTEX_ERROR );
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#endif
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return( ret );
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}
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/*
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* Check a cookie
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*/
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int mbedtls_ssl_cookie_check( void *p_ctx,
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const unsigned char *cookie, size_t cookie_len,
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const unsigned char *cli_id, size_t cli_id_len )
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{
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unsigned char ref_hmac[COOKIE_HMAC_LEN];
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int ret = 0;
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unsigned char *p = ref_hmac;
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mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
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unsigned long cur_time, cookie_time;
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if( ctx == NULL || cli_id == NULL )
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return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
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if( cookie_len != COOKIE_LEN )
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return( -1 );
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#if defined(MBEDTLS_THREADING_C)
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if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
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#endif
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if( ssl_cookie_hmac( &ctx->hmac_ctx, cookie,
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&p, p + sizeof( ref_hmac ),
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cli_id, cli_id_len ) != 0 )
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ret = -1;
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#if defined(MBEDTLS_THREADING_C)
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if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
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MBEDTLS_ERR_THREADING_MUTEX_ERROR );
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#endif
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if( ret != 0 )
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return( ret );
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if( mbedtls_ssl_safer_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 )
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return( -1 );
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#if defined(MBEDTLS_HAVE_TIME)
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cur_time = (unsigned long) mbedtls_time( NULL );
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#else
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cur_time = ctx->serial;
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#endif
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cookie_time = ( (unsigned long) cookie[0] << 24 ) |
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( (unsigned long) cookie[1] << 16 ) |
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( (unsigned long) cookie[2] << 8 ) |
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( (unsigned long) cookie[3] );
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if( ctx->timeout != 0 && cur_time - cookie_time > ctx->timeout )
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return( -1 );
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return( 0 );
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}
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#endif /* MBEDTLS_SSL_COOKIE_C */
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