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Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +02001/*
2 * DTLS cookie callbacks implementation
3 *
Bence Szépkúti1e148272020-08-07 13:07:28 +02004 * Copyright The Mbed TLS Contributors
Manuel Pégourié-Gonnard37ff1402015-09-04 14:21:07 +02005 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020018 */
19/*
20 * These session callbacks use a simple chained list
21 * to store and retrieve the session information.
22 */
23
Gilles Peskinedb09ef62020-06-03 01:43:33 +020024#include "common.h"
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020025
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020026#if defined(MBEDTLS_SSL_COOKIE_C)
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020027
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020028#if defined(MBEDTLS_PLATFORM_C)
Manuel Pégourié-Gonnard7f809972015-03-09 17:05:11 +000029#include "mbedtls/platform.h"
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020030#else
Manuel Pégourié-Gonnard7551cb92015-05-26 16:04:06 +020031#define mbedtls_calloc calloc
SimonBd5800b72016-04-26 07:43:27 +010032#define mbedtls_free free
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020033#endif
34
SimonBd5800b72016-04-26 07:43:27 +010035#include "mbedtls/ssl_cookie.h"
Chris Jones84a773f2021-03-05 18:38:47 +000036#include "ssl_misc.h"
Janos Follath73c616b2019-12-18 15:07:04 +000037#include "mbedtls/error.h"
Andres Amaya Garcia1f6301b2018-04-17 09:51:09 -050038#include "mbedtls/platform_util.h"
SimonBd5800b72016-04-26 07:43:27 +010039
Manuel Pégourié-Gonnardd901d172015-02-16 18:37:53 +000040#include <string.h>
41
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020042/*
43 * If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is
TRodziewicz0f82ec62021-05-12 17:49:18 +020044 * available. Try SHA-256 first, 512 wastes resources
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020045 */
Mateusz Starzyke3c48b42021-04-19 16:46:28 +020046#if defined(MBEDTLS_SHA224_C)
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020047#define COOKIE_MD MBEDTLS_MD_SHA224
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +020048#define COOKIE_MD_OUTLEN 32
49#define COOKIE_HMAC_LEN 28
Mateusz Starzyk6326a8d2021-05-10 13:51:53 +020050#elif defined(MBEDTLS_SHA384_C)
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020051#define COOKIE_MD MBEDTLS_MD_SHA384
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +020052#define COOKIE_MD_OUTLEN 48
53#define COOKIE_HMAC_LEN 28
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020054#elif defined(MBEDTLS_SHA1_C)
55#define COOKIE_MD MBEDTLS_MD_SHA1
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +020056#define COOKIE_MD_OUTLEN 20
57#define COOKIE_HMAC_LEN 20
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020058#else
59#error "DTLS hello verify needs SHA-1 or SHA-2"
60#endif
61
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +020062/*
63 * Cookies are formed of a 4-bytes timestamp (or serial number) and
64 * an HMAC of timestemp and client ID.
65 */
66#define COOKIE_LEN ( 4 + COOKIE_HMAC_LEN )
67
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020068void mbedtls_ssl_cookie_init( mbedtls_ssl_cookie_ctx *ctx )
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020069{
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020070 mbedtls_md_init( &ctx->hmac_ctx );
71#if !defined(MBEDTLS_HAVE_TIME)
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +020072 ctx->serial = 0;
73#endif
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020074 ctx->timeout = MBEDTLS_SSL_COOKIE_TIMEOUT;
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +020075
76#if defined(MBEDTLS_THREADING_C)
77 mbedtls_mutex_init( &ctx->mutex );
78#endif
Manuel Pégourié-Gonnardbef8f092014-07-23 23:40:29 +020079}
80
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020081void mbedtls_ssl_cookie_set_timeout( mbedtls_ssl_cookie_ctx *ctx, unsigned long delay )
Manuel Pégourié-Gonnardbef8f092014-07-23 23:40:29 +020082{
83 ctx->timeout = delay;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020084}
85
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020086void mbedtls_ssl_cookie_free( mbedtls_ssl_cookie_ctx *ctx )
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020087{
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020088 mbedtls_md_free( &ctx->hmac_ctx );
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +020089
90#if defined(MBEDTLS_THREADING_C)
Ron Eldor04965ed2017-01-29 18:51:35 +020091 mbedtls_mutex_free( &ctx->mutex );
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +020092#endif
93
Andres Amaya Garcia1f6301b2018-04-17 09:51:09 -050094 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) );
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020095}
96
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020097int mbedtls_ssl_cookie_setup( mbedtls_ssl_cookie_ctx *ctx,
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +020098 int (*f_rng)(void *, unsigned char *, size_t),
99 void *p_rng )
100{
Janos Follath865b3eb2019-12-16 11:46:15 +0000101 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200102 unsigned char key[COOKIE_MD_OUTLEN];
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200103
104 if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200105 return ret ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200106
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200107 ret = mbedtls_md_setup( &ctx->hmac_ctx, mbedtls_md_info_from_type( COOKIE_MD ), 1 );
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200108 if( ret != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200109 return ret ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200110
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200111 ret = mbedtls_md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200112 if( ret != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200113 return ret ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200114
Andres Amaya Garcia1f6301b2018-04-17 09:51:09 -0500115 mbedtls_platform_zeroize( key, sizeof( key ) );
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200116
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200117 return 0 ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200118}
119
120/*
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200121 * Generate the HMAC part of a cookie
122 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200123static int ssl_cookie_hmac( mbedtls_md_context_t *hmac_ctx,
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200124 const unsigned char time[4],
125 unsigned char **p, unsigned char *end,
126 const unsigned char *cli_id, size_t cli_id_len )
127{
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200128 unsigned char hmac_out[COOKIE_MD_OUTLEN];
129
Hanno Becker261602c2017-04-12 14:54:42 +0100130 MBEDTLS_SSL_CHK_BUF_PTR( *p, end, COOKIE_HMAC_LEN );
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200131
Manuel Pégourié-Gonnard6ab9b002015-05-14 11:25:04 +0200132 if( mbedtls_md_hmac_reset( hmac_ctx ) != 0 ||
133 mbedtls_md_hmac_update( hmac_ctx, time, 4 ) != 0 ||
134 mbedtls_md_hmac_update( hmac_ctx, cli_id, cli_id_len ) != 0 ||
135 mbedtls_md_hmac_finish( hmac_ctx, hmac_out ) != 0 )
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200136 {
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200137 return MBEDTLS_ERR_SSL_INTERNAL_ERROR ;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200138 }
139
140 memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
141 *p += COOKIE_HMAC_LEN;
142
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200143 return 0 ;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200144}
145
146/*
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200147 * Generate cookie for DTLS ClientHello verification
148 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200149int mbedtls_ssl_cookie_write( void *p_ctx,
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200150 unsigned char **p, unsigned char *end,
151 const unsigned char *cli_id, size_t cli_id_len )
152{
Janos Follath865b3eb2019-12-16 11:46:15 +0000153 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200154 mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200155 unsigned long t;
Manuel Pégourié-Gonnarde4de0612014-07-23 17:26:48 +0200156
Manuel Pégourié-Gonnard29ad7e82014-07-23 19:12:15 +0200157 if( ctx == NULL || cli_id == NULL )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200158 return MBEDTLS_ERR_SSL_BAD_INPUT_DATA ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200159
Hanno Becker261602c2017-04-12 14:54:42 +0100160 MBEDTLS_SSL_CHK_BUF_PTR( *p, end, COOKIE_LEN );
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200161
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200162#if defined(MBEDTLS_HAVE_TIME)
SimonBd5800b72016-04-26 07:43:27 +0100163 t = (unsigned long) mbedtls_time( NULL );
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200164#else
165 t = ctx->serial++;
166#endif
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200167
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200168 (*p)[0] = (unsigned char)( t >> 24 );
169 (*p)[1] = (unsigned char)( t >> 16 );
170 (*p)[2] = (unsigned char)( t >> 8 );
171 (*p)[3] = (unsigned char)( t );
172 *p += 4;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200173
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200174#if defined(MBEDTLS_THREADING_C)
175 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200176 return MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR, ret ) ;
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200177#endif
178
179 ret = ssl_cookie_hmac( &ctx->hmac_ctx, *p - 4,
180 p, end, cli_id, cli_id_len );
181
182#if defined(MBEDTLS_THREADING_C)
183 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
Chris Jones9f7a6932021-04-14 12:12:09 +0100184 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR,
185 MBEDTLS_ERR_THREADING_MUTEX_ERROR ) );
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200186#endif
187
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200188 return ret ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200189}
190
191/*
192 * Check a cookie
193 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200194int mbedtls_ssl_cookie_check( void *p_ctx,
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200195 const unsigned char *cookie, size_t cookie_len,
196 const unsigned char *cli_id, size_t cli_id_len )
197{
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200198 unsigned char ref_hmac[COOKIE_HMAC_LEN];
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200199 int ret = 0;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200200 unsigned char *p = ref_hmac;
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200201 mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200202 unsigned long cur_time, cookie_time;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200203
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200204 if( ctx == NULL || cli_id == NULL )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200205 return MBEDTLS_ERR_SSL_BAD_INPUT_DATA ;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200206
207 if( cookie_len != COOKIE_LEN )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200208 return -1 ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200209
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200210#if defined(MBEDTLS_THREADING_C)
211 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200212 return MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR, ret ) ;
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200213#endif
214
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200215 if( ssl_cookie_hmac( &ctx->hmac_ctx, cookie,
216 &p, p + sizeof( ref_hmac ),
217 cli_id, cli_id_len ) != 0 )
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200218 ret = -1;
219
220#if defined(MBEDTLS_THREADING_C)
221 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
Chris Jonese11e8142021-04-22 15:28:56 +0100222 return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_SSL_INTERNAL_ERROR,
Chris Jones9f7a6932021-04-14 12:12:09 +0100223 MBEDTLS_ERR_THREADING_MUTEX_ERROR ) );
Manuel Pégourié-Gonnard2a84dfd2015-05-28 15:48:09 +0200224#endif
225
226 if( ret != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200227 return ret ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200228
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200229 if( mbedtls_ssl_safer_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200230 return -1 ;
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200231
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200232#if defined(MBEDTLS_HAVE_TIME)
SimonBd5800b72016-04-26 07:43:27 +0100233 cur_time = (unsigned long) mbedtls_time( NULL );
Manuel Pégourié-Gonnarde9030812014-07-23 21:29:11 +0200234#else
235 cur_time = ctx->serial;
236#endif
237
238 cookie_time = ( (unsigned long) cookie[0] << 24 ) |
239 ( (unsigned long) cookie[1] << 16 ) |
240 ( (unsigned long) cookie[2] << 8 ) |
241 ( (unsigned long) cookie[3] );
242
Manuel Pégourié-Gonnardbef8f092014-07-23 23:40:29 +0200243 if( ctx->timeout != 0 && cur_time - cookie_time > ctx->timeout )
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200244 return -1 ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200245
Mateusz Starzyke36f5b12021-07-22 16:43:35 +0200246 return 0 ;
Manuel Pégourié-Gonnard232edd42014-07-23 16:56:27 +0200247}
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200248#endif /* MBEDTLS_SSL_COOKIE_C */