Kev Mann / mbed-dev-OS5_10_4

features/mbedtls/src/ssl_cookie.c@0:38ceb79fef03, 2018-11-28 (annotated)

Committer:
kevman
Date:
Wed Nov 28 15:10:15 2018 +0000
Revision:
0:38ceb79fef03
RTC modified

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kevman 0:38ceb79fef03 1 /*
kevman 0:38ceb79fef03 2 * DTLS cookie callbacks implementation
kevman 0:38ceb79fef03 3 *
kevman 0:38ceb79fef03 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
kevman 0:38ceb79fef03 5 * SPDX-License-Identifier: Apache-2.0
kevman 0:38ceb79fef03 6 *
kevman 0:38ceb79fef03 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
kevman 0:38ceb79fef03 8 * not use this file except in compliance with the License.
kevman 0:38ceb79fef03 9 * You may obtain a copy of the License at
kevman 0:38ceb79fef03 10 *
kevman 0:38ceb79fef03 11 * http://www.apache.org/licenses/LICENSE-2.0
kevman 0:38ceb79fef03 12 *
kevman 0:38ceb79fef03 13 * Unless required by applicable law or agreed to in writing, software
kevman 0:38ceb79fef03 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
kevman 0:38ceb79fef03 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kevman 0:38ceb79fef03 16 * See the License for the specific language governing permissions and
kevman 0:38ceb79fef03 17 * limitations under the License.
kevman 0:38ceb79fef03 18 *
kevman 0:38ceb79fef03 19 * This file is part of mbed TLS (https://tls.mbed.org)
kevman 0:38ceb79fef03 20 */
kevman 0:38ceb79fef03 21 /*
kevman 0:38ceb79fef03 22 * These session callbacks use a simple chained list
kevman 0:38ceb79fef03 23 * to store and retrieve the session information.
kevman 0:38ceb79fef03 24 */
kevman 0:38ceb79fef03 25
kevman 0:38ceb79fef03 26 #if !defined(MBEDTLS_CONFIG_FILE)
kevman 0:38ceb79fef03 27 #include "mbedtls/config.h"
kevman 0:38ceb79fef03 28 #else
kevman 0:38ceb79fef03 29 #include MBEDTLS_CONFIG_FILE
kevman 0:38ceb79fef03 30 #endif
kevman 0:38ceb79fef03 31
kevman 0:38ceb79fef03 32 #if defined(MBEDTLS_SSL_COOKIE_C)
kevman 0:38ceb79fef03 33
kevman 0:38ceb79fef03 34 #if defined(MBEDTLS_PLATFORM_C)
kevman 0:38ceb79fef03 35 #include "mbedtls/platform.h"
kevman 0:38ceb79fef03 36 #else
kevman 0:38ceb79fef03 37 #define mbedtls_calloc calloc
kevman 0:38ceb79fef03 38 #define mbedtls_free free
kevman 0:38ceb79fef03 39 #endif
kevman 0:38ceb79fef03 40
kevman 0:38ceb79fef03 41 #include "mbedtls/ssl_cookie.h"
kevman 0:38ceb79fef03 42 #include "mbedtls/ssl_internal.h"
kevman 0:38ceb79fef03 43 #include "mbedtls/platform_util.h"
kevman 0:38ceb79fef03 44
kevman 0:38ceb79fef03 45 #include <string.h>
kevman 0:38ceb79fef03 46
kevman 0:38ceb79fef03 47 /*
kevman 0:38ceb79fef03 48 * If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is
kevman 0:38ceb79fef03 49 * available. Try SHA-256 first, 512 wastes resources since we need to stay
kevman 0:38ceb79fef03 50 * with max 32 bytes of cookie for DTLS 1.0
kevman 0:38ceb79fef03 51 */
kevman 0:38ceb79fef03 52 #if defined(MBEDTLS_SHA256_C)
kevman 0:38ceb79fef03 53 #define COOKIE_MD MBEDTLS_MD_SHA224
kevman 0:38ceb79fef03 54 #define COOKIE_MD_OUTLEN 32
kevman 0:38ceb79fef03 55 #define COOKIE_HMAC_LEN 28
kevman 0:38ceb79fef03 56 #elif defined(MBEDTLS_SHA512_C)
kevman 0:38ceb79fef03 57 #define COOKIE_MD MBEDTLS_MD_SHA384
kevman 0:38ceb79fef03 58 #define COOKIE_MD_OUTLEN 48
kevman 0:38ceb79fef03 59 #define COOKIE_HMAC_LEN 28
kevman 0:38ceb79fef03 60 #elif defined(MBEDTLS_SHA1_C)
kevman 0:38ceb79fef03 61 #define COOKIE_MD MBEDTLS_MD_SHA1
kevman 0:38ceb79fef03 62 #define COOKIE_MD_OUTLEN 20
kevman 0:38ceb79fef03 63 #define COOKIE_HMAC_LEN 20
kevman 0:38ceb79fef03 64 #else
kevman 0:38ceb79fef03 65 #error "DTLS hello verify needs SHA-1 or SHA-2"
kevman 0:38ceb79fef03 66 #endif
kevman 0:38ceb79fef03 67
kevman 0:38ceb79fef03 68 /*
kevman 0:38ceb79fef03 69 * Cookies are formed of a 4-bytes timestamp (or serial number) and
kevman 0:38ceb79fef03 70 * an HMAC of timestemp and client ID.
kevman 0:38ceb79fef03 71 */
kevman 0:38ceb79fef03 72 #define COOKIE_LEN ( 4 + COOKIE_HMAC_LEN )
kevman 0:38ceb79fef03 73
kevman 0:38ceb79fef03 74 void mbedtls_ssl_cookie_init( mbedtls_ssl_cookie_ctx *ctx )
kevman 0:38ceb79fef03 75 {
kevman 0:38ceb79fef03 76 mbedtls_md_init( &ctx->hmac_ctx );
kevman 0:38ceb79fef03 77 #if !defined(MBEDTLS_HAVE_TIME)
kevman 0:38ceb79fef03 78 ctx->serial = 0;
kevman 0:38ceb79fef03 79 #endif
kevman 0:38ceb79fef03 80 ctx->timeout = MBEDTLS_SSL_COOKIE_TIMEOUT;
kevman 0:38ceb79fef03 81
kevman 0:38ceb79fef03 82 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 83 mbedtls_mutex_init( &ctx->mutex );
kevman 0:38ceb79fef03 84 #endif
kevman 0:38ceb79fef03 85 }
kevman 0:38ceb79fef03 86
kevman 0:38ceb79fef03 87 void mbedtls_ssl_cookie_set_timeout( mbedtls_ssl_cookie_ctx *ctx, unsigned long delay )
kevman 0:38ceb79fef03 88 {
kevman 0:38ceb79fef03 89 ctx->timeout = delay;
kevman 0:38ceb79fef03 90 }
kevman 0:38ceb79fef03 91
kevman 0:38ceb79fef03 92 void mbedtls_ssl_cookie_free( mbedtls_ssl_cookie_ctx *ctx )
kevman 0:38ceb79fef03 93 {
kevman 0:38ceb79fef03 94 mbedtls_md_free( &ctx->hmac_ctx );
kevman 0:38ceb79fef03 95
kevman 0:38ceb79fef03 96 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 97 mbedtls_mutex_free( &ctx->mutex );
kevman 0:38ceb79fef03 98 #endif
kevman 0:38ceb79fef03 99
kevman 0:38ceb79fef03 100 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) );
kevman 0:38ceb79fef03 101 }
kevman 0:38ceb79fef03 102
kevman 0:38ceb79fef03 103 int mbedtls_ssl_cookie_setup( mbedtls_ssl_cookie_ctx *ctx,
kevman 0:38ceb79fef03 104 int (*f_rng)(void *, unsigned char *, size_t),
kevman 0:38ceb79fef03 105 void *p_rng )
kevman 0:38ceb79fef03 106 {
kevman 0:38ceb79fef03 107 int ret;
kevman 0:38ceb79fef03 108 unsigned char key[COOKIE_MD_OUTLEN];
kevman 0:38ceb79fef03 109
kevman 0:38ceb79fef03 110 if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
kevman 0:38ceb79fef03 111 return( ret );
kevman 0:38ceb79fef03 112
kevman 0:38ceb79fef03 113 ret = mbedtls_md_setup( &ctx->hmac_ctx, mbedtls_md_info_from_type( COOKIE_MD ), 1 );
kevman 0:38ceb79fef03 114 if( ret != 0 )
kevman 0:38ceb79fef03 115 return( ret );
kevman 0:38ceb79fef03 116
kevman 0:38ceb79fef03 117 ret = mbedtls_md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
kevman 0:38ceb79fef03 118 if( ret != 0 )
kevman 0:38ceb79fef03 119 return( ret );
kevman 0:38ceb79fef03 120
kevman 0:38ceb79fef03 121 mbedtls_platform_zeroize( key, sizeof( key ) );
kevman 0:38ceb79fef03 122
kevman 0:38ceb79fef03 123 return( 0 );
kevman 0:38ceb79fef03 124 }
kevman 0:38ceb79fef03 125
kevman 0:38ceb79fef03 126 /*
kevman 0:38ceb79fef03 127 * Generate the HMAC part of a cookie
kevman 0:38ceb79fef03 128 */
kevman 0:38ceb79fef03 129 static int ssl_cookie_hmac( mbedtls_md_context_t *hmac_ctx,
kevman 0:38ceb79fef03 130 const unsigned char time[4],
kevman 0:38ceb79fef03 131 unsigned char **p, unsigned char *end,
kevman 0:38ceb79fef03 132 const unsigned char *cli_id, size_t cli_id_len )
kevman 0:38ceb79fef03 133 {
kevman 0:38ceb79fef03 134 unsigned char hmac_out[COOKIE_MD_OUTLEN];
kevman 0:38ceb79fef03 135
kevman 0:38ceb79fef03 136 if( (size_t)( end - *p ) < COOKIE_HMAC_LEN )
kevman 0:38ceb79fef03 137 return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
kevman 0:38ceb79fef03 138
kevman 0:38ceb79fef03 139 if( mbedtls_md_hmac_reset( hmac_ctx ) != 0 ||
kevman 0:38ceb79fef03 140 mbedtls_md_hmac_update( hmac_ctx, time, 4 ) != 0 ||
kevman 0:38ceb79fef03 141 mbedtls_md_hmac_update( hmac_ctx, cli_id, cli_id_len ) != 0 ||
kevman 0:38ceb79fef03 142 mbedtls_md_hmac_finish( hmac_ctx, hmac_out ) != 0 )
kevman 0:38ceb79fef03 143 {
kevman 0:38ceb79fef03 144 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
kevman 0:38ceb79fef03 145 }
kevman 0:38ceb79fef03 146
kevman 0:38ceb79fef03 147 memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
kevman 0:38ceb79fef03 148 *p += COOKIE_HMAC_LEN;
kevman 0:38ceb79fef03 149
kevman 0:38ceb79fef03 150 return( 0 );
kevman 0:38ceb79fef03 151 }
kevman 0:38ceb79fef03 152
kevman 0:38ceb79fef03 153 /*
kevman 0:38ceb79fef03 154 * Generate cookie for DTLS ClientHello verification
kevman 0:38ceb79fef03 155 */
kevman 0:38ceb79fef03 156 int mbedtls_ssl_cookie_write( void *p_ctx,
kevman 0:38ceb79fef03 157 unsigned char **p, unsigned char *end,
kevman 0:38ceb79fef03 158 const unsigned char *cli_id, size_t cli_id_len )
kevman 0:38ceb79fef03 159 {
kevman 0:38ceb79fef03 160 int ret;
kevman 0:38ceb79fef03 161 mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
kevman 0:38ceb79fef03 162 unsigned long t;
kevman 0:38ceb79fef03 163
kevman 0:38ceb79fef03 164 if( ctx == NULL || cli_id == NULL )
kevman 0:38ceb79fef03 165 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 166
kevman 0:38ceb79fef03 167 if( (size_t)( end - *p ) < COOKIE_LEN )
kevman 0:38ceb79fef03 168 return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
kevman 0:38ceb79fef03 169
kevman 0:38ceb79fef03 170 #if defined(MBEDTLS_HAVE_TIME)
kevman 0:38ceb79fef03 171 t = (unsigned long) mbedtls_time( NULL );
kevman 0:38ceb79fef03 172 #else
kevman 0:38ceb79fef03 173 t = ctx->serial++;
kevman 0:38ceb79fef03 174 #endif
kevman 0:38ceb79fef03 175
kevman 0:38ceb79fef03 176 (*p)[0] = (unsigned char)( t >> 24 );
kevman 0:38ceb79fef03 177 (*p)[1] = (unsigned char)( t >> 16 );
kevman 0:38ceb79fef03 178 (*p)[2] = (unsigned char)( t >> 8 );
kevman 0:38ceb79fef03 179 (*p)[3] = (unsigned char)( t );
kevman 0:38ceb79fef03 180 *p += 4;
kevman 0:38ceb79fef03 181
kevman 0:38ceb79fef03 182 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 183 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
kevman 0:38ceb79fef03 184 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
kevman 0:38ceb79fef03 185 #endif
kevman 0:38ceb79fef03 186
kevman 0:38ceb79fef03 187 ret = ssl_cookie_hmac( &ctx->hmac_ctx, *p - 4,
kevman 0:38ceb79fef03 188 p, end, cli_id, cli_id_len );
kevman 0:38ceb79fef03 189
kevman 0:38ceb79fef03 190 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 191 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
kevman 0:38ceb79fef03 192 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
kevman 0:38ceb79fef03 193 MBEDTLS_ERR_THREADING_MUTEX_ERROR );
kevman 0:38ceb79fef03 194 #endif
kevman 0:38ceb79fef03 195
kevman 0:38ceb79fef03 196 return( ret );
kevman 0:38ceb79fef03 197 }
kevman 0:38ceb79fef03 198
kevman 0:38ceb79fef03 199 /*
kevman 0:38ceb79fef03 200 * Check a cookie
kevman 0:38ceb79fef03 201 */
kevman 0:38ceb79fef03 202 int mbedtls_ssl_cookie_check( void *p_ctx,
kevman 0:38ceb79fef03 203 const unsigned char *cookie, size_t cookie_len,
kevman 0:38ceb79fef03 204 const unsigned char *cli_id, size_t cli_id_len )
kevman 0:38ceb79fef03 205 {
kevman 0:38ceb79fef03 206 unsigned char ref_hmac[COOKIE_HMAC_LEN];
kevman 0:38ceb79fef03 207 int ret = 0;
kevman 0:38ceb79fef03 208 unsigned char *p = ref_hmac;
kevman 0:38ceb79fef03 209 mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx;
kevman 0:38ceb79fef03 210 unsigned long cur_time, cookie_time;
kevman 0:38ceb79fef03 211
kevman 0:38ceb79fef03 212 if( ctx == NULL || cli_id == NULL )
kevman 0:38ceb79fef03 213 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 214
kevman 0:38ceb79fef03 215 if( cookie_len != COOKIE_LEN )
kevman 0:38ceb79fef03 216 return( -1 );
kevman 0:38ceb79fef03 217
kevman 0:38ceb79fef03 218 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 219 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
kevman 0:38ceb79fef03 220 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret );
kevman 0:38ceb79fef03 221 #endif
kevman 0:38ceb79fef03 222
kevman 0:38ceb79fef03 223 if( ssl_cookie_hmac( &ctx->hmac_ctx, cookie,
kevman 0:38ceb79fef03 224 &p, p + sizeof( ref_hmac ),
kevman 0:38ceb79fef03 225 cli_id, cli_id_len ) != 0 )
kevman 0:38ceb79fef03 226 ret = -1;
kevman 0:38ceb79fef03 227
kevman 0:38ceb79fef03 228 #if defined(MBEDTLS_THREADING_C)
kevman 0:38ceb79fef03 229 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
kevman 0:38ceb79fef03 230 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR +
kevman 0:38ceb79fef03 231 MBEDTLS_ERR_THREADING_MUTEX_ERROR );
kevman 0:38ceb79fef03 232 #endif
kevman 0:38ceb79fef03 233
kevman 0:38ceb79fef03 234 if( ret != 0 )
kevman 0:38ceb79fef03 235 return( ret );
kevman 0:38ceb79fef03 236
kevman 0:38ceb79fef03 237 if( mbedtls_ssl_safer_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 )
kevman 0:38ceb79fef03 238 return( -1 );
kevman 0:38ceb79fef03 239
kevman 0:38ceb79fef03 240 #if defined(MBEDTLS_HAVE_TIME)
kevman 0:38ceb79fef03 241 cur_time = (unsigned long) mbedtls_time( NULL );
kevman 0:38ceb79fef03 242 #else
kevman 0:38ceb79fef03 243 cur_time = ctx->serial;
kevman 0:38ceb79fef03 244 #endif
kevman 0:38ceb79fef03 245
kevman 0:38ceb79fef03 246 cookie_time = ( (unsigned long) cookie[0] << 24 ) |
kevman 0:38ceb79fef03 247 ( (unsigned long) cookie[1] << 16 ) |
kevman 0:38ceb79fef03 248 ( (unsigned long) cookie[2] << 8 ) |
kevman 0:38ceb79fef03 249 ( (unsigned long) cookie[3] );
kevman 0:38ceb79fef03 250
kevman 0:38ceb79fef03 251 if( ctx->timeout != 0 && cur_time - cookie_time > ctx->timeout )
kevman 0:38ceb79fef03 252 return( -1 );
kevman 0:38ceb79fef03 253
kevman 0:38ceb79fef03 254 return( 0 );
kevman 0:38ceb79fef03 255 }
kevman 0:38ceb79fef03 256 #endif /* MBEDTLS_SSL_COOKIE_C */