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Dependents: Encypting_Funcional
library/ssl_cookie.c@1:5906897fd9a3, 2019-06-04 (annotated)
- Committer:
- williequesada
- Date:
- Tue Jun 04 17:48:29 2019 +0000
- Revision:
- 1:5906897fd9a3
- Parent:
- 0:cdf462088d13
pablo
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
markrad | 0:cdf462088d13 | 1 | /* |
markrad | 0:cdf462088d13 | 2 | * DTLS cookie callbacks implementation |
markrad | 0:cdf462088d13 | 3 | * |
markrad | 0:cdf462088d13 | 4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved |
markrad | 0:cdf462088d13 | 5 | * SPDX-License-Identifier: Apache-2.0 |
markrad | 0:cdf462088d13 | 6 | * |
markrad | 0:cdf462088d13 | 7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may |
markrad | 0:cdf462088d13 | 8 | * not use this file except in compliance with the License. |
markrad | 0:cdf462088d13 | 9 | * You may obtain a copy of the License at |
markrad | 0:cdf462088d13 | 10 | * |
markrad | 0:cdf462088d13 | 11 | * http://www.apache.org/licenses/LICENSE-2.0 |
markrad | 0:cdf462088d13 | 12 | * |
markrad | 0:cdf462088d13 | 13 | * Unless required by applicable law or agreed to in writing, software |
markrad | 0:cdf462088d13 | 14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
markrad | 0:cdf462088d13 | 15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
markrad | 0:cdf462088d13 | 16 | * See the License for the specific language governing permissions and |
markrad | 0:cdf462088d13 | 17 | * limitations under the License. |
markrad | 0:cdf462088d13 | 18 | * |
markrad | 0:cdf462088d13 | 19 | * This file is part of mbed TLS (https://tls.mbed.org) |
markrad | 0:cdf462088d13 | 20 | */ |
markrad | 0:cdf462088d13 | 21 | /* |
markrad | 0:cdf462088d13 | 22 | * These session callbacks use a simple chained list |
markrad | 0:cdf462088d13 | 23 | * to store and retrieve the session information. |
markrad | 0:cdf462088d13 | 24 | */ |
markrad | 0:cdf462088d13 | 25 | |
markrad | 0:cdf462088d13 | 26 | #if !defined(MBEDTLS_CONFIG_FILE) |
markrad | 0:cdf462088d13 | 27 | #include "mbedtls/config.h" |
markrad | 0:cdf462088d13 | 28 | #else |
markrad | 0:cdf462088d13 | 29 | #include MBEDTLS_CONFIG_FILE |
markrad | 0:cdf462088d13 | 30 | #endif |
markrad | 0:cdf462088d13 | 31 | |
markrad | 0:cdf462088d13 | 32 | #if defined(MBEDTLS_SSL_COOKIE_C) |
markrad | 0:cdf462088d13 | 33 | |
markrad | 0:cdf462088d13 | 34 | #if defined(MBEDTLS_PLATFORM_C) |
markrad | 0:cdf462088d13 | 35 | #include "mbedtls/platform.h" |
markrad | 0:cdf462088d13 | 36 | #else |
markrad | 0:cdf462088d13 | 37 | #define mbedtls_calloc calloc |
markrad | 0:cdf462088d13 | 38 | #define mbedtls_free free |
markrad | 0:cdf462088d13 | 39 | #endif |
markrad | 0:cdf462088d13 | 40 | |
markrad | 0:cdf462088d13 | 41 | #include "mbedtls/ssl_cookie.h" |
markrad | 0:cdf462088d13 | 42 | #include "mbedtls/ssl_internal.h" |
markrad | 0:cdf462088d13 | 43 | |
markrad | 0:cdf462088d13 | 44 | #include <string.h> |
markrad | 0:cdf462088d13 | 45 | |
markrad | 0:cdf462088d13 | 46 | /* Implementation that should never be optimized out by the compiler */ |
markrad | 0:cdf462088d13 | 47 | static void mbedtls_zeroize( void *v, size_t n ) { |
markrad | 0:cdf462088d13 | 48 | volatile unsigned char *p = v; while( n-- ) *p++ = 0; |
markrad | 0:cdf462088d13 | 49 | } |
markrad | 0:cdf462088d13 | 50 | |
markrad | 0:cdf462088d13 | 51 | /* |
markrad | 0:cdf462088d13 | 52 | * If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is |
markrad | 0:cdf462088d13 | 53 | * available. Try SHA-256 first, 512 wastes resources since we need to stay |
markrad | 0:cdf462088d13 | 54 | * with max 32 bytes of cookie for DTLS 1.0 |
markrad | 0:cdf462088d13 | 55 | */ |
markrad | 0:cdf462088d13 | 56 | #if defined(MBEDTLS_SHA256_C) |
markrad | 0:cdf462088d13 | 57 | #define COOKIE_MD MBEDTLS_MD_SHA224 |
markrad | 0:cdf462088d13 | 58 | #define COOKIE_MD_OUTLEN 32 |
markrad | 0:cdf462088d13 | 59 | #define COOKIE_HMAC_LEN 28 |
markrad | 0:cdf462088d13 | 60 | #elif defined(MBEDTLS_SHA512_C) |
markrad | 0:cdf462088d13 | 61 | #define COOKIE_MD MBEDTLS_MD_SHA384 |
markrad | 0:cdf462088d13 | 62 | #define COOKIE_MD_OUTLEN 48 |
markrad | 0:cdf462088d13 | 63 | #define COOKIE_HMAC_LEN 28 |
markrad | 0:cdf462088d13 | 64 | #elif defined(MBEDTLS_SHA1_C) |
markrad | 0:cdf462088d13 | 65 | #define COOKIE_MD MBEDTLS_MD_SHA1 |
markrad | 0:cdf462088d13 | 66 | #define COOKIE_MD_OUTLEN 20 |
markrad | 0:cdf462088d13 | 67 | #define COOKIE_HMAC_LEN 20 |
markrad | 0:cdf462088d13 | 68 | #else |
markrad | 0:cdf462088d13 | 69 | #error "DTLS hello verify needs SHA-1 or SHA-2" |
markrad | 0:cdf462088d13 | 70 | #endif |
markrad | 0:cdf462088d13 | 71 | |
markrad | 0:cdf462088d13 | 72 | /* |
markrad | 0:cdf462088d13 | 73 | * Cookies are formed of a 4-bytes timestamp (or serial number) and |
markrad | 0:cdf462088d13 | 74 | * an HMAC of timestemp and client ID. |
markrad | 0:cdf462088d13 | 75 | */ |
markrad | 0:cdf462088d13 | 76 | #define COOKIE_LEN ( 4 + COOKIE_HMAC_LEN ) |
markrad | 0:cdf462088d13 | 77 | |
markrad | 0:cdf462088d13 | 78 | void mbedtls_ssl_cookie_init( mbedtls_ssl_cookie_ctx *ctx ) |
markrad | 0:cdf462088d13 | 79 | { |
markrad | 0:cdf462088d13 | 80 | mbedtls_md_init( &ctx->hmac_ctx ); |
markrad | 0:cdf462088d13 | 81 | #if !defined(MBEDTLS_HAVE_TIME) |
markrad | 0:cdf462088d13 | 82 | ctx->serial = 0; |
markrad | 0:cdf462088d13 | 83 | #endif |
markrad | 0:cdf462088d13 | 84 | ctx->timeout = MBEDTLS_SSL_COOKIE_TIMEOUT; |
markrad | 0:cdf462088d13 | 85 | |
markrad | 0:cdf462088d13 | 86 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 87 | mbedtls_mutex_init( &ctx->mutex ); |
markrad | 0:cdf462088d13 | 88 | #endif |
markrad | 0:cdf462088d13 | 89 | } |
markrad | 0:cdf462088d13 | 90 | |
markrad | 0:cdf462088d13 | 91 | void mbedtls_ssl_cookie_set_timeout( mbedtls_ssl_cookie_ctx *ctx, unsigned long delay ) |
markrad | 0:cdf462088d13 | 92 | { |
markrad | 0:cdf462088d13 | 93 | ctx->timeout = delay; |
markrad | 0:cdf462088d13 | 94 | } |
markrad | 0:cdf462088d13 | 95 | |
markrad | 0:cdf462088d13 | 96 | void mbedtls_ssl_cookie_free( mbedtls_ssl_cookie_ctx *ctx ) |
markrad | 0:cdf462088d13 | 97 | { |
markrad | 0:cdf462088d13 | 98 | mbedtls_md_free( &ctx->hmac_ctx ); |
markrad | 0:cdf462088d13 | 99 | |
markrad | 0:cdf462088d13 | 100 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 101 | mbedtls_mutex_init( &ctx->mutex ); |
markrad | 0:cdf462088d13 | 102 | #endif |
markrad | 0:cdf462088d13 | 103 | |
markrad | 0:cdf462088d13 | 104 | mbedtls_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) ); |
markrad | 0:cdf462088d13 | 105 | } |
markrad | 0:cdf462088d13 | 106 | |
markrad | 0:cdf462088d13 | 107 | int mbedtls_ssl_cookie_setup( mbedtls_ssl_cookie_ctx *ctx, |
markrad | 0:cdf462088d13 | 108 | int (*f_rng)(void *, unsigned char *, size_t), |
markrad | 0:cdf462088d13 | 109 | void *p_rng ) |
markrad | 0:cdf462088d13 | 110 | { |
markrad | 0:cdf462088d13 | 111 | int ret; |
markrad | 0:cdf462088d13 | 112 | unsigned char key[COOKIE_MD_OUTLEN]; |
markrad | 0:cdf462088d13 | 113 | |
markrad | 0:cdf462088d13 | 114 | if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 ) |
markrad | 0:cdf462088d13 | 115 | return( ret ); |
markrad | 0:cdf462088d13 | 116 | |
markrad | 0:cdf462088d13 | 117 | ret = mbedtls_md_setup( &ctx->hmac_ctx, mbedtls_md_info_from_type( COOKIE_MD ), 1 ); |
markrad | 0:cdf462088d13 | 118 | if( ret != 0 ) |
markrad | 0:cdf462088d13 | 119 | return( ret ); |
markrad | 0:cdf462088d13 | 120 | |
markrad | 0:cdf462088d13 | 121 | ret = mbedtls_md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) ); |
markrad | 0:cdf462088d13 | 122 | if( ret != 0 ) |
markrad | 0:cdf462088d13 | 123 | return( ret ); |
markrad | 0:cdf462088d13 | 124 | |
markrad | 0:cdf462088d13 | 125 | mbedtls_zeroize( key, sizeof( key ) ); |
markrad | 0:cdf462088d13 | 126 | |
markrad | 0:cdf462088d13 | 127 | return( 0 ); |
markrad | 0:cdf462088d13 | 128 | } |
markrad | 0:cdf462088d13 | 129 | |
markrad | 0:cdf462088d13 | 130 | /* |
markrad | 0:cdf462088d13 | 131 | * Generate the HMAC part of a cookie |
markrad | 0:cdf462088d13 | 132 | */ |
markrad | 0:cdf462088d13 | 133 | static int ssl_cookie_hmac( mbedtls_md_context_t *hmac_ctx, |
markrad | 0:cdf462088d13 | 134 | const unsigned char time[4], |
markrad | 0:cdf462088d13 | 135 | unsigned char **p, unsigned char *end, |
markrad | 0:cdf462088d13 | 136 | const unsigned char *cli_id, size_t cli_id_len ) |
markrad | 0:cdf462088d13 | 137 | { |
markrad | 0:cdf462088d13 | 138 | unsigned char hmac_out[COOKIE_MD_OUTLEN]; |
markrad | 0:cdf462088d13 | 139 | |
markrad | 0:cdf462088d13 | 140 | if( (size_t)( end - *p ) < COOKIE_HMAC_LEN ) |
markrad | 0:cdf462088d13 | 141 | return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
markrad | 0:cdf462088d13 | 142 | |
markrad | 0:cdf462088d13 | 143 | if( mbedtls_md_hmac_reset( hmac_ctx ) != 0 || |
markrad | 0:cdf462088d13 | 144 | mbedtls_md_hmac_update( hmac_ctx, time, 4 ) != 0 || |
markrad | 0:cdf462088d13 | 145 | mbedtls_md_hmac_update( hmac_ctx, cli_id, cli_id_len ) != 0 || |
markrad | 0:cdf462088d13 | 146 | mbedtls_md_hmac_finish( hmac_ctx, hmac_out ) != 0 ) |
markrad | 0:cdf462088d13 | 147 | { |
markrad | 0:cdf462088d13 | 148 | return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
markrad | 0:cdf462088d13 | 149 | } |
markrad | 0:cdf462088d13 | 150 | |
markrad | 0:cdf462088d13 | 151 | memcpy( *p, hmac_out, COOKIE_HMAC_LEN ); |
markrad | 0:cdf462088d13 | 152 | *p += COOKIE_HMAC_LEN; |
markrad | 0:cdf462088d13 | 153 | |
markrad | 0:cdf462088d13 | 154 | return( 0 ); |
markrad | 0:cdf462088d13 | 155 | } |
markrad | 0:cdf462088d13 | 156 | |
markrad | 0:cdf462088d13 | 157 | /* |
markrad | 0:cdf462088d13 | 158 | * Generate cookie for DTLS ClientHello verification |
markrad | 0:cdf462088d13 | 159 | */ |
markrad | 0:cdf462088d13 | 160 | int mbedtls_ssl_cookie_write( void *p_ctx, |
markrad | 0:cdf462088d13 | 161 | unsigned char **p, unsigned char *end, |
markrad | 0:cdf462088d13 | 162 | const unsigned char *cli_id, size_t cli_id_len ) |
markrad | 0:cdf462088d13 | 163 | { |
markrad | 0:cdf462088d13 | 164 | int ret; |
markrad | 0:cdf462088d13 | 165 | mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx; |
markrad | 0:cdf462088d13 | 166 | unsigned long t; |
markrad | 0:cdf462088d13 | 167 | |
markrad | 0:cdf462088d13 | 168 | if( ctx == NULL || cli_id == NULL ) |
markrad | 0:cdf462088d13 | 169 | return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
markrad | 0:cdf462088d13 | 170 | |
markrad | 0:cdf462088d13 | 171 | if( (size_t)( end - *p ) < COOKIE_LEN ) |
markrad | 0:cdf462088d13 | 172 | return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
markrad | 0:cdf462088d13 | 173 | |
markrad | 0:cdf462088d13 | 174 | #if defined(MBEDTLS_HAVE_TIME) |
markrad | 0:cdf462088d13 | 175 | t = (unsigned long) mbedtls_time( NULL ); |
markrad | 0:cdf462088d13 | 176 | #else |
markrad | 0:cdf462088d13 | 177 | t = ctx->serial++; |
markrad | 0:cdf462088d13 | 178 | #endif |
markrad | 0:cdf462088d13 | 179 | |
markrad | 0:cdf462088d13 | 180 | (*p)[0] = (unsigned char)( t >> 24 ); |
markrad | 0:cdf462088d13 | 181 | (*p)[1] = (unsigned char)( t >> 16 ); |
markrad | 0:cdf462088d13 | 182 | (*p)[2] = (unsigned char)( t >> 8 ); |
markrad | 0:cdf462088d13 | 183 | (*p)[3] = (unsigned char)( t ); |
markrad | 0:cdf462088d13 | 184 | *p += 4; |
markrad | 0:cdf462088d13 | 185 | |
markrad | 0:cdf462088d13 | 186 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 187 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
markrad | 0:cdf462088d13 | 188 | return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret ); |
markrad | 0:cdf462088d13 | 189 | #endif |
markrad | 0:cdf462088d13 | 190 | |
markrad | 0:cdf462088d13 | 191 | ret = ssl_cookie_hmac( &ctx->hmac_ctx, *p - 4, |
markrad | 0:cdf462088d13 | 192 | p, end, cli_id, cli_id_len ); |
markrad | 0:cdf462088d13 | 193 | |
markrad | 0:cdf462088d13 | 194 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 195 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
markrad | 0:cdf462088d13 | 196 | return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + |
markrad | 0:cdf462088d13 | 197 | MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
markrad | 0:cdf462088d13 | 198 | #endif |
markrad | 0:cdf462088d13 | 199 | |
markrad | 0:cdf462088d13 | 200 | return( ret ); |
markrad | 0:cdf462088d13 | 201 | } |
markrad | 0:cdf462088d13 | 202 | |
markrad | 0:cdf462088d13 | 203 | /* |
markrad | 0:cdf462088d13 | 204 | * Check a cookie |
markrad | 0:cdf462088d13 | 205 | */ |
markrad | 0:cdf462088d13 | 206 | int mbedtls_ssl_cookie_check( void *p_ctx, |
markrad | 0:cdf462088d13 | 207 | const unsigned char *cookie, size_t cookie_len, |
markrad | 0:cdf462088d13 | 208 | const unsigned char *cli_id, size_t cli_id_len ) |
markrad | 0:cdf462088d13 | 209 | { |
markrad | 0:cdf462088d13 | 210 | unsigned char ref_hmac[COOKIE_HMAC_LEN]; |
markrad | 0:cdf462088d13 | 211 | int ret = 0; |
markrad | 0:cdf462088d13 | 212 | unsigned char *p = ref_hmac; |
markrad | 0:cdf462088d13 | 213 | mbedtls_ssl_cookie_ctx *ctx = (mbedtls_ssl_cookie_ctx *) p_ctx; |
markrad | 0:cdf462088d13 | 214 | unsigned long cur_time, cookie_time; |
markrad | 0:cdf462088d13 | 215 | |
markrad | 0:cdf462088d13 | 216 | if( ctx == NULL || cli_id == NULL ) |
markrad | 0:cdf462088d13 | 217 | return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
markrad | 0:cdf462088d13 | 218 | |
markrad | 0:cdf462088d13 | 219 | if( cookie_len != COOKIE_LEN ) |
markrad | 0:cdf462088d13 | 220 | return( -1 ); |
markrad | 0:cdf462088d13 | 221 | |
markrad | 0:cdf462088d13 | 222 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 223 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
markrad | 0:cdf462088d13 | 224 | return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + ret ); |
markrad | 0:cdf462088d13 | 225 | #endif |
markrad | 0:cdf462088d13 | 226 | |
markrad | 0:cdf462088d13 | 227 | if( ssl_cookie_hmac( &ctx->hmac_ctx, cookie, |
markrad | 0:cdf462088d13 | 228 | &p, p + sizeof( ref_hmac ), |
markrad | 0:cdf462088d13 | 229 | cli_id, cli_id_len ) != 0 ) |
markrad | 0:cdf462088d13 | 230 | ret = -1; |
markrad | 0:cdf462088d13 | 231 | |
markrad | 0:cdf462088d13 | 232 | #if defined(MBEDTLS_THREADING_C) |
markrad | 0:cdf462088d13 | 233 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
markrad | 0:cdf462088d13 | 234 | return( MBEDTLS_ERR_SSL_INTERNAL_ERROR + |
markrad | 0:cdf462088d13 | 235 | MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
markrad | 0:cdf462088d13 | 236 | #endif |
markrad | 0:cdf462088d13 | 237 | |
markrad | 0:cdf462088d13 | 238 | if( ret != 0 ) |
markrad | 0:cdf462088d13 | 239 | return( ret ); |
markrad | 0:cdf462088d13 | 240 | |
markrad | 0:cdf462088d13 | 241 | if( mbedtls_ssl_safer_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 ) |
markrad | 0:cdf462088d13 | 242 | return( -1 ); |
markrad | 0:cdf462088d13 | 243 | |
markrad | 0:cdf462088d13 | 244 | #if defined(MBEDTLS_HAVE_TIME) |
markrad | 0:cdf462088d13 | 245 | cur_time = (unsigned long) mbedtls_time( NULL ); |
markrad | 0:cdf462088d13 | 246 | #else |
markrad | 0:cdf462088d13 | 247 | cur_time = ctx->serial; |
markrad | 0:cdf462088d13 | 248 | #endif |
markrad | 0:cdf462088d13 | 249 | |
markrad | 0:cdf462088d13 | 250 | cookie_time = ( (unsigned long) cookie[0] << 24 ) | |
markrad | 0:cdf462088d13 | 251 | ( (unsigned long) cookie[1] << 16 ) | |
markrad | 0:cdf462088d13 | 252 | ( (unsigned long) cookie[2] << 8 ) | |
markrad | 0:cdf462088d13 | 253 | ( (unsigned long) cookie[3] ); |
markrad | 0:cdf462088d13 | 254 | |
markrad | 0:cdf462088d13 | 255 | if( ctx->timeout != 0 && cur_time - cookie_time > ctx->timeout ) |
markrad | 0:cdf462088d13 | 256 | return( -1 ); |
markrad | 0:cdf462088d13 | 257 | |
markrad | 0:cdf462088d13 | 258 | return( 0 ); |
markrad | 0:cdf462088d13 | 259 | } |
markrad | 0:cdf462088d13 | 260 | #endif /* MBEDTLS_SSL_COOKIE_C */ |