erkin yucel / mbed-os

mbed os with nrf51 internal bandgap enabled to read battery level

Dependents:   BLE_file_test BLE_Blink ExternalEncoder

features/mbedtls/src/entropy.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elessair 0:f269e3021894 1 /*
elessair 0:f269e3021894 2 * Entropy accumulator implementation
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
elessair 0:f269e3021894 5 * SPDX-License-Identifier: Apache-2.0
elessair 0:f269e3021894 6 *
elessair 0:f269e3021894 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
elessair 0:f269e3021894 8 * not use this file except in compliance with the License.
elessair 0:f269e3021894 9 * You may obtain a copy of the License at
elessair 0:f269e3021894 10 *
elessair 0:f269e3021894 11 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 12 *
elessair 0:f269e3021894 13 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
elessair 0:f269e3021894 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 16 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 17 * limitations under the License.
elessair 0:f269e3021894 18 *
elessair 0:f269e3021894 19 * This file is part of mbed TLS (https://tls.mbed.org)
elessair 0:f269e3021894 20 */
elessair 0:f269e3021894 21
elessair 0:f269e3021894 22 #if !defined(MBEDTLS_CONFIG_FILE)
elessair 0:f269e3021894 23 #include "mbedtls/config.h"
elessair 0:f269e3021894 24 #else
elessair 0:f269e3021894 25 #include MBEDTLS_CONFIG_FILE
elessair 0:f269e3021894 26 #endif
elessair 0:f269e3021894 27
elessair 0:f269e3021894 28 #if defined(MBEDTLS_ENTROPY_C)
elessair 0:f269e3021894 29
elessair 0:f269e3021894 30 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
elessair 0:f269e3021894 31 #warning "**** WARNING! MBEDTLS_TEST_NULL_ENTROPY defined! "
elessair 0:f269e3021894 32 #warning "**** THIS BUILD HAS NO DEFINED ENTROPY SOURCES "
elessair 0:f269e3021894 33 #warning "**** THIS BUILD IS *NOT* SUITABLE FOR PRODUCTION USE "
elessair 0:f269e3021894 34 #endif
elessair 0:f269e3021894 35
elessair 0:f269e3021894 36 #include "mbedtls/entropy.h"
elessair 0:f269e3021894 37 #include "mbedtls/entropy_poll.h"
elessair 0:f269e3021894 38
elessair 0:f269e3021894 39 #include <string.h>
elessair 0:f269e3021894 40
elessair 0:f269e3021894 41 #if defined(MBEDTLS_FS_IO)
elessair 0:f269e3021894 42 #include <stdio.h>
elessair 0:f269e3021894 43 #endif
elessair 0:f269e3021894 44
elessair 0:f269e3021894 45 #if defined(MBEDTLS_ENTROPY_NV_SEED)
elessair 0:f269e3021894 46 #include "mbedtls/platform.h"
elessair 0:f269e3021894 47 #endif
elessair 0:f269e3021894 48
elessair 0:f269e3021894 49 #if defined(MBEDTLS_SELF_TEST)
elessair 0:f269e3021894 50 #if defined(MBEDTLS_PLATFORM_C)
elessair 0:f269e3021894 51 #include "mbedtls/platform.h"
elessair 0:f269e3021894 52 #else
elessair 0:f269e3021894 53 #include <stdio.h>
elessair 0:f269e3021894 54 #define mbedtls_printf printf
elessair 0:f269e3021894 55 #endif /* MBEDTLS_PLATFORM_C */
elessair 0:f269e3021894 56 #endif /* MBEDTLS_SELF_TEST */
elessair 0:f269e3021894 57
elessair 0:f269e3021894 58 #if defined(MBEDTLS_HAVEGE_C)
elessair 0:f269e3021894 59 #include "mbedtls/havege.h"
elessair 0:f269e3021894 60 #endif
elessair 0:f269e3021894 61
elessair 0:f269e3021894 62 /* Implementation that should never be optimized out by the compiler */
elessair 0:f269e3021894 63 static void mbedtls_zeroize( void *v, size_t n ) {
elessair 0:f269e3021894 64 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
elessair 0:f269e3021894 65 }
elessair 0:f269e3021894 66
elessair 0:f269e3021894 67 #define ENTROPY_MAX_LOOP 256 /**< Maximum amount to loop before error */
elessair 0:f269e3021894 68
elessair 0:f269e3021894 69 void mbedtls_entropy_init( mbedtls_entropy_context *ctx )
elessair 0:f269e3021894 70 {
elessair 0:f269e3021894 71 memset( ctx, 0, sizeof(mbedtls_entropy_context) );
elessair 0:f269e3021894 72
elessair 0:f269e3021894 73 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 74 mbedtls_mutex_init( &ctx->mutex );
elessair 0:f269e3021894 75 #endif
elessair 0:f269e3021894 76
elessair 0:f269e3021894 77 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
elessair 0:f269e3021894 78 mbedtls_sha512_starts( &ctx->accumulator, 0 );
elessair 0:f269e3021894 79 #else
elessair 0:f269e3021894 80 mbedtls_sha256_starts( &ctx->accumulator, 0 );
elessair 0:f269e3021894 81 #endif
elessair 0:f269e3021894 82 #if defined(MBEDTLS_HAVEGE_C)
elessair 0:f269e3021894 83 mbedtls_havege_init( &ctx->havege_data );
elessair 0:f269e3021894 84 #endif
elessair 0:f269e3021894 85
elessair 0:f269e3021894 86 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
elessair 0:f269e3021894 87 mbedtls_entropy_add_source( ctx, mbedtls_null_entropy_poll, NULL,
elessair 0:f269e3021894 88 1, MBEDTLS_ENTROPY_SOURCE_STRONG );
elessair 0:f269e3021894 89 #endif
elessair 0:f269e3021894 90
elessair 0:f269e3021894 91 #if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
elessair 0:f269e3021894 92 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
elessair 0:f269e3021894 93 mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL,
elessair 0:f269e3021894 94 MBEDTLS_ENTROPY_MIN_PLATFORM,
elessair 0:f269e3021894 95 MBEDTLS_ENTROPY_SOURCE_STRONG );
elessair 0:f269e3021894 96 #endif
elessair 0:f269e3021894 97 #if defined(MBEDTLS_TIMING_C)
elessair 0:f269e3021894 98 mbedtls_entropy_add_source( ctx, mbedtls_hardclock_poll, NULL,
elessair 0:f269e3021894 99 MBEDTLS_ENTROPY_MIN_HARDCLOCK,
elessair 0:f269e3021894 100 MBEDTLS_ENTROPY_SOURCE_WEAK );
elessair 0:f269e3021894 101 #endif
elessair 0:f269e3021894 102 #if defined(MBEDTLS_HAVEGE_C)
elessair 0:f269e3021894 103 mbedtls_entropy_add_source( ctx, mbedtls_havege_poll, &ctx->havege_data,
elessair 0:f269e3021894 104 MBEDTLS_ENTROPY_MIN_HAVEGE,
elessair 0:f269e3021894 105 MBEDTLS_ENTROPY_SOURCE_STRONG );
elessair 0:f269e3021894 106 #endif
elessair 0:f269e3021894 107 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
elessair 0:f269e3021894 108 mbedtls_entropy_add_source( ctx, mbedtls_hardware_poll, NULL,
elessair 0:f269e3021894 109 MBEDTLS_ENTROPY_MIN_HARDWARE,
elessair 0:f269e3021894 110 MBEDTLS_ENTROPY_SOURCE_STRONG );
elessair 0:f269e3021894 111 #endif
elessair 0:f269e3021894 112 #if defined(MBEDTLS_ENTROPY_NV_SEED)
elessair 0:f269e3021894 113 mbedtls_entropy_add_source( ctx, mbedtls_nv_seed_poll, NULL,
elessair 0:f269e3021894 114 MBEDTLS_ENTROPY_BLOCK_SIZE,
elessair 0:f269e3021894 115 MBEDTLS_ENTROPY_SOURCE_STRONG );
elessair 0:f269e3021894 116 #endif
elessair 0:f269e3021894 117 #endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */
elessair 0:f269e3021894 118 }
elessair 0:f269e3021894 119
elessair 0:f269e3021894 120 void mbedtls_entropy_free( mbedtls_entropy_context *ctx )
elessair 0:f269e3021894 121 {
elessair 0:f269e3021894 122 #if defined(MBEDTLS_HAVEGE_C)
elessair 0:f269e3021894 123 mbedtls_havege_free( &ctx->havege_data );
elessair 0:f269e3021894 124 #endif
elessair 0:f269e3021894 125 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 126 mbedtls_mutex_free( &ctx->mutex );
elessair 0:f269e3021894 127 #endif
elessair 0:f269e3021894 128 mbedtls_zeroize( ctx, sizeof( mbedtls_entropy_context ) );
elessair 0:f269e3021894 129 }
elessair 0:f269e3021894 130
elessair 0:f269e3021894 131 int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx,
elessair 0:f269e3021894 132 mbedtls_entropy_f_source_ptr f_source, void *p_source,
elessair 0:f269e3021894 133 size_t threshold, int strong )
elessair 0:f269e3021894 134 {
elessair 0:f269e3021894 135 int index, ret = 0;
elessair 0:f269e3021894 136
elessair 0:f269e3021894 137 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 138 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
elessair 0:f269e3021894 139 return( ret );
elessair 0:f269e3021894 140 #endif
elessair 0:f269e3021894 141
elessair 0:f269e3021894 142 index = ctx->source_count;
elessair 0:f269e3021894 143 if( index >= MBEDTLS_ENTROPY_MAX_SOURCES )
elessair 0:f269e3021894 144 {
elessair 0:f269e3021894 145 ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES;
elessair 0:f269e3021894 146 goto exit;
elessair 0:f269e3021894 147 }
elessair 0:f269e3021894 148
elessair 0:f269e3021894 149 ctx->source[index].f_source = f_source;
elessair 0:f269e3021894 150 ctx->source[index].p_source = p_source;
elessair 0:f269e3021894 151 ctx->source[index].threshold = threshold;
elessair 0:f269e3021894 152 ctx->source[index].strong = strong;
elessair 0:f269e3021894 153
elessair 0:f269e3021894 154 ctx->source_count++;
elessair 0:f269e3021894 155
elessair 0:f269e3021894 156 exit:
elessair 0:f269e3021894 157 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 158 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
elessair 0:f269e3021894 159 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
elessair 0:f269e3021894 160 #endif
elessair 0:f269e3021894 161
elessair 0:f269e3021894 162 return( ret );
elessair 0:f269e3021894 163 }
elessair 0:f269e3021894 164
elessair 0:f269e3021894 165 /*
elessair 0:f269e3021894 166 * Entropy accumulator update
elessair 0:f269e3021894 167 */
elessair 0:f269e3021894 168 static int entropy_update( mbedtls_entropy_context *ctx, unsigned char source_id,
elessair 0:f269e3021894 169 const unsigned char *data, size_t len )
elessair 0:f269e3021894 170 {
elessair 0:f269e3021894 171 unsigned char header[2];
elessair 0:f269e3021894 172 unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE];
elessair 0:f269e3021894 173 size_t use_len = len;
elessair 0:f269e3021894 174 const unsigned char *p = data;
elessair 0:f269e3021894 175
elessair 0:f269e3021894 176 if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE )
elessair 0:f269e3021894 177 {
elessair 0:f269e3021894 178 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
elessair 0:f269e3021894 179 mbedtls_sha512( data, len, tmp, 0 );
elessair 0:f269e3021894 180 #else
elessair 0:f269e3021894 181 mbedtls_sha256( data, len, tmp, 0 );
elessair 0:f269e3021894 182 #endif
elessair 0:f269e3021894 183 p = tmp;
elessair 0:f269e3021894 184 use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
elessair 0:f269e3021894 185 }
elessair 0:f269e3021894 186
elessair 0:f269e3021894 187 header[0] = source_id;
elessair 0:f269e3021894 188 header[1] = use_len & 0xFF;
elessair 0:f269e3021894 189
elessair 0:f269e3021894 190 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
elessair 0:f269e3021894 191 mbedtls_sha512_update( &ctx->accumulator, header, 2 );
elessair 0:f269e3021894 192 mbedtls_sha512_update( &ctx->accumulator, p, use_len );
elessair 0:f269e3021894 193 #else
elessair 0:f269e3021894 194 mbedtls_sha256_update( &ctx->accumulator, header, 2 );
elessair 0:f269e3021894 195 mbedtls_sha256_update( &ctx->accumulator, p, use_len );
elessair 0:f269e3021894 196 #endif
elessair 0:f269e3021894 197
elessair 0:f269e3021894 198 return( 0 );
elessair 0:f269e3021894 199 }
elessair 0:f269e3021894 200
elessair 0:f269e3021894 201 int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
elessair 0:f269e3021894 202 const unsigned char *data, size_t len )
elessair 0:f269e3021894 203 {
elessair 0:f269e3021894 204 int ret;
elessair 0:f269e3021894 205
elessair 0:f269e3021894 206 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 207 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
elessair 0:f269e3021894 208 return( ret );
elessair 0:f269e3021894 209 #endif
elessair 0:f269e3021894 210
elessair 0:f269e3021894 211 ret = entropy_update( ctx, MBEDTLS_ENTROPY_SOURCE_MANUAL, data, len );
elessair 0:f269e3021894 212
elessair 0:f269e3021894 213 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 214 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
elessair 0:f269e3021894 215 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
elessair 0:f269e3021894 216 #endif
elessair 0:f269e3021894 217
elessair 0:f269e3021894 218 return( ret );
elessair 0:f269e3021894 219 }
elessair 0:f269e3021894 220
elessair 0:f269e3021894 221 /*
elessair 0:f269e3021894 222 * Run through the different sources to add entropy to our accumulator
elessair 0:f269e3021894 223 */
elessair 0:f269e3021894 224 static int entropy_gather_internal( mbedtls_entropy_context *ctx )
elessair 0:f269e3021894 225 {
elessair 0:f269e3021894 226 int ret, i, have_one_strong = 0;
elessair 0:f269e3021894 227 unsigned char buf[MBEDTLS_ENTROPY_MAX_GATHER];
elessair 0:f269e3021894 228 size_t olen;
elessair 0:f269e3021894 229
elessair 0:f269e3021894 230 if( ctx->source_count == 0 )
elessair 0:f269e3021894 231 return( MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED );
elessair 0:f269e3021894 232
elessair 0:f269e3021894 233 /*
elessair 0:f269e3021894 234 * Run through our entropy sources
elessair 0:f269e3021894 235 */
elessair 0:f269e3021894 236 for( i = 0; i < ctx->source_count; i++ )
elessair 0:f269e3021894 237 {
elessair 0:f269e3021894 238 if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG )
elessair 0:f269e3021894 239 have_one_strong = 1;
elessair 0:f269e3021894 240
elessair 0:f269e3021894 241 olen = 0;
elessair 0:f269e3021894 242 if( ( ret = ctx->source[i].f_source( ctx->source[i].p_source,
elessair 0:f269e3021894 243 buf, MBEDTLS_ENTROPY_MAX_GATHER, &olen ) ) != 0 )
elessair 0:f269e3021894 244 {
elessair 0:f269e3021894 245 return( ret );
elessair 0:f269e3021894 246 }
elessair 0:f269e3021894 247
elessair 0:f269e3021894 248 /*
elessair 0:f269e3021894 249 * Add if we actually gathered something
elessair 0:f269e3021894 250 */
elessair 0:f269e3021894 251 if( olen > 0 )
elessair 0:f269e3021894 252 {
elessair 0:f269e3021894 253 entropy_update( ctx, (unsigned char) i, buf, olen );
elessair 0:f269e3021894 254 ctx->source[i].size += olen;
elessair 0:f269e3021894 255 }
elessair 0:f269e3021894 256 }
elessair 0:f269e3021894 257
elessair 0:f269e3021894 258 if( have_one_strong == 0 )
elessair 0:f269e3021894 259 return( MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE );
elessair 0:f269e3021894 260
elessair 0:f269e3021894 261 return( 0 );
elessair 0:f269e3021894 262 }
elessair 0:f269e3021894 263
elessair 0:f269e3021894 264 /*
elessair 0:f269e3021894 265 * Thread-safe wrapper for entropy_gather_internal()
elessair 0:f269e3021894 266 */
elessair 0:f269e3021894 267 int mbedtls_entropy_gather( mbedtls_entropy_context *ctx )
elessair 0:f269e3021894 268 {
elessair 0:f269e3021894 269 int ret;
elessair 0:f269e3021894 270
elessair 0:f269e3021894 271 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 272 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
elessair 0:f269e3021894 273 return( ret );
elessair 0:f269e3021894 274 #endif
elessair 0:f269e3021894 275
elessair 0:f269e3021894 276 ret = entropy_gather_internal( ctx );
elessair 0:f269e3021894 277
elessair 0:f269e3021894 278 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 279 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
elessair 0:f269e3021894 280 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
elessair 0:f269e3021894 281 #endif
elessair 0:f269e3021894 282
elessair 0:f269e3021894 283 return( ret );
elessair 0:f269e3021894 284 }
elessair 0:f269e3021894 285
elessair 0:f269e3021894 286 int mbedtls_entropy_func( void *data, unsigned char *output, size_t len )
elessair 0:f269e3021894 287 {
elessair 0:f269e3021894 288 int ret, count = 0, i, done;
elessair 0:f269e3021894 289 mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data;
elessair 0:f269e3021894 290 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
elessair 0:f269e3021894 291
elessair 0:f269e3021894 292 if( len > MBEDTLS_ENTROPY_BLOCK_SIZE )
elessair 0:f269e3021894 293 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
elessair 0:f269e3021894 294
elessair 0:f269e3021894 295 #if defined(MBEDTLS_ENTROPY_NV_SEED)
elessair 0:f269e3021894 296 /* Update the NV entropy seed before generating any entropy for outside
elessair 0:f269e3021894 297 * use.
elessair 0:f269e3021894 298 */
elessair 0:f269e3021894 299 if( ctx->initial_entropy_run == 0 )
elessair 0:f269e3021894 300 {
elessair 0:f269e3021894 301 ctx->initial_entropy_run = 1;
elessair 0:f269e3021894 302 if( ( ret = mbedtls_entropy_update_nv_seed( ctx ) ) != 0 )
elessair 0:f269e3021894 303 return( ret );
elessair 0:f269e3021894 304 }
elessair 0:f269e3021894 305 #endif
elessair 0:f269e3021894 306
elessair 0:f269e3021894 307 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 308 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
elessair 0:f269e3021894 309 return( ret );
elessair 0:f269e3021894 310 #endif
elessair 0:f269e3021894 311
elessair 0:f269e3021894 312 /*
elessair 0:f269e3021894 313 * Always gather extra entropy before a call
elessair 0:f269e3021894 314 */
elessair 0:f269e3021894 315 do
elessair 0:f269e3021894 316 {
elessair 0:f269e3021894 317 if( count++ > ENTROPY_MAX_LOOP )
elessair 0:f269e3021894 318 {
elessair 0:f269e3021894 319 ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
elessair 0:f269e3021894 320 goto exit;
elessair 0:f269e3021894 321 }
elessair 0:f269e3021894 322
elessair 0:f269e3021894 323 if( ( ret = entropy_gather_internal( ctx ) ) != 0 )
elessair 0:f269e3021894 324 goto exit;
elessair 0:f269e3021894 325
elessair 0:f269e3021894 326 done = 1;
elessair 0:f269e3021894 327 for( i = 0; i < ctx->source_count; i++ )
elessair 0:f269e3021894 328 if( ctx->source[i].size < ctx->source[i].threshold )
elessair 0:f269e3021894 329 done = 0;
elessair 0:f269e3021894 330 }
elessair 0:f269e3021894 331 while( ! done );
elessair 0:f269e3021894 332
elessair 0:f269e3021894 333 memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
elessair 0:f269e3021894 334
elessair 0:f269e3021894 335 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
elessair 0:f269e3021894 336 mbedtls_sha512_finish( &ctx->accumulator, buf );
elessair 0:f269e3021894 337
elessair 0:f269e3021894 338 /*
elessair 0:f269e3021894 339 * Reset accumulator and counters and recycle existing entropy
elessair 0:f269e3021894 340 */
elessair 0:f269e3021894 341 memset( &ctx->accumulator, 0, sizeof( mbedtls_sha512_context ) );
elessair 0:f269e3021894 342 mbedtls_sha512_starts( &ctx->accumulator, 0 );
elessair 0:f269e3021894 343 mbedtls_sha512_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
elessair 0:f269e3021894 344
elessair 0:f269e3021894 345 /*
elessair 0:f269e3021894 346 * Perform second SHA-512 on entropy
elessair 0:f269e3021894 347 */
elessair 0:f269e3021894 348 mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
elessair 0:f269e3021894 349 #else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
elessair 0:f269e3021894 350 mbedtls_sha256_finish( &ctx->accumulator, buf );
elessair 0:f269e3021894 351
elessair 0:f269e3021894 352 /*
elessair 0:f269e3021894 353 * Reset accumulator and counters and recycle existing entropy
elessair 0:f269e3021894 354 */
elessair 0:f269e3021894 355 memset( &ctx->accumulator, 0, sizeof( mbedtls_sha256_context ) );
elessair 0:f269e3021894 356 mbedtls_sha256_starts( &ctx->accumulator, 0 );
elessair 0:f269e3021894 357 mbedtls_sha256_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
elessair 0:f269e3021894 358
elessair 0:f269e3021894 359 /*
elessair 0:f269e3021894 360 * Perform second SHA-256 on entropy
elessair 0:f269e3021894 361 */
elessair 0:f269e3021894 362 mbedtls_sha256( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
elessair 0:f269e3021894 363 #endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
elessair 0:f269e3021894 364
elessair 0:f269e3021894 365 for( i = 0; i < ctx->source_count; i++ )
elessair 0:f269e3021894 366 ctx->source[i].size = 0;
elessair 0:f269e3021894 367
elessair 0:f269e3021894 368 memcpy( output, buf, len );
elessair 0:f269e3021894 369
elessair 0:f269e3021894 370 ret = 0;
elessair 0:f269e3021894 371
elessair 0:f269e3021894 372 exit:
elessair 0:f269e3021894 373 #if defined(MBEDTLS_THREADING_C)
elessair 0:f269e3021894 374 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
elessair 0:f269e3021894 375 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
elessair 0:f269e3021894 376 #endif
elessair 0:f269e3021894 377
elessair 0:f269e3021894 378 return( ret );
elessair 0:f269e3021894 379 }
elessair 0:f269e3021894 380
elessair 0:f269e3021894 381 #if defined(MBEDTLS_ENTROPY_NV_SEED)
elessair 0:f269e3021894 382 int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx )
elessair 0:f269e3021894 383 {
elessair 0:f269e3021894 384 int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
elessair 0:f269e3021894 385 unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ];
elessair 0:f269e3021894 386
elessair 0:f269e3021894 387 /* Read new seed and write it to NV */
elessair 0:f269e3021894 388 if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
elessair 0:f269e3021894 389 return( ret );
elessair 0:f269e3021894 390
elessair 0:f269e3021894 391 if( mbedtls_nv_seed_write( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
elessair 0:f269e3021894 392 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
elessair 0:f269e3021894 393
elessair 0:f269e3021894 394 /* Manually update the remaining stream with a separator value to diverge */
elessair 0:f269e3021894 395 memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
elessair 0:f269e3021894 396 mbedtls_entropy_update_manual( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
elessair 0:f269e3021894 397
elessair 0:f269e3021894 398 return( 0 );
elessair 0:f269e3021894 399 }
elessair 0:f269e3021894 400 #endif /* MBEDTLS_ENTROPY_NV_SEED */
elessair 0:f269e3021894 401
elessair 0:f269e3021894 402 #if defined(MBEDTLS_FS_IO)
elessair 0:f269e3021894 403 int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path )
elessair 0:f269e3021894 404 {
elessair 0:f269e3021894 405 int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
elessair 0:f269e3021894 406 FILE *f;
elessair 0:f269e3021894 407 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
elessair 0:f269e3021894 408
elessair 0:f269e3021894 409 if( ( f = fopen( path, "wb" ) ) == NULL )
elessair 0:f269e3021894 410 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
elessair 0:f269e3021894 411
elessair 0:f269e3021894 412 if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
elessair 0:f269e3021894 413 goto exit;
elessair 0:f269e3021894 414
elessair 0:f269e3021894 415 if( fwrite( buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f ) != MBEDTLS_ENTROPY_BLOCK_SIZE )
elessair 0:f269e3021894 416 {
elessair 0:f269e3021894 417 ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
elessair 0:f269e3021894 418 goto exit;
elessair 0:f269e3021894 419 }
elessair 0:f269e3021894 420
elessair 0:f269e3021894 421 ret = 0;
elessair 0:f269e3021894 422
elessair 0:f269e3021894 423 exit:
elessair 0:f269e3021894 424 fclose( f );
elessair 0:f269e3021894 425 return( ret );
elessair 0:f269e3021894 426 }
elessair 0:f269e3021894 427
elessair 0:f269e3021894 428 int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path )
elessair 0:f269e3021894 429 {
elessair 0:f269e3021894 430 FILE *f;
elessair 0:f269e3021894 431 size_t n;
elessair 0:f269e3021894 432 unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ];
elessair 0:f269e3021894 433
elessair 0:f269e3021894 434 if( ( f = fopen( path, "rb" ) ) == NULL )
elessair 0:f269e3021894 435 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
elessair 0:f269e3021894 436
elessair 0:f269e3021894 437 fseek( f, 0, SEEK_END );
elessair 0:f269e3021894 438 n = (size_t) ftell( f );
elessair 0:f269e3021894 439 fseek( f, 0, SEEK_SET );
elessair 0:f269e3021894 440
elessair 0:f269e3021894 441 if( n > MBEDTLS_ENTROPY_MAX_SEED_SIZE )
elessair 0:f269e3021894 442 n = MBEDTLS_ENTROPY_MAX_SEED_SIZE;
elessair 0:f269e3021894 443
elessair 0:f269e3021894 444 if( fread( buf, 1, n, f ) != n )
elessair 0:f269e3021894 445 {
elessair 0:f269e3021894 446 fclose( f );
elessair 0:f269e3021894 447 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
elessair 0:f269e3021894 448 }
elessair 0:f269e3021894 449
elessair 0:f269e3021894 450 fclose( f );
elessair 0:f269e3021894 451
elessair 0:f269e3021894 452 mbedtls_entropy_update_manual( ctx, buf, n );
elessair 0:f269e3021894 453
elessair 0:f269e3021894 454 return( mbedtls_entropy_write_seed_file( ctx, path ) );
elessair 0:f269e3021894 455 }
elessair 0:f269e3021894 456 #endif /* MBEDTLS_FS_IO */
elessair 0:f269e3021894 457
elessair 0:f269e3021894 458 #if defined(MBEDTLS_SELF_TEST)
elessair 0:f269e3021894 459 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
elessair 0:f269e3021894 460 /*
elessair 0:f269e3021894 461 * Dummy source function
elessair 0:f269e3021894 462 */
elessair 0:f269e3021894 463 static int entropy_dummy_source( void *data, unsigned char *output,
elessair 0:f269e3021894 464 size_t len, size_t *olen )
elessair 0:f269e3021894 465 {
elessair 0:f269e3021894 466 ((void) data);
elessair 0:f269e3021894 467
elessair 0:f269e3021894 468 memset( output, 0x2a, len );
elessair 0:f269e3021894 469 *olen = len;
elessair 0:f269e3021894 470
elessair 0:f269e3021894 471 return( 0 );
elessair 0:f269e3021894 472 }
elessair 0:f269e3021894 473 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
elessair 0:f269e3021894 474
elessair 0:f269e3021894 475 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
elessair 0:f269e3021894 476
elessair 0:f269e3021894 477 static int mbedtls_entropy_source_self_test_gather( unsigned char *buf, size_t buf_len )
elessair 0:f269e3021894 478 {
elessair 0:f269e3021894 479 int ret = 0;
elessair 0:f269e3021894 480 size_t entropy_len = 0;
elessair 0:f269e3021894 481 size_t olen = 0;
elessair 0:f269e3021894 482 size_t attempts = buf_len;
elessair 0:f269e3021894 483
elessair 0:f269e3021894 484 while( attempts > 0 && entropy_len < buf_len )
elessair 0:f269e3021894 485 {
elessair 0:f269e3021894 486 if( ( ret = mbedtls_hardware_poll( NULL, buf + entropy_len,
elessair 0:f269e3021894 487 buf_len - entropy_len, &olen ) ) != 0 )
elessair 0:f269e3021894 488 return( ret );
elessair 0:f269e3021894 489
elessair 0:f269e3021894 490 entropy_len += olen;
elessair 0:f269e3021894 491 attempts--;
elessair 0:f269e3021894 492 }
elessair 0:f269e3021894 493
elessair 0:f269e3021894 494 if( entropy_len < buf_len )
elessair 0:f269e3021894 495 {
elessair 0:f269e3021894 496 ret = 1;
elessair 0:f269e3021894 497 }
elessair 0:f269e3021894 498
elessair 0:f269e3021894 499 return( ret );
elessair 0:f269e3021894 500 }
elessair 0:f269e3021894 501
elessair 0:f269e3021894 502
elessair 0:f269e3021894 503 static int mbedtls_entropy_source_self_test_check_bits( const unsigned char *buf,
elessair 0:f269e3021894 504 size_t buf_len )
elessair 0:f269e3021894 505 {
elessair 0:f269e3021894 506 unsigned char set= 0xFF;
elessair 0:f269e3021894 507 unsigned char unset = 0x00;
elessair 0:f269e3021894 508 size_t i;
elessair 0:f269e3021894 509
elessair 0:f269e3021894 510 for( i = 0; i < buf_len; i++ )
elessair 0:f269e3021894 511 {
elessair 0:f269e3021894 512 set &= buf[i];
elessair 0:f269e3021894 513 unset |= buf[i];
elessair 0:f269e3021894 514 }
elessair 0:f269e3021894 515
elessair 0:f269e3021894 516 return( set == 0xFF || unset == 0x00 );
elessair 0:f269e3021894 517 }
elessair 0:f269e3021894 518
elessair 0:f269e3021894 519 /*
elessair 0:f269e3021894 520 * A test to ensure hat the entropy sources are functioning correctly
elessair 0:f269e3021894 521 * and there is no obvious failure. The test performs the following checks:
elessair 0:f269e3021894 522 * - The entropy source is not providing only 0s (all bits unset) or 1s (all
elessair 0:f269e3021894 523 * bits set).
elessair 0:f269e3021894 524 * - The entropy source is not providing values in a pattern. Because the
elessair 0:f269e3021894 525 * hardware could be providing data in an arbitrary length, this check polls
elessair 0:f269e3021894 526 * the hardware entropy source twice and compares the result to ensure they
elessair 0:f269e3021894 527 * are not equal.
elessair 0:f269e3021894 528 * - The error code returned by the entropy source is not an error.
elessair 0:f269e3021894 529 */
elessair 0:f269e3021894 530 int mbedtls_entropy_source_self_test( int verbose )
elessair 0:f269e3021894 531 {
elessair 0:f269e3021894 532 int ret = 0;
elessair 0:f269e3021894 533 unsigned char buf0[2 * sizeof( unsigned long long int )];
elessair 0:f269e3021894 534 unsigned char buf1[2 * sizeof( unsigned long long int )];
elessair 0:f269e3021894 535
elessair 0:f269e3021894 536 if( verbose != 0 )
elessair 0:f269e3021894 537 mbedtls_printf( " ENTROPY_BIAS test: " );
elessair 0:f269e3021894 538
elessair 0:f269e3021894 539 memset( buf0, 0x00, sizeof( buf0 ) );
elessair 0:f269e3021894 540 memset( buf1, 0x00, sizeof( buf1 ) );
elessair 0:f269e3021894 541
elessair 0:f269e3021894 542 if( ( ret = mbedtls_entropy_source_self_test_gather( buf0, sizeof( buf0 ) ) ) != 0 )
elessair 0:f269e3021894 543 goto cleanup;
elessair 0:f269e3021894 544 if( ( ret = mbedtls_entropy_source_self_test_gather( buf1, sizeof( buf1 ) ) ) != 0 )
elessair 0:f269e3021894 545 goto cleanup;
elessair 0:f269e3021894 546
elessair 0:f269e3021894 547 /* Make sure that the returned values are not all 0 or 1 */
elessair 0:f269e3021894 548 if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf0, sizeof( buf0 ) ) ) != 0 )
elessair 0:f269e3021894 549 goto cleanup;
elessair 0:f269e3021894 550 if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf1, sizeof( buf1 ) ) ) != 0 )
elessair 0:f269e3021894 551 goto cleanup;
elessair 0:f269e3021894 552
elessair 0:f269e3021894 553 /* Make sure that the entropy source is not returning values in a
elessair 0:f269e3021894 554 * pattern */
elessair 0:f269e3021894 555 ret = memcmp( buf0, buf1, sizeof( buf0 ) ) == 0;
elessair 0:f269e3021894 556
elessair 0:f269e3021894 557 cleanup:
elessair 0:f269e3021894 558 if( verbose != 0 )
elessair 0:f269e3021894 559 {
elessair 0:f269e3021894 560 if( ret != 0 )
elessair 0:f269e3021894 561 mbedtls_printf( "failed\n" );
elessair 0:f269e3021894 562 else
elessair 0:f269e3021894 563 mbedtls_printf( "passed\n" );
elessair 0:f269e3021894 564
elessair 0:f269e3021894 565 mbedtls_printf( "\n" );
elessair 0:f269e3021894 566 }
elessair 0:f269e3021894 567
elessair 0:f269e3021894 568 return( ret != 0 );
elessair 0:f269e3021894 569 }
elessair 0:f269e3021894 570
elessair 0:f269e3021894 571 #endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */
elessair 0:f269e3021894 572
elessair 0:f269e3021894 573 /*
elessair 0:f269e3021894 574 * The actual entropy quality is hard to test, but we can at least
elessair 0:f269e3021894 575 * test that the functions don't cause errors and write the correct
elessair 0:f269e3021894 576 * amount of data to buffers.
elessair 0:f269e3021894 577 */
elessair 0:f269e3021894 578 int mbedtls_entropy_self_test( int verbose )
elessair 0:f269e3021894 579 {
elessair 0:f269e3021894 580 int ret = 1;
elessair 0:f269e3021894 581 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
elessair 0:f269e3021894 582 mbedtls_entropy_context ctx;
elessair 0:f269e3021894 583 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
elessair 0:f269e3021894 584 unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
elessair 0:f269e3021894 585 size_t i, j;
elessair 0:f269e3021894 586 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
elessair 0:f269e3021894 587
elessair 0:f269e3021894 588 if( verbose != 0 )
elessair 0:f269e3021894 589 mbedtls_printf( " ENTROPY test: " );
elessair 0:f269e3021894 590
elessair 0:f269e3021894 591 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
elessair 0:f269e3021894 592 mbedtls_entropy_init( &ctx );
elessair 0:f269e3021894 593
elessair 0:f269e3021894 594 /* First do a gather to make sure we have default sources */
elessair 0:f269e3021894 595 if( ( ret = mbedtls_entropy_gather( &ctx ) ) != 0 )
elessair 0:f269e3021894 596 goto cleanup;
elessair 0:f269e3021894 597
elessair 0:f269e3021894 598 ret = mbedtls_entropy_add_source( &ctx, entropy_dummy_source, NULL, 16,
elessair 0:f269e3021894 599 MBEDTLS_ENTROPY_SOURCE_WEAK );
elessair 0:f269e3021894 600 if( ret != 0 )
elessair 0:f269e3021894 601 goto cleanup;
elessair 0:f269e3021894 602
elessair 0:f269e3021894 603 if( ( ret = mbedtls_entropy_update_manual( &ctx, buf, sizeof buf ) ) != 0 )
elessair 0:f269e3021894 604 goto cleanup;
elessair 0:f269e3021894 605
elessair 0:f269e3021894 606 /*
elessair 0:f269e3021894 607 * To test that mbedtls_entropy_func writes correct number of bytes:
elessair 0:f269e3021894 608 * - use the whole buffer and rely on ASan to detect overruns
elessair 0:f269e3021894 609 * - collect entropy 8 times and OR the result in an accumulator:
elessair 0:f269e3021894 610 * any byte should then be 0 with probably 2^(-64), so requiring
elessair 0:f269e3021894 611 * each of the 32 or 64 bytes to be non-zero has a false failure rate
elessair 0:f269e3021894 612 * of at most 2^(-58) which is acceptable.
elessair 0:f269e3021894 613 */
elessair 0:f269e3021894 614 for( i = 0; i < 8; i++ )
elessair 0:f269e3021894 615 {
elessair 0:f269e3021894 616 if( ( ret = mbedtls_entropy_func( &ctx, buf, sizeof( buf ) ) ) != 0 )
elessair 0:f269e3021894 617 goto cleanup;
elessair 0:f269e3021894 618
elessair 0:f269e3021894 619 for( j = 0; j < sizeof( buf ); j++ )
elessair 0:f269e3021894 620 acc[j] |= buf[j];
elessair 0:f269e3021894 621 }
elessair 0:f269e3021894 622
elessair 0:f269e3021894 623 for( j = 0; j < sizeof( buf ); j++ )
elessair 0:f269e3021894 624 {
elessair 0:f269e3021894 625 if( acc[j] == 0 )
elessair 0:f269e3021894 626 {
elessair 0:f269e3021894 627 ret = 1;
elessair 0:f269e3021894 628 goto cleanup;
elessair 0:f269e3021894 629 }
elessair 0:f269e3021894 630 }
elessair 0:f269e3021894 631
elessair 0:f269e3021894 632 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
elessair 0:f269e3021894 633 if( ( ret = mbedtls_entropy_source_self_test( 0 ) ) != 0 )
elessair 0:f269e3021894 634 goto cleanup;
elessair 0:f269e3021894 635 #endif
elessair 0:f269e3021894 636
elessair 0:f269e3021894 637 cleanup:
elessair 0:f269e3021894 638 mbedtls_entropy_free( &ctx );
elessair 0:f269e3021894 639 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
elessair 0:f269e3021894 640
elessair 0:f269e3021894 641 if( verbose != 0 )
elessair 0:f269e3021894 642 {
elessair 0:f269e3021894 643 if( ret != 0 )
elessair 0:f269e3021894 644 mbedtls_printf( "failed\n" );
elessair 0:f269e3021894 645 else
elessair 0:f269e3021894 646 mbedtls_printf( "passed\n" );
elessair 0:f269e3021894 647
elessair 0:f269e3021894 648 mbedtls_printf( "\n" );
elessair 0:f269e3021894 649 }
elessair 0:f269e3021894 650
elessair 0:f269e3021894 651 return( ret != 0 );
elessair 0:f269e3021894 652 }
elessair 0:f269e3021894 653 #endif /* MBEDTLS_SELF_TEST */
elessair 0:f269e3021894 654
elessair 0:f269e3021894 655 #endif /* MBEDTLS_ENTROPY_C */