Mark Radbourne / mbedtls

mbed TLS Build

Dependents:   Encrypt_Decrypt1 mbed_blink_tls encrypt encrypt

library/entropy.c@0:cdf462088d13, 2017-01-05 (annotated)

Committer:
markrad
Date:
Thu Jan 05 00:18:44 2017 +0000
Revision:
0:cdf462088d13
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
markrad 0:cdf462088d13 1 /*
markrad 0:cdf462088d13 2 * Entropy accumulator implementation
markrad 0:cdf462088d13 3 *
markrad 0:cdf462088d13 4 * Copyright (C) 2006-2016, 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 #if !defined(MBEDTLS_CONFIG_FILE)
markrad 0:cdf462088d13 23 #include "mbedtls/config.h"
markrad 0:cdf462088d13 24 #else
markrad 0:cdf462088d13 25 #include MBEDTLS_CONFIG_FILE
markrad 0:cdf462088d13 26 #endif
markrad 0:cdf462088d13 27
markrad 0:cdf462088d13 28 #if defined(MBEDTLS_ENTROPY_C)
markrad 0:cdf462088d13 29
markrad 0:cdf462088d13 30 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
markrad 0:cdf462088d13 31 #warning "**** WARNING! MBEDTLS_TEST_NULL_ENTROPY defined! "
markrad 0:cdf462088d13 32 #warning "**** THIS BUILD HAS NO DEFINED ENTROPY SOURCES "
markrad 0:cdf462088d13 33 #warning "**** THIS BUILD IS *NOT* SUITABLE FOR PRODUCTION USE "
markrad 0:cdf462088d13 34 #endif
markrad 0:cdf462088d13 35
markrad 0:cdf462088d13 36 #include "mbedtls/entropy.h"
markrad 0:cdf462088d13 37 #include "mbedtls/entropy_poll.h"
markrad 0:cdf462088d13 38
markrad 0:cdf462088d13 39 #include <string.h>
markrad 0:cdf462088d13 40
markrad 0:cdf462088d13 41 #if defined(MBEDTLS_FS_IO)
markrad 0:cdf462088d13 42 #include <stdio.h>
markrad 0:cdf462088d13 43 #endif
markrad 0:cdf462088d13 44
markrad 0:cdf462088d13 45 #if defined(MBEDTLS_ENTROPY_NV_SEED)
markrad 0:cdf462088d13 46 #include "mbedtls/platform.h"
markrad 0:cdf462088d13 47 #endif
markrad 0:cdf462088d13 48
markrad 0:cdf462088d13 49 #if defined(MBEDTLS_SELF_TEST)
markrad 0:cdf462088d13 50 #if defined(MBEDTLS_PLATFORM_C)
markrad 0:cdf462088d13 51 #include "mbedtls/platform.h"
markrad 0:cdf462088d13 52 #else
markrad 0:cdf462088d13 53 #include <stdio.h>
markrad 0:cdf462088d13 54 #define mbedtls_printf printf
markrad 0:cdf462088d13 55 #endif /* MBEDTLS_PLATFORM_C */
markrad 0:cdf462088d13 56 #endif /* MBEDTLS_SELF_TEST */
markrad 0:cdf462088d13 57
markrad 0:cdf462088d13 58 #if defined(MBEDTLS_HAVEGE_C)
markrad 0:cdf462088d13 59 #include "mbedtls/havege.h"
markrad 0:cdf462088d13 60 #endif
markrad 0:cdf462088d13 61
markrad 0:cdf462088d13 62 /* Implementation that should never be optimized out by the compiler */
markrad 0:cdf462088d13 63 static void mbedtls_zeroize( void *v, size_t n ) {
markrad 0:cdf462088d13 64 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
markrad 0:cdf462088d13 65 }
markrad 0:cdf462088d13 66
markrad 0:cdf462088d13 67 #define ENTROPY_MAX_LOOP 256 /**< Maximum amount to loop before error */
markrad 0:cdf462088d13 68
markrad 0:cdf462088d13 69 void mbedtls_entropy_init( mbedtls_entropy_context *ctx )
markrad 0:cdf462088d13 70 {
markrad 0:cdf462088d13 71 memset( ctx, 0, sizeof(mbedtls_entropy_context) );
markrad 0:cdf462088d13 72
markrad 0:cdf462088d13 73 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 74 mbedtls_mutex_init( &ctx->mutex );
markrad 0:cdf462088d13 75 #endif
markrad 0:cdf462088d13 76
markrad 0:cdf462088d13 77 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
markrad 0:cdf462088d13 78 mbedtls_sha512_starts( &ctx->accumulator, 0 );
markrad 0:cdf462088d13 79 #else
markrad 0:cdf462088d13 80 mbedtls_sha256_starts( &ctx->accumulator, 0 );
markrad 0:cdf462088d13 81 #endif
markrad 0:cdf462088d13 82 #if defined(MBEDTLS_HAVEGE_C)
markrad 0:cdf462088d13 83 mbedtls_havege_init( &ctx->havege_data );
markrad 0:cdf462088d13 84 #endif
markrad 0:cdf462088d13 85
markrad 0:cdf462088d13 86 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
markrad 0:cdf462088d13 87 mbedtls_entropy_add_source( ctx, mbedtls_null_entropy_poll, NULL,
markrad 0:cdf462088d13 88 1, MBEDTLS_ENTROPY_SOURCE_STRONG );
markrad 0:cdf462088d13 89 #endif
markrad 0:cdf462088d13 90
markrad 0:cdf462088d13 91 #if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
markrad 0:cdf462088d13 92 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
markrad 0:cdf462088d13 93 mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL,
markrad 0:cdf462088d13 94 MBEDTLS_ENTROPY_MIN_PLATFORM,
markrad 0:cdf462088d13 95 MBEDTLS_ENTROPY_SOURCE_STRONG );
markrad 0:cdf462088d13 96 #endif
markrad 0:cdf462088d13 97 #if defined(MBEDTLS_TIMING_C)
markrad 0:cdf462088d13 98 mbedtls_entropy_add_source( ctx, mbedtls_hardclock_poll, NULL,
markrad 0:cdf462088d13 99 MBEDTLS_ENTROPY_MIN_HARDCLOCK,
markrad 0:cdf462088d13 100 MBEDTLS_ENTROPY_SOURCE_WEAK );
markrad 0:cdf462088d13 101 #endif
markrad 0:cdf462088d13 102 #if defined(MBEDTLS_HAVEGE_C)
markrad 0:cdf462088d13 103 mbedtls_entropy_add_source( ctx, mbedtls_havege_poll, &ctx->havege_data,
markrad 0:cdf462088d13 104 MBEDTLS_ENTROPY_MIN_HAVEGE,
markrad 0:cdf462088d13 105 MBEDTLS_ENTROPY_SOURCE_STRONG );
markrad 0:cdf462088d13 106 #endif
markrad 0:cdf462088d13 107 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
markrad 0:cdf462088d13 108 mbedtls_entropy_add_source( ctx, mbedtls_hardware_poll, NULL,
markrad 0:cdf462088d13 109 MBEDTLS_ENTROPY_MIN_HARDWARE,
markrad 0:cdf462088d13 110 MBEDTLS_ENTROPY_SOURCE_STRONG );
markrad 0:cdf462088d13 111 #endif
markrad 0:cdf462088d13 112 #if defined(MBEDTLS_ENTROPY_NV_SEED)
markrad 0:cdf462088d13 113 mbedtls_entropy_add_source( ctx, mbedtls_nv_seed_poll, NULL,
markrad 0:cdf462088d13 114 MBEDTLS_ENTROPY_BLOCK_SIZE,
markrad 0:cdf462088d13 115 MBEDTLS_ENTROPY_SOURCE_STRONG );
markrad 0:cdf462088d13 116 #endif
markrad 0:cdf462088d13 117 #endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */
markrad 0:cdf462088d13 118 }
markrad 0:cdf462088d13 119
markrad 0:cdf462088d13 120 void mbedtls_entropy_free( mbedtls_entropy_context *ctx )
markrad 0:cdf462088d13 121 {
markrad 0:cdf462088d13 122 #if defined(MBEDTLS_HAVEGE_C)
markrad 0:cdf462088d13 123 mbedtls_havege_free( &ctx->havege_data );
markrad 0:cdf462088d13 124 #endif
markrad 0:cdf462088d13 125 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 126 mbedtls_mutex_free( &ctx->mutex );
markrad 0:cdf462088d13 127 #endif
markrad 0:cdf462088d13 128 mbedtls_zeroize( ctx, sizeof( mbedtls_entropy_context ) );
markrad 0:cdf462088d13 129 }
markrad 0:cdf462088d13 130
markrad 0:cdf462088d13 131 int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx,
markrad 0:cdf462088d13 132 mbedtls_entropy_f_source_ptr f_source, void *p_source,
markrad 0:cdf462088d13 133 size_t threshold, int strong )
markrad 0:cdf462088d13 134 {
markrad 0:cdf462088d13 135 int index, ret = 0;
markrad 0:cdf462088d13 136
markrad 0:cdf462088d13 137 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 138 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
markrad 0:cdf462088d13 139 return( ret );
markrad 0:cdf462088d13 140 #endif
markrad 0:cdf462088d13 141
markrad 0:cdf462088d13 142 index = ctx->source_count;
markrad 0:cdf462088d13 143 if( index >= MBEDTLS_ENTROPY_MAX_SOURCES )
markrad 0:cdf462088d13 144 {
markrad 0:cdf462088d13 145 ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES;
markrad 0:cdf462088d13 146 goto exit;
markrad 0:cdf462088d13 147 }
markrad 0:cdf462088d13 148
markrad 0:cdf462088d13 149 ctx->source[index].f_source = f_source;
markrad 0:cdf462088d13 150 ctx->source[index].p_source = p_source;
markrad 0:cdf462088d13 151 ctx->source[index].threshold = threshold;
markrad 0:cdf462088d13 152 ctx->source[index].strong = strong;
markrad 0:cdf462088d13 153
markrad 0:cdf462088d13 154 ctx->source_count++;
markrad 0:cdf462088d13 155
markrad 0:cdf462088d13 156 exit:
markrad 0:cdf462088d13 157 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 158 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
markrad 0:cdf462088d13 159 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
markrad 0:cdf462088d13 160 #endif
markrad 0:cdf462088d13 161
markrad 0:cdf462088d13 162 return( ret );
markrad 0:cdf462088d13 163 }
markrad 0:cdf462088d13 164
markrad 0:cdf462088d13 165 /*
markrad 0:cdf462088d13 166 * Entropy accumulator update
markrad 0:cdf462088d13 167 */
markrad 0:cdf462088d13 168 static int entropy_update( mbedtls_entropy_context *ctx, unsigned char source_id,
markrad 0:cdf462088d13 169 const unsigned char *data, size_t len )
markrad 0:cdf462088d13 170 {
markrad 0:cdf462088d13 171 unsigned char header[2];
markrad 0:cdf462088d13 172 unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE];
markrad 0:cdf462088d13 173 size_t use_len = len;
markrad 0:cdf462088d13 174 const unsigned char *p = data;
markrad 0:cdf462088d13 175
markrad 0:cdf462088d13 176 if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE )
markrad 0:cdf462088d13 177 {
markrad 0:cdf462088d13 178 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
markrad 0:cdf462088d13 179 mbedtls_sha512( data, len, tmp, 0 );
markrad 0:cdf462088d13 180 #else
markrad 0:cdf462088d13 181 mbedtls_sha256( data, len, tmp, 0 );
markrad 0:cdf462088d13 182 #endif
markrad 0:cdf462088d13 183 p = tmp;
markrad 0:cdf462088d13 184 use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
markrad 0:cdf462088d13 185 }
markrad 0:cdf462088d13 186
markrad 0:cdf462088d13 187 header[0] = source_id;
markrad 0:cdf462088d13 188 header[1] = use_len & 0xFF;
markrad 0:cdf462088d13 189
markrad 0:cdf462088d13 190 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
markrad 0:cdf462088d13 191 mbedtls_sha512_update( &ctx->accumulator, header, 2 );
markrad 0:cdf462088d13 192 mbedtls_sha512_update( &ctx->accumulator, p, use_len );
markrad 0:cdf462088d13 193 #else
markrad 0:cdf462088d13 194 mbedtls_sha256_update( &ctx->accumulator, header, 2 );
markrad 0:cdf462088d13 195 mbedtls_sha256_update( &ctx->accumulator, p, use_len );
markrad 0:cdf462088d13 196 #endif
markrad 0:cdf462088d13 197
markrad 0:cdf462088d13 198 return( 0 );
markrad 0:cdf462088d13 199 }
markrad 0:cdf462088d13 200
markrad 0:cdf462088d13 201 int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
markrad 0:cdf462088d13 202 const unsigned char *data, size_t len )
markrad 0:cdf462088d13 203 {
markrad 0:cdf462088d13 204 int ret;
markrad 0:cdf462088d13 205
markrad 0:cdf462088d13 206 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 207 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
markrad 0:cdf462088d13 208 return( ret );
markrad 0:cdf462088d13 209 #endif
markrad 0:cdf462088d13 210
markrad 0:cdf462088d13 211 ret = entropy_update( ctx, MBEDTLS_ENTROPY_SOURCE_MANUAL, data, len );
markrad 0:cdf462088d13 212
markrad 0:cdf462088d13 213 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 214 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
markrad 0:cdf462088d13 215 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
markrad 0:cdf462088d13 216 #endif
markrad 0:cdf462088d13 217
markrad 0:cdf462088d13 218 return( ret );
markrad 0:cdf462088d13 219 }
markrad 0:cdf462088d13 220
markrad 0:cdf462088d13 221 /*
markrad 0:cdf462088d13 222 * Run through the different sources to add entropy to our accumulator
markrad 0:cdf462088d13 223 */
markrad 0:cdf462088d13 224 static int entropy_gather_internal( mbedtls_entropy_context *ctx )
markrad 0:cdf462088d13 225 {
markrad 0:cdf462088d13 226 int ret, i, have_one_strong = 0;
markrad 0:cdf462088d13 227 unsigned char buf[MBEDTLS_ENTROPY_MAX_GATHER];
markrad 0:cdf462088d13 228 size_t olen;
markrad 0:cdf462088d13 229
markrad 0:cdf462088d13 230 if( ctx->source_count == 0 )
markrad 0:cdf462088d13 231 return( MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED );
markrad 0:cdf462088d13 232
markrad 0:cdf462088d13 233 /*
markrad 0:cdf462088d13 234 * Run through our entropy sources
markrad 0:cdf462088d13 235 */
markrad 0:cdf462088d13 236 for( i = 0; i < ctx->source_count; i++ )
markrad 0:cdf462088d13 237 {
markrad 0:cdf462088d13 238 if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG )
markrad 0:cdf462088d13 239 have_one_strong = 1;
markrad 0:cdf462088d13 240
markrad 0:cdf462088d13 241 olen = 0;
markrad 0:cdf462088d13 242 if( ( ret = ctx->source[i].f_source( ctx->source[i].p_source,
markrad 0:cdf462088d13 243 buf, MBEDTLS_ENTROPY_MAX_GATHER, &olen ) ) != 0 )
markrad 0:cdf462088d13 244 {
markrad 0:cdf462088d13 245 return( ret );
markrad 0:cdf462088d13 246 }
markrad 0:cdf462088d13 247
markrad 0:cdf462088d13 248 /*
markrad 0:cdf462088d13 249 * Add if we actually gathered something
markrad 0:cdf462088d13 250 */
markrad 0:cdf462088d13 251 if( olen > 0 )
markrad 0:cdf462088d13 252 {
markrad 0:cdf462088d13 253 entropy_update( ctx, (unsigned char) i, buf, olen );
markrad 0:cdf462088d13 254 ctx->source[i].size += olen;
markrad 0:cdf462088d13 255 }
markrad 0:cdf462088d13 256 }
markrad 0:cdf462088d13 257
markrad 0:cdf462088d13 258 if( have_one_strong == 0 )
markrad 0:cdf462088d13 259 return( MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE );
markrad 0:cdf462088d13 260
markrad 0:cdf462088d13 261 return( 0 );
markrad 0:cdf462088d13 262 }
markrad 0:cdf462088d13 263
markrad 0:cdf462088d13 264 /*
markrad 0:cdf462088d13 265 * Thread-safe wrapper for entropy_gather_internal()
markrad 0:cdf462088d13 266 */
markrad 0:cdf462088d13 267 int mbedtls_entropy_gather( mbedtls_entropy_context *ctx )
markrad 0:cdf462088d13 268 {
markrad 0:cdf462088d13 269 int ret;
markrad 0:cdf462088d13 270
markrad 0:cdf462088d13 271 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 272 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
markrad 0:cdf462088d13 273 return( ret );
markrad 0:cdf462088d13 274 #endif
markrad 0:cdf462088d13 275
markrad 0:cdf462088d13 276 ret = entropy_gather_internal( ctx );
markrad 0:cdf462088d13 277
markrad 0:cdf462088d13 278 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 279 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
markrad 0:cdf462088d13 280 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
markrad 0:cdf462088d13 281 #endif
markrad 0:cdf462088d13 282
markrad 0:cdf462088d13 283 return( ret );
markrad 0:cdf462088d13 284 }
markrad 0:cdf462088d13 285
markrad 0:cdf462088d13 286 int mbedtls_entropy_func( void *data, unsigned char *output, size_t len )
markrad 0:cdf462088d13 287 {
markrad 0:cdf462088d13 288 int ret, count = 0, i, done;
markrad 0:cdf462088d13 289 mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data;
markrad 0:cdf462088d13 290 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
markrad 0:cdf462088d13 291
markrad 0:cdf462088d13 292 if( len > MBEDTLS_ENTROPY_BLOCK_SIZE )
markrad 0:cdf462088d13 293 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
markrad 0:cdf462088d13 294
markrad 0:cdf462088d13 295 #if defined(MBEDTLS_ENTROPY_NV_SEED)
markrad 0:cdf462088d13 296 /* Update the NV entropy seed before generating any entropy for outside
markrad 0:cdf462088d13 297 * use.
markrad 0:cdf462088d13 298 */
markrad 0:cdf462088d13 299 if( ctx->initial_entropy_run == 0 )
markrad 0:cdf462088d13 300 {
markrad 0:cdf462088d13 301 ctx->initial_entropy_run = 1;
markrad 0:cdf462088d13 302 if( ( ret = mbedtls_entropy_update_nv_seed( ctx ) ) != 0 )
markrad 0:cdf462088d13 303 return( ret );
markrad 0:cdf462088d13 304 }
markrad 0:cdf462088d13 305 #endif
markrad 0:cdf462088d13 306
markrad 0:cdf462088d13 307 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 308 if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
markrad 0:cdf462088d13 309 return( ret );
markrad 0:cdf462088d13 310 #endif
markrad 0:cdf462088d13 311
markrad 0:cdf462088d13 312 /*
markrad 0:cdf462088d13 313 * Always gather extra entropy before a call
markrad 0:cdf462088d13 314 */
markrad 0:cdf462088d13 315 do
markrad 0:cdf462088d13 316 {
markrad 0:cdf462088d13 317 if( count++ > ENTROPY_MAX_LOOP )
markrad 0:cdf462088d13 318 {
markrad 0:cdf462088d13 319 ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
markrad 0:cdf462088d13 320 goto exit;
markrad 0:cdf462088d13 321 }
markrad 0:cdf462088d13 322
markrad 0:cdf462088d13 323 if( ( ret = entropy_gather_internal( ctx ) ) != 0 )
markrad 0:cdf462088d13 324 goto exit;
markrad 0:cdf462088d13 325
markrad 0:cdf462088d13 326 done = 1;
markrad 0:cdf462088d13 327 for( i = 0; i < ctx->source_count; i++ )
markrad 0:cdf462088d13 328 if( ctx->source[i].size < ctx->source[i].threshold )
markrad 0:cdf462088d13 329 done = 0;
markrad 0:cdf462088d13 330 }
markrad 0:cdf462088d13 331 while( ! done );
markrad 0:cdf462088d13 332
markrad 0:cdf462088d13 333 memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
markrad 0:cdf462088d13 334
markrad 0:cdf462088d13 335 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
markrad 0:cdf462088d13 336 mbedtls_sha512_finish( &ctx->accumulator, buf );
markrad 0:cdf462088d13 337
markrad 0:cdf462088d13 338 /*
markrad 0:cdf462088d13 339 * Reset accumulator and counters and recycle existing entropy
markrad 0:cdf462088d13 340 */
markrad 0:cdf462088d13 341 memset( &ctx->accumulator, 0, sizeof( mbedtls_sha512_context ) );
markrad 0:cdf462088d13 342 mbedtls_sha512_starts( &ctx->accumulator, 0 );
markrad 0:cdf462088d13 343 mbedtls_sha512_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
markrad 0:cdf462088d13 344
markrad 0:cdf462088d13 345 /*
markrad 0:cdf462088d13 346 * Perform second SHA-512 on entropy
markrad 0:cdf462088d13 347 */
markrad 0:cdf462088d13 348 mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
markrad 0:cdf462088d13 349 #else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
markrad 0:cdf462088d13 350 mbedtls_sha256_finish( &ctx->accumulator, buf );
markrad 0:cdf462088d13 351
markrad 0:cdf462088d13 352 /*
markrad 0:cdf462088d13 353 * Reset accumulator and counters and recycle existing entropy
markrad 0:cdf462088d13 354 */
markrad 0:cdf462088d13 355 memset( &ctx->accumulator, 0, sizeof( mbedtls_sha256_context ) );
markrad 0:cdf462088d13 356 mbedtls_sha256_starts( &ctx->accumulator, 0 );
markrad 0:cdf462088d13 357 mbedtls_sha256_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
markrad 0:cdf462088d13 358
markrad 0:cdf462088d13 359 /*
markrad 0:cdf462088d13 360 * Perform second SHA-256 on entropy
markrad 0:cdf462088d13 361 */
markrad 0:cdf462088d13 362 mbedtls_sha256( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
markrad 0:cdf462088d13 363 #endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
markrad 0:cdf462088d13 364
markrad 0:cdf462088d13 365 for( i = 0; i < ctx->source_count; i++ )
markrad 0:cdf462088d13 366 ctx->source[i].size = 0;
markrad 0:cdf462088d13 367
markrad 0:cdf462088d13 368 memcpy( output, buf, len );
markrad 0:cdf462088d13 369
markrad 0:cdf462088d13 370 ret = 0;
markrad 0:cdf462088d13 371
markrad 0:cdf462088d13 372 exit:
markrad 0:cdf462088d13 373 #if defined(MBEDTLS_THREADING_C)
markrad 0:cdf462088d13 374 if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
markrad 0:cdf462088d13 375 return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
markrad 0:cdf462088d13 376 #endif
markrad 0:cdf462088d13 377
markrad 0:cdf462088d13 378 return( ret );
markrad 0:cdf462088d13 379 }
markrad 0:cdf462088d13 380
markrad 0:cdf462088d13 381 #if defined(MBEDTLS_ENTROPY_NV_SEED)
markrad 0:cdf462088d13 382 int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx )
markrad 0:cdf462088d13 383 {
markrad 0:cdf462088d13 384 int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
markrad 0:cdf462088d13 385 unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ];
markrad 0:cdf462088d13 386
markrad 0:cdf462088d13 387 /* Read new seed and write it to NV */
markrad 0:cdf462088d13 388 if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
markrad 0:cdf462088d13 389 return( ret );
markrad 0:cdf462088d13 390
markrad 0:cdf462088d13 391 if( mbedtls_nv_seed_write( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
markrad 0:cdf462088d13 392 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
markrad 0:cdf462088d13 393
markrad 0:cdf462088d13 394 /* Manually update the remaining stream with a separator value to diverge */
markrad 0:cdf462088d13 395 memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
markrad 0:cdf462088d13 396 mbedtls_entropy_update_manual( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
markrad 0:cdf462088d13 397
markrad 0:cdf462088d13 398 return( 0 );
markrad 0:cdf462088d13 399 }
markrad 0:cdf462088d13 400 #endif /* MBEDTLS_ENTROPY_NV_SEED */
markrad 0:cdf462088d13 401
markrad 0:cdf462088d13 402 #if defined(MBEDTLS_FS_IO)
markrad 0:cdf462088d13 403 int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path )
markrad 0:cdf462088d13 404 {
markrad 0:cdf462088d13 405 int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
markrad 0:cdf462088d13 406 FILE *f;
markrad 0:cdf462088d13 407 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
markrad 0:cdf462088d13 408
markrad 0:cdf462088d13 409 if( ( f = fopen( path, "wb" ) ) == NULL )
markrad 0:cdf462088d13 410 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
markrad 0:cdf462088d13 411
markrad 0:cdf462088d13 412 if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
markrad 0:cdf462088d13 413 goto exit;
markrad 0:cdf462088d13 414
markrad 0:cdf462088d13 415 if( fwrite( buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f ) != MBEDTLS_ENTROPY_BLOCK_SIZE )
markrad 0:cdf462088d13 416 {
markrad 0:cdf462088d13 417 ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
markrad 0:cdf462088d13 418 goto exit;
markrad 0:cdf462088d13 419 }
markrad 0:cdf462088d13 420
markrad 0:cdf462088d13 421 ret = 0;
markrad 0:cdf462088d13 422
markrad 0:cdf462088d13 423 exit:
markrad 0:cdf462088d13 424 fclose( f );
markrad 0:cdf462088d13 425 return( ret );
markrad 0:cdf462088d13 426 }
markrad 0:cdf462088d13 427
markrad 0:cdf462088d13 428 int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path )
markrad 0:cdf462088d13 429 {
markrad 0:cdf462088d13 430 FILE *f;
markrad 0:cdf462088d13 431 size_t n;
markrad 0:cdf462088d13 432 unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ];
markrad 0:cdf462088d13 433
markrad 0:cdf462088d13 434 if( ( f = fopen( path, "rb" ) ) == NULL )
markrad 0:cdf462088d13 435 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
markrad 0:cdf462088d13 436
markrad 0:cdf462088d13 437 fseek( f, 0, SEEK_END );
markrad 0:cdf462088d13 438 n = (size_t) ftell( f );
markrad 0:cdf462088d13 439 fseek( f, 0, SEEK_SET );
markrad 0:cdf462088d13 440
markrad 0:cdf462088d13 441 if( n > MBEDTLS_ENTROPY_MAX_SEED_SIZE )
markrad 0:cdf462088d13 442 n = MBEDTLS_ENTROPY_MAX_SEED_SIZE;
markrad 0:cdf462088d13 443
markrad 0:cdf462088d13 444 if( fread( buf, 1, n, f ) != n )
markrad 0:cdf462088d13 445 {
markrad 0:cdf462088d13 446 fclose( f );
markrad 0:cdf462088d13 447 return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
markrad 0:cdf462088d13 448 }
markrad 0:cdf462088d13 449
markrad 0:cdf462088d13 450 fclose( f );
markrad 0:cdf462088d13 451
markrad 0:cdf462088d13 452 mbedtls_entropy_update_manual( ctx, buf, n );
markrad 0:cdf462088d13 453
markrad 0:cdf462088d13 454 return( mbedtls_entropy_write_seed_file( ctx, path ) );
markrad 0:cdf462088d13 455 }
markrad 0:cdf462088d13 456 #endif /* MBEDTLS_FS_IO */
markrad 0:cdf462088d13 457
markrad 0:cdf462088d13 458 #if defined(MBEDTLS_SELF_TEST)
markrad 0:cdf462088d13 459 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
markrad 0:cdf462088d13 460 /*
markrad 0:cdf462088d13 461 * Dummy source function
markrad 0:cdf462088d13 462 */
markrad 0:cdf462088d13 463 static int entropy_dummy_source( void *data, unsigned char *output,
markrad 0:cdf462088d13 464 size_t len, size_t *olen )
markrad 0:cdf462088d13 465 {
markrad 0:cdf462088d13 466 ((void) data);
markrad 0:cdf462088d13 467
markrad 0:cdf462088d13 468 memset( output, 0x2a, len );
markrad 0:cdf462088d13 469 *olen = len;
markrad 0:cdf462088d13 470
markrad 0:cdf462088d13 471 return( 0 );
markrad 0:cdf462088d13 472 }
markrad 0:cdf462088d13 473 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
markrad 0:cdf462088d13 474
markrad 0:cdf462088d13 475 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
markrad 0:cdf462088d13 476
markrad 0:cdf462088d13 477 static int mbedtls_entropy_source_self_test_gather( unsigned char *buf, size_t buf_len )
markrad 0:cdf462088d13 478 {
markrad 0:cdf462088d13 479 int ret = 0;
markrad 0:cdf462088d13 480 size_t entropy_len = 0;
markrad 0:cdf462088d13 481 size_t olen = 0;
markrad 0:cdf462088d13 482 size_t attempts = buf_len;
markrad 0:cdf462088d13 483
markrad 0:cdf462088d13 484 while( attempts > 0 && entropy_len < buf_len )
markrad 0:cdf462088d13 485 {
markrad 0:cdf462088d13 486 if( ( ret = mbedtls_hardware_poll( NULL, buf + entropy_len,
markrad 0:cdf462088d13 487 buf_len - entropy_len, &olen ) ) != 0 )
markrad 0:cdf462088d13 488 return( ret );
markrad 0:cdf462088d13 489
markrad 0:cdf462088d13 490 entropy_len += olen;
markrad 0:cdf462088d13 491 attempts--;
markrad 0:cdf462088d13 492 }
markrad 0:cdf462088d13 493
markrad 0:cdf462088d13 494 if( entropy_len < buf_len )
markrad 0:cdf462088d13 495 {
markrad 0:cdf462088d13 496 ret = 1;
markrad 0:cdf462088d13 497 }
markrad 0:cdf462088d13 498
markrad 0:cdf462088d13 499 return( ret );
markrad 0:cdf462088d13 500 }
markrad 0:cdf462088d13 501
markrad 0:cdf462088d13 502
markrad 0:cdf462088d13 503 static int mbedtls_entropy_source_self_test_check_bits( const unsigned char *buf,
markrad 0:cdf462088d13 504 size_t buf_len )
markrad 0:cdf462088d13 505 {
markrad 0:cdf462088d13 506 unsigned char set= 0xFF;
markrad 0:cdf462088d13 507 unsigned char unset = 0x00;
markrad 0:cdf462088d13 508 size_t i;
markrad 0:cdf462088d13 509
markrad 0:cdf462088d13 510 for( i = 0; i < buf_len; i++ )
markrad 0:cdf462088d13 511 {
markrad 0:cdf462088d13 512 set &= buf[i];
markrad 0:cdf462088d13 513 unset |= buf[i];
markrad 0:cdf462088d13 514 }
markrad 0:cdf462088d13 515
markrad 0:cdf462088d13 516 return( set == 0xFF || unset == 0x00 );
markrad 0:cdf462088d13 517 }
markrad 0:cdf462088d13 518
markrad 0:cdf462088d13 519 /*
markrad 0:cdf462088d13 520 * A test to ensure hat the entropy sources are functioning correctly
markrad 0:cdf462088d13 521 * and there is no obvious failure. The test performs the following checks:
markrad 0:cdf462088d13 522 * - The entropy source is not providing only 0s (all bits unset) or 1s (all
markrad 0:cdf462088d13 523 * bits set).
markrad 0:cdf462088d13 524 * - The entropy source is not providing values in a pattern. Because the
markrad 0:cdf462088d13 525 * hardware could be providing data in an arbitrary length, this check polls
markrad 0:cdf462088d13 526 * the hardware entropy source twice and compares the result to ensure they
markrad 0:cdf462088d13 527 * are not equal.
markrad 0:cdf462088d13 528 * - The error code returned by the entropy source is not an error.
markrad 0:cdf462088d13 529 */
markrad 0:cdf462088d13 530 int mbedtls_entropy_source_self_test( int verbose )
markrad 0:cdf462088d13 531 {
markrad 0:cdf462088d13 532 int ret = 0;
markrad 0:cdf462088d13 533 unsigned char buf0[2 * sizeof( unsigned long long int )];
markrad 0:cdf462088d13 534 unsigned char buf1[2 * sizeof( unsigned long long int )];
markrad 0:cdf462088d13 535
markrad 0:cdf462088d13 536 if( verbose != 0 )
markrad 0:cdf462088d13 537 mbedtls_printf( " ENTROPY_BIAS test: " );
markrad 0:cdf462088d13 538
markrad 0:cdf462088d13 539 memset( buf0, 0x00, sizeof( buf0 ) );
markrad 0:cdf462088d13 540 memset( buf1, 0x00, sizeof( buf1 ) );
markrad 0:cdf462088d13 541
markrad 0:cdf462088d13 542 if( ( ret = mbedtls_entropy_source_self_test_gather( buf0, sizeof( buf0 ) ) ) != 0 )
markrad 0:cdf462088d13 543 goto cleanup;
markrad 0:cdf462088d13 544 if( ( ret = mbedtls_entropy_source_self_test_gather( buf1, sizeof( buf1 ) ) ) != 0 )
markrad 0:cdf462088d13 545 goto cleanup;
markrad 0:cdf462088d13 546
markrad 0:cdf462088d13 547 /* Make sure that the returned values are not all 0 or 1 */
markrad 0:cdf462088d13 548 if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf0, sizeof( buf0 ) ) ) != 0 )
markrad 0:cdf462088d13 549 goto cleanup;
markrad 0:cdf462088d13 550 if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf1, sizeof( buf1 ) ) ) != 0 )
markrad 0:cdf462088d13 551 goto cleanup;
markrad 0:cdf462088d13 552
markrad 0:cdf462088d13 553 /* Make sure that the entropy source is not returning values in a
markrad 0:cdf462088d13 554 * pattern */
markrad 0:cdf462088d13 555 ret = memcmp( buf0, buf1, sizeof( buf0 ) ) == 0;
markrad 0:cdf462088d13 556
markrad 0:cdf462088d13 557 cleanup:
markrad 0:cdf462088d13 558 if( verbose != 0 )
markrad 0:cdf462088d13 559 {
markrad 0:cdf462088d13 560 if( ret != 0 )
markrad 0:cdf462088d13 561 mbedtls_printf( "failed\n" );
markrad 0:cdf462088d13 562 else
markrad 0:cdf462088d13 563 mbedtls_printf( "passed\n" );
markrad 0:cdf462088d13 564
markrad 0:cdf462088d13 565 mbedtls_printf( "\n" );
markrad 0:cdf462088d13 566 }
markrad 0:cdf462088d13 567
markrad 0:cdf462088d13 568 return( ret != 0 );
markrad 0:cdf462088d13 569 }
markrad 0:cdf462088d13 570
markrad 0:cdf462088d13 571 #endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */
markrad 0:cdf462088d13 572
markrad 0:cdf462088d13 573 /*
markrad 0:cdf462088d13 574 * The actual entropy quality is hard to test, but we can at least
markrad 0:cdf462088d13 575 * test that the functions don't cause errors and write the correct
markrad 0:cdf462088d13 576 * amount of data to buffers.
markrad 0:cdf462088d13 577 */
markrad 0:cdf462088d13 578 int mbedtls_entropy_self_test( int verbose )
markrad 0:cdf462088d13 579 {
markrad 0:cdf462088d13 580 int ret = 1;
markrad 0:cdf462088d13 581 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
markrad 0:cdf462088d13 582 mbedtls_entropy_context ctx;
markrad 0:cdf462088d13 583 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
markrad 0:cdf462088d13 584 unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
markrad 0:cdf462088d13 585 size_t i, j;
markrad 0:cdf462088d13 586 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
markrad 0:cdf462088d13 587
markrad 0:cdf462088d13 588 if( verbose != 0 )
markrad 0:cdf462088d13 589 mbedtls_printf( " ENTROPY test: " );
markrad 0:cdf462088d13 590
markrad 0:cdf462088d13 591 #if !defined(MBEDTLS_TEST_NULL_ENTROPY)
markrad 0:cdf462088d13 592 mbedtls_entropy_init( &ctx );
markrad 0:cdf462088d13 593
markrad 0:cdf462088d13 594 /* First do a gather to make sure we have default sources */
markrad 0:cdf462088d13 595 if( ( ret = mbedtls_entropy_gather( &ctx ) ) != 0 )
markrad 0:cdf462088d13 596 goto cleanup;
markrad 0:cdf462088d13 597
markrad 0:cdf462088d13 598 ret = mbedtls_entropy_add_source( &ctx, entropy_dummy_source, NULL, 16,
markrad 0:cdf462088d13 599 MBEDTLS_ENTROPY_SOURCE_WEAK );
markrad 0:cdf462088d13 600 if( ret != 0 )
markrad 0:cdf462088d13 601 goto cleanup;
markrad 0:cdf462088d13 602
markrad 0:cdf462088d13 603 if( ( ret = mbedtls_entropy_update_manual( &ctx, buf, sizeof buf ) ) != 0 )
markrad 0:cdf462088d13 604 goto cleanup;
markrad 0:cdf462088d13 605
markrad 0:cdf462088d13 606 /*
markrad 0:cdf462088d13 607 * To test that mbedtls_entropy_func writes correct number of bytes:
markrad 0:cdf462088d13 608 * - use the whole buffer and rely on ASan to detect overruns
markrad 0:cdf462088d13 609 * - collect entropy 8 times and OR the result in an accumulator:
markrad 0:cdf462088d13 610 * any byte should then be 0 with probably 2^(-64), so requiring
markrad 0:cdf462088d13 611 * each of the 32 or 64 bytes to be non-zero has a false failure rate
markrad 0:cdf462088d13 612 * of at most 2^(-58) which is acceptable.
markrad 0:cdf462088d13 613 */
markrad 0:cdf462088d13 614 for( i = 0; i < 8; i++ )
markrad 0:cdf462088d13 615 {
markrad 0:cdf462088d13 616 if( ( ret = mbedtls_entropy_func( &ctx, buf, sizeof( buf ) ) ) != 0 )
markrad 0:cdf462088d13 617 goto cleanup;
markrad 0:cdf462088d13 618
markrad 0:cdf462088d13 619 for( j = 0; j < sizeof( buf ); j++ )
markrad 0:cdf462088d13 620 acc[j] |= buf[j];
markrad 0:cdf462088d13 621 }
markrad 0:cdf462088d13 622
markrad 0:cdf462088d13 623 for( j = 0; j < sizeof( buf ); j++ )
markrad 0:cdf462088d13 624 {
markrad 0:cdf462088d13 625 if( acc[j] == 0 )
markrad 0:cdf462088d13 626 {
markrad 0:cdf462088d13 627 ret = 1;
markrad 0:cdf462088d13 628 goto cleanup;
markrad 0:cdf462088d13 629 }
markrad 0:cdf462088d13 630 }
markrad 0:cdf462088d13 631
markrad 0:cdf462088d13 632 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
markrad 0:cdf462088d13 633 if( ( ret = mbedtls_entropy_source_self_test( 0 ) ) != 0 )
markrad 0:cdf462088d13 634 goto cleanup;
markrad 0:cdf462088d13 635 #endif
markrad 0:cdf462088d13 636
markrad 0:cdf462088d13 637 cleanup:
markrad 0:cdf462088d13 638 mbedtls_entropy_free( &ctx );
markrad 0:cdf462088d13 639 #endif /* !MBEDTLS_TEST_NULL_ENTROPY */
markrad 0:cdf462088d13 640
markrad 0:cdf462088d13 641 if( verbose != 0 )
markrad 0:cdf462088d13 642 {
markrad 0:cdf462088d13 643 if( ret != 0 )
markrad 0:cdf462088d13 644 mbedtls_printf( "failed\n" );
markrad 0:cdf462088d13 645 else
markrad 0:cdf462088d13 646 mbedtls_printf( "passed\n" );
markrad 0:cdf462088d13 647
markrad 0:cdf462088d13 648 mbedtls_printf( "\n" );
markrad 0:cdf462088d13 649 }
markrad 0:cdf462088d13 650
markrad 0:cdf462088d13 651 return( ret != 0 );
markrad 0:cdf462088d13 652 }
markrad 0:cdf462088d13 653 #endif /* MBEDTLS_SELF_TEST */
markrad 0:cdf462088d13 654
markrad 0:cdf462088d13 655 #endif /* MBEDTLS_ENTROPY_C */