[398] | 1 | /*
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| 2 | * Platform-specific and custom entropy polling functions
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| 3 | *
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| 4 | * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
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| 5 | * SPDX-License-Identifier: Apache-2.0
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| 6 | *
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| 7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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| 8 | * not use this file except in compliance with the License.
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| 9 | * You may obtain a copy of the License at
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| 10 | *
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| 11 | * http://www.apache.org/licenses/LICENSE-2.0
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| 12 | *
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| 13 | * Unless required by applicable law or agreed to in writing, software
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| 14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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| 15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 16 | * See the License for the specific language governing permissions and
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| 17 | * limitations under the License.
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| 18 | *
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| 19 | * This file is part of mbed TLS (https://tls.mbed.org)
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| 20 | */
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| 21 |
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| 22 | #if defined(__linux__)
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| 23 | /* Ensure that syscall() is available even when compiling with -std=c99 */
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| 24 | #define _GNU_SOURCE
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| 25 | #endif
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| 26 |
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| 27 | #if !defined(MBEDTLS_CONFIG_FILE)
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| 28 | #include "mbedtls/config.h"
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| 29 | #else
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| 30 | #include MBEDTLS_CONFIG_FILE
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| 31 | #endif
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| 32 |
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| 33 | #include <string.h>
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| 34 |
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| 35 | #if defined(MBEDTLS_ENTROPY_C)
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| 36 |
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| 37 | #include "mbedtls/entropy.h"
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| 38 | #include "mbedtls/entropy_poll.h"
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| 39 |
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| 40 | #if defined(MBEDTLS_TIMING_C)
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| 41 | #include "mbedtls/timing.h"
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| 42 | #endif
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| 43 | #if defined(MBEDTLS_HAVEGE_C)
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| 44 | #include "mbedtls/havege.h"
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| 45 | #endif
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| 46 | #if defined(MBEDTLS_ENTROPY_NV_SEED)
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| 47 | #include "mbedtls/platform.h"
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| 48 | #endif
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| 49 |
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| 50 | #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
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| 51 |
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| 52 | #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
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| 53 | !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
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| 54 | !defined(__HAIKU__)
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| 55 | #error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in config.h"
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| 56 | #endif
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| 57 |
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| 58 | #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
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| 59 |
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| 60 | #if !defined(_WIN32_WINNT)
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| 61 | #define _WIN32_WINNT 0x0400
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| 62 | #endif
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| 63 | #include <windows.h>
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| 64 | #include <wincrypt.h>
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| 65 |
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| 66 | int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
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| 67 | size_t *olen )
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| 68 | {
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| 69 | HCRYPTPROV provider;
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| 70 | ((void) data);
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| 71 | *olen = 0;
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| 72 |
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| 73 | if( CryptAcquireContext( &provider, NULL, NULL,
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| 74 | PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
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| 75 | {
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| 76 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 77 | }
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| 78 |
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| 79 | if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
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| 80 | {
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| 81 | CryptReleaseContext( provider, 0 );
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| 82 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 83 | }
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| 84 |
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| 85 | CryptReleaseContext( provider, 0 );
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| 86 | *olen = len;
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| 87 |
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| 88 | return( 0 );
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| 89 | }
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| 90 | #else /* _WIN32 && !EFIX64 && !EFI32 */
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| 91 |
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| 92 | /*
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| 93 | * Test for Linux getrandom() support.
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| 94 | * Since there is no wrapper in the libc yet, use the generic syscall wrapper
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| 95 | * available in GNU libc and compatible libc's (eg uClibc).
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| 96 | */
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| 97 | #if defined(__linux__) && defined(__GLIBC__)
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| 98 | #include <unistd.h>
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| 99 | #include <sys/syscall.h>
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| 100 | #if defined(SYS_getrandom)
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| 101 | #define HAVE_GETRANDOM
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| 102 | #include <errno.h>
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| 103 |
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| 104 | static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
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| 105 | {
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| 106 | /* MemSan cannot understand that the syscall writes to the buffer */
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| 107 | #if defined(__has_feature)
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| 108 | #if __has_feature(memory_sanitizer)
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| 109 | memset( buf, 0, buflen );
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| 110 | #endif
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| 111 | #endif
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| 112 | return( syscall( SYS_getrandom, buf, buflen, flags ) );
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| 113 | }
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| 114 | #endif /* SYS_getrandom */
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| 115 | #endif /* __linux__ */
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| 116 |
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| 117 | #include <stdio.h>
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| 118 |
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| 119 | int mbedtls_platform_entropy_poll( void *data,
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| 120 | unsigned char *output, size_t len, size_t *olen )
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| 121 | {
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| 122 | FILE *file;
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| 123 | size_t read_len;
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| 124 | int ret;
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| 125 | ((void) data);
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| 126 |
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| 127 | #if defined(HAVE_GETRANDOM)
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| 128 | ret = getrandom_wrapper( output, len, 0 );
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| 129 | if( ret >= 0 )
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| 130 | {
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| 131 | *olen = ret;
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| 132 | return( 0 );
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| 133 | }
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| 134 | else if( errno != ENOSYS )
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| 135 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 136 | /* Fall through if the system call isn't known. */
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| 137 | #else
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| 138 | ((void) ret);
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| 139 | #endif /* HAVE_GETRANDOM */
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| 140 |
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| 141 | *olen = 0;
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| 142 |
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| 143 | file = fopen( "/dev/urandom", "rb" );
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| 144 | if( file == NULL )
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| 145 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 146 |
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| 147 | read_len = fread( output, 1, len, file );
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| 148 | if( read_len != len )
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| 149 | {
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| 150 | fclose( file );
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| 151 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 152 | }
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| 153 |
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| 154 | fclose( file );
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| 155 | *olen = len;
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| 156 |
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| 157 | return( 0 );
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| 158 | }
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| 159 | #endif /* _WIN32 && !EFIX64 && !EFI32 */
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| 160 | #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
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| 161 |
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| 162 | #if defined(MBEDTLS_TEST_NULL_ENTROPY)
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| 163 | int mbedtls_null_entropy_poll( void *data,
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| 164 | unsigned char *output, size_t len, size_t *olen )
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| 165 | {
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| 166 | ((void) data);
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| 167 | ((void) output);
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| 168 | *olen = 0;
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| 169 |
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| 170 | if( len < sizeof(unsigned char) )
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| 171 | return( 0 );
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| 172 |
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| 173 | *olen = sizeof(unsigned char);
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| 174 |
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| 175 | return( 0 );
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| 176 | }
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| 177 | #endif
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| 178 |
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| 179 | #if defined(MBEDTLS_TIMING_C)
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| 180 | int mbedtls_hardclock_poll( void *data,
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| 181 | unsigned char *output, size_t len, size_t *olen )
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| 182 | {
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| 183 | unsigned long timer = mbedtls_timing_hardclock();
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| 184 | ((void) data);
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| 185 | *olen = 0;
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| 186 |
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| 187 | if( len < sizeof(unsigned long) )
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| 188 | return( 0 );
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| 189 |
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| 190 | memcpy( output, &timer, sizeof(unsigned long) );
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| 191 | *olen = sizeof(unsigned long);
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| 192 |
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| 193 | return( 0 );
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| 194 | }
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| 195 | #endif /* MBEDTLS_TIMING_C */
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| 196 |
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| 197 | #if defined(MBEDTLS_HAVEGE_C)
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| 198 | int mbedtls_havege_poll( void *data,
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| 199 | unsigned char *output, size_t len, size_t *olen )
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| 200 | {
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| 201 | mbedtls_havege_state *hs = (mbedtls_havege_state *) data;
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| 202 | *olen = 0;
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| 203 |
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| 204 | if( mbedtls_havege_random( hs, output, len ) != 0 )
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| 205 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 206 |
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| 207 | *olen = len;
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| 208 |
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| 209 | return( 0 );
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| 210 | }
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| 211 | #endif /* MBEDTLS_HAVEGE_C */
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| 212 |
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| 213 | #if defined(MBEDTLS_ENTROPY_NV_SEED)
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| 214 | int mbedtls_nv_seed_poll( void *data,
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| 215 | unsigned char *output, size_t len, size_t *olen )
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| 216 | {
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| 217 | unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
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| 218 | size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
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| 219 | ((void) data);
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| 220 |
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| 221 | memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
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| 222 |
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| 223 | if( mbedtls_nv_seed_read( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
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| 224 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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| 225 |
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| 226 | if( len < use_len )
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| 227 | use_len = len;
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| 228 |
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| 229 | memcpy( output, buf, use_len );
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| 230 | *olen = use_len;
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| 231 |
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| 232 | return( 0 );
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| 233 | }
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| 234 | #endif /* MBEDTLS_ENTROPY_NV_SEED */
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| 235 |
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| 236 | #endif /* MBEDTLS_ENTROPY_C */
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