reactos/dll/3rdparty/mbedtls/entropy_poll.c

   1 /*
   2  *  Platform-specific and custom entropy polling functions
   3  *
   4  *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
   5  *  SPDX-License-Identifier: Apache-2.0
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   8  *  not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *  http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  15  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License.
  18  *
  19  *  This file is part of mbed TLS (https://tls.mbed.org)
  20  */
  21
  22 #if !defined(MBEDTLS_CONFIG_FILE)
  23 #include "mbedtls/config.h"
  24 #else
  25 #include MBEDTLS_CONFIG_FILE
  26 #endif
  27
  28 #if defined(MBEDTLS_ENTROPY_C)
  29
  30 #include "mbedtls/entropy.h"
  31 #include "mbedtls/entropy_poll.h"
  32
  33 #if defined(MBEDTLS_TIMING_C)
  34 #include <string.h>
  35 #include "mbedtls/timing.h"
  36 #endif
  37 #if defined(MBEDTLS_HAVEGE_C)
  38 #include "mbedtls/havege.h"
  39 #endif
  40 #if defined(MBEDTLS_ENTROPY_NV_SEED)
  41 #include "mbedtls/platform.h"
  42 #endif
  43
  44 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
  45
  46 #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
  47     !defined(__APPLE__) && !defined(_WIN32)
  48 #error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in config.h"
  49 #endif
  50
  51 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
  52
  53 #if !defined(_WIN32_WINNT)
  54 #define _WIN32_WINNT 0x0400
  55 #endif
  56 #include <windows.h>
  57 #include <wincrypt.h>
  58
  59 int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
  60                            size_t *olen )
  61 {
  62     HCRYPTPROV provider;
  63     ((void) data);
  64     *olen = 0;
  65
  66     if( CryptAcquireContext( &provider, NULL, NULL,
  67                               PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
  68     {
  69         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
  70     }
  71
  72     if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
  73     {
  74         CryptReleaseContext( provider, 0 );
  75         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
  76     }
  77
  78     CryptReleaseContext( provider, 0 );
  79     *olen = len;
  80
  81     return( 0 );
  82 }
  83 #else /* _WIN32 && !EFIX64 && !EFI32 */
  84
  85 /*
  86  * Test for Linux getrandom() support.
  87  * Since there is no wrapper in the libc yet, use the generic syscall wrapper
  88  * available in GNU libc and compatible libc's (eg uClibc).
  89  */
  90 #if defined(__linux__) && defined(__GLIBC__)
  91 #include <unistd.h>
  92 #include <sys/syscall.h>
  93 #if defined(SYS_getrandom)
  94 #define HAVE_GETRANDOM
  95
  96 static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
  97 {
  98     /* MemSan cannot understand that the syscall writes to the buffer */
  99 #if defined(__has_feature)
 100 #if __has_feature(memory_sanitizer)
 101     memset( buf, 0, buflen );
 102 #endif
 103 #endif
 104
 105     return( syscall( SYS_getrandom, buf, buflen, flags ) );
 106 }
 107
 108 #include <sys/utsname.h>
 109 /* Check if version is at least 3.17.0 */
 110 static int check_version_3_17_plus( void )
 111 {
 112     int minor;
 113     struct utsname un;
 114     const char *ver;
 115
 116     /* Get version information */
 117     uname(&un);
 118     ver = un.release;
 119
 120     /* Check major version; assume a single digit */
 121     if( ver[0] < '3' || ver[0] > '9' || ver [1] != '.' )
 122         return( -1 );
 123
 124     if( ver[0] - '0' > 3 )
 125         return( 0 );
 126
 127     /* Ok, so now we know major == 3, check minor.
 128      * Assume 1 or 2 digits. */
 129     if( ver[2] < '0' || ver[2] > '9' )
 130         return( -1 );
 131
 132     minor = ver[2] - '0';
 133
 134     if( ver[3] >= '0' && ver[3] <= '9' )
 135         minor = 10 * minor + ver[3] - '0';
 136     else if( ver [3] != '.' )
 137         return( -1 );
 138
 139     if( minor < 17 )
 140         return( -1 );
 141
 142     return( 0 );
 143 }
 144 static int has_getrandom = -1;
 145 #endif /* SYS_getrandom */
 146 #endif /* __linux__ */
 147
 148 #include <stdio.h>
 149
 150 int mbedtls_platform_entropy_poll( void *data,
 151                            unsigned char *output, size_t len, size_t *olen )
 152 {
 153     FILE *file;
 154     size_t read_len;
 155     ((void) data);
 156
 157 #if defined(HAVE_GETRANDOM)
 158     if( has_getrandom == -1 )
 159         has_getrandom = ( check_version_3_17_plus() == 0 );
 160
 161     if( has_getrandom )
 162     {
 163         int ret;
 164
 165         if( ( ret = getrandom_wrapper( output, len, 0 ) ) < 0 )
 166             return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 167
 168         *olen = ret;
 169         return( 0 );
 170     }
 171 #endif /* HAVE_GETRANDOM */
 172
 173     *olen = 0;
 174
 175     file = fopen( "/dev/urandom", "rb" );
 176     if( file == NULL )
 177         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 178
 179     read_len = fread( output, 1, len, file );
 180     if( read_len != len )
 181     {
 182         fclose( file );
 183         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 184     }
 185
 186     fclose( file );
 187     *olen = len;
 188
 189     return( 0 );
 190 }
 191 #endif /* _WIN32 && !EFIX64 && !EFI32 */
 192 #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
 193
 194 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
 195 int mbedtls_null_entropy_poll( void *data,
 196                     unsigned char *output, size_t len, size_t *olen )
 197 {
 198     ((void) data);
 199     ((void) output);
 200     *olen = 0;
 201
 202     if( len < sizeof(unsigned char) )
 203         return( 0 );
 204
 205     *olen = sizeof(unsigned char);
 206
 207     return( 0 );
 208 }
 209 #endif
 210
 211 #if defined(MBEDTLS_TIMING_C)
 212 int mbedtls_hardclock_poll( void *data,
 213                     unsigned char *output, size_t len, size_t *olen )
 214 {
 215     unsigned long timer = mbedtls_timing_hardclock();
 216     ((void) data);
 217     *olen = 0;
 218
 219     if( len < sizeof(unsigned long) )
 220         return( 0 );
 221
 222     memcpy( output, &timer, sizeof(unsigned long) );
 223     *olen = sizeof(unsigned long);
 224
 225     return( 0 );
 226 }
 227 #endif /* MBEDTLS_TIMING_C */
 228
 229 #if defined(MBEDTLS_HAVEGE_C)
 230 int mbedtls_havege_poll( void *data,
 231                  unsigned char *output, size_t len, size_t *olen )
 232 {
 233     mbedtls_havege_state *hs = (mbedtls_havege_state *) data;
 234     *olen = 0;
 235
 236     if( mbedtls_havege_random( hs, output, len ) != 0 )
 237         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 238
 239     *olen = len;
 240
 241     return( 0 );
 242 }
 243 #endif /* MBEDTLS_HAVEGE_C */
 244
 245 #if defined(MBEDTLS_ENTROPY_NV_SEED)
 246 int mbedtls_nv_seed_poll( void *data,
 247                           unsigned char *output, size_t len, size_t *olen )
 248 {
 249     unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
 250     size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
 251     ((void) data);
 252
 253     memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
 254
 255     if( mbedtls_nv_seed_read( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
 256       return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 257
 258     if( len < use_len )
 259       use_len = len;
 260
 261     memcpy( output, buf, use_len );
 262     *olen = use_len;
 263
 264     return( 0 );
 265 }
 266 #endif /* MBEDTLS_ENTROPY_NV_SEED */
 267
 268 #endif /* MBEDTLS_ENTROPY_C */