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

   1 /*
   2  *  Platform-specific and custom entropy polling functions
   3  *
   4  *  Copyright (C) 2006-2015, 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
  41 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
  42 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
  43
  44 #if !defined(_WIN32_WINNT)
  45 #define _WIN32_WINNT 0x0400
  46 #endif
  47 #include <windows.h>
  48 #include <wincrypt.h>
  49
  50 int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
  51                            size_t *olen )
  52 {
  53     HCRYPTPROV provider;
  54     ((void) data);
  55     *olen = 0;
  56
  57     if( CryptAcquireContext( &provider, NULL, NULL,
  58                               PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
  59     {
  60         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
  61     }
  62
  63     if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
  64         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
  65
  66     CryptReleaseContext( provider, 0 );
  67     *olen = len;
  68
  69     return( 0 );
  70 }
  71 #else /* _WIN32 && !EFIX64 && !EFI32 */
  72
  73 /*
  74  * Test for Linux getrandom() support.
  75  * Since there is no wrapper in the libc yet, use the generic syscall wrapper
  76  * available in GNU libc and compatible libc's (eg uClibc).
  77  */
  78 #if defined(__linux__) && defined(__GLIBC__)
  79 #include <unistd.h>
  80 #include <sys/syscall.h>
  81 #if defined(SYS_getrandom)
  82 #define HAVE_GETRANDOM
  83
  84 static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
  85 {
  86     /* MemSan cannot understand that the syscall writes to the buffer */
  87 #if defined(__has_feature)
  88 #if __has_feature(memory_sanitizer)
  89     memset( buf, 0, buflen );
  90 #endif
  91 #endif
  92
  93     return( syscall( SYS_getrandom, buf, buflen, flags ) );
  94 }
  95
  96 #include <sys/utsname.h>
  97 /* Check if version is at least 3.17.0 */
  98 static int check_version_3_17_plus( void )
  99 {
 100     int minor;
 101     struct utsname un;
 102     const char *ver;
 103
 104     /* Get version information */
 105     uname(&un);
 106     ver = un.release;
 107
 108     /* Check major version; assume a single digit */
 109     if( ver[0] < '3' || ver[0] > '9' || ver [1] != '.' )
 110         return( -1 );
 111
 112     if( ver[0] - '0' > 3 )
 113         return( 0 );
 114
 115     /* Ok, so now we know major == 3, check minor.
 116      * Assume 1 or 2 digits. */
 117     if( ver[2] < '0' || ver[2] > '9' )
 118         return( -1 );
 119
 120     minor = ver[2] - '0';
 121
 122     if( ver[3] >= '0' && ver[3] <= '9' )
 123         minor = 10 * minor + ver[3] - '0';
 124     else if( ver [3] != '.' )
 125         return( -1 );
 126
 127     if( minor < 17 )
 128         return( -1 );
 129
 130     return( 0 );
 131 }
 132 static int has_getrandom = -1;
 133 #endif /* SYS_getrandom */
 134 #endif /* __linux__ */
 135
 136 #include <stdio.h>
 137
 138 int mbedtls_platform_entropy_poll( void *data,
 139                            unsigned char *output, size_t len, size_t *olen )
 140 {
 141     FILE *file;
 142     size_t read_len;
 143     ((void) data);
 144
 145 #if defined(HAVE_GETRANDOM)
 146     if( has_getrandom == -1 )
 147         has_getrandom = ( check_version_3_17_plus() == 0 );
 148
 149     if( has_getrandom )
 150     {
 151         int ret;
 152
 153         if( ( ret = getrandom_wrapper( output, len, 0 ) ) < 0 )
 154             return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 155
 156         *olen = ret;
 157         return( 0 );
 158     }
 159 #endif /* HAVE_GETRANDOM */
 160
 161     *olen = 0;
 162
 163     file = fopen( "/dev/urandom", "rb" );
 164     if( file == NULL )
 165         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 166
 167     read_len = fread( output, 1, len, file );
 168     if( read_len != len )
 169     {
 170         fclose( file );
 171         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 172     }
 173
 174     fclose( file );
 175     *olen = len;
 176
 177     return( 0 );
 178 }
 179 #endif /* _WIN32 && !EFIX64 && !EFI32 */
 180 #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
 181
 182 #if defined(MBEDTLS_TIMING_C)
 183 int mbedtls_hardclock_poll( void *data,
 184                     unsigned char *output, size_t len, size_t *olen )
 185 {
 186     unsigned long timer = mbedtls_timing_hardclock();
 187     ((void) data);
 188     *olen = 0;
 189
 190     if( len < sizeof(unsigned long) )
 191         return( 0 );
 192
 193     memcpy( output, &timer, sizeof(unsigned long) );
 194     *olen = sizeof(unsigned long);
 195
 196     return( 0 );
 197 }
 198 #endif /* MBEDTLS_TIMING_C */
 199
 200 #if defined(MBEDTLS_HAVEGE_C)
 201 int mbedtls_havege_poll( void *data,
 202                  unsigned char *output, size_t len, size_t *olen )
 203 {
 204     mbedtls_havege_state *hs = (mbedtls_havege_state *) data;
 205     *olen = 0;
 206
 207     if( mbedtls_havege_random( hs, output, len ) != 0 )
 208         return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
 209
 210     *olen = len;
 211
 212     return( 0 );
 213 }
 214 #endif /* MBEDTLS_HAVEGE_C */
 215
 216 #endif /* MBEDTLS_ENTROPY_C */