/* * Platform-specific and custom entropy polling functions * * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * This file is part of mbed TLS (https://tls.mbed.org) */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_ENTROPY_C) #include "mbedtls/entropy.h" #include "mbedtls/entropy_poll.h" #if defined(MBEDTLS_TIMING_C) #include <string.h> #include "mbedtls/timing.h" #endif #if defined(MBEDTLS_HAVEGE_C) #include "mbedtls/havege.h" #endif #if defined(MBEDTLS_ENTROPY_NV_SEED) #include "mbedtls/platform.h" #endif #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY) #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \ !defined(__APPLE__) && !defined(_WIN32) #error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in config.h" #endif #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) #if !defined(_WIN32_WINNT) #define _WIN32_WINNT 0x0400 #endif #include <windows.h> #include <wincrypt.h> int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { HCRYPTPROV provider; ((void) data); *olen = 0; if( CryptAcquireContext( &provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE ) { return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); } if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE ) { CryptReleaseContext( provider, 0 ); return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); } CryptReleaseContext( provider, 0 ); *olen = len; return( 0 ); } #else /* _WIN32 && !EFIX64 && !EFI32 */ /* * Test for Linux getrandom() support. * Since there is no wrapper in the libc yet, use the generic syscall wrapper * available in GNU libc and compatible libc's (eg uClibc). */ #if defined(__linux__) && defined(__GLIBC__) #include <unistd.h> #include <sys/syscall.h> #if defined(SYS_getrandom) #define HAVE_GETRANDOM static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags ) { /* MemSan cannot understand that the syscall writes to the buffer */ #if defined(__has_feature) #if __has_feature(memory_sanitizer) memset( buf, 0, buflen ); #endif #endif return( syscall( SYS_getrandom, buf, buflen, flags ) ); } #include <sys/utsname.h> /* Check if version is at least 3.17.0 */ static int check_version_3_17_plus( void ) { int minor; struct utsname un; const char *ver; /* Get version information */ uname(&un); ver = un.release; /* Check major version; assume a single digit */ if( ver[0] < '3' || ver[0] > '9' || ver [1] != '.' ) return( -1 ); if( ver[0] - '0' > 3 ) return( 0 ); /* Ok, so now we know major == 3, check minor. * Assume 1 or 2 digits. */ if( ver[2] < '0' || ver[2] > '9' ) return( -1 ); minor = ver[2] - '0'; if( ver[3] >= '0' && ver[3] <= '9' ) minor = 10 * minor + ver[3] - '0'; else if( ver [3] != '.' ) return( -1 ); if( minor < 17 ) return( -1 ); return( 0 ); } static int has_getrandom = -1; #endif /* SYS_getrandom */ #endif /* __linux__ */ #include <stdio.h> int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { FILE *file; size_t read_len; ((void) data); #if defined(HAVE_GETRANDOM) if( has_getrandom == -1 ) has_getrandom = ( check_version_3_17_plus() == 0 ); if( has_getrandom ) { int ret; if( ( ret = getrandom_wrapper( output, len, 0 ) ) < 0 ) return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); *olen = ret; return( 0 ); } #endif /* HAVE_GETRANDOM */ *olen = 0; file = fopen( "/dev/urandom", "rb" ); if( file == NULL ) return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); read_len = fread( output, 1, len, file ); if( read_len != len ) { fclose( file ); return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); } fclose( file ); *olen = len; return( 0 ); } #endif /* _WIN32 && !EFIX64 && !EFI32 */ #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */ #if defined(MBEDTLS_TEST_NULL_ENTROPY) int mbedtls_null_entropy_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { ((void) data); ((void) output); *olen = 0; if( len < sizeof(unsigned char) ) return( 0 ); *olen = sizeof(unsigned char); return( 0 ); } #endif #if defined(MBEDTLS_TIMING_C) int mbedtls_hardclock_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { unsigned long timer = mbedtls_timing_hardclock(); ((void) data); *olen = 0; if( len < sizeof(unsigned long) ) return( 0 ); memcpy( output, &timer, sizeof(unsigned long) ); *olen = sizeof(unsigned long); return( 0 ); } #endif /* MBEDTLS_TIMING_C */ #if defined(MBEDTLS_HAVEGE_C) int mbedtls_havege_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { mbedtls_havege_state *hs = (mbedtls_havege_state *) data; *olen = 0; if( mbedtls_havege_random( hs, output, len ) != 0 ) return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); *olen = len; return( 0 ); } #endif /* MBEDTLS_HAVEGE_C */ #if defined(MBEDTLS_ENTROPY_NV_SEED) int mbedtls_nv_seed_poll( void *data, unsigned char *output, size_t len, size_t *olen ) { unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE; ((void) data); memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE ); if( mbedtls_nv_seed_read( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 ) return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); if( len < use_len ) use_len = len; memcpy( output, buf, use_len ); *olen = use_len; return( 0 ); } #endif /* MBEDTLS_ENTROPY_NV_SEED */ #endif /* MBEDTLS_ENTROPY_C */