/*
* Platform-specific and custom entropy polling functions
*
* Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: GPL-2.0
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if defined(__linux__)
/* Ensure that syscall() is available even when compiling with -std=c99 */
#define _GNU_SOURCE
#endif
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include <string.h>
#if defined(MBEDTLS_ENTROPY_C)
#include "mbedtls/entropy.h"
#include "mbedtls/entropy_poll.h"
#if defined(MBEDTLS_TIMING_C)
#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) && !defined(__QNXNTO__) && \
!defined(__HAIKU__)
#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 */