/* * 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 #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 #include 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 #include #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 /* 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 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 */