| /* |
| * Platform-specific and custom entropy polling functions |
| * |
| * Copyright The Mbed TLS Contributors |
| * 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. |
| */ |
| |
| #if defined(__linux__) && !defined(_GNU_SOURCE) |
| /* Ensure that syscall() is available even when compiling with -std=c99 */ |
| #define _GNU_SOURCE |
| #endif |
| |
| #include "common.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_ENTROPY_C) |
| |
| #include "mbedtls/entropy.h" |
| #include "entropy_poll.h" |
| #include "mbedtls/error.h" |
| |
| #if defined(MBEDTLS_TIMING_C) |
| #include "mbedtls/timing.h" |
| #endif |
| #include "mbedtls/platform.h" |
| |
| #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY) |
| |
| #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \ |
| !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \ |
| !defined(__HAIKU__) && !defined(__midipix__) |
| #error \ |
| "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in mbedtls_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__)) || defined(__midipix__)) |
| #include <unistd.h> |
| #include <sys/syscall.h> |
| #if defined(SYS_getrandom) |
| #define HAVE_GETRANDOM |
| #include <errno.h> |
| |
| 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); |
| } |
| #endif /* SYS_getrandom */ |
| #endif /* __linux__ || __midipix__ */ |
| |
| #if defined(__FreeBSD__) || defined(__DragonFly__) |
| #include <sys/param.h> |
| #if (defined(__FreeBSD__) && __FreeBSD_version >= 1200000) || \ |
| (defined(__DragonFly__) && __DragonFly_version >= 500700) |
| #include <errno.h> |
| #include <sys/random.h> |
| #define HAVE_GETRANDOM |
| static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags) |
| { |
| return getrandom(buf, buflen, flags); |
| } |
| #endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) || |
| (__DragonFly__ && __DragonFly_version >= 500700) */ |
| #endif /* __FreeBSD__ || __DragonFly__ */ |
| |
| /* |
| * Some BSD systems provide KERN_ARND. |
| * This is equivalent to reading from /dev/urandom, only it doesn't require an |
| * open file descriptor, and provides up to 256 bytes per call (basically the |
| * same as getentropy(), but with a longer history). |
| * |
| * Documentation: https://netbsd.gw.com/cgi-bin/man-cgi?sysctl+7 |
| */ |
| #if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(HAVE_GETRANDOM) |
| #include <sys/param.h> |
| #include <sys/sysctl.h> |
| #if defined(KERN_ARND) |
| #define HAVE_SYSCTL_ARND |
| |
| static int sysctl_arnd_wrapper(unsigned char *buf, size_t buflen) |
| { |
| int name[2]; |
| size_t len; |
| |
| name[0] = CTL_KERN; |
| name[1] = KERN_ARND; |
| |
| while (buflen > 0) { |
| len = buflen > 256 ? 256 : buflen; |
| if (sysctl(name, 2, buf, &len, NULL, 0) == -1) { |
| return -1; |
| } |
| buflen -= len; |
| buf += len; |
| } |
| return 0; |
| } |
| #endif /* KERN_ARND */ |
| #endif /* __FreeBSD__ || __NetBSD__ */ |
| |
| #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; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| ((void) data); |
| |
| #if defined(HAVE_GETRANDOM) |
| ret = getrandom_wrapper(output, len, 0); |
| if (ret >= 0) { |
| *olen = ret; |
| return 0; |
| } else if (errno != ENOSYS) { |
| return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; |
| } |
| /* Fall through if the system call isn't known. */ |
| #else |
| ((void) ret); |
| #endif /* HAVE_GETRANDOM */ |
| |
| #if defined(HAVE_SYSCTL_ARND) |
| ((void) file); |
| ((void) read_len); |
| if (sysctl_arnd_wrapper(output, len) == -1) { |
| return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; |
| } |
| *olen = len; |
| return 0; |
| #else |
| |
| *olen = 0; |
| |
| file = fopen("/dev/urandom", "rb"); |
| if (file == NULL) { |
| return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; |
| } |
| |
| /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */ |
| mbedtls_setbuf(file, NULL); |
| |
| 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 /* HAVE_SYSCTL_ARND */ |
| } |
| #endif /* _WIN32 && !EFIX64 && !EFI32 */ |
| #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */ |
| |
| #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 */ |