/* * QEMU Crypto random number provider * * Copyright (c) 2015-2016 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see <http://www.gnu.org/licenses/>. * */ #include "qemu/osdep.h" #include "crypto/random.h" #include "qapi/error.h" #ifdef _WIN32 #include <wincrypt.h> static HCRYPTPROV hCryptProv; #else static int fd; /* a file handle to either /dev/urandom or /dev/random */ #endif int qcrypto_random_init(Error **errp) { #ifndef _WIN32 /* TBD perhaps also add support for BSD getentropy / Linux * getrandom syscalls directly */ fd = open("/dev/urandom", O_RDONLY); if (fd == -1 && errno == ENOENT) { fd = open("/dev/random", O_RDONLY); } if (fd < 0) { error_setg(errp, "No /dev/urandom or /dev/random found"); return -1; } #else if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL, CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) { error_setg_win32(errp, GetLastError(), "Unable to create cryptographic provider"); return -1; } #endif return 0; } int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED, size_t buflen G_GNUC_UNUSED, Error **errp) { #ifndef _WIN32 int ret = -1; int got; while (buflen > 0) { got = read(fd, buf, buflen); if (got < 0) { error_setg_errno(errp, errno, "Unable to read random bytes"); goto cleanup; } else if (!got) { error_setg(errp, "Unexpected EOF reading random bytes"); goto cleanup; } buflen -= got; buf += got; } ret = 0; cleanup: return ret; #else if (!CryptGenRandom(hCryptProv, buflen, buf)) { error_setg_win32(errp, GetLastError(), "Unable to read random bytes"); return -1; } return 0; #endif }