diff options
Diffstat (limited to 'shared/nm-utils/nm-random-utils.c')
| -rw-r--r-- | shared/nm-utils/nm-random-utils.c | 165 |
1 files changed, 0 insertions, 165 deletions
diff --git a/shared/nm-utils/nm-random-utils.c b/shared/nm-utils/nm-random-utils.c deleted file mode 100644 index d7c7da42..00000000 --- a/shared/nm-utils/nm-random-utils.c +++ /dev/null @@ -1,165 +0,0 @@ -/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */ -/* NetworkManager -- Network link manager - * - * 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, write to the - * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, - * Boston, MA 02110-1301 USA. - * - * (C) Copyright 2017 Red Hat, Inc. - */ - -#include "nm-default.h" - -#include "nm-random-utils.h" - -#include <fcntl.h> - -#if USE_SYS_RANDOM_H -#include <sys/random.h> -#else -#include <linux/random.h> -#endif - -#include "nm-shared-utils.h" - -/*****************************************************************************/ - -/** - * nm_utils_random_bytes: - * @p: the buffer to fill - * @n: the number of bytes to write to @p. - * - * Uses getrandom() or reads /dev/urandom to fill the buffer - * with random data. If all fails, as last fallback it uses - * GRand to fill the buffer with pseudo random numbers. - * The function always succeeds in writing some random numbers - * to the buffer. The return value of FALSE indicates that the - * obtained bytes are probably not of good randomness. - * - * Returns: whether the written bytes are good. If you - * don't require good randomness, you can ignore the return - * value. - * - * Note that if calling getrandom() fails because there is not enough - * entropy (at early boot), the function will read /dev/urandom. - * Which of course, still has low entropy, and cause kernel to log - * a warning. - */ -gboolean -nm_utils_random_bytes (void *p, size_t n) -{ - int fd; - int r; - gboolean has_high_quality = TRUE; - gboolean urandom_success; - guint8 *buf = p; - gboolean avoid_urandom = FALSE; - - g_return_val_if_fail (p, FALSE); - g_return_val_if_fail (n > 0, FALSE); - -#if HAVE_GETRANDOM - { - static gboolean have_syscall = TRUE; - - if (have_syscall) { - r = getrandom (buf, n, GRND_NONBLOCK); - if (r > 0) { - if ((size_t) r == n) - return TRUE; - - /* no or partial read. There is not enough entropy. - * Fill the rest reading from urandom, and remember that - * some bits are not high quality. */ - nm_assert (r < n); - buf += r; - n -= r; - has_high_quality = FALSE; - - /* At this point, we don't want to read /dev/urandom, because - * the entropy pool is low (early boot?), and asking for more - * entropy causes kernel messages to be logged. - * - * We use our fallback via GRand. Note that g_rand_new() also - * tries to seed itself with data from /dev/urandom, but since - * we reuse the instance, it shouldn't matter. */ - avoid_urandom = TRUE; - } else { - if (errno == ENOSYS) { - /* no support for getrandom(). We don't know whether - * we urandom will give us good quality. Assume yes. */ - have_syscall = FALSE; - } else { - /* unknown error. We'll read urandom below, but we don't have - * high-quality randomness. */ - has_high_quality = FALSE; - } - } - } - } -#endif - - urandom_success = FALSE; - if (!avoid_urandom) { -fd_open: - fd = open ("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOCTTY); - if (fd < 0) { - r = errno; - if (r == EINTR) - goto fd_open; - } else { - r = nm_utils_fd_read_loop_exact (fd, buf, n, TRUE); - nm_close (fd); - if (r >= 0) - urandom_success = TRUE; - } - } - - if (!urandom_success) { - static _nm_thread_local GRand *rand = NULL; - gsize i; - int j; - - /* we failed to fill the bytes reading from urandom. - * Fill the bits using GRand pseudo random numbers. - * - * We don't have good quality. - */ - has_high_quality = FALSE; - - if (G_UNLIKELY (!rand)) - rand = g_rand_new (); - - nm_assert (n > 0); - i = 0; - for (;;) { - const union { - guint32 v32; - guint8 v8[4]; - } v = { - .v32 = g_rand_int (rand), - }; - - for (j = 0; j < 4; ) { - buf[i++] = v.v8[j++]; - if (i >= n) - goto done; - } - } -done: - ; - } - - return has_high_quality; -} |