mirror of
https://codeberg.org/libreboot/lbmk.git
synced 2026-07-11 05:52:36 +02:00
Leah Rowe
87 lines
1.6 KiB
C
87 lines
1.6 KiB
C
/* SPDX-License-Identifier: MIT
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* Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
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*
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* Random number generation
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*/
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#ifndef RAND_H
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#define RAND_H
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#ifdef __OpenBSD__
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#include <sys/param.h>
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#endif
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#include <sys/types.h>
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#ifndef USE_URANDOM
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#define USE_URANDOM 0
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#endif
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#include <errno.h>
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#if defined(USE_URANDOM) && \
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((USE_URANDOM) > 0)
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#include <fcntl.h> /* if not arc4random: /dev/urandom */
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#endif
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#include <limits.h>
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#include <stddef.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "../include/common.h"
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void
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rset(void *buf, size_t n)
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{
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int saved_errno = errno;
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#if (defined(__OpenBSD__) || defined(__FreeBSD__) || \
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defined(__NetBSD__) || defined(__APPLE__) || \
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defined(__DragonFly__)) && !(defined(USE_URANDOM) && \
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((USE_URANDOM) > 0))
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arc4random_buf(buf, n);
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goto out;
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#else
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size_t off = errno = 0;
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ssize_t rc = 0;
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#if defined(USE_URANDOM) && \
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((USE_URANDOM) > 0)
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int fd = -1;
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if ((fd = open("/dev/urandom", O_RDONLY)) < 0)
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goto err;
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retry_rand:
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if ((rc = read(fd, buf + off, n - off)) < 0) {
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#elif defined(__linux__)
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retry_rand:
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if ((rc = (ssize_t)syscall(SYS_getrandom,
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buf + off, n - off, 0)) < 0) {
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#else
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#error Unsupported operating system (possibly unsecure randomisation)
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#endif
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if (errno == EINTR ||
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errno == EAGAIN) {
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usleep(100);
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goto retry_rand;
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}
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goto err; /* possibly unsupported by kernel */
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}
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if ((off += (size_t)rc) < n)
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goto retry_rand;
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goto out;
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err:
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err_no_cleanup(1, ECANCELED,
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"Randomisation failure, possibly unsupported in your kernel.");
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exit(EXIT_FAILURE);
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#endif
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out:
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errno = saved_errno;
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}
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#endif
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