3 # SPDX-License-Identifier: BSD-2-Clause-FreeBSD
5 # Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org
8 # Redistribution and use in source and binary forms, with or without
9 # modification, are permitted provided that the following conditions
11 # 1. Redistributions of source code must retain the above copyright
12 # notice, this list of conditions and the following disclaimer.
13 # 2. Redistributions in binary form must reproduce the above copyright
14 # notice, this list of conditions and the following disclaimer in the
15 # documentation and/or other materials provided with the distribution.
17 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 # This script is called by cron to store bits of randomness which are
32 # then used to seed /dev/random on boot.
34 # Originally developed by Doug Barton, dougb@FreeBSD.org
38 # If there is a global system configuration file, suck it in.
40 if [ -r /etc/defaults/rc.conf ]; then
41 . /etc/defaults/rc.conf
42 source_rc_confs 2>/dev/null
43 elif [ -r /etc/rc.conf ]; then
44 . /etc/rc.conf 2>/dev/null
47 [ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0
49 case ${entropy_dir} in
54 entropy_dir=${entropy_dir:-/var/db/entropy}
58 entropy_save_sz=${entropy_save_sz:-4096}
59 entropy_save_num=${entropy_save_num:-8}
61 if [ ! -d "${entropy_dir}" ]; then
62 install -d -o operator -g operator -m 0700 "${entropy_dir}" || {
63 logger -is -t "$0" The entropy directory "${entropy_dir}" does \
64 not exist, and cannot be created. Therefore no entropy can \
68 cd "${entropy_dir}" || {
69 logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \
70 Entropy file rotation is aborted.; exit 1; }
72 for f in saved-entropy.*; do
73 case "${f}" in saved-entropy.\*) continue ;; esac # No files match
74 [ ${f#saved-entropy\.} -gt ${entropy_save_num} ] && unlink ${f}
79 # Scan slots [1..$entropy_save_num), picking an empty slot or the oldest
80 # existing file if no empty slot was available.
82 # 1. Find out the first regular file or empty slot (and its serial number)
85 while [ ${n} -le ${entropy_save_num} ]; do
86 save_file="saved-entropy.${n}"
87 if [ ! -e "${save_file}" -o -f "${save_file}" ]; then
91 "${save_file}" is not a regular file, skipped.
96 # 2. Start from (serial number + 1), and check if the slot is empty
97 # or is an older regular file, update save_file pointer in either
98 # case, and break early if we found an empty slot.
100 if [ -f ${save_file} ]; then
102 while [ ${n} -le ${entropy_save_num} ]; do
103 next_file=saved-entropy.${n}
104 if [ -f "${next_file}" ]; then
105 [ "${next_file}" -ot "${save_file}" ] && \
106 save_file="${next_file}"
107 elif [ ! -e "${next_file}" ]; then
108 save_file="${next_file}"
112 "${next_file}" is not a regular file, skipped.
118 # 3. Check if the pointer we have in hand is really a regular file or
119 # an empty slot, and bail out as that means there is no available slot.
121 if [ -e "${save_file}" -a ! -f "${save_file}" ]; then
123 No available slot in "${entropy_dir}", save entropy is aborted.
127 # Save entropy to the selected slot.
128 chmod 600 "${save_file}" 2>/dev/null || :
129 dd if=/dev/random of="${save_file}" bs=${entropy_save_sz} count=1 2>/dev/null
130 chflags nodump "${save_file}" 2>/dev/null || :
131 fsync "${save_file}" "."