1#!/bin/sh 2# 3# SPDX-License-Identifier: BSD-2-Clause 4# 5# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org 6# All rights reserved. 7# 8# Redistribution and use in source and binary forms, with or without 9# modification, are permitted provided that the following conditions 10# are met: 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. 16# 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 27# SUCH DAMAGE. 28# 29 30# This script is called by cron to store bits of randomness which are 31# then used to seed /dev/random on boot. 32 33# Originally developed by Doug Barton, dougb@FreeBSD.org 34 35PATH=/bin:/usr/bin 36 37# If there is a global system configuration file, suck it in. 38# 39if [ -r /etc/defaults/rc.conf ]; then 40 . /etc/defaults/rc.conf 41 source_rc_confs 2>/dev/null 42elif [ -r /etc/rc.conf ]; then 43 . /etc/rc.conf 2>/dev/null 44fi 45 46[ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0 47 48case ${entropy_dir} in 49[Nn][Oo]) 50 exit 0 51 ;; 52*) 53 entropy_dir=${entropy_dir:-/var/db/entropy} 54 ;; 55esac 56 57entropy_save_sz=${entropy_save_sz:-4096} 58entropy_save_num=${entropy_save_num:-8} 59 60if [ ! -d "${entropy_dir}" ]; then 61 install -d -o operator -g operator -m 0700 "${entropy_dir}" || { 62 logger -is -t "$0" The entropy directory "${entropy_dir}" does \ 63 not exist, and cannot be created. Therefore no entropy can \ 64 be saved.; exit 1; } 65fi 66 67cd "${entropy_dir}" || { 68 logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \ 69 Entropy file rotation is aborted.; exit 1; } 70 71for f in saved-entropy.*; do 72 case "${f}" in saved-entropy.\*) continue ;; esac # No files match 73 [ ${f#saved-entropy\.} -gt ${entropy_save_num} ] && unlink ${f} 74done 75 76umask 177 77 78# Scan slots [1..$entropy_save_num), picking an empty slot or the oldest 79# existing file if no empty slot was available. 80# 81# 1. Find out the first regular file or empty slot (and its serial number) 82# 83n=1 84while [ ${n} -le ${entropy_save_num} ]; do 85 save_file="saved-entropy.${n}" 86 if [ ! -e "${save_file}" -o -f "${save_file}" ]; then 87 break 88 else 89 logger -is -t "$0" \ 90 "${save_file}" is not a regular file, skipped. 91 fi 92 n=$(( ${n} + 1 )) 93done 94# 95# 2. Start from (serial number + 1), and check if the slot is empty 96# or is an older regular file, update save_file pointer in either 97# case, and break early if we found an empty slot. 98# 99if [ -f ${save_file} ]; then 100 n=$(( ${n} + 1 )) 101 while [ ${n} -le ${entropy_save_num} ]; do 102 next_file=saved-entropy.${n} 103 if [ -f "${next_file}" ]; then 104 [ "${next_file}" -ot "${save_file}" ] && \ 105 save_file="${next_file}" 106 elif [ ! -e "${next_file}" ]; then 107 save_file="${next_file}" 108 break 109 else 110 logger -is -t "$0" \ 111 "${next_file}" is not a regular file, skipped. 112 fi 113 n=$(( ${n} + 1 )) 114 done 115fi 116# 117# 3. Check if the pointer we have in hand is really a regular file or 118# an empty slot, and bail out as that means there is no available slot. 119# 120if [ -e "${save_file}" -a ! -f "${save_file}" ]; then 121 logger -is -t "$0" \ 122 No available slot in "${entropy_dir}", save entropy is aborted. 123 exit 1 124fi 125 126# Save entropy to the selected slot. 127chmod 600 "${save_file}" 2>/dev/null || : 128dd if=/dev/random of="${save_file}" bs=${entropy_save_sz} count=1 2>/dev/null 129chflags nodump "${save_file}" 2>/dev/null || : 130fsync "${save_file}" "." 131 132exit 0 133