19d3b54ecd
Before this commit, the save-entropy script rotates entropy files like logs. This involves creating a new file that holds the entropy and renaming of all existing entropy files. However, the entropy data do not really need to be kept in a particular order, and replacing the oldest file is sufficient. This commit replaces the rotation with a scan in the [1..entropy_save_num] space that finds the first empty slot, or the slot of the oldest file, and writes entropy into that slot. This also fixes an issue that prevents save-entropy from saving any entropy when there is one non-regular file in any slot as a side effect. Based on an earlier patch from peterj@. PR: 134225 Reported by: peterj Reviewed by: csprng (cem, markm) MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D22612
134 lines
4.2 KiB
Bash
Executable File
134 lines
4.2 KiB
Bash
Executable File
#!/bin/sh
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#
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# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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#
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# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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# SUCH DAMAGE.
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#
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# $FreeBSD$
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# This script is called by cron to store bits of randomness which are
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# then used to seed /dev/random on boot.
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# Originally developed by Doug Barton, dougb@FreeBSD.org
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PATH=/bin:/usr/bin
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# If there is a global system configuration file, suck it in.
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#
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if [ -r /etc/defaults/rc.conf ]; then
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. /etc/defaults/rc.conf
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source_rc_confs 2>/dev/null
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elif [ -r /etc/rc.conf ]; then
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. /etc/rc.conf 2>/dev/null
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fi
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[ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0
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case ${entropy_dir} in
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[Nn][Oo])
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exit 0
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;;
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*)
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entropy_dir=${entropy_dir:-/var/db/entropy}
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;;
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esac
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entropy_save_sz=${entropy_save_sz:-4096}
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entropy_save_num=${entropy_save_num:-8}
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if [ ! -d "${entropy_dir}" ]; then
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install -d -o operator -g operator -m 0700 "${entropy_dir}" || {
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logger -is -t "$0" The entropy directory "${entropy_dir}" does \
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not exist, and cannot be created. Therefore no entropy can \
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be saved.; exit 1; }
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fi
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cd "${entropy_dir}" || {
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logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \
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Entropy file rotation is aborted.; exit 1; }
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for f in saved-entropy.*; do
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case "${f}" in saved-entropy.\*) continue ;; esac # No files match
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[ ${f#saved-entropy\.} -gt ${entropy_save_num} ] && unlink ${f}
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done
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umask 177
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# Scan slots [1..$entropy_save_num), picking an empty slot or the oldest
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# existing file if no empty slot was available.
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#
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# 1. Find out the first regular file or empty slot (and its serial number)
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#
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n=1
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while [ ${n} -le ${entropy_save_num} ]; do
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save_file="saved-entropy.${n}"
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if [ ! -e "${save_file}" -o -f "${save_file}" ]; then
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break
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else
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logger -is -t "$0" \
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"${save_file}" is not a regular file, skipped.
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fi
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n=$(( ${n} + 1 ))
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done
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#
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# 2. Start from (serial number + 1), and check if the slot is empty
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# or is an older regular file, update save_file pointer in either
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# case, and break early if we found an empty slot.
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#
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if [ -f ${save_file} ]; then
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n=$(( ${n} + 1 ))
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while [ ${n} -le ${entropy_save_num} ]; do
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next_file=saved-entropy.${n}
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if [ -f "${next_file}" ]; then
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[ "${next_file}" -ot "${save_file}" ] && \
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save_file="${next_file}"
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elif [ ! -e "${next_file}" ]; then
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save_file="${next_file}"
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break
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else
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logger -is -t "$0" \
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"${next_file}" is not a regular file, skipped.
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fi
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n=$(( ${n} + 1 ))
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done
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fi
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#
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# 3. Check if the pointer we have in hand is really a regular file or
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# an empty slot, and bail out as that means there is no available slot.
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#
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if [ -e "${save_file}" -a ! -f "${save_file}" ]; then
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logger -is -t "$0" \
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No available slot in "${entropy_dir}", save entropy is aborted.
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exit 1
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fi
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# Save entropy to the selected slot.
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chmod 600 "${save_file}" 2>/dev/null || :
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dd if=/dev/random of="${save_file}" bs=${entropy_save_sz} count=1 2>/dev/null
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chflags nodump "${save_file}" 2>/dev/null || :
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fsync "${save_file}" "."
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exit 0
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