forked from public/airgap
71 lines
1.6 KiB
Bash
Executable File
71 lines
1.6 KiB
Bash
Executable File
#! /bin/sh
|
|
#
|
|
# Preserve the random seed between reboots. See urandom(4).
|
|
#
|
|
|
|
# Quietly do nothing if /dev/urandom does not exist
|
|
[ -c /dev/urandom ] || exit 0
|
|
|
|
URANDOM_SEED="/var/lib/random-seed"
|
|
|
|
# shellcheck source=/dev/null
|
|
[ -r "/etc/default/urandom" ] && . "/etc/default/urandom"
|
|
|
|
if pool_bits=$(cat /proc/sys/kernel/random/poolsize 2> /dev/null); then
|
|
pool_size=$((pool_bits/8))
|
|
else
|
|
pool_size=512
|
|
fi
|
|
|
|
init_rng() {
|
|
[ -f "$URANDOM_SEED" ] || return 0
|
|
printf 'Initializing random number generator: '
|
|
dd if="$URANDOM_SEED" bs="$pool_size" of=/dev/urandom count=1 2> /dev/null
|
|
status=$?
|
|
if [ "$status" -eq 0 ]; then
|
|
echo "OK"
|
|
else
|
|
echo "FAIL"
|
|
fi
|
|
return "$status"
|
|
}
|
|
|
|
save_random_seed() {
|
|
printf 'Saving random seed: '
|
|
status=1
|
|
if touch "$URANDOM_SEED.new" 2> /dev/null; then
|
|
old_umask=$(umask)
|
|
umask 077
|
|
dd if=/dev/urandom of="$URANDOM_SEED.tmp" bs="$pool_size" count=1 2> /dev/null
|
|
cat "$URANDOM_SEED" "$URANDOM_SEED.tmp" 2>/dev/null \
|
|
| sha256sum \
|
|
| cut -d ' ' -f 1 > "$URANDOM_SEED.new" && \
|
|
mv "$URANDOM_SEED.new" "$URANDOM_SEED" && status=0
|
|
rm -f "$URANDOM_SEED.tmp"
|
|
umask "$old_umask"
|
|
if [ "$status" -eq 0 ]; then
|
|
echo "OK"
|
|
else
|
|
echo "FAIL"
|
|
fi
|
|
|
|
else
|
|
echo "SKIP (read-only file system detected)"
|
|
fi
|
|
return "$status"
|
|
}
|
|
|
|
case "$1" in
|
|
start|restart|reload)
|
|
# Carry a random seed from start-up to start-up
|
|
# Load and then save the whole entropy pool
|
|
init_rng && save_random_seed;;
|
|
stop)
|
|
# Carry a random seed from shut-down to start-up
|
|
# Save the whole entropy pool
|
|
save_random_seed;;
|
|
*)
|
|
echo "Usage: $0 {start|stop|restart|reload}"
|
|
exit 1
|
|
esac
|