mirror of
git://git.openwrt.org/openwrt/openwrt.git
synced 2025-10-31 05:54:26 -04:00
3946a55291
This commit:
1) seed /dev/urandom with the saved seeds as early as possible
(see /lib/preinit/81_urandom_seed)
2) save a seed at /etc/urandom.seed if it doesn't exists
3) save a new seed each boot at "system.@system[0].urandom_seed"
(see /etc/init.d/urandom_seed)
We use getrandom() so we are sure /dev/urandom pool is initialized
Seed size is 512 bytes (ie /proc/sys/kernel/random/poolsize / 8)
it's the same size as in ubuntu 14.04 and all systemd systems
Seeding /dev/urandom doesn't change entropy estimation, so we still have
"random: ubus urandom read with 4 bits of entropy available"
messages in the logs, but we can now ignore them if
after "urandom-seed: Seeding with ..." message
Saving a new seed on each boot is disabled by default to avoid too much
writes without user consent
v2: log preinit messages to /dev/kmsg
v3: use non generic function name for logging, as /lib/preinit/ files
are all sourced together in /etc/preinit
v4: after a lot of discussion on the ML, use a uci config param
v5: config param is now the path of the seed
Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>
Acked-by: Jo-Philipp Wich <jo@mein.io>
25 lines
703 B
Bash
25 lines
703 B
Bash
#!/bin/sh
|
|
|
|
log_urandom_seed() {
|
|
echo "urandom-seed: $1" > /dev/kmsg
|
|
}
|
|
|
|
_do_urandom_seed() {
|
|
[ -f "$1" ] || { log_urandom_seed "Seed file not found ($1)"; return; }
|
|
[ -O "$1" -a -G "$1" -a ! -x "$1" ] || { log_urandom_seed "Wrong owner / permissions for $1"; return; }
|
|
|
|
log_urandom_seed "Seeding with $1"
|
|
cat "$1" > /dev/urandom
|
|
}
|
|
|
|
do_urandom_seed() {
|
|
[ -c /dev/urandom ] || { log_urandom_seed "Something is wrong with /dev/urandom"; return; }
|
|
|
|
_do_urandom_seed "/etc/urandom.seed"
|
|
|
|
SEED="$(uci -q get system.@system[0].urandom_seed)"
|
|
[ "${SEED:0:1}" == "/" -a "$SEED" != "/etc/urandom.seed" ] && _do_urandom_seed "$SEED"
|
|
}
|
|
|
|
boot_hook_add preinit_main do_urandom_seed
|