openwrtv3/package/base-files/files/lib/preinit
Etienne CHAMPETIER 3946a55291 base-files: seed /dev/urandom
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>
2016-06-30 22:48:39 +02:00
..
02_default_set_state base-files: preinit: Fixed sourcing of diag.sh in /etc/preinit. This caused errors due to frequent use of /proc/cpuinfo to determine board name to pick led layout. Now diag.sh (which only defines set_state and any helper functions) is sourced by a proper preinit function during preinit_main, which is after /proc has been brought up, unlike in /etc/preinit 2011-07-07 02:52:02 +00:00
10_indicate_failsafe base-files: Allow to disable failsafe mode 2016-04-19 10:07:35 +02:00
10_indicate_preinit branding: add LEDE branding 2016-03-24 22:40:13 +01:00
10_sysinfo base-files: fix error message during boot 2016-04-11 11:58:57 +02:00
30_failsafe_wait base-files: Allow to disable failsafe mode 2016-04-19 10:07:35 +02:00
40_run_failsafe_hook base-files: Allow to disable failsafe mode 2016-04-19 10:07:35 +02:00
50_indicate_regular_preinit add "preinit_regular" diag.sh set_state argument 2014-12-15 10:37:00 +00:00
70_initramfs_test base-files: fix whitespaces 2013-12-09 11:30:14 +00:00
80_mount_root base-files: keep sysupgrade.tgz until /etc/init.d/done has been called 2015-03-22 15:11:20 +00:00
81_urandom_seed base-files: seed /dev/urandom 2016-06-30 22:48:39 +02:00
99_10_failsafe_login base-files: fix some failsafe issues 2016-05-23 11:03:25 +02:00
99_10_run_init base-files: fix whitespaces 2013-12-09 11:30:14 +00:00