Re: Linux messages full of `random: get_random_u32 called from`

From: Pavel Machek
Date: Sun Apr 29 2018 - 17:19:14 EST


On Sun 2018-04-29 13:20:33, Sultan Alsawaf wrote:
> On Sun, Apr 29, 2018 at 08:41:01PM +0200, Pavel Machek wrote:
> > Umm. No. https://www.youtube.com/watch?v=xneBjc8z0DE
>
> Okay, but /dev/urandom isn't a solution to this problem because it isn't usable
> until crng init is complete, so it suffers from the same init lag as
> /dev/random.

So -- I'm pretty sure systemd and friends should be using
/dev/urandom. Maybe gpg wants to use /dev/random. _Maybe_.

[ 2.948192] random: systemd: uninitialized urandom read (16 bytes
read)
[ 2.953526] systemd[1]: systemd 215 running in system mode. (+PAM
+AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ
-SECCOMP -APPARMOR)
[ 2.980278] systemd[1]: Detected architecture 'x86'.
[ 3.115072] usb 5-2: New USB device found, idVendor=0483,
idProduct=2016, bcdDevice= 0.01
[ 3.119633] usb 5-2: New USB device strings: Mfr=1, Product=2,
SerialNumber=0
[ 3.124147] usb 5-2: Product: Biometric Coprocessor
[ 3.128621] usb 5-2: Manufacturer: STMicroelectronics
[ 3.163839] systemd[1]: Failed to insert module 'ipv6'
[ 3.181266] systemd[1]: Set hostname to <amd>.
[ 3.267243] random: systemd-sysv-ge: uninitialized urandom read (16
bytes read)
[ 3.669590] random: systemd-sysv-ge: uninitialized urandom read (16
bytes read)
[ 3.696242] random: systemd: uninitialized urandom read (16 bytes
read)
[ 3.700066] random: systemd: uninitialized urandom read (16 bytes
read)
[ 3.703716] random: systemd: uninitialized urandom read (16 bytes
read)

Anyway, urandom should need to be seeded once, and then provide random
data forever... which is not impression I get from the dmesg output
above. Boot clearly proceeds... somehow. So now I'm confused.

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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