Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Dr. Julius]

Manually downgrading a few hundred packages one-by-one and rebooting each
time was not an option so here's what I did:

1. Replaced the ExecStart line in lightdm.service by:
ExecStart=/usr/bin/strace -fty -P /dev/random -P /dev/urandom -o
/var/log/lightdm/strace.log /usr/sbin/lightdm

2. Using a combination of the strace log and atop, found a suspicious (long
running) access to /dev/random by a child process of gnome-keyring-deamon

3. Uninstalled the gnome-keyring package

4. The issue disappeared...

So AFAICT, it seems that this issue is caused by gnome-keyring making
blocking calls to the RNG.
Possibly here

?

What's weird is that the gnome-keyring package was not affected by the
dist-upgrade, so the behavior may have been triggered by a change in
another package...

Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Fri, 2018-10-12 at 16:13 +0200, Dr. Julius wrote:
> > Ok. It would really help if you could narrow the package involved which
> > actually changed the behavior
> >
> >
> Do you have any idea on how i could do that ?

Try to downgrade packages one by one until the behavior disappear?

Regards
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Dr. Julius]

Le ven. 12 oct. 2018 à 13:06, Yves-Alexis Perez  a
écrit :

>
> Ok. It would really help if you could narrow the package involved which
> actually changed the behavior
>
>
Do you have any idea on how i could do that ?

Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Fri, 2018-10-12 at 06:42 +0200, Dr. Julius wrote:
> 
> The issue still persists using the 4.17 kernel.

Ok. It would really help if you could narrow the package involved which
actually changed the behavior (whether it's lightdm or not), because for now I
wasn't able to reproduce (but since it's the RNG it's not surprising)

Regards,
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Dr. Julius]

Hi,

The issue still persists using the 4.17 kernel.

Regards,
Jules.

Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Tue, 2018-10-09 at 17:53 +0200, Dr. Julius wrote:
> They are all 64bit machines but with different hardware.
> I attached the apt history for one of them.

Can you try reverting to the 4.17 kernel and report back?

Regards,
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Dr. Julius]

They are all 64bit machines but with different hardware.
I attached the apt history for one of them.

Start-Date: 2018-10-09  01:56:33
Commandline: apt dist-upgrade -y
Requested-By:  (1000)
Install: atril:amd64 (1.20.2-1, automatic), linux-headers-4.18.0-2-common:amd64 (4.18.10-1, automatic), libjs-mathjax:amd64 (2.7.4+dfsg-1, automatic), fonts-mathjax:amd64 (2.7.4+dfsg-1, automatic), python3-libdiscid:amd64 (1.0-3+b1, automatic), libaom0:amd64 (1.0.0-3, automatic), libxnvctrl0:amd64 (390.67-1, automatic), libunbound8:amd64 (1.8.0-1, automatic), linux-image-4.18.0-2-amd64:amd64 (4.18.10-1, automatic), libx264-155:amd64 (2:0.155.2917+git0a84d98-2, automatic), atril-common:amd64 (1.20.2-1, automatic), libgail-3-0:amd64 (3.24.1-2, automatic), libatrilview3:amd64 (1.20.2-1, automatic), liblivemedia64:amd64 (2018.09.18-1, automatic), libatrildocument3:amd64 (1.20.2-1, automatic), libqrencode4:amd64 (4.0.2-1, automatic), libcaja-extension1:amd64 (1.20.2-5, automatic), linux-headers-4.18.0-2-amd64:amd64 (4.18.10-1, automatic)
Upgrade: libpython3.7-minimal:amd64 (3.7.0-6, 3.7.1~rc1-1), libreoffice-wiki-publisher:amd64 (1.2.0+LibO6.1.1~rc1-2, 1.2.0+LibO6.1.2-1), vlc-bin:amd64 (3.0.4-1, 3.0.4-2+b1), evince:amd64 (3.30.0-2, 3.30.1-1), firebird3.0-server-core:amd64 (3.0.3.32900.ds4-4, 3.0.4.33055.ds4-2), libqmi-proxy:amd64 (1.20.0-1, 1.20.0-1.1), python-sip:amd64 (4.19.12+dfsg-1, 4.19.13+dfsg-1), libreoffice-math:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libmpx2:amd64 (8.2.0-5, 8.2.0-7), libsoup-gnome2.4-1:amd64 (2.64.0-2, 2.64.1-3), exim4-base:amd64 (4.91-7, 4.91-8), vlc-plugin-video-output:amd64 (3.0.4-1, 3.0.4-2+b1), libreoffice-script-provider-js:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libgpgmepp6:amd64 (1.11.1-1, 1.11.1-1.1), libkrb5-3:amd64 (1.16-2, 1.16.1-1), libavformat58:amd64 (7:4.0.2-1+b1, 7:4.0.2-2+b1), libreoffice-report-builder-bin:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libgssapi-krb5-2:amd64 (1.16-2, 1.16.1-1), xfce4-sensors-plugin:amd64 (1.3.0-1, 1.3.0-2), libpython3.6-minimal:amd64 (3.6.6-4, 3.6.7~rc1-1), libservlet3.1-java:amd64 (8.5.33-1, 8.5.34-1), libisofs6:amd64 (1.4.8-1, 1.5.0-1), exo-utils:amd64 (0.12.2-1, 0.12.2-2), libavfilter7:amd64 (7:4.0.2-1+b1, 7:4.0.2-2+b1), gstreamer1.0-alsa:amd64 (1.14.2-1, 1.14.4-1), libthunarx-3-0:amd64 (1.8.1-1, 1.8.2-1), thunar-data:amd64 (1.8.1-1, 1.8.2-1), php-gd:amd64 (1:7.2+62, 1:7.2+63), libplist3:amd64 (2.0.0-4, 2.0.0-5), libisccfg160:amd64 (1:9.11.4.P1+dfsg-1, 1:9.11.4.P2+dfsg-3), libvte-2.91-0:amd64 (0.52.2-1, 0.54.1-1), libreoffice-sdbc-postgresql:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libxdot4:amd64 (2.40.1-3, 2.40.1-5), libgroupsock8:amd64 (2018.09.06-1, 2018.09.18-1), libqt5test5:amd64 (5.11.1+dfsg-7, 5.11.1+dfsg-9), xserver-xorg-video-amdgpu:amd64 (18.0.1-1+b1, 18.1.0-1), gir1.2-gtk-3.0:amd64 (3.24.0-1, 3.24.1-2), php-xml:amd64 (1:7.2+62, 1:7.2+63), gnupg-utils:amd64 (2.2.10-1, 2.2.10-3), gvfs-backends:amd64 (1.36.2-1, 1.38.0-2), python3.7-venv:amd64 (3.7.0-6, 3.7.1~rc1-1), ffmpeg:amd64 (7:4.0.2-1+b1, 7:4.0.2-2+b1), libsasl2-modules-db:amd64 (2.1.27~101-g0780600+dfsg-3.1, 2.1.27~rc8-1), linux-libc-dev:amd64 (4.18.6-1, 4.18.10-1), xserver-common:amd64 (2:1.20.1-1, 2:1.20.1-4), libevdocument3-4:amd64 (3.30.0-2, 3.30.1-1), gir1.2-secret-1:amd64 (0.18.6-2, 0.18.6-3), gnupg-agent:amd64 (2.2.10-1, 2.2.10-3), gir1.2-soup-2.4:amd64 (2.64.0-2, 2.64.1-3), libapt-inst2.0:amd64 (1.6.4, 1.7.0), gpg-wks-client:amd64 (2.2.10-1, 2.2.10-3), libxapian30:amd64 (1.4.7-2, 1.4.7-4), vlc-plugin-samba:amd64 (3.0.4-1, 3.0.4-2+b1), openssl:amd64 (1.1.1~~pre9-1, 1.1.1-1), libblockdev-swap2:amd64 (2.16-2, 2.20-2), ruby2.5:amd64 (2.5.1-5, 2.5.1-6), php-zip:amd64 (1:7.2+62, 1:7.2+63), qt5-gtk-platformtheme:amd64 (5.11.1+dfsg-7, 5.11.1+dfsg-9), xserver-xorg-core:amd64 (2:1.20.1-1, 2:1.20.1-4), task-french:amd64 (3.45, 3.46), gir1.2-gdkpixbuf-2.0:amd64 (2.38.0+dfsg-2, 2.38.0+dfsg-6), tasksel-data:amd64 (3.45, 3.46), gnupg-l10n:amd64 (2.2.10-1, 2.2.10-3), libgdk-pixbuf2.0-0:amd64 (2.38.0+dfsg-2, 2.38.0+dfsg-6), libqt5help5:amd64 (5.11.1-5, 5.11.1-6), libproxy1v5:amd64 (0.4.15-1, 0.4.15-3), sane-utils:amd64 (1.0.27-1, 1.0.27-3), libpython3.6-dev:amd64 (3.6.6-4, 3.6.7~rc1-1), libegl-mesa0:amd64 (18.1.7-1, 18.1.8-1), libreoffice-gtk2:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libopenal1:amd64 (1:1.18.2-3+b1, 1:1.19.0-2), va-driver-all:amd64 (2.2.0-1, 2.3.0-2), libreoffice-java-common:amd64 (1:6.1.1~rc1-2, 1:6.1.2-1), libswresample3:amd64 (7:4.0.2-1+b1, 7:4.0.2-2+b1), libcpprest2.10:amd64 (2.10.5-1, 2.10.6-1), vlc-plugin-qt:amd64 (3.0.4-1, 3.0.4-2+b1), php-common:amd64 (1:62, 1:63), task-desktop:amd64 (3.45, 3.46), git-man:amd64 (1:2.19.0~rc2-1, 1:2.19.1-1), libtumbler-1-0:amd64 (0.2.1-1, 0.2.3-1), libnumbertext-data:amd64 (1.0-2, 1.0-3), libbrotli1:amd64 (1.0.5-2, 1.0.6-1), libsystemd0:amd64 (239-8, 239-10), libpulsedsp:amd64 (12.2-1, 12.2-2), libgtk-3-common:amd64 (3.24.0-1, 3.24.1-2), libarchive-zip-perl:amd64 (1.63-1, 1.64-1), xsane:amd64 (0.999-5, 0.999-6), apt:amd64 (1.6.4, 1.7.0), libreoffice-base:amd64 

Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Tue, 2018-10-09 at 15:58 +0200, Dr. Julius wrote:
> FYI, I upgraded four other machines yesterday, all running buster/sid with
> xfce4 & lightdm, and they all exhibit the same behavior.
> They all have libbsd at the latest (0.9.1-1) version, so it seems the fix
> in #898088 doesn't apply here...

Can you identify which upgrades where apply so there's a chance to isolate the
faulty package?

Is the hardware identical accross all machines?

Regards,
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Dr. Julius]

FYI, I upgraded four other machines yesterday, all running buster/sid with
xfce4 & lightdm, and they all exhibit the same behavior.
They all have libbsd at the latest (0.9.1-1) version, so it seems the fix
in #898088 doesn't apply here...

Regards,
Jules.

Le mar. 9 oct. 2018 à 13:56, Yves-Alexis Perez  a écrit :

> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA256
>
> On Tue, 2018-10-09 at 08:15 +0200, Yves-Alexis Perez wrote:
> > Inded I'd say it's the same cause (your system doesn't have enough
> entropy).
> > I'll try to find the Xorg bug.
> >
> So it looks to me like #898088 but it's supposedly fixed. Please
> double-check
> on your side.
>
> Regards,
> - --
> Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Tue, 2018-10-09 at 13:56 +0200, Yves-Alexis Perez wrote:
> On Tue, 2018-10-09 at 08:15 +0200, Yves-Alexis Perez wrote:
> > Inded I'd say it's the same cause (your system doesn't have enough
> > entropy).
> > I'll try to find the Xorg bug.
> > 
> So it looks to me like #898088 but it's supposedly fixed. Please double-
> check
> on your side.

Some more investigation:

- - lightdm creates the cookie by itself, using g_random_int() [1]
- - g_random_int() is provided by glib, and calls by itself g_rand_int() with
the global random object provided via get_global_random() [2]
- - if needed, get_global_random() initialize the object via g_rand_new() [3]
- - g_rand_new() seeds using /dev/urandom [4]

Reading from /dev/urandom shouldn't block, so I'm a bit confused at your issue
right now.

[1] 
https://sources.debian.org/src/lightdm/1.26.0-3/src/x-authority.c/?hl=63#L63
[2] https://sources.debian.org/src/glib2.0/2.58.1-2/glib/grand.c/?hl=650#L650
[3] https://sources.debian.org/src/glib2.0/2.58.1-2/glib/grand.c/?hl=621#L622
[4] https://sources.debian.org/src/glib2.0/2.58.1-2/glib/grand.c/?hl=231#L218
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On Tue, 2018-10-09 at 08:15 +0200, Yves-Alexis Perez wrote:
> Inded I'd say it's the same cause (your system doesn't have enough entropy).
> I'll try to find the Xorg bug.
> 
So it looks to me like #898088 but it's supposedly fixed. Please double-check
on your side.

Regards,
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Yves-Alexis Perez]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

control: severity -1 normal

On Tue, 2018-10-09 at 03:04 +0200, Jules Bernable wrote:
> Package: lightdm
> Version: 1.26.0-3
> Severity: grave
> Justification: renders package unusable

This is not a correct severity, the system is not unusable.
> 
> Dear Maintainer,
> 
> On my buster/sid system, LightDM hangs indefinitely on first login until
> entropy is generated via mouse or keyboard input.
> The login process seems to be delayed by the kernel itself, until the
> following
> lines appear in journalctl:
> 
> kernel: random: crng init done
> kernel: random: 7 urandom warning(s) missed due to ratelimiting

To be honest, it's unlikely to be a problem in LightDM itself, I'd say it's
rather in generating the Xorg cookie.
> 
> 
> This issue also seems related to bug #897572

Inded I'd say it's the same cause (your system doesn't have enough entropy).
I'll try to find the Xorg bug.

Regards,
- -- 
Yves-Alexis
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Bug#910631: lightdm: first login hangs waiting for user-generated entropy

[Jules Bernable]

Package: lightdm
Version: 1.26.0-3
Severity: grave
Justification: renders package unusable

Dear Maintainer,

On my buster/sid system, LightDM hangs indefinitely on first login until
entropy is generated via mouse or keyboard input.
The login process seems to be delayed by the kernel itself, until the following
lines appear in journalctl:

kernel: random: crng init done
kernel: random: 7 urandom warning(s) missed due to ratelimiting

Installing the haveged package fixes the issue, as mentioned in the following
thread:
https://unix.stackexchange.com/questions/442698/when-i-log-in-it-hangs-until-
crng-init-done

This issue also seems related to bug #897572



-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.18.0-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), 
LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages lightdm depends on:
ii  adduser3.118
ii  dbus   1.12.10-1
ii  debconf [debconf-2.0]  1.5.69
ii  libaudit1  1:2.8.4-2
ii  libc6  2.27-6
ii  libgcrypt201.8.3-1
ii  libglib2.0-0   2.58.1-2
ii  libpam-systemd 239-10
ii  libpam0g   1.1.8-3.8
ii  libxcb11.13-3
ii  libxdmcp6  1:1.1.2-3
ii  lightdm-gtk-greeter [lightdm-greeter]  2.0.5-1
ii  lsb-base   9.20170808

Versions of packages lightdm recommends:
ii  xserver-xorg  1:7.7+19

Versions of packages lightdm suggests:
pn  accountsservice  
ii  upower   0.99.8-2
pn  xserver-xephyr   

-- Configuration Files:
/etc/lightdm/lightdm.conf changed [not included]

-- debconf information:
* shared/default-x-display-manager: lightdm
  lightdm/daemon_name: /usr/sbin/lightdm