I experience this same behaviour using lightdm + KDE plasma. I've also tested lightdm + unity which did not trigger this behaviour. This install uses local passwd/shadow/group files. Both tests were after a fresh boot.
harm@harm-XPS-13-9360:~$ lsb_release -a; cat /proc/version
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic
Linux version 4.15.0-29-generic (buildd@lgw01-amd64-057) (gcc version 7.3.0
(Ubuntu 7.3.0-16ubuntu3)) #31-Ubuntu SMP Tue Jul 17 15:39:52 UTC 2018
harm@harm-XPS-13-9360:~$ groups; groups $(whoami)
harm
harm : harm adm dialout cdrom sudo dip plugdev netdev lpadmin sambashare
libvirt docker
harm@harm-XPS-13-9360:~$ id; id $(whoami)
uid=1000(harm) gid=1000(harm) groups=1000(harm)
uid=1000(harm) gid=1000(harm)
groups=1000(harm),4(adm),20(dialout),24(cdrom),27(sudo),30(dip),46(plugdev),109(netdev),113(lpadmin),128(sambashare),135(libvirt),999(docker)
harm@harm-XPS-13-9360:~$ cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.
passwd: compat systemd
group: compat systemd
shadow: compat
gshadow: files
hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
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You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to policykit-1 in Ubuntu.
https://bugs.launchpad.net/bugs/1784964
Title:
Regression due to CVE-2018-1116 (processes not inheriting user's
groups )
Status in policykit-1 package in Ubuntu:
Confirmed
Bug description:
This report is tracking a possible regression caused by the recent
CVE-2018-1116 patches to policykit-1.
On 18.04, since package upgrades on July 23rd, and after the first
reboot since then on Aug 1st, I hit an issue with the primary (sudo,
adm, etc...) user getting Permission Denied trying to do:
tail -f /var/log/syslog
when that file is owned by syslog:adm and is g=r.
I then found that "groups" reports only the $USER and not the entire
list, but "groups $USER" reports all the groups correctly.
The user shell is set to /usr/bin/tmux and /etc/tmux.conf has "set -g
default-shell /bin/bash"
After changing the user's shell back to /bin/bash and logging in on
tty1 the list of groups shows correctly for the /bin/bash process
running on tty1.
I investigated and found that for the affected processes, such as the
tmux process, /proc/$PID/loginuid = 4294967295 whereas the /bin/bash
process on tty1 correctly reported 1000. The same with the respective
gid_map and uid_map.
4294967295 == -1 == 0xFFFFFFFF
The recent CVE patch to policykit has several functions where it does
"uid = -1" which seems to tie in to my findings so far.
I also noticed Ubuntu is still based on version 0.105 which was
released in 2012 - upstream released 0.115 with the CVE patch.
I suspect the backporting has missed something.
The Ubuntu backport patch is:
https://git.launchpad.net/ubuntu/+source/policykit-1/commit/?h=applied/ubuntu
/bionic-devel&id=840c50182f5ab1ba28c1d20cce4c207364852935
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/policykit-1/+bug/1784964/+subscriptions
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