apt update fails on docker ubuntu:20.04 armv7 gpg error

[Claudio Usai]

Running apt update on a ubuntu:20.04 armv7 fresh image fails due to GPG keys, also date seems to be wrong as you can see at the end of the output. I tried to reproduce the issue in using the images ubuntu:16.04 and ubuntu:18.04 but everything went okay so the issue seems related to the image and not to my machine or configuration.

pi@raspberrypi:~ $ docker run -it ubuntu:20.04 bash
root@70511ccc9094:/# apt update
Get:1 http://ports.ubuntu.com/ubuntu-ports focal InRelease [265 kB]
Get:2 http://ports.ubuntu.com/ubuntu-ports focal-updates InRelease [111 kB]
Get:3 http://ports.ubuntu.com/ubuntu-ports focal-backports InRelease [98.3 kB]
Err:1 http://ports.ubuntu.com/ubuntu-ports focal InRelease
  At least one invalid signature was encountered.
Err:2 http://ports.ubuntu.com/ubuntu-ports focal-updates InRelease
  At least one invalid signature was encountered.
Get:4 http://ports.ubuntu.com/ubuntu-ports focal-security InRelease [107 kB]
Err:3 http://ports.ubuntu.com/ubuntu-ports focal-backports InRelease
  At least one invalid signature was encountered.
Err:4 http://ports.ubuntu.com/ubuntu-ports focal-security InRelease
  At least one invalid signature was encountered.
Reading package lists... Done
W: GPG error: http://ports.ubuntu.com/ubuntu-ports focal InRelease: At least one invalid signature was encountered.
E: The repository 'http://ports.ubuntu.com/ubuntu-ports focal InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ports.ubuntu.com/ubuntu-ports focal-updates InRelease: At least one invalid signature was encountered.
E: The repository 'http://ports.ubuntu.com/ubuntu-ports focal-updates InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ports.ubuntu.com/ubuntu-ports focal-backports InRelease: At least one invalid signature was encountered.
E: The repository 'http://ports.ubuntu.com/ubuntu-ports focal-backports InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ports.ubuntu.com/ubuntu-ports focal-security InRelease: At least one invalid signature was encountered.
E: The repository 'http://ports.ubuntu.com/ubuntu-ports focal-security InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
root@70511ccc9094:/# uname -a
Linux 70511ccc9094 5.4.51-v7l+ #1327 SMP Thu Jul 23 11:04:39 BST 2020 armv7l armv7l armv7l GNU/Linux
root@70511ccc9094:/# date
Sat Feb 21 00:54:19 UTC 1970

[Tianon Gravi (tianon)]

This is the same (unfortunate) seccomp issue as https://github.com/tianon/docker-brew-ubuntu-core/issues/183 :(