Description:
I've updated twice and both times the unit file at
/usr/lib/systemd/system/tor.service
was overwritten and the User=tor and Group=tor was removed. The tor
daemon then fails to bootstrap and retries until the tor network
receives too many requests and prevents you from making more.

Additional info:
* package version(s)
tor 0.4.4.6-1
* config and/or log files etc.

Relevant output from journalctl -u tor:

Dec 04 07:33:05 host systemd[1]: Starting Anonymizing overlay network for TCP...
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.880 [notice] Tor 0.4.4.6 running on Linux with Libevent 2.1.12-stable, OpenSSL 1.1.1h, Zlib 1.2.11, Liblzma 5.2.5, and Libzstd 1.4.5.
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.880 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.881 [notice] Read configuration file "/etc/tor/torrc".
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.887 [warn] /var/lib/tor is not owned by this user (root, 0) but by tor (43). Perhaps you are running Tor as the wrong user?
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.887 [warn] Failed to parse/validate config: Couldn't access private data directory "/var/lib/tor"
Dec 04 07:33:05 host tor[332]: Dec 04 07:33:05.887 [err] Reading config failed--see warnings above.
Dec 04 07:33:05 host systemd[1]: tor.service: Control process exited, code=exited, status=1/FAILURE
Dec 04 07:33:05 host systemd[1]: tor.service: Failed with result 'exit-code'.
Dec 04 07:33:05 host systemd[1]: Failed to start Anonymizing overlay network for TCP.
Dec 04 07:33:06 host systemd[1]: tor.service: Scheduled restart job, restart counter is at 1.
Dec 04 07:33:06 host systemd[1]: Stopped Anonymizing overlay network for TCP.
Dec 04 07:33:06 host systemd[1]: Starting Anonymizing overlay network for TCP...
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.151 [notice] Tor 0.4.4.6 running on Linux with Libevent 2.1.12-stable, OpenSSL 1.1.1h, Zlib 1.2.11, Liblzma 5.2.5, and Libzstd 1.4.5.
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.152 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.152 [notice] Read configuration file "/etc/tor/torrc".
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.155 [warn] /var/lib/tor is not owned by this user (root, 0) but by tor (43). Perhaps you are running Tor as the wrong user?
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.157 [warn] Failed to parse/validate config: Couldn't access private data directory "/var/lib/tor"
Dec 04 07:33:06 host tor[368]: Dec 04 07:33:06.157 [err] Reading config failed--see warnings above.
Dec 04 07:33:06 host systemd[1]: tor.service: Control process exited, code=exited, status=1/FAILURE
Dec 04 07:33:06 host systemd[1]: tor.service: Failed with result 'exit-code'.
Dec 04 07:33:06 host systemd[1]: Failed to start Anonymizing overlay network for TCP.
Dec 04 07:33:06 host systemd[1]: tor.service: Scheduled restart job, restart counter is at 2.
Dec 04 07:33:06 host systemd[1]: Stopped Anonymizing overlay network for TCP.
Dec 04 07:33:06 host systemd[1]: Starting Anonymizing overlay network for TCP...

...

Dec 04 07:33:06 host systemd[1]: Starting Anonymizing overlay network for TCP...
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.000 [notice] Tor 0.4.4.6 running on Linux with Libevent 2.1.12-stable, OpenSSL 1.1.1h, Zlib 1.2.11, Liblzma 5.2.5, and Libzstd 1.4.5.
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.004 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.004 [notice] Read configuration file "/etc/tor/torrc".
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.008 [warn] /var/lib/tor is not owned by this user (root, 0) but by tor (43). Perhaps you are running Tor as the wrong user?
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.010 [warn] Failed to parse/validate config: Couldn't access private data directory "/var/lib/tor"
Dec 04 07:33:07 host tor[650]: Dec 04 07:33:07.010 [err] Reading config failed--see warnings above.
Dec 04 07:33:07 host systemd[1]: tor.service: Control process exited, code=exited, status=1/FAILURE
Dec 04 07:33:07 host systemd[1]: tor.service: Failed with result 'exit-code'.
Dec 04 07:33:07 host systemd[1]: Failed to start Anonymizing overlay network for TCP.
Dec 04 07:33:07 host systemd[1]: tor.service: Scheduled restart job, restart counter is at 5.
Dec 04 07:33:07 host systemd[1]: Stopped Anonymizing overlay network for TCP.
Dec 04 07:33:07 host systemd[1]: tor.service: Start request repeated too quickly.
Dec 04 07:33:07 host systemd[1]: tor.service: Failed with result 'exit-code'.
Dec 04 07:33:07 host systemd[1]: Failed to start Anonymizing overlay network for TCP.


I fixed the issue by simply adding the parameters back. Here is the
corrected unit file:

# tor.service -- this systemd configuration file for Tor sets up a
# relatively conservative, hardened Tor service. You may need to
# edit it if you are making changes to your Tor configuration that it
# does not allow. Package maintainers: this should be a starting point
# for your tor.service; it is not the last point.

[Unit]
Description=Anonymizing overlay network for TCP
After=syslog.target network.target nss-lookup.target

[Service]
Type=notify
NotifyAccess=all
ExecStartPre=/usr/bin/tor -f /etc/tor/torrc --verify-config
ExecStart=/usr/bin/tor -f /etc/tor/torrc
ExecReload=/bin/kill -HUP ${MAINPID}
KillSignal=SIGINT
TimeoutSec=60
Restart=on-failure
WatchdogSec=1m
LimitNOFILE=32768

# Hardening
User=tor
Group=tor
PrivateTmp=yes
PrivateDevices=yes
ProtectHome=yes
ProtectSystem=full
ReadOnlyDirectories=/
ReadWriteDirectories=-/var/lib/tor
ReadWriteDirectories=-/var/log/tor
NoNewPrivileges=yes
CapabilityBoundingSet=CAP_SETUID CAP_SETGID CAP_NET_BIND_SERVICE CAP_DAC_READ_SEARCH

[Install]
WantedBy=multi-user.target


Steps to reproduce:
updating or removing the User=tor and Group=tor lines from the unit file

Side note:
I don't know how to check which version of the package originally made
the change or if it was this file that was changed and not something
else.