Off by one in Unbound 1.16.0 verbosity setting.

[buggysolid]

Describe the bug
The verbosity option in unbound.conf for controlling the log level information is being incremented plus one of what is defined in the config. .e.g. verbosity: -1 will result in a verbosity: 0 at runtime.

To reproduce
Steps to reproduce the behavior:

1. Follow build from source instructions here https://unbound.docs.nlnetlabs.nl/en/latest/getting-started/installation.html#building-from-source-compiling on Ubuntu 20.04.1 LTS
2. Use the unbound.conf as suggested here https://unbound.docs.nlnetlabs.nl/en/latest/getting-started/configuration.html
3. Append a verbosity: -1 option to the unbound.conf
4. sudo useradd unbound
5. sudo chown -R unbound /usr/local/etc/unbound
6. sudo ldconfig
7. sudo -u unbound unbound-anchor
8. sudo -u unbound unbound-control-setup
9. Enable remote-control in unbound.conf
10. sudo systemctl stop systemd-resolved
11. sudo unbound -v
12. unbound-control status

Expected behavior
Unbound fails to run due to attempting to start with an invalid verbosity level configuration of -1.

System:

• Unbound version: 1.16.0
• OS: Ubuntu 20.04.1 LTS
• unbound -V output:

root@ubuntu-s-1vcpu-1gb-ams3-01:~# unbound -V
Version 1.16.0

Configure line:
Linked libs: mini-event internal (it uses select), OpenSSL 1.1.1f  31 Mar 2020
Linked modules: dns64 respip validator iterator

BSD licensed, see LICENSE in source package for details.
Report bugs to unbound-bugs@nlnetlabs.nl or https://github.com/NLnetLabs/unbound/issues
root@ubuntu-s-1vcpu-1gb-ams3-01:~#

Additional information

You can see that unbound-checkconf correctly identifies the invalid option of verbosity: -1 which if it is invalid should cause Unbound to not start when you attempt to execute Unbound but something is incrementing the verbosity statement at runtime.

root@ubuntu-s-1vcpu-1gb-ams3-01:~# sudo unbound -v
[1655978380] unbound[28024:0] notice: Start of unbound 1.16.0.
root@ubuntu-s-1vcpu-1gb-ams3-01:~# unbound-control status
version: 1.16.0
verbosity: 0
threads: 1
modules: 2 [ validator iterator ]
uptime: 9 seconds
options: reuseport control(ssl)
unbound (pid 28026) is running...
root@ubuntu-s-1vcpu-1gb-ams3-01:~# unbound-checkconf
[1655978446] unbound-checkconf[28028:0] fatal error: verbosity value < 0
root@ubuntu-s-1vcpu-1gb-ams3-01:~#

I haven't dug much more into this issue re: where in the code is causing this, but it is clearly a bug.

[TCY16]

Hi @buggysolid, thanks for the in depth bug report!
You're correct that the verbosity is incremented when unbound is started. This is due to the command you use to start unbound: unbound -v, which increments the config verbosity with 1.
Unbound currently accepts verbosity levels under 0 and treats these as 0. Unless this causes any big errors, we don't see a reason to change this behaviour. I'll see if i can make the manpage a little clearer though!

[buggysolid]

Unbound currently accepts verbosity levels under 0 and treats these as 0. Unless this causes any big errors, we don't see a reason to change this behaviour.

It hasn't caused me any errors but I can think of a case in which someone runs unbound-checkconf before starting Unbound during a provisioning process to validate there config. If that utility borks AFAIK it will set a non-zero exit code.

I'll see if i can make the manpage a little clearer though!

That would be good, I wouldn't exactly describe it as a bug either but it wasn't clear from the documentation.

[TCY16]

Closing this issue in the hope that the clarification in the manpage is enough