#5028 DHCP client options defined as integers are quoted and make DHCP server unable to start

[bajobongo]

Client options defined as (arrays of) integers are quoted for hosts (if hosts are defined in separated files), i.e.
dhcpd.conf contains:

...
option option-246 code 246 = string;
option tftp-server-address code 150 = array of ip-address;
option option-131 code 131 = { ip-address , unsigned integer 16 , unsigned integer 8 };
...
include "/etc/dhcp/host1.conf";
include "/etc/dhcp/host2.conf";
include "/etc/dhcp/host3.conf";

Example of host3.conf is:

host host_3 {
 option option-131 "237.7.7.7 22222 10"; # <-- QUOTED (INCORRECT!)
 option option-246 "some string";
 fixed-address 192.168.1.103;
 hardware ethernet xx:xx:xx:xx:xx;
}

Problem observed on Ubuntu 16.04 (x64) and isc-dhcp

[bajobongo]

I've checked and the fact that host is defined in separate file doesn't matter.

[Jamie Cameron]

Have you tried to upgrading to Webmin 1.860? It should fix this.

[bajobongo]

Yes, and it didn't fix.

[Robert Falkenberg]

The issue still happens with version 1.953 on Ubuntu 16.04.4 with ISC DHCPd version 4.3.3

I am wondering about the existence of this bug, since it should have been fixed already in [#4664] from 2015 and in [#4777] later in 2016.

Steps to reproduce:

I manually define the following options in dhcpd.conf by directly editing the file:

option rfc3442-classless-static-routes code 121 = array of integer 8;
option ms-classless-static-routes code 249 = array of integer 8;

and later

                option rfc3442-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;
                option ms-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;

(values are changed for this bug report)
Subsequently, after viewing those options in Webmin under "Servers > DHCP Server > [a network range] > Edit Client Options", I can see those custom options and their arguments.
However, after pressing "Save", these arguments are enclosed by parentheses in the config file, as follows:

                option rfc3442-classless-static-routes "19 , 172 , 27 , 0 , 10 , 20 , 30 , 40";
                option ms-classless-static-routes "19 , 172 , 27 , 0 , 10 , 20 , 30 , 40";

Finally, the DHCP service fails to start due to incorrect syntax: Number expected.

Note: Changing "integer" to "unsigned integer" makes no difference.

[Jamie Cameron]

Just re-tested this with Webmin 1.953, and was unable to reproduce the problem. Unless you're editing a value that is already quoted in dhcpd.conf, in which case Webmin will try to preserve it.

[Robert Falkenberg]

Hi,
thanks for the reply!

I'm on exactly the same version: 1.953. (Ubuntu Linux 16.04.4, Linux 4.4.0-174-generic on x86_64)

Did you check the newly written file "dhcpd.conf" after viewing the "Edit Client Options" and after pressing "Save"? (without changing any field)

Whether before of after pressing "save" - the textfield in Webmin's GUI always shows the values without quotation. However, the argument in the output file will be quoted after the first press of "save".

[Robert Falkenberg]

Just made some more tests and found something:

In my example, the part with

option rfc3442-classless-static-routes code 121 = array of integer 8;
option ms-classless-static-routes code 249 = array of integer 8;

ist located in global scope within dhcpd.conf, while the second part is nested inside subscopes as follows:

shared-network NAME {
    ...
    subnet x.y.z.zz netmask 255.255.255.0 {
                ...
                option rfc3442-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;
                option ms-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;
                ...
    }
}

If I move those routes up into the global scope, the output is correct and not quoted by the Webmin.

Is this behaviour intended?

[Robert Falkenberg]

Hello,

as I said in my last post, if I move the following options

shared-network NAME {
    ...
    subnet x.y.z.zz netmask 255.255.255.0 {
                ...
                option rfc3442-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;
                option ms-classless-static-routes 19 , 172 , 27 , 0 , 10 , 20 , 30 , 40;
                ...
    }
}

into the global scope, Webmin handles the arguments correctly and performs no unintended quoting.

However, since my dhcpd.conf covers multiple subnets, I cannot simply define the static route in the global scope for all networks.

I also tried the opposite way and moved the part with

option rfc3442-classless-static-routes code 121 = array of integer 8;
option ms-classless-static-routes code 249 = array of integer 8;

into the subnet definition. While this is also fine for Webmin (no unintended quoting), the ISC DHCP fails to start and complains about

Aug 18 15:48:57 corerouter-ng dhcpd[31562]: /etc/dhcp/dhcpd.conf line 50: option definitions may not be scoped.
Aug 18 15:48:57 corerouter-ng dhcpd[31562]: option rfc3442-classless-static-routes code
...
Aug 18 15:48:57 corerouter-ng dhcpd[31562]: /etc/dhcp/dhcpd.conf line 52: unknown option dhcp.rfc3442-classless-static-routes
...
Aug 18 15:48:57 corerouter-ng dhcpd[31562]: Configuration file errors encountered -- exiting

So this is not an option.
Is there any possibility to teach Webmin to inherit these two global options to the nested scope of "shared-network" and "subnet" in order to provide a proper (unquoted) treatment of the numeric arguments?

Best Regards
Robert

[Jamie Cameron]

That's surprising, because Webmin shouldn't treat option definitions any differently regardless of which scope their they are in.

Would it be possible to get a copy of your entire dhcpd.conf file? You can email it to jcameron@webmin.com

[Jamie Cameron]

Thanks for the config - I think I see cause of this bug, and have checked in a fix at https://github.com/webmin/webmin/commit/677948bd9a20a316cc0abe456e147fb2719eb1eb