Domain set objects over 1024 bytes crash Dnsmasq

[filippocarletti]

If the total size of domain names exceeds 1024 bytes Dnsmasq refuses to start (syntax error).

Steps to reproduce

• Create a Domain set object with many long names
• Apply config

Expected behavior

Dnsmasq running

Actual behavior

Dnsmasq stopped, name resolution broken

See also

We found and fixed the problem in NethServer 7:
NethServer/nethserver-squid@931f391

[gsanchietti]

Fix applied for NS7 is not applicable in this scenario, because rules can handle only one set.

I suggest to just add a validator inside the UI.

[filippocarletti]

We need to split the single domain set into multiple sets and create a rule for every set.

[gsanchietti]

We need to split the single domain set into multiple sets and create a rule for every set.

Splitting the rules means managing one rule from the UI that translates to multiple rules inside UCI: this is not possible by design.
Nor the object library nor the UI support managing multiple rules from a single entry.

[andre8244]

Testing version

23.05.5-ns.1.3.0-31-g6a6ff7e

Test case

Verify the bug is no longer reproducible

[andre8244]

After more thorough testing, it appears 1024 is too high as a maximum value, since additional characters will be included in /var/etc/dnsmasq.conf. Gonna submit a PR setting the maximum to 960 for safety.

[andre8244]

Updated testing version: 23.05.5-ns.1.3.0-31-g6a6ff7e

[francio87]

Confirm fixed ✅