Files
container/Sources
Maxime Grenu 1951816427 fix(dns): validate nameserver addresses are valid IP addresses (#534)
## What

Add a `DNS.validate()` method that verifies all nameserver entries are
valid IPv4 or IPv6 addresses. The method is called from
`Vminitd.configureDNS()` before applying the configuration.

## Why

Closes #467. Currently, any arbitrary string can be passed as a
nameserver in `DNSConfiguration`, which silently results in an invalid
`/etc/resolv.conf` inside the container. Hostname strings like
`dns.example.com` would be written to resolv.conf but would not work as
nameservers.

## How

- Added `DNS.validate() throws` method in `DNSConfiguration.swift` that
iterates over all nameservers and attempts to parse each as either an
`IPv4Address` or `IPv6Address` (using the existing parsers in
`ContainerizationExtras`)
- Added `import ContainerizationExtras` to `DNSConfiguration.swift` (the
`Containerization` target already depends on `ContainerizationExtras`)
- Called `config.validate()` at the start of `Vminitd.configureDNS()` so
validation happens before any GRPC call

## Testing

Added 6 new unit tests in `DNSTests.swift`:
- ✅ Valid IPv4 nameservers accepted
- ✅ Valid IPv6 nameservers accepted  
- ✅ Mixed IPv4/IPv6 nameservers accepted
- ✅ Empty nameserver list accepted
- ❌ Hostname rejected
- ❌ Invalid address rejected

## Checklist

- [x] Tests added
- [x] No breaking changes to existing API (validate() is a new method,
existing init is unchanged)
- [x] Follows existing patterns (uses ContainerizationExtras IP address
types, ContainerizationError for errors)

Signed-off-by: Maxime Grenu <maxime.grenu@gmail.com>
2026-03-25 02:40:07 -07:00
..