Codex independent review identified a critical security issue: when cluster
validation fails, the previous fix fell back to permissive mode (allowing
ALL nodes), making the proxy a potential SSRF/network scanner for any
container that could reach the socket.
NEW BEHAVIOR:
When cluster validation is unavailable (IPC blocked), fall back to
localhost-only validation instead of permissive mode. This maintains
security while still allowing self-monitoring.
Implementation:
- Added validateAsLocalhost() method to nodeValidator
- Calls discoverLocalHostAddresses() to get local IPs/hostnames
- Only allows requests matching the local host
- Blocks requests to other cluster members or arbitrary hosts
Test results on delly (clustered node with IPC blocked):
- Request to 192.168.0.5 (self): ALLOWED, temps fetched
- Request to 192.168.0.134 (cluster peer): BLOCKED with node_not_localhost
- No more "allowing all nodes" security regression
Related to #571 - addresses Codex security audit feedback
This prevents the proxy from being abused as a network scanner while
still solving the original temperature monitoring issue.
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