hostcfgd: Validate RADIUS server fields before creating PAM files

[ashutosh-agrawal]

What I did

Added validation for the RADIUS server address and authentication port before using the entry to generate RADIUS configuration.

hostcfgd uses these fields in the filename for each server’s PAM configuration. It previously assumed that both values were valid. A bad address or port could result in an unexpected filename or an invalid RADIUS configuration.

How I did it

• Validate the server address with ipaddress.ip_address().
• Require the authentication port to be between 1 and 65535.
• Skip invalid server entries and log the address and port without logging the configured passkey.
• Leave valid IPv4 and IPv6 server entries unchanged.

How I verified it

Added coverage for valid IPv4 and IPv6 addresses, malformed addresses, non-numeric ports, and ports outside the valid range.

python3 -m pytest tests/hostcfgd/hostcfgd_radius_test.py -q

Result: 8 passed.

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