lib: add warning when binding inspector to public IP

[DemianParkhomenko]

Add isLoopback function to internal/net module to check if a given host is a loopback address.

Add a warning when binding the inspector to a public IP with an open port, as it allows external hosts to connect to the inspector.

Fixes: #23444
Refs: https://nodejs.org/api/cli.html#--inspecthostport IANA IPv4 Special-Purpose Address Registry
IANA IPv6 Special-Purpose Address Registry
Special-Use Domain Names

[nodejs-github-bot]

Review requested:

• @nodejs/net

[LiviaMedeiros]

Should we really warn for these? IMHO binding to IP in private subnet is usually fine.

[DemianParkhomenko]

The condition when to warn was discussed in #23756 (review) and #23756 (comment). So, I think we should warn for all non-loopback addresses. WDYT?

[Imran-imtiaz48]

Overall Comments:
Great work on implementing the inspector-related logic and improving security awareness for users when binding the inspector to a public IP. The added validation and warning mechanism demonstrates a thoughtful approach to ensuring safety and guiding users toward secure practices.
Specific Suggestions:

1. Security Warning:
   o The warning message regarding binding the inspector to a public IP is excellent. However, consider rephrasing the message for conciseness and clarity, such as:
   o 'Binding the inspector to a public IP is insecure. It allows external hosts to connect to the inspector and potentially perform remote code execution. Refer to the documentation: https://nodejs.org/api/cli.html#--inspecthostport'
   This reduces redundancy and ensures the warning remains impactful.
2. Documentation URL:
   o Ensure the provided documentation URL is current and accurate. You might want to verify if the URL points to the specific section for --inspect-host/port in the Node.js CLI docs.
3. Validation Enhancements:
   o The isLoopback check is a great addition. To further improve, consider logging the specific host being checked in case debugging becomes necessary for unusual cases.
4. Error Handling:
   o Ensure that the ERR_INSPECTOR_NOT_AVAILABLE exception is sufficiently descriptive for developers to understand why the inspector might not be available. Providing actionable guidance (e.g., checking the Node.js version or enabling certain build flags) could enhance user experience.
5. Coding Style:
   o The logic is clear and concise. Just ensure adherence to consistent indentation (e.g., within the if blocks) for readability.
   Minor Suggestions:
   • Add inline comments to the isLoopback and validateInt32 checks for better maintainability.
   • Consider unit testing or including examples in the documentation on how to use the inspectorOpen function securely.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.24%. Comparing base (03dcd70) to head (1f7c20a).
Report is 946 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #55736      +/-   ##
==========================================
+ Coverage   88.40%   90.24%   +1.83%     
==========================================
  Files         654      629      -25     
  Lines      187655   184875    -2780     
  Branches    36109    36213     +104     
==========================================
+ Hits       165905   166837     +932     
+ Misses      14990    11011    -3979     
- Partials     6760     7027     +267     

Files with missing lines	Coverage Δ
lib/inspector.js	96.91% <100.00%> (+0.63%)	⬆️
lib/internal/net.js	100.00% <100.00%> (ø)

... and 327 files with indirect coverage changes

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[DemianParkhomenko]

@anonrig @LiviaMedeiros I've made the requested changes. Could you make a review?

[LiviaMedeiros]

I still think that warning on binding within local network is redundant, but i guess it makes sense for people behind ISP's NAT or in other potentially hostile private networks. We can adjust this later if there will be complains.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/65819/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/65827/