[BED-6605] Allow negative serials for x509 certificate verification

[definitelynotagoblin]

Prior to Go 1.23, negative serial numbers were allowed in certificates. Some clients are reporting errors using Azurehound in their proxy environments under their current configurations. We can relax our need for perfectly compliant certificates here to accommodate.

Summary by CodeRabbit

• Chores
  • Added build-time configuration for enhanced certificate handling on non-Windows platforms.

[coderabbitai]

Walkthrough

A //go:debug x509negativeserial=1 directive is added to main.go following the existing non-Windows build tags. This is a build-time debug flag directive with no impact on runtime behavior or code logic.

Changes

Cohort / File(s)	Summary
Build Debug Directive main.go	Added //go:debug x509negativeserial=1 directive after existing //go:build !windows and +build !windows lines

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

• Minimal change: single debug directive addition with no functional impact
• No code logic modifications or runtime behavior changes
• No testing implications

Poem

🐰 A whisker-twitch of build flags bright,
No logic changed, just debug light!
The rabbit hops through tagged lines clean,
Where x509 secrets now are seen.
Compile with care, the directive's small—
But builds stronger, one and all! 🔐

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly references the main change: adding support for negative x509 certificate serials via a go:debug directive.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch anemeth/x509-negative-serials

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

main.go (1)

21-22: The x509negativeserial directive is valid and correctly implemented.

This directive enables Go 1.23's pre-1.23 behavior for parsing certificates with negative serial numbers, addressing the breaking change in crypto/x509.ParseCertificate. The //go:debug pragma syntax shown is correct and documented.

Adding an inline comment explaining the directive's purpose would improve maintainability:

 //go:build !windows
 // +build !windows
 
+// Allow negative serial numbers in x509 certificates for proxy compatibility.
 //go:debug x509negativeserial=1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 267ed0d and dab7635.

📒 Files selected for processing (1)

• main.go (1 hunks)