sec(config): harden validatePathChars and ulimit expression resolution

[Tei1988]

Harden path/config control character validation and enable dynamic expression resolution for ulimit configurations.

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PR created automatically by Jules for task 2396359926746966550 started by @Tei1988

Summary by CodeRabbit

• Bug Fixes

  • Improved path validation by rejecting invalid UTF-8 and Unicode control characters.
  • Improved handling of ulimit expressions, including environment-based values and host-context-dependent paths.
  • Added safe failure when ulimit expressions reference missing environment variables.

• Tests

  • Added coverage for path validation and ulimit expression resolution scenarios.

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ℹ️ Recent review info

⚙️ Run configuration

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Run ID: 53822f70-1364-498f-a02d-7678eec21a62

📥 Commits

Reviewing files that changed from the base of the PR and between 3244111 and 34167bd.

📒 Files selected for processing (1)

• internal/config/feature_security_control_chars_ulimit_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• internal/config/feature_security_control_chars_ulimit_test.go

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📝 Walkthrough

Walkthrough

The change extends path validation to reject malformed UTF-8 and Unicode control characters. Ulimit resolution now supports expressions, host-context paths, and environment-backed values with resolver error handling. Tests cover both validation areas.

Changes

Configuration validation and resolution

Layer / File(s)	Summary
Unicode-aware path validation internal/config/path.go, internal/config/feature_security_control_chars_ulimit_test.go	validatePathChars now rejects invalid UTF-8 sequences and Unicode control characters while retaining positional error reporting. Tests cover invalid and valid paths.
Expression-aware ulimit resolution internal/config/resolver.go, internal/config/resolver_helpers.go, internal/config/feature_security_control_chars_ulimit_test.go, internal/config/ulimit_test.go	Ulimit values are conditionally resolved through an ExpressionResolver before validation and parsing. Tests cover resolved values, missing variables, existing resolution paths, and validation errors.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: 🔵 Low · up to 34167

The change is not expected to alter runtime behavior, but an added test still violates the project’s naming/static-analysis rule and may keep required checks from passing; merge requires owner awareness and follow-up.

Sequence Diagram(s)

sequenceDiagram
  participant Configuration
  participant ExpressionResolver
  participant resolveUlimits
  Configuration->>Configuration: Detect expressions and host-context paths
  Configuration->>ExpressionResolver: Create resolver when required
  Configuration->>resolveUlimits: Pass resolver and raw ulimit values
  resolveUlimits->>ExpressionResolver: Resolve each ulimit expression
  ExpressionResolver-->>resolveUlimits: Resolved value or error
  resolveUlimits-->>Configuration: Parsed limits or resolution error

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🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description states the main change but omits the required related-task section and checklist, including testing and specification checks.	Add the required 関連タスク and チェックリスト sections, and record the applicable task, test results, specification updates, and documentation checks.
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the two main changes: stronger path validation and ulimit expression resolution.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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Inline comments:
In `@internal/config/feature_security_control_chars_ulimit_test.go`:
- Around line 22-24: Rename the local variable errC1_NEL to errC1NEL in the test
and update its Error assertion reference accordingly, preserving the existing
validation and expected message.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 3f28da21-5b28-4f2b-a7fd-08c9bd653aca

📥 Commits

Reviewing files that changed from the base of the PR and between f52e514 and 3244111.

📒 Files selected for processing (5)

• internal/config/feature_security_control_chars_ulimit_test.go
• internal/config/path.go
• internal/config/resolver.go
• internal/config/resolver_helpers.go
• internal/config/ulimit_test.go

Included review availability: Your plan includes up to 1 review per rolling hour; 0 remain after this review.

[Tei1988]

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