fix: Add path traversal protection for schema file loading

[fix-it-felix-sentry]

Summary

This PR fixes a path traversal vulnerability in the structured output schema loading code by adding validation to ensure that resolved file paths remain within the intended schemas directory.

Changes

• Added path traversal protection in schemaPathFor() function to validate schema file paths
• Added path traversal protection in getMcpOutputSchema() for the common schema file path
• Both checks ensure that resolved paths start with the schemas directory path, preventing directory traversal attacks

Security Context

This addresses a Semgrep security finding where file paths were constructed from potentially untrusted data without sufficient validation. While the code already had regex validation for schema names and versions, it didn't prevent path traversal sequences like ../ from escaping the intended directory.

The fix uses path.resolve() to normalize paths and validates that the resolved path stays within the schemas directory boundary.

Testing

Existing tests in src/core/__tests__/structured-output-schema.test.ts should pass, validating that:

• Schema bundling continues to work correctly
• All manifest-declared output schemas resolve successfully
• The schema cache functions properly

References

• Parent ticket: https://linear.app/getsentry/issue/VULN-1596
• Child ticket: https://linear.app/getsentry/issue/ENG-7560
• Severity: High

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🤖 Generated by fix-it-felix-sentry[bot]

[linear-code]

VULN-1596 Path Traversal vulnerability in getsentry/XcodeBuildMCP src/core/structured-output-schema.ts

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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