🛡️ Sentinel: [CRITICAL] Fix Path Traversal in AbstractDiskBasedService

[tomdesair]

🚨 Severity: CRITICAL
💡 Vulnerability: Path traversal vulnerability in AbstractDiskBasedService.getPathInStorageDirectory. It was resolving user-supplied UploadId values against the base directory without checking if the resulting path escaped the storage boundary. Additionally, the UploadId class's encoding logic does not prevent URL-safe characters like . from being used.
🎯 Impact: An attacker could craft a malicious UploadId (e.g. ../../../etc/passwd or encoded variants) causing the server to read or overwrite arbitrary files on the disk, completely compromising the system.
🔧 Fix: Refactored getPathInStorageDirectory to normalize the resolved absolute path and verify it begins with the normalized absolute storagePath using Path.startsWith(). If it escapes the directory, an IllegalArgumentException is thrown.
✅ Verification: Unit tests execution via mvn test pass without regressions. Run mvn test to verify.

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PR created automatically by Jules for task 14854299696497648661 started by @tomdesair

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[coveralls]

coverage: 94.854% (-0.07%) from 94.92% — fix-path-traversal-14854299696497648661 into master