Potential fix for code scanning alert no. 95: Uncontrolled data used in path expression

[alitokmen]

Potential fix for https://github.com/codehaus-cargo/cargo/security/code-scanning/95

The safest minimal fix is to validate and normalize relativeFile in FileManager.saveFile(...) before appending it to the workspace path, then enforce that the resolved target remains inside the workspace directory.

Best concrete approach (without changing intended functionality):

• In extensions/daemon/webapp/src/main/java/org/codehaus/cargo/daemon/file/FileManager.java:
  • Add a private helper method that:
    • rejects null/empty names,
    • rejects absolute paths,
    • resolves workspaceDir.resolve(relativeFile).normalize(),
    • verifies the normalized path starts with normalized workspace dir,
    • returns the safe normalized path as string.
  • Use this helper in both saveFile(String relativeFile, InputStream inputStream) and saveFile(String handleId, String relativeFile, InputStream inputStream) so both write paths are protected.
• Add java.nio.file.Path and java.nio.file.Paths imports.
• Throw IllegalArgumentException on invalid path input (keeps behavior explicit and avoids silent rewriting).

This preserves existing behavior for valid relative inputs while blocking traversal and absolute-path abuse.

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