[CRITICAL] MCP CLI installers build shell commands from unescaped paths

[Daliys]

Problem

The MCP CLI installer paths build shell command strings by concatenating resolved executable paths and project-derived script paths, then pass the result to bash -c or cmd.exe /c.

Project paths and executable paths are not shell-escaped before interpolation.

Evidence

• Editor/MCPCliInstaller.cs:309-316 wraps the caller-built command string in bash -c "..." or cmd.exe /c "...".
• Editor/MCPCliInstaller.Codex.cs:36-40 concatenates codexPath, pythonPath, and scriptPath into shell commands.
• Editor/MCPCliInstaller.ClaudeCode.cs:39-43 uses the same pattern for Claude Code.
• Editor/MCPCliInstaller.Gemini.cs:33-38 uses the same pattern for Gemini and includes --trust in the add command.
• scriptPath comes from the Unity project location, so it can include shell metacharacters if the checkout directory is named maliciously or unusually.

Impact

A project checked out into a path containing quotes or shell metacharacters can break out of the intended command and execute unintended shell syntax when the user runs the integration link action. This affects Codex, Claude Code, and Gemini installer flows.

Suggested fix

Avoid shell wrapping. Use ProcessStartInfo.FileName plus ArgumentList for each executable and argument. If a shell is unavoidable, centralize platform-correct escaping and cover paths containing quotes, spaces, $(), backticks, semicolons, ampersands, pipes, and Windows metacharacters.

Source report

Imported from audit report items:

• security (11) / Editor/MCPCliInstaller.cs:309
• security (11) / Editor/MCPCliInstaller.Codex.cs:40
• security (11) / Editor/MCPCliInstaller.ClaudeCode.cs:43
• security (11) / Editor/MCPCliInstaller.Gemini.cs:37

These were combined because all four entries describe the same shell command construction root cause.

[Daliys]

Additional imported audit item for the same root cause:

• security (8) / Editor/MCPCliInstaller.cs:314 calls out the Windows cmd.exe /c "..." quoting variant of the same shell-command construction problem, especially paths containing &, |, %, ^, or nested quotes.

[Daliys]

Additional imported audit item for the same root cause:

• security (15) / Editor/MCPCliInstaller.cs:309 repeats the shell command injection issue for Integration UI command construction. Covered by this issue.

[Daliys]

Fixed in PR #154.