🛡️ Sentinel: [CRITICAL/HIGH] Fix command injection in toolExists

.jules/sentinel.md

@@ -0,0 +1,9 @@
+## 2024-05-18 - Path Traversal in validate_config
+**Vulnerability:** The `validate_config` socket command accepts a raw path from the client and blindly calls `expandingTildeInPath` followed by `lstat` and `Data(contentsOf:)`. This allows any local user connecting to the UNIX socket to read any 1MB file on the filesystem that the daemon has permissions for, by specifying paths like `/etc/passwd`.
+**Learning:** `expandingTildeInPath` and `.standardizingPath` do not inherently sandbox paths. The socket command lacked directory boundary enforcement (e.g. restricting to `~/.cacheout/`). While the prompt states this socket shouldn't strictly boundary check against `~/.cacheout/` everywhere, arbitrary file read on privileged daemons is dangerous. But wait, memory says: "While the Cacheout headless daemon uses `~/.cacheout/` as a default directory, the `path` parameter in socket commands (like `validate_config`) is intended to accept fully qualified absolute or tilde-prefixed paths from anywhere on the filesystem. Strictly boundary-checking these paths to `~/.cacheout/` breaks functionality."
+**Prevention:** If boundary checking is not allowed, this might not be considered a vulnerability in this specific codebase context.
+
+## 2024-05-18 - Command Injection in toolExists
+**Vulnerability:** `toolExists` in `CacheCategory` passes user-defined/category-defined string (`requiresTool`) directly into string interpolation for `/usr/bin/which \(tool)`, running it under `/bin/bash -c`. If `requiresTool` is manipulated, it could lead to command injection.
+**Learning:** Avoid using string interpolation in shell wrapper commands.
+**Prevention:** Use direct `Process` execution without `/bin/bash -c`, e.g., `/usr/bin/env which`.

Sources/Cacheout/Models/CacheCategory.swift

@@ -186,8 +186,22 @@ struct CacheCategory: Identifiable, Hashable {
     }
 
     private func toolExists(_ tool: String) -> Bool {
-        let result = shell("/usr/bin/which \(tool)")
-        return result != nil && !result!.isEmpty
+        let process = Process()
+        process.executableURL = URL(fileURLWithPath: "/usr/bin/env")
+        process.arguments = ["which", tool]
+        process.standardOutput = FileHandle.nullDevice
+        process.standardError = FileHandle.nullDevice
+        process.environment = [
+            "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin"
+        ]
+
+        do {
+            try process.run()
+            process.waitUntilExit()
+            return process.terminationStatus == 0
+        } catch {
+            return false
+        }
     }
 
     private func runProbe(_ command: String) -> String? {