[ENHANCEMENT] FileUtil additions + sandboxing

[cyn0x8]

Briefly describe the issue(s) fixed.

im currently working on a mod launcher/manager/updater mod, and require certain file manipulation functions that are blacklisted and also not currently present in FileUtil, so this pr aims to expand FileUtil functionality by adding the following:

moveFile(path:String, destination:String):Void

deleteFile(path:String):Void

getFileSize(path:String):Int

isDirectory(path:String):Bool

readDir(path:String):Array<String>

moveDir(path:String, destination:String, ?ignore:Array<String>):Void

deleteDir(path:String, recursive:Bool = false, ?ignore:Array<String>):Void

getDirSize(path:String):Int

rename(path:String, newName:String, keepExtension:Bool = true):Void

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this pr also sandboxes all the functions!! the core functionality is now housed in FileUtilBase (used only internally, blacklisted in scripts), which FileUtil uses, sanitizing the paths first and preventing them from leaving the game folder

functions that have the capability to modify/delete are prevented from messing with assets, manifest and everything in it, plugins and everything in it, and the dlls and game executable

@:keep was also added to both classes so that while source may not use all the functions, mods will still be able to

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all functions above have been tested; if anyone finds any faults, please make them known

[AbnormalPoof]

Wouldn't this theoretically allow mods to do malicious things? Unless somehow directories that are not Funkin's are restricted.

[cyn0x8]

Wouldn't this theoretically allow mods to do malicious things? Unless somehow directories that are not Funkin's are restricted.

mods can already do that with the functions already in FileUtil like going ../ repeatedly upwards out of the game root directory and then back down to some important file and overwriting it or something

var root:String = "./";
while (FileUtil.doesFileExist(root)) {root += "../";}
FileUtil.writeStringToPath(root.substring(0, root.length - 6) + "some important path here", "", FileWriteMode.Force);

though sandboxing to only the game root directory is definitely needed i think thats an issue for another pr

[AbnormalPoof]

Fair enough! Sandboxing would be very nice.

[cyn0x8]

Fair enough! Sandboxing would be very nice.

itd be an easy addition like using this in all the functions that have a path input

/**
 * Prevent paths from exiting the root.
 *
 * @param path The path to sanitize.
 * @return The sanitized path.
 */
public static function sanitizePath(path:String):String
{
  path = path.trim().replace('\\', '/');

  if (path.contains(':'))
  {
    path = path.substring(path.lastIndexOf(':') + 1);
  }

  while (path.charAt(0) == '/')
  {
    path = path.substring(1);
  }

  var parts:Array<String> = path.split('/');
  var sanitized:Array<String> = [];
  for (part in parts)
  {
    switch (part)
    {
      case '.':
      case '':
        continue;
      case '..':
        if (sanitized.length > 0) sanitized.pop();
      default:
        sanitized.push(part);
    }
  }

  return sanitized.join('/');
}

however the problem is that theres a few places internally where they use the functions to do stuff outside of the root folder (unit tests/polymod asset redirect/etc)

[cyn0x8]

it works

[tposejank]

Shouldn't it be better to extend FileUtilBase and override all functions including those that cause trouble or am i dumb ?

[cyn0x8]

Shouldn't it be better to extend FileUtilBase and override all functions including those that cause trouble or am i dumb ?

will do that rn lol

[cyn0x8]

wait nvm static doesnt have inheritance

pr is fine so far

[EliteMasterEric]

Pretty interesting!

Of note, you could change the names so that the one that gets used by the core game is still FileUtil, and the one that the scripts uses is called something like FileUtilSandboxed, and then you can add a Polymod import alias which replaces imports of FileUtil with FileUtilSandboxed.

[tposejank]

why isn't this merged yet..... grrrrr.....

[cyn0x8]

why isn't this merged yet..... grrrrr.....

this is a sizeable pr and also related to security stuff so im not surprised if it takes a while to review and merge