Sudo for Cygwin

What is this?

This tool emulates Unix sudo in cygwin. It allows you to run applications in elevated user mode from a non-elevated cygwin shell.

It is based on nu774's tool and has full terminal support, so you can run interactive applications like vim or a shell through it.

Requirements

cygwin-sudo requires Python >= 3.5. You can get it by installing python3 with the cygwin installer.

How to setup

Clone this repository or just download cygwin-sudo.py.

You can test if the script works by running python3 cygwin-sudo.py id -nG and comparing the output with just running id -nG. Running the command through cygwin-sudo should add an Administrator group to the outputed list.

For convenience, you might want to add an alias to this script, eg:

alias sudo="python3 /path-to-cygwin-sudo/cygwin-sudo.py"

Usage examples

$ sudo vim /etc/hosts
$ sudo cp foo.txt /cygdrive/c/Program Files/
$ sudo cygstart cmd  # open elevated standard command prompt
$ sudo cygstart regedit
$ sudo bash  # open elevated shell

Note that it will open an UAC prompt every time it is run, so if you want to run multiple commands in succession, you should open an elevated shell (see example above) and run your commands from there

How it works

When run, cygwin-sudo uses cygstart to run a second process in elevated mode. For security reasons, Windows prevents most kinds of communication between elevated and non-elevated processes. So, the elevated process connects to the non-elevated process via TCP for communication. To prevent other processes from interfering with this connection, it's secured with a random password.

The elevated process will then run the given command and exchange input and output with the original process via the TCP connection. The command is run in a pty, so it acts as if running in an ordinary terminal. Therefore, you can run interactive console-based programs like vim or less.

Related Projects

• nu774's sudo-for-cygwin: The inspiration for this tool
• wsl-sudo: A wsl version of this tool