Bash, Applescript, and Sshuttle (Python): Creating a multi-jump into the multiverse...


Summary:
Basically, I work through VPN's most of my existence.  The problem lies when I have to switch to different VPN's it disrupts my communications w/ other tools that only exist in one VPN, but not the other.  There does appear to be tools around some of these things, but I wanted something quick and dirty.  AND DIRTY it is.  This enables me to stay connected to the main VPN and cheat by sshuttle'ing through systems of access temporarily.

Details:
I'm using MACOS and to launch a terminal in a new window turned me on to AppleScript.  I wanted to pass two variables.
1st was basically an identifier for the end system I wanted to shuttle my traffic through.
2nd was to pass a password variable to any system inbetween that was not setup w/ my SSH public key.

So I made a bash function, to call applescript to open my terminals to run what is effectively a python binary.  It works, but has several prerequisites for it to run smoothly.  The nice thing about this script, it demonstrates the utility of a bash function and how you can make use of AppleScript.

Would any sane person need this?  Probably not, but who am I to judge.

PreReqs:
  1. sshuttle
  2. visudo modifications (optional), but useful.
    1. Cmnd_Alias for sshuttle so you can define a NOPASSWD sudo'er for sshuttle ONLY
    2. This is super important, because you don't want to enable NOPASSWD for all applications.  Although I don't know why I stress this point since I'm probably breaking so many security rules as it is.  Oh well.
    3. Cmnd_Alias SSHUTTLE = /usr/bin/env PYTHONPATH=/usr/local/Cellar/sshuttle/0.78.5/libexec/lib/python3.7/site-packages /usr/local/Cellar/sshuttle/0.78.5/libexec/bin/python3.7 /usr/local/bin/sshuttle --method auto --firewall
    4. yourUsername ALL=(root) NOPASSWD: SSHUTTLE
  3. SSHHostKeyChecking (Optional) disable
    1. I'm going to change this later, but as a quick and dirty, I'm basically saying I don't care about security because I KNOW the endpoints I'm connecting to.  Need to make it a bit more strict, but the goal is to skip the "yes" I accept the host key automatically.
    2. ~/.ssh/config
      1. Host *
           StrictHostKeyChecking no
           UserKnownHostsFile=/dev/null
Simple Diagram Example:
Effectively there is either no route or firewall preventing access to the networks I need to get to.  This diagram basically demonstrates how I can use shuttle to proxy my mac to the networks I need.

Script:

Comments

Kahy said…
Are you doing the visudo modifications on your local box or the box you are ssh'ing into?

Great script - working on something similar
February 25, 2020 at 7:33 AM
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