Simple location aware ssh tunneling for Chrome (Mac)

This is both a nice toy to have in a Big Brother Is Watching sense, and a glaring example of why one should never log in and use a Mac (or any other system obviously) as an Administrator. Just have a Regular Guy account, and escalate to Administrator/Root when needed. For example, this tool could be inserted by a script to cause all your browsing traffic to route through a proxy server of an attackers choosing. If you're not running as an Administrator, you can't write the file without escalating. (Example of the risk, though it wouldn't help here, since there is LCE to root...goddammit Apple...)

I had a use case recently where I wanted to have multiple copies of Chromium start in different profiles and with different proxy settings. I'm getting to the point at which I don't think that's really feasible, in that any new instance will assume the proxy settings of any already running instance.

BUT, I did get some cool location aware-ish proxying set up. Since one use case involves laptops, I'd like to see it use a local proxy when I'm home, and a remote proxy when I'm not at home (hosted VPS for instance).

I'm using ssh to set up a SOCKS5 proxy, and push all traffic including DNS through the tunnel, ssh'ing to different hosts based on different local system IPs. I have it checking en0 and en1 and if their IPs match my home subnet, it ssh's to a local system, if they are anything else, it will run against a publicly hosted system to which I can ssh.

Next step is to clean up after itself, so when you run Chromium (or Chrome), it will detect IPs, ssh to the appropriate host, and connect using that tunnel. When Chromium closes, it cleans up the SSH session so it's not just hanging around.

To use - Have a local and remote host you can ssh to using keys, and which allow you to forward. On the Mac, navigate to /Applications/Chromium.app/Contents/MacOS/. Rename Chromium to Chromium-bin. Drop this script in, chmod appropriately, and name it Chromium. Now when the Chromium app is run, it runs our script to set up proxies and launch the browser:


#! /bin/bash

ip0=`ifconfig en0 | grep -v inet6 | grep inet | awk '{print $2}' | awk -F "." '{print $1"."$2"."$3}'`
ip1=`ifconfig en1 | grep -v inet6 | grep inet | awk '{print $2}' | awk -F "." '{print $1"."$2"."$3}'`

if [ -z "$ip0"  ]
  then
   if [ "$ip1" = "192.168.30" ]
     then
       ssh -C2qTnN -D 8181 username@192.168.30.241 &

       proxypid=`jobs -p`
       /Applications/Chromium.app/Contents/MacOS/Chromium-bin --proxy-server="socks5://127.0.0.1:8181" --host-resolver-rules="MAP * ~NOTFOUND, EXCLUDE 127.0.0.1" --profile-directory=Tunnl 2>&1 /dev/null

       kill $proxypid

      else

        ssh -C2qTnN -D 8181 username@publichost.com &

        proxypid=`jobs -p`
        /Applications/Chromium.app/Contents/MacOS/Chromium-bin --proxy-server="socks5://127.0.0.1:8181" --host-resolver-rules="MAP * ~NOTFOUND, EXCLUDE 127.0.0.1" --profile-directory=Tunnl 2>&1 /dev/null

        kill $proxypid

      fi

  elif [ "$ip0" = "192.168.30" ]
    then
      ssh -C2qTnN -D 8181 username@192.168.30.241 &

      proxypid=`jobs -p`
      /Applications/Chromium.app/Contents/MacOS/Chromium-bin --proxy-server="socks5://127.0.0.1:8181" --host-resolver-rules="MAP * ~NOTFOUND, EXCLUDE 127.0.0.1" --profile-directory=Tunnl 2>&1 /dev/null

      kill $proxypid

  else

      ssh -C2qTnN -D 8181 username@publichost.com &

      proxypid=`jobs -p`
      /Applications/Chromium.app/Contents/MacOS/Chromium-bin --proxy-server="socks5://127.0.0.1:8181" --host-resolver-rules="MAP * ~NOTFOUND, EXCLUDE 127.0.0.1" --profile-directory=Tunnl 2>&1 /dev/null

      kill $proxypid

fi