Transparent Proxying on a single machine - iptables

help
1

Hi :smiley:

Iā€™d like to proxy trasparent on a single system ( run mitmproxy -T)
on a ubuntu while sending traffic out of the same system.

The problem is the ip tables settings. I used
sudo iptables -t nat -A OUTPUT -p tcp -m owner ! --uid-owner root --dport 443 -j REDIRECT --to-port 8080
sudo iptables -t nat -A OUTPUT -p tcp -m owner ! --uid-owner root --dport 80 -j REDIRECT --to-port 8080
but this requires mitmproxy to be run as root and processes to be proxied as non root. I would like to proxy
packets from both root AND non-root processes

Unfortunately
sudo iptables -t nat -A OUTPUT -p tcp -m owner ! --pid-owner pid--dport 443 -j REDIRECT --to-port 8080
sudo iptables -t nat -A OUTPUT -p tcp -m owner ! --pid-owner pid --dport 80 -j REDIRECT --to-port 8080
does not work as pid-owner is not longer part of the iptables.

I also tried
sudo iptables -t nat -A OUTPUT -p tcp ! --sport 8080 --dport 443 -j REDIRECT --to-port 8080
sudo iptables -t nat -A OUTPUT -p tcp ! --sport 8080 --dport 80 -j REDIRECT --to-port 8080
but ended into a routing loop.

Has anybody any idea how to configure iptables to achieve my goal?

2

One way to fix this would be to create your own user for mitmproxy and run mitmproxy as that user. What do you think?

3

Of course you are right, thanks :smiley:
Just too obvious^^