valdisxp1/rpi-autossh repository overview

⁠valdisxp1/autossh

Docker container for creating tunnels with autossh.

• Both interactive and automated initialization available
• Generates its own SSH key
• Option for skipping "Are you sure you want to continue connecting" (implictly trusting the server key)

⁠Usage

⁠Interactive

docker run -it -e HOST="[email protected]" -e FORWARD="your forwards goes here" valdisxp1/autossh 

Remember to forward the ports

example:

docker run -it -e HOST="root@localhost" -e PORT=2222 -p8080:8080 -e FORWARD="-L:8080:localhost:80 -D5050" valdisxp1/autossh

1. Start the container with the command.

2. Wait for it to generate the SSH key.

3. Copy the key to ~/.ssh/authorized_keys for your target and then press enter.

4. Choose whether or not to trust the server key ("Are you sure you want to continue connecting (yes/no)"). Run ssh-keygen -lf <(ssh-keyscan localhost 2>/dev/null) on the server to compare. Alternetively you can blindly trust the server not a man in the middle⁠. This can be skipped by setting -e TRUST="yes".

5. It does a test connection first then the tunnel is running.

⁠Automated

1. Create known_hosts and the ssh key (id_rsa, id_rsa.pub), i.e. the only files in /root/.ssh directory. Therefore they can be placed in a single directory.

Generating the ssh key:

ssh-keygen -t rsa -b 4096 -N '' -f id_rsa

known_hosts can be populated from output of ssh-keyscan -H <host> or set -e TRUST="yes".

1. start the container.

docker run -v path-to-created-config:/root/.ssh/ -e HOST="[email protected]" -e FORWARD="your forwards goes here" valdisxp1/autossh 

or

docker run -v path-to-known_hosts:/root/.ssh/known_hosts -v path-to-id_rsa:/root/.ssh/id_rsa -v path-to-id_rsa.pub:/root/.ssh/id_rsa.pub -e HOST="[email protected]" -e FORWARD="your forwards goes here" valdisxp1/autossh 

⁠Environment variables

• HOST user@hostname of the target ssh server
• PORT ssh port to connect; default is 22
• FORWARD ssh port forwards seperated by a space. See man ssh or online⁠ for full reference.
• TRUST set to yes or all to skip "Are you sure you want to continue connecting" (implictly trusting the server key).
• VERBOSE set to true to enable ssh verbose output.

⁠Gotchas

• To be able access local forwards use -L:local_port:remote_host:remote_port instead of -Llocal_port:remote_host:remote_port. Leading : allows external connections.
• For simplicity, enviroment variables are not sanitised. Arbitrary autossh arguments can be added in FORWARD or arbitrary commands injected.