innernet

A private network system that uses WireGuard under the hood. See the announcement blog post for a longer-winded explanation.

innernet is similar in its goals to Slack's nebula or Tailscale, but takes a bit of a different approach. It aims to take advantage of existing networking concepts like CIDRs and the security properties of WireGuard to turn your computer's basic IP networking into more powerful ACL primitives.

innernet is not an official WireGuard project, and WireGuard is a registered trademark of Jason A. Donenfeld.

This has not received an independent security audit, and should be considered experimental software at this early point in its lifetime.

Usage

Peer Initialization

Let's assume the invitation file generated in the steps above have been transferred to the machine a network admin will be using.

You can initialize the client with

sudo innernet install /path/to/invitation.toml

You can customize the network name if you want to, or leave it at the default. innernet will then connect to the innernet server via WireGuard, generate a new key pair, and register that pair with the server. The private key in the invitation file can no longer be used.

If everything was successful, the new peer is on the network. You can run things like

sudo innernet list

or

sudo innernet list --tree

to view the current network and all CIDRs visible to this peer.

Since we created an admin peer, we can also add new peers and CIDRs from this peer via innernet instead of having to always run commands on the server.

Adding Associations between CIDRs

In order for peers from one CIDR to be able to contact peers in another CIDR, those two CIDRs must be "associated" with each other.

With the admin peer we created above, let's add a new CIDR for some theoretical CI servers we have.

sudo innernet add-cidr <interface>

The name is ci-servers and the CIDR is 10.60.64.0/24, but for this example it can be anything.

For now, we want peers in the humans CIDR to be able to access peers in the ci-servers CIDR.

sudo innernet add-association <interface>

The CLI will ask you to select the two CIDRs you want to associate. That's all it takes to allow peers in two different CIDRs to communicate!

You can verify the association with

sudo innernet list-associations <interface>

and associations can be deleted with

sudo innernet delete-associations <interface>

Enabling/Disabling Peers

For security reasons, IP addresses cannot be re-used by new peers, and therefore peers cannot be deleted. However, they can be disabled. Disabled peers will not show up in the list of peers when fetching the config for an interface.

Disable a peer with

sudo innernet disable-peer <interface>

Or re-enable a peer with

sudo innernet enable-peer <interface>

Specifying a Manual Endpoint

The innernet server will try to use the internet endpoint it sees from a peer so other peers can connect to that peer as well. This doesn't always work and you may want to set an endpoint explicitly. To set an endpoint, use

sudo innernet override-endpoint <interface>

You can go back to automatic endpoint discovery with

sudo innernet override-endpoint -u <interface>

Setting the Local WireGuard Listen Port

If you want to change the port which WireGuard listens on, use

sudo innernet set-listen-port <interface>

or unset the port and use a randomized port with

sudo innernet set-listen-port -u <interface>

Remove Network

To permanently uninstall a created network, use

sudo innernet-server uninstall <interface>

Use with care!

Security recommendations

If you're running a service on innernet, there are some important security considerations.

Enable strict Reverse Path Filtering (RFC 3704)

Strict RPF prevents packets from other interfaces from having internal source IP addresses. This is not the default on Linux, even though it is the right choice for 99.99% of situations. You can enable it by adding the following to a /etc/sysctl.d/60-network-security.conf:

net.ipv4.conf.all.rp_filter=1
net.ipv4.conf.default.rp_filter=1

Bind to the WireGuard device

If possible, to ensure that packets are only ever transmitted over the WireGuard interface, it's recommended that you use SO_BINDTODEVICE on Linux or IP_BOUND_IF on macOS/BSDs. If you have strict reverse path filtering, though, this is less of a concern.

IP addresses alone often aren't enough authentication

Even following all the above precautions, rogue applications on a peer's machines could be able to make requests on their behalf unless you add extra layers of authentication to mitigate this CSRF-type vector.

It's recommended that you carefully consider this possibility before deciding that the source IP is sufficient for your authentication needs on a service.

Installation

innernet has only officially been tested on Linux and MacOS, but we hope to support as many platforms as is feasible!

Runtime Dependencies

It's assumed that WireGuard is installed on your system, either via the kernel module in Linux 5.6 and later, or via the wireguard-go userspace implementation.

WireGuard Installation Instructions

Arch Linux

pacman -S innernet

Debian and Ubuntu

@tommie is kindly providing Debian/Ubuntu innernet builds in the https://github.com/tommie/innernet-debian repository.

Other Linux Distributions

We're looking for volunteers who are able to set up external builds for popular distributions. Please see issue #203.

macOS

brew install tonarino/innernet/innernet

Cargo

# to install innernet:
cargo install --git https://github.com/tonarino/innernet --tag v1.6.4 innernet-client

# to install innernet-server:
cargo install --git https://github.com/tonarino/innernet --tag v1.6.4 innernet-server

Note that you'll be responsible for updating manually.

Development

Cargo build feature for SELinux

If your target system uses SELinux, you will want to enable the 'selinux' feature when building the innernet binary. This will ensure that innernet maintains the correct selinux context on the /etc/hosts file when adding hosts. To do so add --features selinux to the cargo build options. The selinux-devel package will need to be installed for the correct headers.

innernet-server Build dependencies

• rustc / cargo (version 1.50.0 or higher)
• libclang (see more info at https://crates.io/crates/clang-sys)
• libsqlite3

Build:

cargo build --release --bin innernet-server

The resulting binary will be located at ./target/release/innernet-server

innernet Client CLI Build dependencies

• rustc / cargo (version 1.50.0 or higher)
• libclang (see more info at https://crates.io/crates/clang-sys)

Build:

cargo build --release --bin innernet

The resulting binary will be located at ./target/release/innernet

Testing

You can manually invoke Docker-based tests assuming you have Docker daemon running. If you specify --interactive flag, it allows you to attach to the server and client innernet Docker containers, so you can test various innernet commands inside a sandboxed environment.

docker-tests/build-docker-images.sh
docker-tests/run-docker-tests.sh [--interactive]

If you are developing a new feature, please consider adding a new test case to run-docker-tests.sh (example PR).

Releases

Please run the release script from a Linux machine: generated shell completions depend on available wireguard backends and Mac doesn't support the kernel backend.

1. Fetch and check-out the main branch.
2. Run ./release.sh [patch|major|minor|rc]
3. Push the main branch and the created tag to the repo.
4. Publish crates that have publish = true to crates.io.