Wireguard network manager
Status: TESTING - On older linux version, ip command acts different
- iproute2-ss190107 OK
- iproute2-ss131122 NOT OK (actually my static server...)
- iproute2-5.14.0 OK
Motivation / Problem
Situation is a couple of vps, some IoT devices in the home network and couple of roaming laptops/iPads/smartphones. Till now a quite complex setup involving wireguard, openvpn, ssh'ing from box to box was in use.
Using wireguard all the time is not an option, because then the Laptop in the home network would route traffic to the box one meter away via the long route (the vps somewhere in the Internet), instead of using the short path within the home network.
An alternative could have been tinc, but tinc - licensed under GPL v2 - may never hit iOs/iPadOS AppStore. So not a solution.
Solution / Idea
Use wireguard and add the missing management part. This shall:
- bring up and configure wireguard devices
- perform the key management/exchange
- set up routes automagically
- identify shorter routes
Instead of manually creating keys (which is still the case in gui versions) the network uses one file to be distributed to all participants. Here a work in progress example (filename net.yaml):
network:
sharedKey: YDUBM6FhERePZ4gPlxzAbCN7K61BPjy7HApWYL+P128=
subnet: 10.1.1.0/8
peers:
- endPoint: 192.168.1.70:50000
adminPort: 55555
wgIp: 10.1.1.1
- endPoint: 192.168.1.212:50000
adminPort: 55555
wgIp: 10.1.1.2
The sharedKey can be created with wg genkey
.
Unfortunately there is still the need to define at least ONE static peer.
Bring up e.g. alice, bob and charlie would be just:
ALICE'S BOX> wg_netmanager -c net.yaml wg0 10.1.1.1 alice
BOB'S BOX> wg_netmanager -c net.yaml wg0 10.1.1.16 bob
CHARLIE'S BOX> wg_netmanager -c net.yaml wg0 10.1.1.21 charlie
with alice being reachable on 192.168.1.70
Definitions/Nomenclatura
- Node: Participant in the network
- Peer: Node reachable directly via wireguard interface
- Dynamic peer: synonym for peer
- Static server: Fixed address/port either in internet or in intranet
- Dynamic server: Any node (24/7) behind a firewall
- Roaming client: Any node, which is switching IP-address
- Mobile client: Roaming client with data volume limitation
Status
Node support:
- Static server in config file
- Static server per dynamic dns
- Static server per command line parameter
- Dynamic server
- Roaming client
- Mobile client
OS-Support
- Linux
- MacOS
- Windows
- iOS/iPadOS
- Android
- FreeBSD
- OpenBSD
Wireguard-Interface
- Kernel-driver + Command ip/wg
- wiregard-go + Command ip/wg
- boringtun + Command ip/wg
- boringtun (embedded) + ip
Network
- Connection established between two static servers (fixed address)
- Connection established between dynamic node and static server
- Connection established between two dynamic nodes in same subnet
- Connection established between two dynamic nodes using their visible outside connections aka NAT traversal
Routing
- Sets up routes to reach all network participants
- Gateway feature of nodes
System integration
- systemd
- rc-based system
Admin
- TUI interface
- REST API
- Web UI frontend
Testing
Using namespaces several boxes can be simulated on one linux machine. See as example
Technical Background
wg_manager will add and delete routes on demand on two levels:
- As routing policy of the kernel using
ip route add <ip>/32 dev <wg_dev>
- If a node is directly reachable, by adding a peer entry in the wireguard configuration with a list of allowed ip's. This list includes the peer and all further nodes, for which this peer can forward traffic to.
Security Consideration
In case one node of this wireguard network is compromised, then the implications are severe. The symmetric key can be distributed and any attacker's node can join the network.
With the current implementation an attacker could even issue this command:
ATTACKER'S BOX> wg_netmanager -c net.yaml wg0 8.8.8.8 alice
And ALL network participants will start to route any DNS request addressed to 8.8.8.8 to the ATTACKER's box.
This is actually a very cool feature and on the other hand quite frightening.
Update
Depending on the linux version, ip route add
wants to find an interface with the corresponding subnet. If not successful, then it will throw a "no such process error".
Remedy is, that the wireguard interface is associated with IP and resp. netmask. without adding a route:
ip addr add 10.1.1.1/24 dev wg0 noprefixroute
Consequently, in the config-file the subnet has to specified. If the subnet does not include 8.8.8.8, then other nodes will not accept it - unless the defined subnet includes 8.8.8.8