Jonas Nick
34a18f92ee
The `netns-exec` wrapper was created with `group = ""`, which makes the
`security.wrappers` activation run `chown ${allowedUser}:`. GNU chown
resolves the trailing colon to the owner's login group, and because the
operator is defined with `isNormalUser = true`, that group is the shared
group `users`. Together with mode 550, this made the wrapper executable
by every normal user on the host instead of only by `allowedUser`.
The wrapper carries `cap_sys_admin=ep` and the NixOS security wrapper
performs no owner check, so any normal user could enter `nb-joinmarket`,
the only netns that `netns-exec` permits. This exposes joinmarketd's
unauthenticated control port on 127.0.0.1 inside that netns and allows
sending packets from the joinmarket netns address. This can only ever become a
problem if there's a second, normal user on the host.
Use mode 500 so that only `allowedUser` can execute the wrapper. Also
set the group to `root`, so that `users` doesn't silently become an
authorized group again if the mode is ever loosened.
The netns-isolation test asserted this property with
`runuser -u clightning -- netns-exec nb-bitcoind ip a`, which fails
regardless of the file mode, because `clightning` is a system user with
its own group and `nb-bitcoind` is not in netns-exec's allowlist.
Replace it with a check that a normal user is denied by the exec
permissions, and assert the reason for each failure instead of only the
exit status.
nix-bitcoin is a collection of Nix packages and NixOS modules for easily installing full-featured Bitcoin nodes with an emphasis on security.
Overview
nix-bitcoin can be used for personal or merchant wallets, public infrastructure or for Bitcoin application backends. In all cases, the aim is to provide security and privacy by default. However, while nix-bitcoin is used in production today, it is still considered experimental.
nix-bitcoin nodes can be deployed on dedicated hardware, virtual machines or containers. The Nix packages and NixOS modules can be used independently and combined freely.
nix-bitcoin is built on top of Nix and NixOS which provide powerful abstractions to keep it highly customizable and maintainable. Testament to this are nix-bitcoin's robust security features and its potent test framework. However, running nix-bitcoin does not require any previous experience with the Nix ecosystem.
Get started
- See the examples for an overview of all features.
- To setup a new node from scratch, see the installation instructions.
- To add nix-bitcoin to an existing NixOS configuration, see importable-configuration.nix and the Flake example.
Docs
Hint: To show a table of contents, click the button (
) in the
top left corner of the documents.
- NixOS options search
- Hardware requirements
- Installation
- Configuration and maintenance
- Using services
- FAQ
Features
A configuration preset for setting up a secure node
- All applications use Tor for outbound connections and support accepting inbound connections via onion services.
NixOS modules (src)
- Application services
- bitcoind
- clightning with support for announcing an onion service
and database replication.
Available plugins:- clboss: automated C-Lightning Node Manager
- currencyrate: currency converter
- monitor: helps you analyze the health of your peers and channels
- rebalance: keeps your channels balanced
- trustedcoin (experimental): replaces bitcoind with trusted public explorers
- zmq: publishes notifications via ZeroMQ to configured endpoints
- lnd with support for announcing an onion service and static channel backups
- Lightning Loop
- Lightning Pool
- charge-lnd: policy-based channel fee manager
- lndconnect: connect your wallet to lnd or clightning via WireGuard or Tor
- Ride The Lightning: web interface for
lndandclightning - mempool: Bitcoin visualizer, explorer, and API service
- electrs: Electrum server
- fulcrum: Electrum server (see the module for a comparison with electrs)
- btcpayserver
- liquid: federated sidechain
- JoinMarket
- bitcoin-core-hwi
- Helper
- netns-isolation: isolates applications on the network-level via network namespaces
- nodeinfo: script which prints info about the node's services
- backups: duplicity backups of all your node's important files
- operator: configures a non-root user who has access to client tools (e.g.
bitcoin-cli,lightning-cli)
Security
See SECURITY.md for the security policy and how to report a vulnerability.
nix-bitcoin aims to achieve a high degree of security by building on the following principles:
- Simplicity: Only services enabled in
configuration.nixand their dependencies are installed, support for doas (sudo alternative), code is continuously reviewed and refined. - Integrity: The Nix package manager guarantees that all dependencies are exactly specified, packages can be built from source to reduce reliance on binary caches, nix-bitcoin merge commits are signed, all commits are approved by multiple nix-bitcoin developers, upstream packages are cryptographically verified where possible, we use this software ourselves.
- Principle of Least Privilege: Services operate with least privileges; they each have their own user and are restricted further with systemd features, RPC whitelisting and netns-isolation. There's a non-root user operator to interact with the various services.
- Defense-in-depth: nix-bitcoin supports a hardened kernel, services are confined through discretionary access control, Linux namespaces, dbus firewall and seccomp-bpf with continuous improvements.
Note that if the machine you're deploying from is insecure, there is nothing nix-bitcoin can do to protect itself.
Security fund
The nix-bitcoin security fund is a 2 of 3 bitcoin multisig address open for donations, used to reward
security researchers who discover vulnerabilities in nix-bitcoin or its upstream dependencies.
See Security Fund for details.
Developing
See dev/README.
Troubleshooting
If you are having problems with nix-bitcoin check the FAQ or submit an issue.
There's also a Matrix room at #general:nixbitcoin.org.
We are always happy to help.