Brad Fitzpatrick
2ee809d10d
The ts_omit_<name> build tags omit a feature at build time; there has
been no way to do the same at runtime. Some users (either proactively
or in response to a security announcement) might like a way to disable
a feature that's linked-in in their binaries that they're not using.
Then a mitigation announcement can say "set this env var" without
asking users to rebuild or wait for a new release.
This adds env var TS_DISABLE_FEATURE, a comma-separated list of
feature names to disable, and the listed set is reported by the
debug-optional-features LocalAPI endpoint next to the registered set.
The legacy per-feature knobs such as TS_DISABLE_SSH_SERVER and
TS_DISABLE_TAILDROP keep working independently.
A disabled feature behaves as if it had not been linked: it is absent
from feature.IsRegistered, its hooks are unset, and its extensions and
handlers are not registered. Three pieces make that happen:
* feature.Register now returns bool, false when disabled, and
feature packages gate their registration init on it. It was added
to the feature packages that never called it (including taildrop
and ssh), which also completes the picture reported by
debug-optional-features. taildrop, routecheck, favorites, and
serviceclientprefs had registration split across several inits and
now register from one gated init.
* ipnext.RegisterExtension ignores a disabled feature's extension.
* feature.Hook.Set and feature.Hooks.Add walk the call stack and
silently skip when the calling package under feature/<name> is
disabled. This covers sub-packages such as
feature/captiveportal/netcheckhook, which cannot call Register
themselves without colliding with their parent, and future
packages whose authors forget the gate.
ssh/tailssh's registrations moved from its inits into tailssh.Register,
called from feature/ssh's gated init. The aws and kube state stores and
syspolicy's Windows store registration are gated too.
feature/register_disable_test.go runs this test binary as a child
process (it links condregister, as tailscaled does) with
TS_DISABLE_FEATURE set to every registered feature at once, and fails
if any of them register anyway, so a feature that ignores the variable
cannot land.
Updates #12614
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I720af6ccab844ae060a9dfd1539fee577fd483e3
Tailscale
Private WireGuard® networks made easy
Overview
This repository contains the majority of Tailscale's open source code.
Notably, it includes the tailscaled daemon and
the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows,
macOS, and to varying degrees
on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's
code, but this repo doesn't contain the mobile GUI code.
Other Tailscale repos of note:
- the Android app is at https://github.com/tailscale/tailscale-android
- the Synology package is at https://github.com/tailscale/tailscale-synology
- the QNAP package is at https://github.com/tailscale/tailscale-qpkg
- the Chocolatey packaging is at https://github.com/tailscale/tailscale-chocolatey
For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.
Using
We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.
Other clients
The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.
Building
We always require the latest Go release, currently Go 1.27. (While we build releases with our Go fork, its use is not required.)
go install tailscale.com/cmd/tailscale{,d}
If you're packaging Tailscale for distribution, use build_dist.sh
instead, to burn commit IDs and version info into the binaries:
./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled
If your distro has conventions that preclude the use of
build_dist.sh, please do the equivalent of what it does in your
distro's way, so that bug reports contain useful version information.
Bugs
Please file any issues about this code or the hosted service on the issue tracker.
Contributing
PRs welcome! But please file bugs. Commit messages should reference bugs.
We require Developer Certificate of
Origin
Signed-off-by lines in commits.
See commit-messages.md (or skim git log) for our commit message style.
About Us
Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:
- https://github.com/tailscale/tailscale/graphs/contributors
- https://github.com/tailscale/tailscale-android/graphs/contributors
Legal
WireGuard is a registered trademark of Jason A. Donenfeld.