Percy Wegmann 232a2d627c tailfs: only impersonate unprivileged user if able to sudo -u as that user
When serving TailFS shares, tailscaled executes another tailscaled to act as a
file server. It attempts to execute this child process as an unprivileged user
using sudo -u. This is important to avoid accessing files as root, which would
result in potential privilege escalation.

Previously, tailscaled assumed that it was running as someone who can sudo -u,
and would fail if it was unable to sudo -u.

With this commit, if tailscaled is unable to sudo -u as the requested user, and
tailscaled is not running as root, then tailscaled executes the the file server
process under the same identity that ran tailscaled, since this is already an
unprivileged identity.

In the unlikely event that tailscaled is running as root but is unable to
sudo -u, it will refuse to run the child file server process in order to avoid
privilege escalation.

Updates tailscale/corp#16827

Signed-off-by: Percy Wegmann <percy@tailscale.com>
2024-03-01 17:42:19 -06:00
2020-02-10 22:16:30 -08:00
2024-02-07 18:10:15 -08:00
2024-02-07 18:10:15 -08:00
2024-02-15 17:24:49 -06:00

Tailscale

https://tailscale.com

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:

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 1.22. (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 git log for our commit message style. It's basically the same as Go's style.

About Us

Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:

WireGuard is a registered trademark of Jason A. Donenfeld.

Description
The easiest, most secure way to use WireGuard and 2FA.
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