[PATCH v2 00/17] WireGuard: Secure Network Tunnel

[Jason A. Donenfeld]

This patchset is available on git.kernel.org in this branch, where it may be
pulled directly for inclusion into net-next:

  * https://git.kernel.org/pub/scm/linux/kernel/git/zx2c4/linux.git/log/?h=jd/wireguard

WireGuard is a secure network tunnel written especially for Linux, which
has faced around three years of serious development, deployment, and
scrutiny. It delivers excellent performance and is extremely easy to
use and configure. It has been designed with the primary goal of being
both easy to audit by virtue of being small and highly secure from a
cryptography and systems security perspective. WireGuard is used by some
massive companies pushing enormous amounts of traffic, and likely
already today you've consumed bytes that at some point transited through
a WireGuard tunnel. Even as an out-of-tree module, WireGuard has been
integrated into various userspace tools, Linux distributions, mobile
phones, and data centers. There are ports in several languages to
several operating systems, and even commercial hardware and services
sold integrating WireGuard. It is time, therefore, for WireGuard to be
properly integrated into Linux.

Ample information, including documentation, installation instructions,
and project details, is available at:

  * https://www.wireguard.com/
  * https://www.wireguard.com/papers/wireguard.pdf

As it is currently an out-of-tree module, it lives in its own git repo
and has its own mailing list, and every commit for the module is tested
against every stable kernel since 3.10 on a variety of architectures
using an extensive test suite:

  * https://git.zx2c4.com/WireGuard
    https://git.kernel.org/pub/scm/linux/kernel/git/zx2c4/WireGuard.git/
  * https://lists.zx2c4.com/mailman/listinfo/wireguard
  * https://www.wireguard.com/build-status/

The project has been broadly discussed at conferences, and was presented
to the Netdev developers in Seoul last November, where a paper was
released detailing some interesting aspects of the project. Dave asked
me after the talk if I would consider sending in a v1 "sooner rather
than later", hence this patchset. A decision is still waiting from the
LPC network track committee, but an update on these topics may be
presented in Vancouver in a few months. Presentations:

  * https://www.wireguard.com/presentations/
  * https://www.wireguard.com/papers/wireguard-netdev22.pdf

The cryptography in the protocol itself has been formally verified by
several independent academic teams with positive results, and I know of
two additional efforts on their way to further corroborate those
findings. The version 1 protocol is "complete", and so the purpose of
this review is to assess the implementation of the protocol. However, it
still may be of interest to know that the thing you're reviewing uses a
protocol with various nice security properties:

  * https://www.wireguard.com/formal-verification/

This patchset is divided into three segments. The first introduces a very
simple helper for working with the FPU state for the purposes of amortizing
SIMD operations. The second segment is a small collection of cryptographic
primitives, split up into several commits by primitive and by hardware. The
third is WireGuard itself, presented as an unintrusive and self-contained
virtual network driver.

It is intended that this entire patch series enter the kernel through
DaveM's net-next tree.

Changes v1->v2:
  - Zinc has been split into multiple patches.
  - Zinc has been split into multiple config options.
  - WireGuard has been wrapped at 80 characters.
  - Numerous cleanups of inside WireGuard.
  - Splitting out the simd helper into linux/.
  - Simplification of bitwise arithmetic inside some Zinc primitives.
  - Better handling of unaligned buffers inside Zinc.
  - Expanded CC list.

Enjoy,
Jason