obfs4proxy/meek_lite utls fork

Yawning Angel (yawning at schwanenlied dot me)

What?

This is a fork of utls for the specific purpose of improving obfs4proxy's meek_lite transport.

Functional differences:

• Go v1.11 module metadata files have been added.
• The handshake no longer fails if the remote server selects a curve that is not the 0th preferred curve (X25519). This issue is primarily observable with the Azure host used for the Tor Browser meek bridge, and the HelloFirefox_63 profile.
• The handshake no longer fails against servers that support the TLS Certificate Compression draft.
• HelloGolang is totally busted, and no longer resembles crypto/tls.
• The AES block cipher and GHASH implementation will be timing side-channel safe on architectures where the crypto/aes one is not.

Why?

I was bored and it was an easy way to make meek_lite less awful.

Why don't you upstream the changes?

It's a pet project done in my spare time and I want to use a strong/viral copyleft license for the vast majority of my pet projects going forward.

I used to have a more liberal view on licensing but certain entities have ruined it for everybody. The portions of the code that I have not written or altered are naturally under the original license.

You changed something and broke my project!

Your tears are delicious, and your code will burn.