…dflare/go (#222)

* crypto/tls: Add hybrid post-quantum key agreement  (#13)

* import: client-side KEM from cloudflare/go

* import: server-side KEM from cloudflare/go

* fix: modify test to get rid of CFEvents.

Note: uTLS does not promise any server-side functionality, and this change is made to be able to conduct unit tests which requires both side to be able to handle KEM Curves.

Co-authored-by: Christopher Wood <caw@heapingbits.net>
Co-Authored-By: Bas Westerbaan <bas@westerbaan.name>

----

Based on:

* crypto/tls: Add hybrid post-quantum key agreement 

Adds X25519Kyber512Draft00, X25519Kyber768Draft00, and
P256Kyber768Draft00 hybrid post-quantum key agreements with temporary
group identifiers.

The hybrid post-quantum key exchanges uses plain X{25519,448} instead
of HPKE, which we assume will be more likely to be adopted. The order
is chosen to match CECPQ2.

Not enabled by default.

Adds CFEvents to detect `HelloRetryRequest`s and to signal which
key agreement was used.

Co-authored-by: Christopher Wood <caw@heapingbits.net>

 [bas, 1.20.1: also adds P256Kyber768Draft00]
 [pwu, 1.20.4: updated circl to v1.3.3, moved code to cfevent.go]

* crypto: add support for CIRCL signature schemes

* only partially port the commit from cloudflare/go. We would stick to the official x509 at the cost of incompatibility.

Co-Authored-By: Bas Westerbaan <bas@westerbaan.name>
Co-Authored-By: Christopher Patton <3453007+cjpatton@users.noreply.github.com>
Co-Authored-By: Peter Wu <peter@lekensteyn.nl>

* crypto/tls: add new X25519Kyber768Draft00 code point

Ported from cloudflare/go to support the upcoming new post-quantum keyshare.

----

* Point tls.X25519Kyber768Draft00 to the new 0x6399 identifier while the
  old 0xfe31 identifier is available as tls.X25519Kyber768Draft00Old.
* Make sure that the kem.PrivateKey can always be mapped to the CurveID
  that was linked to it. This is needed since we now have two ID
  aliasing to the same scheme, and clients need to be able to detect
  whether the key share presented by the server actually matches the key
  share that the client originally sent.
* Update tests, add the new identifier and remove unnecessary code.

Link: https://mailarchive.ietf.org/arch/msg/tls/HAWpNpgptl--UZNSYuvsjB-Pc2k/
Link: https://datatracker.ietf.org/doc/draft-tls-westerbaan-xyber768d00/02/
Co-Authored-By: Peter Wu <peter@lekensteyn.nl>
Co-Authored-By: Bas Westerbaan <bas@westerbaan.name>

---------

Co-authored-by: Bas Westerbaan <bas@westerbaan.name>
Co-authored-by: Christopher Patton <3453007+cjpatton@users.noreply.github.com>
Co-authored-by: Peter Wu <peter@lekensteyn.nl>

* Redesign KeySharesEcdheParameters into KeySharesParameters which supports multiple types of keys.

* Optimize program logic to prevent using unwanted keys

* new: PQ and other parrots

Add new preset parrots:
- HelloChrome_114_Padding_PSK_Shuf
- HelloChrome_115_PQ
- HelloChrome_115_PQ_PSK

* new: ShuffleChromeTLSExtensions

Implement a new function `ShuffleChromeTLSExtensions(exts []TLSExtension) []TLSExtension`.

* update: include psk parameter for parrot-related functions

Update following functions' prototype to accept an optional pskExtension (of type *FakePreSharedKeyExtension):
- `UClient(conn net.Conn, config *Config, clientHelloID ClientHelloID)` => `UClient(conn net.Conn, config *Config, clientHelloID ClientHelloID, pskExtension ...*FakePreSharedKeyExtension)`
- `UTLSIdToSpec(id ClientHelloID)` => `UTLSIdToSpec(id ClientHelloID, pskExtension ...*FakePreSharedKeyExtension)`

* new: pre-defined error from UTLSIdToSpec

Update UTLSIdToSpec to return more comprehensive errors by pre-defining them, allowing easier error comparing/unwrapping.