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mirror of https://github.com/golang/go synced 2024-11-15 04:20:22 -07:00
go/doc/next/6-stdlib
Roland Shoemaker 9eeb627f60 crypto/tls: add ech client support
This CL adds a (very opinionated) client-side ECH implementation.

In particular, if a user configures a ECHConfigList, by setting the
Config.EncryptedClientHelloConfigList, but we determine that none of
the configs are appropriate, we will not fallback to plaintext SNI, and
will instead return an error. It is then up to the user to decide if
they wish to fallback to plaintext themselves (by removing the config
list).

Additionally if Config.EncryptedClientHelloConfigList is provided, we
will not offer TLS support lower than 1.3, since negotiating any other
version, while offering ECH, is a hard error anyway. Similarly, if a
user wishes to fallback to plaintext SNI by using 1.2, they may do so
by removing the config list.

With regard to PSK GREASE, we match the boringssl  behavior, which does
not include PSK identities/binders in the outer hello when doing ECH.

If the server rejects ECH, we will return a ECHRejectionError error,
which, if provided by the server, will contain a ECHConfigList in the
RetryConfigList field containing configs that should be used if the user
wishes to retry. It is up to the user to replace their existing
Config.EncryptedClientHelloConfigList with the retry config list.

Fixes #63369

Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest
Change-Id: I9bc373c044064221a647a388ac61624efd6bbdbf
Reviewed-on: https://go-review.googlesource.com/c/go/+/578575
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-05-23 03:10:12 +00:00
..
99-minor crypto/tls: add ech client support 2024-05-23 03:10:12 +00:00
0-heading.md doc: fix various release notes mistakes 2024-03-15 03:39:16 +00:00
1-time.md doc: make use of simpler symbol links for relnotes 2024-04-12 20:57:18 +00:00
2-unique.md doc: simplify links for release notes 2024-05-20 18:34:13 +00:00
3-iter.md doc: simplify links for release notes 2024-05-20 18:34:13 +00:00
3-structs.md doc: correct issue number for release note 2024-05-22 16:06:02 +00:00