In CL 709854 we enabled strict validation for a number of properties of
domain names (and their constraints). This caused significant breakage,
since we didn't previously disallow the creation of certificates which
contained these malformed domains.
Rollback a number of the properties we enforced, making domainNameValid
only enforce the same properties that domainToReverseLabels does. Since
this also undoes some of the DoS protections our initial fix enabled,
this change also adds caching of constraints in isValid (which perhaps
is the fix we should've initially chosen).
Updates #75835
Fixes #75828
Change-Id: Ie6ca6b4f30e9b8a143692b64757f7bbf4671ed0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/710735
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Damien Neil <dneil@google.com>