crypto/x509: treat hostnames with colons as invalid

Colons are port separators, so it's risky to allow them in hostnames.
Per the CL 231377 rule, if we at least consider them invalid we will not
apply wildcard processing to them, making behavior a little more
predictable.

We were considering hostnames with colons valid (against spec) because
that meant we'd not ignore them in Common Name. (There was at least
one deployment that was putting colons in Common Name and expecting it
to verify.)

Now that Common Name is ignored by default, those clients will break
again, so it's a good time to drop the exception. Hopefully they moved
to SANs, where invalid hostnames are checked 1:1 (ignoring wildcards)
but still work. (If they didn't, this change means they can't use
GODEBUG=x509ignoreCN=0 to opt back in, but again you don't get to use a
legacy deprecated field AND invalid hostnames.)

Updates #24151

Change-Id: Id44b4fecb2d620480acdfc65fea1473f7abbca7f
Reviewed-on: https://go-review.googlesource.com/c/go/+/231381
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
3 files changed
tree: 76c86297ddadb90fb189b5311414ef3dbf4f5cb5
  1. .github/
  2. api/
  3. doc/
  4. lib/
  5. misc/
  6. src/
  7. test/
  8. .gitattributes
  9. .gitignore
  10. AUTHORS
  11. CONTRIBUTING.md
  12. CONTRIBUTORS
  13. favicon.ico
  14. LICENSE
  15. PATENTS
  16. README.md
  17. robots.txt
  18. SECURITY.md
README.md

The Go Programming Language

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Gopher image Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.

Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.

Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.

Download and Install

Binary Distributions

Official binary distributions are available at https://golang.org/dl/.

After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.

Install From Source

If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.

Contributing

Go is the work of thousands of contributors. We appreciate your help!

To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html

Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.