CC @FiloSottile @rolandshoemaker via https://dev.golang.org/owners

Hello, are there any updates?

@andreasschulze If you are looking for a shot term work around you can use https://github.com/hochhaus/crypto/commit/ba7d272dee0b9dccf253ddc91a14797a6af88f47.

If this change is directionally acceptable to an OWNER I could clean it up and submit upstream.

@hochhaus: my go skills are limited. Could you show me how to use your version https://github.com/hochhaus/crypto/commit/ba7d272dee0b9dccf253ddc91a14797a6af88f47?

I would try it here: https://github.com/andreasschulze/scmdhttpd/blob/main/scmdhttpd.go

@andreasschulze Absolutely. The API change is very minimal. Basically just add the PreferredChain to your autocert.Manager. It might look something like:

cm := &autocert.Manager{
  Cache:      autocert.DirCache(filepath.Join(*certdir, certsDir)),
  Prompt:     autocert.AcceptTOS,
  HostPolicy: hostPolicy(),
  PreferredChain: "ISRG Root X1",
}

Depending on your needs you will need to modify the value of the PreferredChain.

yes, PreferredChain: "ISRG Root X1" is what most users would choose ...

how do I decleare "please use https://github.com/hochhaus/crypto/commit/ba7d272dee0b9dccf253ddc91a14797a6af88f47"?
I assume, I've to change something here?

@andreasschulze I use bazel / rules_go (instead of the normal go build tools) so unfortunately I'm not sure the correct method to plug this into scmdhttpd. Does updating the import to github.com/hochhaus/crypto/acme/autocert not work?

ok, this is my change

I've removed all certs from cache and let autocert fetch a new one. But the server still deliver DST Root CA X3
Checked with openssl s_client -connect scmdhttpd.example:443 -showcerts ...

The file in the cache contain 3 PEM blocks.

• leaf issued by R3
• R3 issued by ISRG Root X1
• ISRG Root X1 issued by the expired DST Root CA X3

Hi @andreasschulze. Thanks. You are correct -- my change is buggy. Can you try https://github.com/hochhaus/crypto/commit/cceb102a4601f585dbc03ecdff0ae8483cd1f310 instead?

I reimplemented this feature from memory without testing as it originally was written in a closed source repo. During the rewrite I incorrectly checked x509Cert.Subject.CommonName instead of x509Cert.Issuer.CommonName.

Yea! with this commit, go1.18beta2 and a forced cert renew the server now no longer present DST Root CA X3 in the TLS handshake

Glad it worked! Thanks for debugging.

now we've to wait your change get merged upstream ...

If an OWNER is willing to review I will clean it up, add tests and send it out.

@hochhaus Could you please make a pull request with your change?

Webserver using acme/autocert/autocert.go still deliver the old "DST Root CA X3". Users like to disable this.

is there a chance, to get this fixed (at least let the user have a choice) in go-1.20? What would be needed? I'like to see some progress.

are there any news / progress?
using go-1.21 acme/autocert/autocert.go still deliver the old "DST Root CA X3" :-/