x/crypto/acme: Directory.AuthzURL isn't checked for pre-auth support, in client.Authorize()

[nathanaelle]

What version of Go are you using (go version)?

go version go1.14.7 darwin/amd64

Does this issue reproduce with the latest release?

yes, with any release of crypto/acme with ACMEv2 support

What did you do?

_, err := lestencryptStagingV2client.Authorize("example.com")

What did you expect to see?

{directotyURL} doesn't support pre-authorization flow

What did you see instead?

Post "": unsupported protocol scheme ""

this obscure error is returned because AuthzURL is empty for letsencrypt staging v2, and AuthzURL is not tested before calling POST.

[dmitshur]

/cc @FiloSottile @x1ddos per owners.

[x1ddos]

// AuthzURL is used to initiate identifier pre-authorization flow.
// Empty string indicates the flow is unsupported by the CA.
AuthzURL string

https://godoc.org/golang.org/x/crypto/acme#Directory

[nathanaelle]

@x1ddos ,

in this file : https://github.com/golang/crypto/blob/123391ffb6de/acme/acme.go#L466 , you can see :

if _, err := c.Discover(ctx); err != nil {
		return nil, err
	}

there is a discovery made, but … nothing is done with the directory, and the next instruction is to do a POST to AuthzURL.

my point is :
AuthzURL may be checked here and return an error if AuthzURL is empty to avoid this kind or error Post "": unsupported protocol scheme "" .

[nathanaelle]

This issue is about Dev Experience , not cryptography, not RTFM.

I already read the manual and I read also the RFC, how can @x1ddos may guess that ?
if I ignore that in ACMEv1 Pre-auth was mandatory but not in ACMEv2, how possible did I know that this is an issue since the ACMEv2 ?

the Dev Experience issue is Authorize() can return a meaningfull error if AuthzURL is empty.

the error {directotyURL} doesn't support pre-authorization flow carry more meaning than Post "": unsupported protocol scheme ""

but Post "": unsupported protocol scheme "" is returned by post().
so Authorize() need to check if AuthzURL is empty, to return a meaningfull error.

go is not a one-person side-project.
Replying with only a manual citation, seems at least a bit aggressive.
And, if it is possible to establish that aggressive reply was made without any effort to understand the issue, that may become a conduct issue.

English is not my native language, and I live with a brain injury (traumatic injury) that make those kind of social interaction really difficult in any language.

I don't ask any favor, I just expect a reply compatible with https://golang.org/conduct

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