Valid oci reference names disallowed

[owtaylor]

The rules for a valid org.opencontainers.image.ref.name at:

 https://github.com/opencontainers/image-spec/blob/master/annotations.md

Are quite different from the checks in the code, which seem to be (in oci_transport.go)

 var refRegexp = regexp.MustCompile(`^([A-Za-z0-9._-]+)+$`)

For example, app/org.gnome.eog/x86_64/master is valid by the former set of rules and not by the later. (See containers/skopeo#369)

[runcom]

Nice catch

[owtaylor]

In containers/skopeo#369 mtrmac said:

(We may have to break the transport syntax now that an arbitrary number of : is allowed in the .tag :( )

Looking at the code in oci/layout/oci_transport.go I'm wondering if that is necessary - the code disallows ":" in the path component, so that (as I understand it) you can set a policy on /a/b:c and have that be unambiguously refer to path=/a/b, tag=c. Since ':' is not allowed in the path, then I think it should be possible to simply change:

+ sep := strings.LastIndex(reference, ":")
- sep := strings.Index(reference, ":")

If that doesn't work out for some reason, I think "::" would make sense as a separator since the ref-name syntax doesn't allow consecutive separator characters, and most single characters that aren't allowed in the ref-name are problematical in some way (|, $, etc.).

[mtrmac]

This was fixed in #318.

[rhatdan]

@mtrmac If it is fixed, close the issue.

[mtrmac]

Right, I meant to do that and somehow didn’t.