diff --git a/pkg/webhook/bundle.go b/pkg/webhook/bundle.go index 3d2dbf1b..35c75007 100644 --- a/pkg/webhook/bundle.go +++ b/pkg/webhook/bundle.go @@ -7,6 +7,7 @@ import ( "errors" "fmt" "io" + "net/http" "strings" "github.com/google/go-containerregistry/pkg/name" @@ -18,6 +19,26 @@ import ( "github.com/sigstore/sigstore-go/pkg/verify" ) +type noncompliantRegistryTransport struct{} + +// RoundTrip will check if a request and associated response fulfill the following: +// 1. The response returns a 406 status code +// 2. The request path contains /referrers/ +// If both conditions are met, the response's status code will be overwritten to 404 +// This is a temporary solution to handle non compliant registries that return +// an unexpected status code 406 when the go-containerregistry library used +// by this code attempts to make a request to the referrers API. +// The go-containerregistry library can handle 404 response but not a 406 response. +// See the related go-containerregistry issue: https://github.com/google/go-containerregistry/issues/1962 +func (a *noncompliantRegistryTransport) RoundTrip(req *http.Request) (*http.Response, error) { + resp, err := http.DefaultTransport.RoundTrip(req) + if resp.StatusCode == http.StatusNotAcceptable && strings.Contains(req.URL.Path, "/referrers/") { + resp.StatusCode = http.StatusNotFound + } + + return resp, err +} + type VerifiedBundle struct { SGBundle *bundle.ProtobufBundle Result *verify.VerificationResult @@ -93,7 +114,9 @@ func getBundles(ref name.Reference, remoteOpts []remote.Option) ([]*bundle.Proto digest := ref.Context().Digest(desc.Digest.String()) - referrers, err := remote.Referrers(digest, remoteOpts...) + transportOpts := []remote.Option{remote.WithTransport(&noncompliantRegistryTransport{})} + transportOpts = append(transportOpts, remoteOpts...) + referrers, err := remote.Referrers(digest, transportOpts...) if err != nil { return nil, nil, fmt.Errorf("error getting referrers: %w", err) }