feat: support cosign signatures in OCI-SIF files

go.mod

@@ -1,31 +1,74 @@
 module github.com/sylabs/oci-tools
 
-go 1.22.0
+go 1.22.7
 
 require (
 	github.com/containerd/platforms v0.2.1
 	github.com/google/go-containerregistry v0.20.2
 	github.com/opencontainers/image-spec v1.1.0
 	github.com/sebdah/goldie/v2 v2.5.5
+	github.com/sigstore/cosign/v2 v2.4.1
 	github.com/sylabs/sif/v2 v2.20.2
 )
 
 require (
+	github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2 // indirect
+	github.com/blang/semver v3.5.1+incompatible // indirect
 	github.com/containerd/log v0.1.0 // indirect
 	github.com/containerd/stargz-snapshotter/estargz v0.14.3 // indirect
+	github.com/cyberphone/json-canonicalization v0.0.0-20231011164504-785e29786b46 // indirect
 	github.com/docker/cli v27.1.1+incompatible // indirect
-	github.com/docker/distribution v2.8.2+incompatible // indirect
-	github.com/docker/docker-credential-helpers v0.7.0 // indirect
-	github.com/google/go-cmp v0.5.9 // indirect
+	github.com/docker/distribution v2.8.3+incompatible // indirect
+	github.com/docker/docker-credential-helpers v0.8.0 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/go-chi/chi v4.1.2+incompatible // indirect
+	github.com/go-jose/go-jose/v4 v4.0.4 // indirect
+	github.com/go-openapi/analysis v0.23.0 // indirect
+	github.com/go-openapi/errors v0.22.0 // indirect
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/jsonreference v0.21.0 // indirect
+	github.com/go-openapi/loads v0.22.0 // indirect
+	github.com/go-openapi/runtime v0.28.0 // indirect
+	github.com/go-openapi/spec v0.21.0 // indirect
+	github.com/go-openapi/strfmt v0.23.0 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/go-openapi/validate v0.24.0 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
-	github.com/klauspost/compress v1.16.5 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/jedisct1/go-minisign v0.0.0-20230811132847-661be99b8267 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/letsencrypt/boulder v0.0.0-20240620165639-de9c06129bec // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/oklog/ulid v1.3.1 // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/sassoftware/relic v7.2.1+incompatible // indirect
+	github.com/secure-systems-lab/go-securesystemslib v0.8.0 // indirect
 	github.com/sergi/go-diff v1.2.0 // indirect
+	github.com/sigstore/protobuf-specs v0.3.2 // indirect
+	github.com/sigstore/rekor v1.3.6 // indirect
+	github.com/sigstore/sigstore v1.8.11 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect
-	github.com/vbatts/tar-split v0.11.3 // indirect
-	golang.org/x/sync v0.2.0 // indirect
+	github.com/spf13/cobra v1.8.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/theupdateframework/go-tuf v0.7.0 // indirect
+	github.com/titanous/rocacheck v0.0.0-20171023193734-afe73141d399 // indirect
+	github.com/vbatts/tar-split v0.11.5 // indirect
+	go.mongodb.org/mongo-driver v1.14.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.27.0 // indirect
+	golang.org/x/crypto v0.31.0 // indirect
+	golang.org/x/exp v0.0.0-20240613232115-7f521ea00fb8 // indirect
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
 	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/term v0.27.0 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20240827150818-7e3bb234dfed // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

pkg/sourcesink/cosign.go

@@ -0,0 +1,77 @@
+// Copyright 2024-2025 Sylabs Inc. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sourcesink
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	cosignoci "github.com/sigstore/cosign/v2/pkg/oci"
+	cosignremote "github.com/sigstore/cosign/v2/pkg/oci/remote"
+)
+
+// SignedDescriptor provides access to cosign signatures stored against it.
+type SignedDescriptor interface {
+	// CosignImages checks for image manifests providing cosign signatures &
+	// attestations that are associated with the image or index with the descriptor
+	// If image manifests providing cosign signatures and / or attestations
+	// exist, then these images are returned in a name.Reference -> v1.Image map.
+	//
+	// If recursive is true, then if the descriptor is an index, we also check for
+	// signatures and attestations for each of its associated manifests.
+	//
+	// In the returned map, the images are referenced as '_cosign:<tag>', where
+	// <tag> matches the tag at src. The '_cosign' repository placeholder string
+	// is used instead of any original registry & repository names.
+	CosignImages(ctx context.Context, recursive bool) ([]ReferencedImage, error)
+	// SignedImage wraps an image Descriptor as a cosign oci.SignedImage,
+	// allowing access to signatures and attestations stored alongside the image.
+	SignedImage(context.Context) (cosignoci.SignedImage, error)
+	// SignedImageIndex wraps an image index Descriptor as a cosign oci.SignedImageIndex,
+	// allowing access to signatures and attestations stored alongside the image.
+	SignedImageIndex(context.Context) (cosignoci.SignedImageIndex, error)
+}
+
+// CosignPlaceholderRepo is a placeholder repository name for cosign images.
+const CosignPlaceholderRepo = "_cosign"
+
+type ReferencedImage struct {
+	Ref name.Reference
+	Img v1.Image
+}
+
+func NumDescriptorsForCosign(imgs []ReferencedImage) (int64, error) {
+	descCount := int64(0)
+	for _, ri := range imgs {
+		ls, err := ri.Img.Layers()
+		if err != nil {
+			return 0, err
+		}
+		descCount += int64(len(ls) + 2)
+	}
+	return descCount, nil
+}
+
+//nolint:gochecknoglobals
+var cosignSuffixes = []string{
+	cosignremote.SignatureTagSuffix,
+	cosignremote.AttestationTagSuffix,
+}
+
+func CosignTag(h v1.Hash, suffix string) string {
+	return fmt.Sprint(h.Algorithm, "-", h.Hex, ".", suffix)
+}
+
+func CosignRef(imgDigest v1.Hash, imgRef name.Reference, suffix string, opts ...name.Option) (name.Reference, error) {
+	t := CosignTag(imgDigest, suffix)
+	repo := CosignPlaceholderRepo
+	if imgRef != nil {
+		repo = imgRef.Context().Name()
+	}
+	opts = append(opts, name.WithDefaultRegistry(""))
+	return name.ParseReference(repo+":"+t, opts...)
+}