fix: allow cosign download sbom when image is absent (#3245)

* fix: allow cosign download sbom when image is absent Signed-off-by: Vishal Choudhary <[email protected]> * fix: remove lint issue Signed-off-by: Vishal Choudhary <[email protected]> * fix: add errors.As Signed-off-by: Vishal Choudhary <[email protected]> * feat: added comments Signed-off-by: Vishal Choudhary <[email protected]> --------- Signed-off-by: Vishal Choudhary <[email protected]>
sigstore · Oct 17, 2023 · bb4715c · bb4715c
1 parent da66fdd
commit bb4715c
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Showing 2 changed files with 23 additions and 2 deletions.
diff --git a/cmd/cosign/cli/download/attestation.go b/cmd/cosign/cli/download/attestation.go
@@ -18,6 +18,7 @@ package download
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 
 	"github.com/google/go-containerregistry/pkg/name"
@@ -46,8 +47,18 @@ func AttestationCmd(ctx context.Context, regOpts options.RegistryOptions, attOpt
 	}
 
 	se, err := ociremote.SignedEntity(ref, ociremoteOpts...)
+	var entityNotFoundError *ociremote.EntityNotFoundError
 	if err != nil {
-		return err
+		if errors.As(err, &entityNotFoundError) {
+			if digest, ok := ref.(name.Digest); ok {
+				// We don't need to access the original image to download the attached attestation
+				se = ociremote.SignedUnknown(digest)
+			} else {
+				return err
+			}
+		} else {
+			return err
+		}
 	}
 
 	se, err = platform.SignedEntityForPlatform(se, attOptions.Platform)

diff --git a/cmd/cosign/cli/download/sbom.go b/cmd/cosign/cli/download/sbom.go
@@ -44,8 +44,18 @@ func SBOMCmd(
 	}
 
 	se, err := ociremote.SignedEntity(ref, ociremoteOpts...)
+	var entityNotFoundError *ociremote.EntityNotFoundError
 	if err != nil {
-		return nil, err
+		if errors.As(err, &entityNotFoundError) {
+			// We don't need to access the original image to download the attached sbom
+			if digest, ok := ref.(name.Digest); ok {
+				se = ociremote.SignedUnknown(digest)
+			} else {
+				return nil, err
+			}
+		} else {
+			return nil, err
+		}
 	}
 
 	se, err = platform.SignedEntityForPlatform(se, dnOpts.Platform)