constellation/internal/sigstore/verify.go
Adrian Stobbe 3fde118b33
config: enable azure snp version fetcher again + minimum age for latest version (#1899)
* fetch latest version when older than 2 weeks

* extend hack upload tool to pass an upload date

* Revert "config: disable user-facing version Azure SEV SNP fetch for v2.8  (#1882)"

This reverts commit c7b22d314a.

* fix tests

* use NewAzureSEVSNPVersionList for type guarantees

* Revert "use NewAzureSEVSNPVersionList for type guarantees"

This reverts commit 942566453f4b4a2b6dc16f8689248abf1dc47db4.

* assure list is sorted

* improve root.go style

* daniel feedback
2023-06-09 12:48:12 +02:00

67 lines
2.0 KiB
Go

/*
Copyright (c) Edgeless Systems GmbH
SPDX-License-Identifier: AGPL-3.0-only
*/
package sigstore
import (
"bytes"
"crypto"
"encoding/base64"
"fmt"
"github.com/edgelesssys/constellation/v2/internal/api/versionsapi"
"github.com/edgelesssys/constellation/v2/internal/constants"
"github.com/sigstore/sigstore/pkg/cryptoutils"
sigsig "github.com/sigstore/sigstore/pkg/signature"
)
// Verifier checks if the signature of content can be verified.
type Verifier interface {
VerifySignature(content, signature, publicKey []byte) error
}
// CosignVerifier checks if the signature of content can be verified
// using a cosign public key.
type CosignVerifier struct{}
// VerifySignature checks if the signature of content can be verified
// using publicKey.
// signature is expected to be base64 encoded.
// publicKey is expected to be PEM encoded.
func (CosignVerifier) VerifySignature(content, signature, publicKey []byte) error {
sigRaw := base64.NewDecoder(base64.StdEncoding, bytes.NewReader(signature))
pubKeyRaw, err := cryptoutils.UnmarshalPEMToPublicKey(publicKey)
if err != nil {
return fmt.Errorf("unable to parse public key: %w", err)
}
if err := cryptoutils.ValidatePubKey(pubKeyRaw); err != nil {
return fmt.Errorf("unable to validate public key: %w", err)
}
verifier, err := sigsig.LoadVerifier(pubKeyRaw, crypto.SHA256)
if err != nil {
return fmt.Errorf("unable to load verifier: %w", err)
}
if err := verifier.VerifySignature(sigRaw, bytes.NewReader(content)); err != nil {
return fmt.Errorf("unable to verify signature: %w", err)
}
return nil
}
// CosignPublicKeyForVersion returns the public key for the given version.
func CosignPublicKeyForVersion(ver versionsapi.Version) ([]byte, error) {
if err := ver.Validate(); err != nil {
return nil, fmt.Errorf("selecting public key: invalid version %s: %w", ver.ShortPath(), err)
}
if ver.Ref == versionsapi.ReleaseRef && ver.Stream == "stable" {
return []byte(constants.CosignPublicKeyReleases), nil
}
return []byte(constants.CosignPublicKeyDev), nil
}