// VerifyDockerManifestSignature checks that unverifiedSignature uses expectedKeyIdentity to sign unverifiedManifest as expectedDockerReference,
// using mech.
func VerifyDockerManifestSignature(unverifiedSignature, unverifiedManifest []byte,
expectedDockerReference string, mech SigningMechanism, expectedKeyIdentity string) (*Signature, error) {
sig, err := verifyAndExtractSignature(mech, unverifiedSignature, signatureAcceptanceRules{
validateKeyIdentity: func(keyIdentity string) error {
if keyIdentity != expectedKeyIdentity {
return InvalidSignatureError{msg: fmt.Sprintf("Signature by %s does not match expected fingerprint %s", keyIdentity, expectedKeyIdentity)}
}
return nil
},
validateSignedDockerReference: func(signedDockerReference string) error {
if signedDockerReference != expectedDockerReference {
return InvalidSignatureError{msg: fmt.Sprintf("Docker reference %s does not match %s",
signedDockerReference, expectedDockerReference)}
}
return nil
},
validateSignedDockerManifestDigest: func(signedDockerManifestDigest string) error {
matches, err := utils.ManifestMatchesDigest(unverifiedManifest, signedDockerManifestDigest)
if err != nil {
return err
}
if !matches {
return InvalidSignatureError{msg: fmt.Sprintf("Signature for docker digest %s does not match", signedDockerManifestDigest, signedDockerManifestDigest)}
}
return nil
},
})
if err != nil {
return nil, err
}
return sig, nil
}
func (pr *prSignedBy) isSignatureAuthorAccepted(image types.Image, sig []byte) (signatureAcceptanceResult, *Signature, error) {
switch pr.KeyType {
case SBKeyTypeGPGKeys:
case SBKeyTypeSignedByGPGKeys, SBKeyTypeX509Certificates, SBKeyTypeSignedByX509CAs:
// FIXME? Reject this at policy parsing time already?
return sarRejected, nil, fmt.Errorf(`"Unimplemented "keyType" value "%s"`, string(pr.KeyType))
default:
// This should never happen, newPRSignedBy ensures KeyType.IsValid()
return sarRejected, nil, fmt.Errorf(`"Unknown "keyType" value "%s"`, string(pr.KeyType))
}
if pr.KeyPath != "" && pr.KeyData != nil {
return sarRejected, nil, errors.New(`Internal inconsistency: both "keyPath" and "keyData" specified`)
}
// FIXME: move this to per-context initialization
var data []byte
if pr.KeyData != nil {
data = pr.KeyData
} else {
d, err := ioutil.ReadFile(pr.KeyPath)
if err != nil {
return sarRejected, nil, err
}
data = d
}
// FIXME: move this to per-context initialization
dir, err := ioutil.TempDir("", "skopeo-signedBy-")
if err != nil {
return sarRejected, nil, err
}
defer os.RemoveAll(dir)
mech, err := newGPGSigningMechanismInDirectory(dir)
if err != nil {
return sarRejected, nil, err
}
trustedIdentities, err := mech.ImportKeysFromBytes(data)
if err != nil {
return sarRejected, nil, err
}
if len(trustedIdentities) == 0 {
return sarRejected, nil, PolicyRequirementError("No public keys imported")
}
signature, err := verifyAndExtractSignature(mech, sig, signatureAcceptanceRules{
validateKeyIdentity: func(keyIdentity string) error {
for _, trustedIdentity := range trustedIdentities {
if keyIdentity == trustedIdentity {
return nil
}
}
// Coverage: We use a private GPG home directory and only import trusted keys, so this should
// not be reachable.
return PolicyRequirementError(fmt.Sprintf("Signature by key %s is not accepted", keyIdentity))
},
validateSignedDockerReference: func(ref string) error {
if !pr.SignedIdentity.matchesDockerReference(image, ref) {
return PolicyRequirementError(fmt.Sprintf("Signature for identity %s is not accepted", ref))
}
return nil
},
validateSignedDockerManifestDigest: func(digest string) error {
manifest, err := image.Manifest()
if err != nil {
return err
}
digestMatches, err := utils.ManifestMatchesDigest(manifest, digest)
if err != nil {
return err
}
if !digestMatches {
return PolicyRequirementError(fmt.Sprintf("Signature for digest %s does not match", digest))
}
return nil
},
})
if err != nil {
return sarRejected, nil, err
}
return sarAccepted, signature, nil
}