func (prm *prmMatchRepository) matchesDockerReference(image types.Image, signatureDockerReference string) bool {
intended, signature, err := parseDockerReferences(image.IntendedDockerReference(), signatureDockerReference)
if err != nil {
return false
}
return signature.Name() == intended.Name()
}
func (prm *prmMatchExact) matchesDockerReference(image types.Image, signatureDockerReference string) bool {
intended, signature, err := parseDockerReferences(image.IntendedDockerReference(), signatureDockerReference)
if err != nil {
return false
}
// Do not add default tags: image.IntendedDockerReference() has it added already per its construction, and signatureDockerReference should be exact; so, verify that now.
if reference.IsNameOnly(intended) || reference.IsNameOnly(signature) {
return false
}
return signature.String() == intended.String()
}
func (pr *prSignedBy) isRunningImageAllowed(image types.Image) (bool, error) {
sigs, err := image.Signatures()
if err != nil {
return false, err
}
var rejections []error
for _, s := range sigs {
var reason error
switch res, _, err := pr.isSignatureAuthorAccepted(image, s); res {
case sarAccepted:
// One accepted signature is enough.
return true, nil
case sarRejected:
reason = err
case sarUnknown:
// Huh?! This should not happen at all; treat it as any other invalid value.
fallthrough
default:
reason = fmt.Errorf(`Internal error: Unexpected signature verification result "%s"`, string(res))
}
rejections = append(rejections, reason)
}
var summary error
switch len(rejections) {
case 0:
summary = PolicyRequirementError("A signature was required, but no signature exists")
case 1:
summary = rejections[0]
default:
var msgs []string
for _, e := range rejections {
msgs = append(msgs, e.Error())
}
summary = PolicyRequirementError(fmt.Sprintf("None of the signatures were accepted, reasons: %s",
strings.Join(msgs, "; ")))
}
return false, summary
}
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
}
