Example #1
0
// 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
}