feat: cluster addons

vendor/github.com/google/certificate-transparency-go/gossip/minimal/x509ext/x509ext.go

@@ -0,0 +1,91 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package x509ext holds extensions types and values for minimal gossip.
+package x509ext
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/google/certificate-transparency-go"
+	"github.com/google/certificate-transparency-go/asn1"
+	"github.com/google/certificate-transparency-go/tls"
+	"github.com/google/certificate-transparency-go/x509"
+)
+
+// OIDExtensionCTSTH is the OID value for an X.509 extension that holds
+// a log STH value.
+// TODO(drysdale): get an official OID value
+var OIDExtensionCTSTH = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 5}
+
+// OIDExtKeyUsageCTMinimalGossip is the OID value for an extended key usage
+// (EKU) that indicates a leaf certificate is used for the validation of STH
+// values from public CT logs.
+// TODO(drysdale): get an official OID value
+var OIDExtKeyUsageCTMinimalGossip = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 6}
+
+// LogSTHInfo is the structure that gets TLS-encoded into the X.509 extension
+// identified by OIDExtensionCTSTH.
+type LogSTHInfo struct {
+	LogURL            []byte   `tls:"maxlen:255"`
+	Version           tls.Enum `tls:"maxval:255"`
+	TreeSize          uint64
+	Timestamp         uint64
+	SHA256RootHash    ct.SHA256Hash
+	TreeHeadSignature ct.DigitallySigned
+}
+
+// LogSTHInfoFromCert retrieves the STH information embedded in a certificate.
+func LogSTHInfoFromCert(cert *x509.Certificate) (*LogSTHInfo, error) {
+	for _, ext := range cert.Extensions {
+		if ext.Id.Equal(OIDExtensionCTSTH) {
+			var sthInfo LogSTHInfo
+			rest, err := tls.Unmarshal(ext.Value, &sthInfo)
+			if err != nil {
+				return nil, fmt.Errorf("failed to unmarshal STH: %v", err)
+			} else if len(rest) > 0 {
+				return nil, fmt.Errorf("trailing data (%d bytes) after STH", len(rest))
+			}
+			return &sthInfo, nil
+		}
+	}
+	return nil, errors.New("no STH extension found")
+}
+
+// HasSTHInfo indicates whether a certificate has embedded STH information.
+func HasSTHInfo(cert *x509.Certificate) bool {
+	for _, ext := range cert.Extensions {
+		if ext.Id.Equal(OIDExtensionCTSTH) {
+			return true
+		}
+	}
+	return false
+}
+
+// STHFromCert retrieves the STH embedded in a certificate; note the returned STH
+// does not have the LogID field filled in.
+func STHFromCert(cert *x509.Certificate) (*ct.SignedTreeHead, error) {
+	sthInfo, err := LogSTHInfoFromCert(cert)
+	if err != nil {
+		return nil, err
+	}
+	return &ct.SignedTreeHead{
+		Version:           ct.Version(sthInfo.Version),
+		TreeSize:          sthInfo.TreeSize,
+		Timestamp:         sthInfo.Timestamp,
+		SHA256RootHash:    sthInfo.SHA256RootHash,
+		TreeHeadSignature: sthInfo.TreeHeadSignature,
+	}, nil
+}