Certificate Transparency: Fetching of Signed Tree Heads (DRAFT)

components/certificate_transparency/tree_state_tracker.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_
+#define COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/cert/ct_verifier.h"
+
+namespace net {
+class CTLogVerifier;
+class X509Certificate;
+
+namespace ct {
+struct SignedCertificateTimestamp;
+struct SignedTreeHead;
+}  // namespace ct
+
+}  // namespace net
+
+namespace certificate_transparency {
+
+class LogProofFetcher;
+
+// Tracks the state of the Merkle Trees of CT logs Chromium
+// knows about. For now, only stores Signed Tree Heads.
+class TreeStateTracker : public net::CTVerifier::Observer {
+ public:
+  TreeStateTracker(
+      scoped_ptr<LogProofFetcher> fetcher,
+      const std::vector<scoped_refptr<net::CTLogVerifier>>& ct_logs);
+  ~TreeStateTracker() override;
+
+  void OnSCTVerified(net::X509Certificate* cert,
+                     const net::ct::SignedCertificateTimestamp* sct) override;
+
+ private:
+  void RefreshSTHs();
+  void OnSTHFetched(const std::string& log_id,
+                    const net::ct::SignedTreeHead& unverified_sth);
+  void OnSTHFetchingFailed(const std::string& log_id,
+                           int net_error,
+                           int http_response_code);
+
+  // Holds the latest STH fetched and verified for each log.
+  std::map<std::string, net::ct::SignedTreeHead> verified_sths_;
+  // Holds STHs that were received but not checked for consistency.
+  std::map<std::string, net::ct::SignedTreeHead>
+      sths_pending_consistency_check_;
+  // Fetcher for getting STHs and proofs from CT logs.
+  scoped_ptr<LogProofFetcher> fetcher_;
+  // List of CT logs to track.
+  std::map<std::string, scoped_refptr<net::CTLogVerifier>> ct_logs_;
+
+  DISALLOW_COPY_AND_ASSIGN(TreeStateTracker);
+};
+
+}  // namespace certificate_transparency
+
+#endif  // COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_