// Copyright (c) 2012 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.
// TransportSecurityState maintains an in memory database containing the
// list of hosts that currently have transport security enabled. This
// singleton object deals with writing that data out to disk as needed and
// loading it at startup.
// At startup we need to load the transport security state from the
// disk. For the moment, we don't want to delay startup for this load, so we
// let the TransportSecurityState run for a while without being loaded.
// This means that it's possible for pages opened very quickly not to get the
// correct transport security information.
//
// To load the state, we schedule a Task on file_task_runner, which
// deserializes and configures the TransportSecurityState.
//
// The TransportSecurityState object supports running a callback function
// when it changes. This object registers the callback, pointing at itself.
//
// TransportSecurityState calls...
// TransportSecurityPersister::StateIsDirty
// since the callback isn't allowed to block or reenter, we schedule a Task
// on the file task runner after some small amount of time
//
// ...
//
// TransportSecurityPersister::SerializeState
// copies the current state of the TransportSecurityState, serializes
// and writes to disk.
#ifndef NET_HTTP_TRANSPORT_SECURITY_PERSISTER_H_
#define NET_HTTP_TRANSPORT_SECURITY_PERSISTER_H_
#include <string>
#include "base/files/file_path.h"
#include "base/files/important_file_writer.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "net/base/net_export.h"
#include "net/http/transport_security_state.h"
namespace base {
class SequencedTaskRunner;
}
namespace net {
// Reads and updates on-disk TransportSecurity state. Clients of this class
// should create, destroy, and call into it from one thread.
//
// file_task_runner is the task runner this class should use internally to
// perform file IO, and can optionally be associated with a different thread.
class NET_EXPORT TransportSecurityPersister
: public TransportSecurityState::Delegate,
public base::ImportantFileWriter::DataSerializer {
public:
TransportSecurityPersister(TransportSecurityState* state,
const base::FilePath& profile_path,
base::SequencedTaskRunner* file_task_runner,
bool readonly);
virtual ~TransportSecurityPersister();
// Called by the TransportSecurityState when it changes its state.
virtual void StateIsDirty(TransportSecurityState*) OVERRIDE;
// ImportantFileWriter::DataSerializer:
//
// Serializes |transport_security_state_| into |*output|. Returns true if
// all DomainStates were serialized correctly.
//
// The serialization format is JSON; the JSON represents a dictionary of
// host:DomainState pairs (host is a string). The DomainState is
// represented as a dictionary containing the following keys and value
// types (not all keys will always be present):
//
// "sts_include_subdomains": true|false
// "pkp_include_subdomains": true|false
// "created": double
// "expiry": double
// "dynamic_spki_hashes_expiry": double
// "mode": "default"|"force-https"
// legacy value synonyms "strict" = "force-https"
// "pinning-only" = "default"
// legacy value "spdy-only" is unused and ignored
// "static_spki_hashes": list of strings
// legacy key synonym "preloaded_spki_hashes"
// "bad_static_spki_hashes": list of strings
// legacy key synonym "bad_preloaded_spki_hashes"
// "dynamic_spki_hashes": list of strings
//
// The JSON dictionary keys are strings containing
// Base64(SHA256(TransportSecurityState::CanonicalizeHost(domain))).
// The reason for hashing them is so that the stored state does not
// trivially reveal a user's browsing history to an attacker reading the
// serialized state on disk.
virtual bool SerializeData(std::string* data) OVERRIDE;
// Clears any existing non-static entries, and then re-populates
// |transport_security_state_|.
//
// Sets |*dirty| to true if the new state differs from the persisted
// state; false otherwise.
bool LoadEntries(const std::string& serialized, bool* dirty);
private:
// Populates |state| from the JSON string |serialized|. Returns true if
// all entries were parsed and deserialized correctly.
//
// Sets |*dirty| to true if the new state differs from the persisted
// state; false otherwise.
static bool Deserialize(const std::string& serialized,
bool* dirty,
TransportSecurityState* state);
void CompleteLoad(const std::string& state);
TransportSecurityState* transport_security_state_;
// Helper for safely writing the data.
base::ImportantFileWriter writer_;
scoped_refptr<base::SequencedTaskRunner> foreground_runner_;
scoped_refptr<base::SequencedTaskRunner> background_runner_;
// Whether or not we're in read-only mode.
const bool readonly_;
base::WeakPtrFactory<TransportSecurityPersister> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(TransportSecurityPersister);
};
} // namespace net
#endif // NET_HTTP_TRANSPORT_SECURITY_PERSISTER_H_