New policy protobuf protocol.

chrome/browser/policy/cloud_policy_cache.cc

+// Copyright (c) 2011 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.
+
+#include "chrome/browser/policy/cloud_policy_cache.h"
+
+#include <limits>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/task.h"
+#include "base/values.h"
+#include "chrome/browser/browser_thread.h"
+#include "chrome/browser/policy/proto/cloud_policy.pb.h"
+#include "chrome/browser/policy/proto/device_management_backend.pb.h"
+#include "chrome/browser/policy/proto/device_management_constants.h"
+#include "chrome/browser/policy/proto/device_management_local.pb.h"
+// configuration_policy_type.h is generated. See policy_templates.json for
+// policy definitions.
+#include "policy/configuration_policy_type.h"
+
+using google::protobuf::RepeatedPtrField;
+
+namespace policy {
+
+// Saves policy information to a file.
+class PersistCloudPolicyTask : public Task {
+ public:
+  PersistCloudPolicyTask(const FilePath& path,
+                         const em::CloudPolicyResponse* policy_response,
+                         const bool is_unmanaged)
+      : path_(path),
+        policy_response_(policy_response),
+        is_unmanaged_(is_unmanaged) {}
+
+ private:
+  // Task override.
+  virtual void Run();
+
+  const FilePath path_;
+  scoped_ptr<const em::CloudPolicyResponse> policy_response_;
+  const bool is_unmanaged_;
+};
+
+void PersistCloudPolicyTask::Run() {
+  std::string data;
+  em::CachedCloudPolicyResponse cached_policy;
+  if (policy_response_.get())
+    cached_policy.mutable_policy_response()->CopyFrom(*policy_response_);
+  if (is_unmanaged_) {
+    cached_policy.set_unmanaged(true);
+    cached_policy.set_timestamp(
+        base::Time::NowFromSystemTime().ToTimeT());
+  }
+  if (!cached_policy.SerializeToString(&data)) {
+    LOG(WARNING) << "Failed to serialize policy data";
+    return;
+  }
+
+  int size = data.size();
+  if (file_util::WriteFile(path_, data.c_str(), size) != size) {
+    LOG(WARNING) << "Failed to write " << path_.value();
+    return;
+  }
+}
+
+CloudPolicyCache::CloudPolicyCache(
+    const FilePath& backing_file_path)
+    : backing_file_path_(backing_file_path),
+      mandatory_policy_(new PolicyMapType),
+      recommended_policy_(new PolicyMapType),
+      fresh_policy_(false),
+      is_unmanaged_(false) {
+}
+
+CloudPolicyCache::~CloudPolicyCache() {}
+
+void CloudPolicyCache::LoadPolicyFromFile() {
+  if (!file_util::PathExists(backing_file_path_) || fresh_policy_) {
+    return;
+  }
+
+  // Read the protobuf from the file.
+  std::string data;
+  if (!file_util::ReadFileToString(backing_file_path_, &data)) {
+    LOG(WARNING) << "Failed to read policy data from "
+                 << backing_file_path_.value();
+    return;
+  }
+
+  em::CachedCloudPolicyResponse cached_response;
+  if (!cached_response.ParseFromArray(data.c_str(), data.size())) {
+    LOG(WARNING) << "Failed to parse policy data read from "
+                 << backing_file_path_.value();
+    return;
+  }
+  base::Time timestamp;
+  is_unmanaged_ = cached_response.unmanaged();
+  // Decode and swap in the new policy information.
+  scoped_ptr<PolicyMapType> mandatory_policy_map(new PolicyMapType);
+  scoped_ptr<PolicyMapType> recommended_policy_map(new PolicyMapType);
+  bool ok = DecodePolicyResponse(cached_response.policy_response(),
+                                 mandatory_policy_map.get(),
+                                 recommended_policy_map.get(),
+                                 &timestamp);
+  if (is_unmanaged_) {
+    timestamp = base::Time::FromTimeT(cached_response.timestamp());
+  } else {
+    if (!ok) {
+      LOG(WARNING) << "Decoding policy data failed.";
+      return;
+    }
+  }
+  {
+    base::AutoLock lock(lock_);
+    if (!fresh_policy_)
+      mandatory_policy_.reset(mandatory_policy_map.release());
+      recommended_policy_.reset(recommended_policy_map.release());
+    last_policy_refresh_time_ = timestamp;
+  }
+}
+
+bool CloudPolicyCache::SetPolicy(
+    const em::CloudPolicyResponse& policy) {
+  is_unmanaged_ = false;
+  base::Time timestamp;
+  scoped_ptr<PolicyMapType> mandatory_policy_map(new PolicyMapType);
+  scoped_ptr<PolicyMapType> recommended_policy_map(new PolicyMapType);
+  bool ok = DecodePolicyResponse(policy, mandatory_policy_map.get(),
+                                 recommended_policy_map.get(), &timestamp);
+  if (!ok) {
+    // TODO(jkummerow): Signal error to PolicyProvider.
+    return false;
+  }
+  const bool new_policy_differs =
+      !Equals(mandatory_policy_map.get(), mandatory_policy_.get()) ||
+      !Equals(recommended_policy_map.get(), recommended_policy_.get());
+  {
+    base::AutoLock lock(lock_);
+    mandatory_policy_.reset(mandatory_policy_map.release());
+    recommended_policy_.reset(recommended_policy_map.release());
+    fresh_policy_ = true;
+    last_policy_refresh_time_ = timestamp;
+  }
+
+  em::CloudPolicyResponse* policy_copy = new em::CloudPolicyResponse;
+  policy_copy->CopyFrom(policy);
+  BrowserThread::PostTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      new PersistCloudPolicyTask(backing_file_path_, policy_copy, false));
+  return new_policy_differs;
+}
+
+PolicyMapType* CloudPolicyCache::GetPolicy() {
+  base::AutoLock lock(lock_);
+  PolicyMapType* policy_copy = new PolicyMapType;
+  for (PolicyMapType::iterator it = mandatory_policy_->begin();
+      it != mandatory_policy_->end(); ++it) {

[gfeher, 2011/02/02 08:42:45]

Nit: indent.

[Jakob Kummerow, 2011/02/03 14:36:52]

Done.

+    policy_copy->insert(std::make_pair(it->first, it->second->DeepCopy()));
+  }
+  return policy_copy;
+}
+
+void CloudPolicyCache::SetUnmanaged() {
+  is_unmanaged_ = true;
+  {
+    base::AutoLock lock(lock_);
+    mandatory_policy_.reset(new PolicyMapType);
+    recommended_policy_.reset(new PolicyMapType);
+    last_policy_refresh_time_ = base::Time::NowFromSystemTime();
+  }
+  BrowserThread::PostTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      new PersistCloudPolicyTask(backing_file_path_, NULL, true));
+}
+
+// static
+bool CloudPolicyCache::DecodePolicyResponse(
+    const em::CloudPolicyResponse& policy_response,
+    PolicyMapType* mandatory,
+    PolicyMapType* recommended,
+    base::Time* timestamp) {
+  std::string data = policy_response.signed_response();
+
+  if (!VerifySignature(policy_response.signature(), data,
+                       policy_response.certificate_chain())) {
+    LOG(WARNING) << "Failed to verify signature.";
+    return false;
+  }
+
+  em::SignedCloudPolicyResponse response;
+  if (!response.ParseFromArray(data.c_str(), data.size())) {
+    LOG(WARNING) << "Failed to parse SignedCloudPolicyResponse protobuf.";
+    return false;
+  }
+
+  // TODO(jkummerow): Verify response.device_token(). Needs final specification
+  // which token we're actually sending / expecting to get back.
+
+  // TODO(jkummerow): Store response.device_name(), if we decide to transfer
+  // it from the server to the client.
+
+  // Reject policies that claim to be from the future.
+  DCHECK(timestamp);
+  *timestamp = base::Time::FromTimeT(response.timestamp());
+  if (*timestamp > base::Time::NowFromSystemTime()) {

[gfeher, 2011/02/02 08:42:45]

Allow a small difference for safety?

[Jakob Kummerow, 2011/02/03 14:36:52]

Done.

+    LOG(WARNING) << "Rejected policy data, timestamp is from the future.";
+    return false;
+  }
+
+  DecodePolicy(response.settings(), mandatory, recommended);
+  return true;
+}
+
+// static
+bool CloudPolicyCache::VerifySignature(
+    const std::string& signature,
+    const std::string& data,
+    const RepeatedPtrField<std::string>& certificate_chain) {
+  // TODO(jkummerow): Implement this. Non-trivial because we want to do it
+  // for all platforms -> it's enough work to deserve its own CL.
+  // Don't forget to also verify the hostname of the server against the cert.
+  return true;
+}
+
+// static
+bool CloudPolicyCache::Equals(const PolicyMapType* a, const PolicyMapType* b) {
+  for (PolicyMapType::const_iterator it = a->begin(); it != a->end(); ++it) {
+    PolicyMapType::const_iterator is_in_b = b->find(it->first);
+    if (is_in_b == b->end())
+      return false;
+    if (!it->second->Equals(is_in_b->second))
+      return false;
+  }
+  for (PolicyMapType::const_iterator it = b->begin(); it != b->end(); ++it) {
+    if (a->find(it->first) == a->end())
+      return false;
+  }
+  return true;
+}
+
+}  // namespace policy