chrome/browser/metrics/extensions_metrics_provider.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/metrics/extensions_metrics_provider.h"
   6
   7 #include <set>
   8
   9 #include "base/logging.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/strings/stringprintf.h"
  12 #include "chrome/browser/browser_process.h"
  13 #include "chrome/browser/extensions/install_verifier.h"
  14 #include "chrome/browser/profiles/profile_manager.h"
  15 #include "components/metrics/metrics_log.h"
  16 #include "components/metrics/metrics_state_manager.h"
  17 #include "components/metrics/proto/system_profile.pb.h"
  18 #include "extensions/browser/extension_registry.h"
  19 #include "extensions/browser/extension_system.h"
  20 #include "extensions/common/extension_set.h"
  21 #include "third_party/smhasher/src/City.h"
  22
  23 namespace {
  24
  25 // The number of possible hash keys that a client may use.  The UMA client_id
  26 // value is reduced modulo this value to produce the key used by that
  27 // particular client.
  28 const size_t kExtensionListClientKeys = 4096;
  29
  30 // The number of hash buckets into which extension IDs are mapped.  This sets
  31 // the possible output range of the HashExtension function.
  32 const size_t kExtensionListBuckets = 1024;
  33
  34 // Possible states for extensions. The order of these enum values is important,
  35 // and is used when combining the state of multiple extensions and multiple
  36 // profiles. Combining two states should always result in the higher state.
  37 // Ex: One profile is in state FROM_STORE_VERIFIED, and another is in
  38 // FROM_STORE_UNVERIFIED. The state of the two profiles together will be
  39 // FROM_STORE_UNVERIFIED.
  40 // This enum should be kept in sync with the corresponding enum in
  41 // components/metrics/proto/system_profile.proto
  42 enum ExtensionState {
  43   NO_EXTENSIONS,
  44   FROM_STORE_VERIFIED,
  45   FROM_STORE_UNVERIFIED,
  46   OFF_STORE
  47 };
  48
  49 metrics::SystemProfileProto::ExtensionsState ExtensionStateAsProto(
  50     ExtensionState value) {
  51   switch (value) {
  52     case NO_EXTENSIONS:
  53       return metrics::SystemProfileProto::NO_EXTENSIONS;
  54     case FROM_STORE_VERIFIED:
  55       return metrics::SystemProfileProto::NO_OFFSTORE_VERIFIED;
  56     case FROM_STORE_UNVERIFIED:
  57       return metrics::SystemProfileProto::NO_OFFSTORE_UNVERIFIED;
  58     case OFF_STORE:
  59       return metrics::SystemProfileProto::HAS_OFFSTORE;
  60   }
  61   NOTREACHED();
  62   return metrics::SystemProfileProto::NO_EXTENSIONS;
  63 }
  64
  65 // Determines if the |extension| is an extension (can use extension APIs) and is
  66 // not from the webstore. If local information claims the extension is from the
  67 // webstore, we attempt to verify with |verifier| by checking if it has been
  68 // explicitly deemed invalid. If |verifier| is inactive or if the extension is
  69 // unknown to |verifier|, the local information is trusted.
  70 ExtensionState IsOffStoreExtension(
  71     const extensions::Extension& extension,
  72     const extensions::InstallVerifier& verifier) {
  73   if (!extension.is_extension() && !extension.is_legacy_packaged_app())
  74     return NO_EXTENSIONS;
  75
  76   // Component extensions are considered safe.
  77   if (extensions::Manifest::IsComponentLocation(extension.location()))
  78     return NO_EXTENSIONS;
  79
  80   if (verifier.AllowedByEnterprisePolicy(extension.id()))
  81     return NO_EXTENSIONS;
  82
  83   if (!extensions::InstallVerifier::IsFromStore(extension))
  84     return OFF_STORE;
  85
  86   // Local information about the extension implies it is from the store. We try
  87   // to use the install verifier to verify this.
  88   if (!verifier.IsKnownId(extension.id()))
  89     return FROM_STORE_UNVERIFIED;
  90
  91   if (verifier.IsInvalid(extension.id()))
  92     return OFF_STORE;
  93
  94   return FROM_STORE_VERIFIED;
  95 }
  96
  97 // Finds the ExtensionState of |extensions|. The return value will be the
  98 // highest (as defined by the order of ExtensionState) value of each extension
  99 // in |extensions|.
 100 ExtensionState CheckForOffStore(const extensions::ExtensionSet& extensions,
 101                                 const extensions::InstallVerifier& verifier) {
 102   ExtensionState state = NO_EXTENSIONS;
 103   for (extensions::ExtensionSet::const_iterator it = extensions.begin();
 104        it != extensions.end() && state < OFF_STORE;
 105        ++it) {
 106     // Combine the state of each extension, always favoring the higher state as
 107     // defined by the order of ExtensionState.
 108     state = std::max(state, IsOffStoreExtension(**it, verifier));
 109   }
 110   return state;
 111 }
 112
 113 }  // namespace
 114
 115 ExtensionsMetricsProvider::ExtensionsMetricsProvider(
 116     metrics::MetricsStateManager* metrics_state_manager)
 117     : metrics_state_manager_(metrics_state_manager), cached_profile_(NULL) {
 118   DCHECK(metrics_state_manager_);
 119 }
 120
 121 ExtensionsMetricsProvider::~ExtensionsMetricsProvider() {
 122 }
 123
 124 // static
 125 int ExtensionsMetricsProvider::HashExtension(const std::string& extension_id,
 126                                              uint32 client_key) {
 127   DCHECK_LE(client_key, kExtensionListClientKeys);
 128   std::string message =
 129       base::StringPrintf("%u:%s", client_key, extension_id.c_str());
 130   uint64 output = CityHash64(message.data(), message.size());
 131   return output % kExtensionListBuckets;
 132 }
 133
 134 Profile* ExtensionsMetricsProvider::GetMetricsProfile() {
 135   ProfileManager* profile_manager = g_browser_process->profile_manager();
 136   if (!profile_manager)
 137     return NULL;
 138
 139   // If there is a cached profile, reuse that.  However, check that it is still
 140   // valid first.
 141   if (cached_profile_ && profile_manager->IsValidProfile(cached_profile_))
 142     return cached_profile_;
 143
 144   // Find a suitable profile to use, and cache it so that we continue to report
 145   // statistics on the same profile.  We would simply use
 146   // ProfileManager::GetLastUsedProfile(), except that that has the side effect
 147   // of creating a profile if it does not yet exist.
 148   cached_profile_ = profile_manager->GetProfileByPath(
 149       profile_manager->GetLastUsedProfileDir(profile_manager->user_data_dir()));
 150   if (cached_profile_) {
 151     // Ensure that the returned profile is not an incognito profile.
 152     cached_profile_ = cached_profile_->GetOriginalProfile();
 153   }
 154   return cached_profile_;
 155 }
 156
 157 scoped_ptr<extensions::ExtensionSet>
 158 ExtensionsMetricsProvider::GetInstalledExtensions(Profile* profile) {
 159   if (profile) {
 160     return extensions::ExtensionRegistry::Get(profile)
 161         ->GenerateInstalledExtensionsSet();
 162   }
 163   return scoped_ptr<extensions::ExtensionSet>();
 164 }
 165
 166 uint64 ExtensionsMetricsProvider::GetClientID() {
 167   // TODO(blundell): Create a MetricsLog::ClientIDAsInt() API and call it
 168   // here as well as in MetricsLog's population of the client_id field of
 169   // the uma_proto.
 170   return MetricsLog::Hash(metrics_state_manager_->client_id());
 171 }
 172
 173 void ExtensionsMetricsProvider::ProvideSystemProfileMetrics(
 174     metrics::SystemProfileProto* system_profile) {
 175   ProvideOffStoreMetric(system_profile);
 176   ProvideOccupiedBucketMetric(system_profile);
 177 }
 178
 179 void ExtensionsMetricsProvider::ProvideOffStoreMetric(
 180     metrics::SystemProfileProto* system_profile) {
 181   ProfileManager* profile_manager = g_browser_process->profile_manager();
 182   if (!profile_manager)
 183     return;
 184
 185   ExtensionState state = NO_EXTENSIONS;
 186
 187   // The off-store metric includes information from all loaded profiles at the
 188   // time when this metric is generated.
 189   std::vector<Profile*> profiles = profile_manager->GetLoadedProfiles();
 190   for (size_t i = 0u; i < profiles.size() && state < OFF_STORE; ++i) {
 191     extensions::InstallVerifier* verifier =
 192         extensions::ExtensionSystem::Get(profiles[i])->install_verifier();
 193
 194     scoped_ptr<extensions::ExtensionSet> extensions(
 195         GetInstalledExtensions(profiles[i]));
 196     if (!extensions)
 197       continue;
 198
 199     // Combine the state from each profile, always favoring the higher state as
 200     // defined by the order of ExtensionState.
 201     state = std::max(state, CheckForOffStore(*extensions.get(), *verifier));
 202   }
 203
 204   system_profile->set_offstore_extensions_state(ExtensionStateAsProto(state));
 205 }
 206
 207 void ExtensionsMetricsProvider::ProvideOccupiedBucketMetric(
 208     metrics::SystemProfileProto* system_profile) {
 209   // UMA reports do not support multiple profiles, but extensions are installed
 210   // per-profile.  We return the extensions installed in the primary profile.
 211   // In the future, we might consider reporting data about extensions in all
 212   // profiles.
 213   Profile* profile = GetMetricsProfile();
 214
 215   scoped_ptr<extensions::ExtensionSet> extensions(
 216       GetInstalledExtensions(profile));
 217   if (!extensions)
 218     return;
 219
 220   const int client_key = GetClientID() % kExtensionListClientKeys;
 221
 222   std::set<int> buckets;
 223   for (extensions::ExtensionSet::const_iterator it = extensions->begin();
 224        it != extensions->end();
 225        ++it) {
 226     buckets.insert(HashExtension((*it)->id(), client_key));
 227   }
 228
 229   for (std::set<int>::const_iterator it = buckets.begin(); it != buckets.end();
 230        ++it) {
 231     system_profile->add_occupied_extension_bucket(*it);
 232   }
 233 }