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 <algorithm>
   8 #include <set>
   9 #include <vector>
  10
  11 #include "base/logging.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "chrome/browser/browser_process.h"
  15 #include "chrome/browser/extensions/install_verifier.h"
  16 #include "chrome/browser/profiles/profile_manager.h"
  17 #include "components/metrics/metrics_log.h"
  18 #include "components/metrics/metrics_state_manager.h"
  19 #include "components/metrics/proto/system_profile.pb.h"
  20 #include "extensions/browser/extension_registry.h"
  21 #include "extensions/browser/extension_system.h"
  22 #include "extensions/common/extension_set.h"
  23 #include "third_party/smhasher/src/City.h"
  24
  25 namespace {
  26
  27 // The number of possible hash keys that a client may use.  The UMA client_id
  28 // value is reduced modulo this value to produce the key used by that
  29 // particular client.
  30 const size_t kExtensionListClientKeys = 4096;
  31
  32 // The number of hash buckets into which extension IDs are mapped.  This sets
  33 // the possible output range of the HashExtension function.
  34 const size_t kExtensionListBuckets = 1024;
  35
  36 // Possible states for extensions. The order of these enum values is important,
  37 // and is used when combining the state of multiple extensions and multiple
  38 // profiles. Combining two states should always result in the higher state.
  39 // Ex: One profile is in state FROM_STORE_VERIFIED, and another is in
  40 // FROM_STORE_UNVERIFIED. The state of the two profiles together will be
  41 // FROM_STORE_UNVERIFIED.
  42 // This enum should be kept in sync with the corresponding enum in
  43 // components/metrics/proto/system_profile.proto
  44 enum ExtensionState {
  45   NO_EXTENSIONS,
  46   FROM_STORE_VERIFIED,
  47   FROM_STORE_UNVERIFIED,
  48   OFF_STORE
  49 };
  50
  51 metrics::SystemProfileProto::ExtensionsState ExtensionStateAsProto(
  52     ExtensionState value) {
  53   switch (value) {
  54     case NO_EXTENSIONS:
  55       return metrics::SystemProfileProto::NO_EXTENSIONS;
  56     case FROM_STORE_VERIFIED:
  57       return metrics::SystemProfileProto::NO_OFFSTORE_VERIFIED;
  58     case FROM_STORE_UNVERIFIED:
  59       return metrics::SystemProfileProto::NO_OFFSTORE_UNVERIFIED;
  60     case OFF_STORE:
  61       return metrics::SystemProfileProto::HAS_OFFSTORE;
  62   }
  63   NOTREACHED();
  64   return metrics::SystemProfileProto::NO_EXTENSIONS;
  65 }
  66
  67 // Determines if the |extension| is an extension (can use extension APIs) and is
  68 // not from the webstore. If local information claims the extension is from the
  69 // webstore, we attempt to verify with |verifier| by checking if it has been
  70 // explicitly deemed invalid. If |verifier| is inactive or if the extension is
  71 // unknown to |verifier|, the local information is trusted.
  72 ExtensionState IsOffStoreExtension(
  73     const extensions::Extension& extension,
  74     const extensions::InstallVerifier& verifier) {
  75   if (!extension.is_extension() && !extension.is_legacy_packaged_app())
  76     return NO_EXTENSIONS;
  77
  78   // Component extensions are considered safe.
  79   if (extensions::Manifest::IsComponentLocation(extension.location()))
  80     return NO_EXTENSIONS;
  81
  82   if (verifier.AllowedByEnterprisePolicy(extension.id()))
  83     return NO_EXTENSIONS;
  84
  85   if (!extensions::InstallVerifier::IsFromStore(extension))
  86     return OFF_STORE;
  87
  88   // Local information about the extension implies it is from the store. We try
  89   // to use the install verifier to verify this.
  90   if (!verifier.IsKnownId(extension.id()))
  91     return FROM_STORE_UNVERIFIED;
  92
  93   if (verifier.IsInvalid(extension.id()))
  94     return OFF_STORE;
  95
  96   return FROM_STORE_VERIFIED;
  97 }
  98
  99 // Finds the ExtensionState of |extensions|. The return value will be the
 100 // highest (as defined by the order of ExtensionState) value of each extension
 101 // in |extensions|.
 102 ExtensionState CheckForOffStore(const extensions::ExtensionSet& extensions,
 103                                 const extensions::InstallVerifier& verifier) {
 104   ExtensionState state = NO_EXTENSIONS;
 105   for (extensions::ExtensionSet::const_iterator it = extensions.begin();
 106        it != extensions.end() && state < OFF_STORE;
 107        ++it) {
 108     // Combine the state of each extension, always favoring the higher state as
 109     // defined by the order of ExtensionState.
 110     state = std::max(state, IsOffStoreExtension(**it, verifier));
 111   }
 112   return state;
 113 }
 114
 115 }  // namespace
 116
 117 ExtensionsMetricsProvider::ExtensionsMetricsProvider(
 118     metrics::MetricsStateManager* metrics_state_manager)
 119     : metrics_state_manager_(metrics_state_manager), cached_profile_(NULL) {
 120   DCHECK(metrics_state_manager_);
 121 }
 122
 123 ExtensionsMetricsProvider::~ExtensionsMetricsProvider() {
 124 }
 125
 126 // static
 127 int ExtensionsMetricsProvider::HashExtension(const std::string& extension_id,
 128                                              uint32 client_key) {
 129   DCHECK_LE(client_key, kExtensionListClientKeys);
 130   std::string message =
 131       base::StringPrintf("%u:%s", client_key, extension_id.c_str());
 132   uint64 output = CityHash64(message.data(), message.size());
 133   return output % kExtensionListBuckets;
 134 }
 135
 136 Profile* ExtensionsMetricsProvider::GetMetricsProfile() {
 137   ProfileManager* profile_manager = g_browser_process->profile_manager();
 138   if (!profile_manager)
 139     return NULL;
 140
 141   // If there is a cached profile, reuse that.  However, check that it is still
 142   // valid first.
 143   if (cached_profile_ && profile_manager->IsValidProfile(cached_profile_))
 144     return cached_profile_;
 145
 146   // Find a suitable profile to use, and cache it so that we continue to report
 147   // statistics on the same profile.  We would simply use
 148   // ProfileManager::GetLastUsedProfile(), except that that has the side effect
 149   // of creating a profile if it does not yet exist.
 150   cached_profile_ = profile_manager->GetProfileByPath(
 151       profile_manager->GetLastUsedProfileDir(profile_manager->user_data_dir()));
 152   if (cached_profile_) {
 153     // Ensure that the returned profile is not an incognito profile.
 154     cached_profile_ = cached_profile_->GetOriginalProfile();
 155   }
 156   return cached_profile_;
 157 }
 158
 159 scoped_ptr<extensions::ExtensionSet>
 160 ExtensionsMetricsProvider::GetInstalledExtensions(Profile* profile) {
 161   if (profile) {
 162     return extensions::ExtensionRegistry::Get(profile)
 163         ->GenerateInstalledExtensionsSet();
 164   }
 165   return scoped_ptr<extensions::ExtensionSet>();
 166 }
 167
 168 uint64 ExtensionsMetricsProvider::GetClientID() {
 169   // TODO(blundell): Create a MetricsLog::ClientIDAsInt() API and call it
 170   // here as well as in MetricsLog's population of the client_id field of
 171   // the uma_proto.
 172   return metrics::MetricsLog::Hash(metrics_state_manager_->client_id());
 173 }
 174
 175 void ExtensionsMetricsProvider::ProvideSystemProfileMetrics(
 176     metrics::SystemProfileProto* system_profile) {
 177   ProvideOffStoreMetric(system_profile);
 178   ProvideOccupiedBucketMetric(system_profile);
 179 }
 180
 181 void ExtensionsMetricsProvider::ProvideOffStoreMetric(
 182     metrics::SystemProfileProto* system_profile) {
 183   ProfileManager* profile_manager = g_browser_process->profile_manager();
 184   if (!profile_manager)
 185     return;
 186
 187   ExtensionState state = NO_EXTENSIONS;
 188
 189   // The off-store metric includes information from all loaded profiles at the
 190   // time when this metric is generated.
 191   std::vector<Profile*> profiles = profile_manager->GetLoadedProfiles();
 192   for (size_t i = 0u; i < profiles.size() && state < OFF_STORE; ++i) {
 193     extensions::InstallVerifier* verifier =
 194         extensions::InstallVerifier::Get(profiles[i]);
 195
 196     scoped_ptr<extensions::ExtensionSet> extensions(
 197         GetInstalledExtensions(profiles[i]));
 198     if (!extensions)
 199       continue;
 200
 201     // Combine the state from each profile, always favoring the higher state as
 202     // defined by the order of ExtensionState.
 203     state = std::max(state, CheckForOffStore(*extensions.get(), *verifier));
 204   }
 205
 206   system_profile->set_offstore_extensions_state(ExtensionStateAsProto(state));
 207 }
 208
 209 void ExtensionsMetricsProvider::ProvideOccupiedBucketMetric(
 210     metrics::SystemProfileProto* system_profile) {
 211   // UMA reports do not support multiple profiles, but extensions are installed
 212   // per-profile.  We return the extensions installed in the primary profile.
 213   // In the future, we might consider reporting data about extensions in all
 214   // profiles.
 215   Profile* profile = GetMetricsProfile();
 216
 217   scoped_ptr<extensions::ExtensionSet> extensions(
 218       GetInstalledExtensions(profile));
 219   if (!extensions)
 220     return;
 221
 222   const int client_key = GetClientID() % kExtensionListClientKeys;
 223
 224   std::set<int> buckets;
 225   for (extensions::ExtensionSet::const_iterator it = extensions->begin();
 226        it != extensions->end();
 227        ++it) {
 228     buckets.insert(HashExtension((*it)->id(), client_key));
 229   }
 230
 231   for (std::set<int>::const_iterator it = buckets.begin(); it != buckets.end();
 232        ++it) {
 233     system_profile->add_occupied_extension_bucket(*it);
 234   }
 235 }