extensions/browser/updater/extension_downloader.cc

   1 // Copyright (c) 2012 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 "extensions/browser/updater/extension_downloader.h"
   6
   7 #include <utility>
   8
   9 #include "base/bind.h"
  10 #include "base/command_line.h"
  11 #include "base/files/file_path.h"
  12 #include "base/location.h"
  13 #include "base/logging.h"
  14 #include "base/metrics/histogram.h"
  15 #include "base/metrics/sparse_histogram.h"
  16 #include "base/stl_util.h"
  17 #include "base/strings/string_number_conversions.h"
  18 #include "base/strings/string_util.h"
  19 #include "base/strings/stringprintf.h"
  20 #include "base/time/time.h"
  21 #include "base/version.h"
  22 #include "content/public/browser/browser_thread.h"
  23 #include "content/public/browser/notification_details.h"
  24 #include "content/public/browser/notification_service.h"
  25 #include "extensions/browser/extensions_browser_client.h"
  26 #include "extensions/browser/notification_types.h"
  27 #include "extensions/browser/updater/extension_cache.h"
  28 #include "extensions/browser/updater/request_queue_impl.h"
  29 #include "extensions/browser/updater/safe_manifest_parser.h"
  30 #include "extensions/common/extension_urls.h"
  31 #include "extensions/common/manifest_url_handlers.h"
  32 #include "google_apis/gaia/identity_provider.h"
  33 #include "net/base/backoff_entry.h"
  34 #include "net/base/load_flags.h"
  35 #include "net/base/net_errors.h"
  36 #include "net/http/http_request_headers.h"
  37 #include "net/http/http_status_code.h"
  38 #include "net/url_request/url_fetcher.h"
  39 #include "net/url_request/url_request_context_getter.h"
  40 #include "net/url_request/url_request_status.h"
  41
  42 using base::Time;
  43 using base::TimeDelta;
  44 using content::BrowserThread;
  45
  46 namespace extensions {
  47
  48 const char ExtensionDownloader::kBlacklistAppID[] = "com.google.crx.blacklist";
  49
  50 namespace {
  51
  52 const net::BackoffEntry::Policy kDefaultBackoffPolicy = {
  53     // Number of initial errors (in sequence) to ignore before applying
  54     // exponential back-off rules.
  55     0,
  56
  57     // Initial delay for exponential back-off in ms.
  58     2000,
  59
  60     // Factor by which the waiting time will be multiplied.
  61     2,
  62
  63     // Fuzzing percentage. ex: 10% will spread requests randomly
  64     // between 90%-100% of the calculated time.
  65     0.1,
  66
  67     // Maximum amount of time we are willing to delay our request in ms.
  68     -1,
  69
  70     // Time to keep an entry from being discarded even when it
  71     // has no significant state, -1 to never discard.
  72     -1,
  73
  74     // Don't use initial delay unless the last request was an error.
  75     false,
  76 };
  77
  78 const char kAuthUserQueryKey[] = "authuser";
  79
  80 const int kMaxAuthUserValue = 10;
  81 const int kMaxOAuth2Attempts = 3;
  82
  83 const char kNotFromWebstoreInstallSource[] = "notfromwebstore";
  84 const char kDefaultInstallSource[] = "";
  85
  86 const char kGoogleDotCom[] = "google.com";
  87 const char kTokenServiceConsumerId[] = "extension_downloader";
  88 const char kWebstoreOAuth2Scope[] =
  89     "https://www.googleapis.com/auth/chromewebstore.readonly";
  90
  91 #define RETRY_HISTOGRAM(name, retry_count, url)                           \
  92   if ((url).DomainIs(kGoogleDotCom)) {                                    \
  93     UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions." name "RetryCountGoogleUrl", \
  94                                 retry_count,                              \
  95                                 1,                                        \
  96                                 kMaxRetries,                              \
  97                                 kMaxRetries + 1);                         \
  98   } else {                                                                \
  99     UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions." name "RetryCountOtherUrl",  \
 100                                 retry_count,                              \
 101                                 1,                                        \
 102                                 kMaxRetries,                              \
 103                                 kMaxRetries + 1);                         \
 104   }
 105
 106 bool ShouldRetryRequest(const net::URLRequestStatus& status,
 107                         int response_code) {
 108   // Retry if the response code is a server error, or the request failed because
 109   // of network errors as opposed to file errors.
 110   return ((response_code >= 500 && status.is_success()) ||
 111           status.status() == net::URLRequestStatus::FAILED);
 112 }
 113
 114 // This parses and updates a URL query such that the value of the |authuser|
 115 // query parameter is incremented by 1. If parameter was not present in the URL,
 116 // it will be added with a value of 1. All other query keys and values are
 117 // preserved as-is. Returns |false| if the user index exceeds a hard-coded
 118 // maximum.
 119 bool IncrementAuthUserIndex(GURL* url) {
 120   int user_index = 0;
 121   std::string old_query = url->query();
 122   std::vector<std::string> new_query_parts;
 123   url::Component query(0, old_query.length());
 124   url::Component key, value;
 125   while (url::ExtractQueryKeyValue(old_query.c_str(), &query, &key, &value)) {
 126     std::string key_string = old_query.substr(key.begin, key.len);
 127     std::string value_string = old_query.substr(value.begin, value.len);
 128     if (key_string == kAuthUserQueryKey) {
 129       base::StringToInt(value_string, &user_index);
 130     } else {
 131       new_query_parts.push_back(base::StringPrintf(
 132           "%s=%s", key_string.c_str(), value_string.c_str()));
 133     }
 134   }
 135   if (user_index >= kMaxAuthUserValue)
 136     return false;
 137   new_query_parts.push_back(
 138       base::StringPrintf("%s=%d", kAuthUserQueryKey, user_index + 1));
 139   std::string new_query_string = JoinString(new_query_parts, '&');
 140   url::Component new_query(0, new_query_string.size());
 141   url::Replacements<char> replacements;
 142   replacements.SetQuery(new_query_string.c_str(), new_query);
 143   *url = url->ReplaceComponents(replacements);
 144   return true;
 145 }
 146
 147 }  // namespace
 148
 149 UpdateDetails::UpdateDetails(const std::string& id, const Version& version)
 150     : id(id), version(version) {
 151 }
 152
 153 UpdateDetails::~UpdateDetails() {
 154 }
 155
 156 ExtensionDownloader::ExtensionFetch::ExtensionFetch()
 157     : url(), credentials(CREDENTIALS_NONE) {
 158 }
 159
 160 ExtensionDownloader::ExtensionFetch::ExtensionFetch(
 161     const std::string& id,
 162     const GURL& url,
 163     const std::string& package_hash,
 164     const std::string& version,
 165     const std::set<int>& request_ids)
 166     : id(id),
 167       url(url),
 168       package_hash(package_hash),
 169       version(version),
 170       request_ids(request_ids),
 171       credentials(CREDENTIALS_NONE),
 172       oauth2_attempt_count(0) {
 173 }
 174
 175 ExtensionDownloader::ExtensionFetch::~ExtensionFetch() {
 176 }
 177
 178 ExtensionDownloader::ExtensionDownloader(
 179     ExtensionDownloaderDelegate* delegate,
 180     net::URLRequestContextGetter* request_context)
 181     : OAuth2TokenService::Consumer(kTokenServiceConsumerId),
 182       delegate_(delegate),
 183       request_context_(request_context),
 184       manifests_queue_(&kDefaultBackoffPolicy,
 185                        base::Bind(&ExtensionDownloader::CreateManifestFetcher,
 186                                   base::Unretained(this))),
 187       extensions_queue_(&kDefaultBackoffPolicy,
 188                         base::Bind(&ExtensionDownloader::CreateExtensionFetcher,
 189                                    base::Unretained(this))),
 190       extension_cache_(NULL),
 191       enable_extra_update_metrics_(false),
 192       weak_ptr_factory_(this) {
 193   DCHECK(delegate_);
 194   DCHECK(request_context_.get());
 195 }
 196
 197 ExtensionDownloader::~ExtensionDownloader() {
 198 }
 199
 200 bool ExtensionDownloader::AddExtension(const Extension& extension,
 201                                        int request_id) {
 202   // Skip extensions with empty update URLs converted from user
 203   // scripts.
 204   if (extension.converted_from_user_script() &&
 205       ManifestURL::GetUpdateURL(&extension).is_empty()) {
 206     return false;
 207   }
 208
 209   // If the extension updates itself from the gallery, ignore any update URL
 210   // data.  At the moment there is no extra data that an extension can
 211   // communicate to the the gallery update servers.
 212   std::string update_url_data;
 213   if (!ManifestURL::UpdatesFromGallery(&extension))
 214     update_url_data = delegate_->GetUpdateUrlData(extension.id());
 215
 216   std::string install_source;
 217   bool force_update =
 218       delegate_->ShouldForceUpdate(extension.id(), &install_source);
 219   return AddExtensionData(extension.id(),
 220                           *extension.version(),
 221                           extension.GetType(),
 222                           ManifestURL::GetUpdateURL(&extension),
 223                           update_url_data,
 224                           request_id,
 225                           force_update,
 226                           install_source);
 227 }
 228
 229 bool ExtensionDownloader::AddPendingExtension(const std::string& id,
 230                                               const GURL& update_url,
 231                                               int request_id) {
 232   // Use a zero version to ensure that a pending extension will always
 233   // be updated, and thus installed (assuming all extensions have
 234   // non-zero versions).
 235   Version version("0.0.0.0");
 236   DCHECK(version.IsValid());
 237
 238   return AddExtensionData(id,
 239                           version,
 240                           Manifest::TYPE_UNKNOWN,
 241                           update_url,
 242                           std::string(),
 243                           request_id,
 244                           false,
 245                           std::string());
 246 }
 247
 248 void ExtensionDownloader::StartAllPending(ExtensionCache* cache) {
 249   if (cache) {
 250     extension_cache_ = cache;
 251     extension_cache_->Start(base::Bind(&ExtensionDownloader::DoStartAllPending,
 252                                        weak_ptr_factory_.GetWeakPtr()));
 253   } else {
 254     DoStartAllPending();
 255   }
 256 }
 257
 258 void ExtensionDownloader::DoStartAllPending() {
 259   ReportStats();
 260   url_stats_ = URLStats();
 261
 262   for (FetchMap::iterator it = fetches_preparing_.begin();
 263        it != fetches_preparing_.end();
 264        ++it) {
 265     std::vector<linked_ptr<ManifestFetchData>>& list = it->second;
 266     for (size_t i = 0; i < list.size(); ++i) {
 267       StartUpdateCheck(scoped_ptr<ManifestFetchData>(list[i].release()));
 268     }
 269   }
 270   fetches_preparing_.clear();
 271 }
 272
 273 void ExtensionDownloader::StartBlacklistUpdate(
 274     const std::string& version,
 275     const ManifestFetchData::PingData& ping_data,
 276     int request_id) {
 277   // Note: it is very important that we use the https version of the update
 278   // url here to avoid DNS hijacking of the blacklist, which is not validated
 279   // by a public key signature like .crx files are.
 280   scoped_ptr<ManifestFetchData> blacklist_fetch(CreateManifestFetchData(
 281       extension_urls::GetWebstoreUpdateUrl(), request_id));
 282   DCHECK(blacklist_fetch->base_url().SchemeIsSecure());
 283   blacklist_fetch->AddExtension(kBlacklistAppID,
 284                                 version,
 285                                 &ping_data,
 286                                 std::string(),
 287                                 kDefaultInstallSource,
 288                                 false);
 289   StartUpdateCheck(blacklist_fetch.Pass());
 290 }
 291
 292 void ExtensionDownloader::SetWebstoreIdentityProvider(
 293     scoped_ptr<IdentityProvider> identity_provider) {
 294   identity_provider_.swap(identity_provider);
 295 }
 296
 297 bool ExtensionDownloader::AddExtensionData(
 298     const std::string& id,
 299     const Version& version,
 300     Manifest::Type extension_type,
 301     const GURL& extension_update_url,
 302     const std::string& update_url_data,
 303     int request_id,
 304     bool force_update,
 305     const std::string& install_source_override) {
 306   GURL update_url(extension_update_url);
 307   // Skip extensions with non-empty invalid update URLs.
 308   if (!update_url.is_empty() && !update_url.is_valid()) {
 309     LOG(WARNING) << "Extension " << id << " has invalid update url "
 310                  << update_url;
 311     return false;
 312   }
 313
 314   // Make sure we use SSL for store-hosted extensions.
 315   if (extension_urls::IsWebstoreUpdateUrl(update_url) &&
 316       !update_url.SchemeIsSecure())
 317     update_url = extension_urls::GetWebstoreUpdateUrl();
 318
 319   // Skip extensions with empty IDs.
 320   if (id.empty()) {
 321     LOG(WARNING) << "Found extension with empty ID";
 322     return false;
 323   }
 324
 325   if (update_url.DomainIs(kGoogleDotCom)) {
 326     url_stats_.google_url_count++;
 327   } else if (update_url.is_empty()) {
 328     url_stats_.no_url_count++;
 329     // Fill in default update URL.
 330     update_url = extension_urls::GetWebstoreUpdateUrl();
 331   } else {
 332     url_stats_.other_url_count++;
 333   }
 334
 335   switch (extension_type) {
 336     case Manifest::TYPE_THEME:
 337       ++url_stats_.theme_count;
 338       break;
 339     case Manifest::TYPE_EXTENSION:
 340     case Manifest::TYPE_USER_SCRIPT:
 341       ++url_stats_.extension_count;
 342       break;
 343     case Manifest::TYPE_HOSTED_APP:
 344     case Manifest::TYPE_LEGACY_PACKAGED_APP:
 345       ++url_stats_.app_count;
 346       break;
 347     case Manifest::TYPE_PLATFORM_APP:
 348       ++url_stats_.platform_app_count;
 349       break;
 350     case Manifest::TYPE_UNKNOWN:
 351     default:
 352       ++url_stats_.pending_count;
 353       break;
 354   }
 355
 356   std::vector<GURL> update_urls;
 357   update_urls.push_back(update_url);
 358   // If metrics are enabled, also add to ManifestFetchData for the
 359   // webstore update URL.
 360   if (!extension_urls::IsWebstoreUpdateUrl(update_url) &&
 361       enable_extra_update_metrics_) {
 362     update_urls.push_back(extension_urls::GetWebstoreUpdateUrl());
 363   }
 364
 365   for (size_t i = 0; i < update_urls.size(); ++i) {
 366     DCHECK(!update_urls[i].is_empty());
 367     DCHECK(update_urls[i].is_valid());
 368
 369     std::string install_source =
 370         i == 0 ? kDefaultInstallSource : kNotFromWebstoreInstallSource;
 371     if (!install_source_override.empty()) {
 372       install_source = install_source_override;
 373     }
 374
 375     ManifestFetchData::PingData ping_data;
 376     ManifestFetchData::PingData* optional_ping_data = NULL;
 377     if (delegate_->GetPingDataForExtension(id, &ping_data))
 378       optional_ping_data = &ping_data;
 379
 380     // Find or create a ManifestFetchData to add this extension to.
 381     bool added = false;
 382     FetchMap::iterator existing_iter =
 383         fetches_preparing_.find(std::make_pair(request_id, update_urls[i]));
 384     if (existing_iter != fetches_preparing_.end() &&
 385         !existing_iter->second.empty()) {
 386       // Try to add to the ManifestFetchData at the end of the list.
 387       ManifestFetchData* existing_fetch = existing_iter->second.back().get();
 388       if (existing_fetch->AddExtension(id,
 389                                        version.GetString(),
 390                                        optional_ping_data,
 391                                        update_url_data,
 392                                        install_source,
 393                                        force_update)) {
 394         added = true;
 395       }
 396     }
 397     if (!added) {
 398       // Otherwise add a new element to the list, if the list doesn't exist or
 399       // if its last element is already full.
 400       linked_ptr<ManifestFetchData> fetch(
 401           CreateManifestFetchData(update_urls[i], request_id));
 402       fetches_preparing_[std::make_pair(request_id, update_urls[i])].push_back(
 403           fetch);
 404       added = fetch->AddExtension(id,
 405                                   version.GetString(),
 406                                   optional_ping_data,
 407                                   update_url_data,
 408                                   install_source,
 409                                   force_update);
 410       DCHECK(added);
 411     }
 412   }
 413
 414   return true;
 415 }
 416
 417 void ExtensionDownloader::ReportStats() const {
 418   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckExtension",
 419                            url_stats_.extension_count);
 420   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckTheme",
 421                            url_stats_.theme_count);
 422   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckApp", url_stats_.app_count);
 423   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckPackagedApp",
 424                            url_stats_.platform_app_count);
 425   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckPending",
 426                            url_stats_.pending_count);
 427   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckGoogleUrl",
 428                            url_stats_.google_url_count);
 429   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckOtherUrl",
 430                            url_stats_.other_url_count);
 431   UMA_HISTOGRAM_COUNTS_100("Extensions.UpdateCheckNoUrl",
 432                            url_stats_.no_url_count);
 433 }
 434
 435 void ExtensionDownloader::StartUpdateCheck(
 436     scoped_ptr<ManifestFetchData> fetch_data) {
 437   const std::set<std::string>& id_set(fetch_data->extension_ids());
 438
 439   if (!ExtensionsBrowserClient::Get()->IsBackgroundUpdateAllowed()) {
 440     NotifyExtensionsDownloadFailed(id_set,
 441                                    fetch_data->request_ids(),
 442                                    ExtensionDownloaderDelegate::DISABLED);
 443   }
 444
 445   RequestQueue<ManifestFetchData>::iterator i;
 446   for (i = manifests_queue_.begin(); i != manifests_queue_.end(); ++i) {
 447     if (fetch_data->full_url() == i->full_url()) {
 448       // This url is already scheduled to be fetched.
 449       i->Merge(*fetch_data);
 450       return;
 451     }
 452   }
 453
 454   if (manifests_queue_.active_request() &&
 455       manifests_queue_.active_request()->full_url() == fetch_data->full_url()) {
 456     manifests_queue_.active_request()->Merge(*fetch_data);
 457   } else {
 458     UMA_HISTOGRAM_COUNTS(
 459         "Extensions.UpdateCheckUrlLength",
 460         fetch_data->full_url().possibly_invalid_spec().length());
 461
 462     manifests_queue_.ScheduleRequest(fetch_data.Pass());
 463   }
 464 }
 465
 466 void ExtensionDownloader::CreateManifestFetcher() {
 467   if (VLOG_IS_ON(2)) {
 468     std::vector<std::string> id_vector(
 469         manifests_queue_.active_request()->extension_ids().begin(),
 470         manifests_queue_.active_request()->extension_ids().end());
 471     std::string id_list = JoinString(id_vector, ',');
 472     VLOG(2) << "Fetching " << manifests_queue_.active_request()->full_url()
 473             << " for " << id_list;
 474   }
 475
 476   manifest_fetcher_.reset(
 477       net::URLFetcher::Create(kManifestFetcherId,
 478                               manifests_queue_.active_request()->full_url(),
 479                               net::URLFetcher::GET,
 480                               this));
 481   manifest_fetcher_->SetRequestContext(request_context_.get());
 482   manifest_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
 483                                   net::LOAD_DO_NOT_SAVE_COOKIES |
 484                                   net::LOAD_DISABLE_CACHE);
 485   // Update checks can be interrupted if a network change is detected; this is
 486   // common for the retail mode AppPack on ChromeOS. Retrying once should be
 487   // enough to recover in those cases; let the fetcher retry up to 3 times
 488   // just in case. http://crosbug.com/130602
 489   manifest_fetcher_->SetAutomaticallyRetryOnNetworkChanges(3);
 490   manifest_fetcher_->Start();
 491 }
 492
 493 void ExtensionDownloader::OnURLFetchComplete(const net::URLFetcher* source) {
 494   VLOG(2) << source->GetResponseCode() << " " << source->GetURL();
 495
 496   if (source == manifest_fetcher_.get()) {
 497     std::string data;
 498     source->GetResponseAsString(&data);
 499     OnManifestFetchComplete(source->GetURL(),
 500                             source->GetStatus(),
 501                             source->GetResponseCode(),
 502                             source->GetBackoffDelay(),
 503                             data);
 504   } else if (source == extension_fetcher_.get()) {
 505     OnCRXFetchComplete(source,
 506                        source->GetURL(),
 507                        source->GetStatus(),
 508                        source->GetResponseCode(),
 509                        source->GetBackoffDelay());
 510   } else {
 511     NOTREACHED();
 512   }
 513 }
 514
 515 void ExtensionDownloader::OnManifestFetchComplete(
 516     const GURL& url,
 517     const net::URLRequestStatus& status,
 518     int response_code,
 519     const base::TimeDelta& backoff_delay,
 520     const std::string& data) {
 521   // We want to try parsing the manifest, and if it indicates updates are
 522   // available, we want to fire off requests to fetch those updates.
 523   if (status.status() == net::URLRequestStatus::SUCCESS &&
 524       (response_code == 200 || (url.SchemeIsFile() && data.length() > 0))) {
 525     RETRY_HISTOGRAM("ManifestFetchSuccess",
 526                     manifests_queue_.active_request_failure_count(),
 527                     url);
 528     VLOG(2) << "beginning manifest parse for " << url;
 529     scoped_refptr<SafeManifestParser> safe_parser(new SafeManifestParser(
 530         data,
 531         manifests_queue_.reset_active_request().release(),
 532         base::Bind(&ExtensionDownloader::HandleManifestResults,
 533                    weak_ptr_factory_.GetWeakPtr())));
 534     safe_parser->Start();
 535   } else {
 536     VLOG(1) << "Failed to fetch manifest '" << url.possibly_invalid_spec()
 537             << "' response code:" << response_code;
 538     if (ShouldRetryRequest(status, response_code) &&
 539         manifests_queue_.active_request_failure_count() < kMaxRetries) {
 540       manifests_queue_.RetryRequest(backoff_delay);
 541     } else {
 542       RETRY_HISTOGRAM("ManifestFetchFailure",
 543                       manifests_queue_.active_request_failure_count(),
 544                       url);
 545       NotifyExtensionsDownloadFailed(
 546           manifests_queue_.active_request()->extension_ids(),
 547           manifests_queue_.active_request()->request_ids(),
 548           ExtensionDownloaderDelegate::MANIFEST_FETCH_FAILED);
 549     }
 550   }
 551   manifest_fetcher_.reset();
 552   manifests_queue_.reset_active_request();
 553
 554   // If we have any pending manifest requests, fire off the next one.
 555   manifests_queue_.StartNextRequest();
 556 }
 557
 558 void ExtensionDownloader::HandleManifestResults(
 559     const ManifestFetchData& fetch_data,
 560     const UpdateManifest::Results* results) {
 561   // Keep a list of extensions that will not be updated, so that the |delegate_|
 562   // can be notified once we're done here.
 563   std::set<std::string> not_updated(fetch_data.extension_ids());
 564
 565   if (!results) {
 566     NotifyExtensionsDownloadFailed(
 567         not_updated,
 568         fetch_data.request_ids(),
 569         ExtensionDownloaderDelegate::MANIFEST_INVALID);
 570     return;
 571   }
 572
 573   // Examine the parsed manifest and kick off fetches of any new crx files.
 574   std::vector<int> updates;
 575   DetermineUpdates(fetch_data, *results, &updates);
 576   for (size_t i = 0; i < updates.size(); i++) {
 577     const UpdateManifest::Result* update = &(results->list.at(updates[i]));
 578     const std::string& id = update->extension_id;
 579     not_updated.erase(id);
 580
 581     GURL crx_url = update->crx_url;
 582     if (id != kBlacklistAppID) {
 583       NotifyUpdateFound(update->extension_id, update->version);
 584     } else {
 585       // The URL of the blacklist file is returned by the server and we need to
 586       // be sure that we continue to be able to reliably detect whether a URL
 587       // references a blacklist file.
 588       DCHECK(extension_urls::IsBlacklistUpdateUrl(crx_url)) << crx_url;
 589
 590       // Force https (crbug.com/129587).
 591       if (!crx_url.SchemeIsSecure()) {
 592         url::Replacements<char> replacements;
 593         std::string scheme("https");
 594         replacements.SetScheme(scheme.c_str(),
 595                                url::Component(0, scheme.size()));
 596         crx_url = crx_url.ReplaceComponents(replacements);
 597       }
 598     }
 599     scoped_ptr<ExtensionFetch> fetch(
 600         new ExtensionFetch(update->extension_id,
 601                            crx_url,
 602                            update->package_hash,
 603                            update->version,
 604                            fetch_data.request_ids()));
 605     FetchUpdatedExtension(fetch.Pass());
 606   }
 607
 608   // If the manifest response included a <daystart> element, we want to save
 609   // that value for any extensions which had sent a ping in the request.
 610   if (fetch_data.base_url().DomainIs(kGoogleDotCom) &&
 611       results->daystart_elapsed_seconds >= 0) {
 612     Time day_start =
 613         Time::Now() - TimeDelta::FromSeconds(results->daystart_elapsed_seconds);
 614
 615     const std::set<std::string>& extension_ids = fetch_data.extension_ids();
 616     std::set<std::string>::const_iterator i;
 617     for (i = extension_ids.begin(); i != extension_ids.end(); i++) {
 618       const std::string& id = *i;
 619       ExtensionDownloaderDelegate::PingResult& result = ping_results_[id];
 620       result.did_ping = fetch_data.DidPing(id, ManifestFetchData::ROLLCALL);
 621       result.day_start = day_start;
 622     }
 623   }
 624
 625   NotifyExtensionsDownloadFailed(
 626       not_updated,
 627       fetch_data.request_ids(),
 628       ExtensionDownloaderDelegate::NO_UPDATE_AVAILABLE);
 629 }
 630
 631 void ExtensionDownloader::DetermineUpdates(
 632     const ManifestFetchData& fetch_data,
 633     const UpdateManifest::Results& possible_updates,
 634     std::vector<int>* result) {
 635   for (size_t i = 0; i < possible_updates.list.size(); i++) {
 636     const UpdateManifest::Result* update = &possible_updates.list[i];
 637     const std::string& id = update->extension_id;
 638
 639     if (!fetch_data.Includes(id)) {
 640       VLOG(2) << "Ignoring " << id << " from this manifest";
 641       continue;
 642     }
 643
 644     if (VLOG_IS_ON(2)) {
 645       if (update->version.empty())
 646         VLOG(2) << "manifest indicates " << id << " has no update";
 647       else
 648         VLOG(2) << "manifest indicates " << id << " latest version is '"
 649                 << update->version << "'";
 650     }
 651
 652     if (!delegate_->IsExtensionPending(id)) {
 653       // If we're not installing pending extension, and the update
 654       // version is the same or older than what's already installed,
 655       // we don't want it.
 656       std::string version;
 657       if (!delegate_->GetExtensionExistingVersion(id, &version)) {
 658         VLOG(2) << id << " is not installed";
 659         continue;
 660       }
 661
 662       VLOG(2) << id << " is at '" << version << "'";
 663
 664       // We should skip the version check if update was forced.
 665       if (!fetch_data.DidForceUpdate(id)) {
 666         Version existing_version(version);
 667         Version update_version(update->version);
 668         if (!update_version.IsValid() ||
 669             update_version.CompareTo(existing_version) <= 0) {
 670           continue;
 671         }
 672       }
 673     }
 674
 675     // If the update specifies a browser minimum version, do we qualify?
 676     if (update->browser_min_version.length() > 0 &&
 677         !ExtensionsBrowserClient::Get()->IsMinBrowserVersionSupported(
 678             update->browser_min_version)) {
 679       // TODO(asargent) - We may want this to show up in the extensions UI
 680       // eventually. (http://crbug.com/12547).
 681       LOG(WARNING) << "Updated version of extension " << id
 682                    << " available, but requires chrome version "
 683                    << update->browser_min_version;
 684       continue;
 685     }
 686     VLOG(2) << "will try to update " << id;
 687     result->push_back(i);
 688   }
 689 }
 690
 691 // Begins (or queues up) download of an updated extension.
 692 void ExtensionDownloader::FetchUpdatedExtension(
 693     scoped_ptr<ExtensionFetch> fetch_data) {
 694   if (!fetch_data->url.is_valid()) {
 695     // TODO(asargent): This can sometimes be invalid. See crbug.com/130881.
 696     LOG(ERROR) << "Invalid URL: '" << fetch_data->url.possibly_invalid_spec()
 697                << "' for extension " << fetch_data->id;
 698     return;
 699   }
 700
 701   for (RequestQueue<ExtensionFetch>::iterator iter = extensions_queue_.begin();
 702        iter != extensions_queue_.end();
 703        ++iter) {
 704     if (iter->id == fetch_data->id || iter->url == fetch_data->url) {
 705       iter->request_ids.insert(fetch_data->request_ids.begin(),
 706                                fetch_data->request_ids.end());
 707       return;  // already scheduled
 708     }
 709   }
 710
 711   if (extensions_queue_.active_request() &&
 712       extensions_queue_.active_request()->url == fetch_data->url) {
 713     extensions_queue_.active_request()->request_ids.insert(
 714         fetch_data->request_ids.begin(), fetch_data->request_ids.end());
 715   } else {
 716     std::string version;
 717     if (extension_cache_ &&
 718         extension_cache_->GetExtension(fetch_data->id, NULL, &version) &&
 719         version == fetch_data->version) {
 720       base::FilePath crx_path;
 721       // Now get .crx file path and mark extension as used.
 722       extension_cache_->GetExtension(fetch_data->id, &crx_path, &version);
 723       NotifyDelegateDownloadFinished(fetch_data.Pass(), crx_path, false);
 724     } else {
 725       extensions_queue_.ScheduleRequest(fetch_data.Pass());
 726     }
 727   }
 728 }
 729
 730 void ExtensionDownloader::NotifyDelegateDownloadFinished(
 731     scoped_ptr<ExtensionFetch> fetch_data,
 732     const base::FilePath& crx_path,
 733     bool file_ownership_passed) {
 734   delegate_->OnExtensionDownloadFinished(fetch_data->id,
 735                                          crx_path,
 736                                          file_ownership_passed,
 737                                          fetch_data->url,
 738                                          fetch_data->version,
 739                                          ping_results_[fetch_data->id],
 740                                          fetch_data->request_ids);
 741   ping_results_.erase(fetch_data->id);
 742 }
 743
 744 void ExtensionDownloader::CreateExtensionFetcher() {
 745   const ExtensionFetch* fetch = extensions_queue_.active_request();
 746   extension_fetcher_.reset(net::URLFetcher::Create(
 747       kExtensionFetcherId, fetch->url, net::URLFetcher::GET, this));
 748   extension_fetcher_->SetRequestContext(request_context_.get());
 749   extension_fetcher_->SetAutomaticallyRetryOnNetworkChanges(3);
 750
 751   int load_flags = net::LOAD_DISABLE_CACHE;
 752   bool is_secure = fetch->url.SchemeIsSecure();
 753   if (fetch->credentials != ExtensionFetch::CREDENTIALS_COOKIES || !is_secure) {
 754     load_flags |= net::LOAD_DO_NOT_SEND_COOKIES | net::LOAD_DO_NOT_SAVE_COOKIES;
 755   }
 756   extension_fetcher_->SetLoadFlags(load_flags);
 757
 758   // Download CRX files to a temp file. The blacklist is small and will be
 759   // processed in memory, so it is fetched into a string.
 760   if (fetch->id != kBlacklistAppID) {
 761     extension_fetcher_->SaveResponseToTemporaryFile(
 762         BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
 763   }
 764
 765   if (fetch->credentials == ExtensionFetch::CREDENTIALS_OAUTH2_TOKEN &&
 766       is_secure) {
 767     if (access_token_.empty()) {
 768       // We should try OAuth2, but we have no token cached. This
 769       // ExtensionFetcher will be started once the token fetch is complete,
 770       // in either OnTokenFetchSuccess or OnTokenFetchFailure.
 771       DCHECK(identity_provider_.get());
 772       OAuth2TokenService::ScopeSet webstore_scopes;
 773       webstore_scopes.insert(kWebstoreOAuth2Scope);
 774       access_token_request_ =
 775           identity_provider_->GetTokenService()->StartRequest(
 776               identity_provider_->GetActiveAccountId(), webstore_scopes, this);
 777       return;
 778     }
 779     extension_fetcher_->AddExtraRequestHeader(
 780         base::StringPrintf("%s: Bearer %s",
 781                            net::HttpRequestHeaders::kAuthorization,
 782                            access_token_.c_str()));
 783   }
 784
 785   VLOG(2) << "Starting fetch of " << fetch->url << " for " << fetch->id;
 786   extension_fetcher_->Start();
 787 }
 788
 789 void ExtensionDownloader::OnCRXFetchComplete(
 790     const net::URLFetcher* source,
 791     const GURL& url,
 792     const net::URLRequestStatus& status,
 793     int response_code,
 794     const base::TimeDelta& backoff_delay) {
 795   ExtensionFetch& active_request = *extensions_queue_.active_request();
 796   const std::string& id = active_request.id;
 797   if (status.status() == net::URLRequestStatus::SUCCESS &&
 798       (response_code == 200 || url.SchemeIsFile())) {
 799     RETRY_HISTOGRAM("CrxFetchSuccess",
 800                     extensions_queue_.active_request_failure_count(),
 801                     url);
 802     base::FilePath crx_path;
 803     // Take ownership of the file at |crx_path|.
 804     CHECK(source->GetResponseAsFilePath(true, &crx_path));
 805     scoped_ptr<ExtensionFetch> fetch_data =
 806         extensions_queue_.reset_active_request();
 807     if (extension_cache_) {
 808       const std::string& version = fetch_data->version;
 809       extension_cache_->PutExtension(
 810           id,
 811           crx_path,
 812           version,
 813           base::Bind(&ExtensionDownloader::NotifyDelegateDownloadFinished,
 814                      weak_ptr_factory_.GetWeakPtr(),
 815                      base::Passed(&fetch_data)));
 816     } else {
 817       NotifyDelegateDownloadFinished(fetch_data.Pass(), crx_path, true);
 818     }
 819   } else if (IterateFetchCredentialsAfterFailure(
 820                  &active_request, status, response_code)) {
 821     extensions_queue_.RetryRequest(backoff_delay);
 822   } else {
 823     const std::set<int>& request_ids = active_request.request_ids;
 824     const ExtensionDownloaderDelegate::PingResult& ping = ping_results_[id];
 825     VLOG(1) << "Failed to fetch extension '" << url.possibly_invalid_spec()
 826             << "' response code:" << response_code;
 827     if (ShouldRetryRequest(status, response_code) &&
 828         extensions_queue_.active_request_failure_count() < kMaxRetries) {
 829       extensions_queue_.RetryRequest(backoff_delay);
 830     } else {
 831       RETRY_HISTOGRAM("CrxFetchFailure",
 832                       extensions_queue_.active_request_failure_count(),
 833                       url);
 834       // status.error() is 0 (net::OK) or negative. (See net/base/net_errors.h)
 835       UMA_HISTOGRAM_SPARSE_SLOWLY("Extensions.CrxFetchError", -status.error());
 836       delegate_->OnExtensionDownloadFailed(
 837           id, ExtensionDownloaderDelegate::CRX_FETCH_FAILED, ping, request_ids);
 838     }
 839     ping_results_.erase(id);
 840     extensions_queue_.reset_active_request();
 841   }
 842
 843   extension_fetcher_.reset();
 844
 845   // If there are any pending downloads left, start the next one.
 846   extensions_queue_.StartNextRequest();
 847 }
 848
 849 void ExtensionDownloader::NotifyExtensionsDownloadFailed(
 850     const std::set<std::string>& extension_ids,
 851     const std::set<int>& request_ids,
 852     ExtensionDownloaderDelegate::Error error) {
 853   for (std::set<std::string>::const_iterator it = extension_ids.begin();
 854        it != extension_ids.end();
 855        ++it) {
 856     const ExtensionDownloaderDelegate::PingResult& ping = ping_results_[*it];
 857     delegate_->OnExtensionDownloadFailed(*it, error, ping, request_ids);
 858     ping_results_.erase(*it);
 859   }
 860 }
 861
 862 void ExtensionDownloader::NotifyUpdateFound(const std::string& id,
 863                                             const std::string& version) {
 864   UpdateDetails updateInfo(id, Version(version));
 865   content::NotificationService::current()->Notify(
 866       extensions::NOTIFICATION_EXTENSION_UPDATE_FOUND,
 867       content::NotificationService::AllBrowserContextsAndSources(),
 868       content::Details<UpdateDetails>(&updateInfo));
 869 }
 870
 871 bool ExtensionDownloader::IterateFetchCredentialsAfterFailure(
 872     ExtensionFetch* fetch,
 873     const net::URLRequestStatus& status,
 874     int response_code) {
 875   bool auth_failure = status.status() == net::URLRequestStatus::CANCELED ||
 876                       (status.status() == net::URLRequestStatus::SUCCESS &&
 877                        (response_code == net::HTTP_UNAUTHORIZED ||
 878                         response_code == net::HTTP_FORBIDDEN));
 879   if (!auth_failure) {
 880     return false;
 881   }
 882   // Here we decide what to do next if the server refused to authorize this
 883   // fetch.
 884   switch (fetch->credentials) {
 885     case ExtensionFetch::CREDENTIALS_NONE:
 886       if (fetch->url.DomainIs(kGoogleDotCom) && identity_provider_) {
 887         fetch->credentials = ExtensionFetch::CREDENTIALS_OAUTH2_TOKEN;
 888       } else {
 889         fetch->credentials = ExtensionFetch::CREDENTIALS_COOKIES;
 890       }
 891       return true;
 892     case ExtensionFetch::CREDENTIALS_OAUTH2_TOKEN:
 893       fetch->oauth2_attempt_count++;
 894       // OAuth2 may fail due to an expired access token, in which case we
 895       // should invalidate the token and try again.
 896       if (response_code == net::HTTP_UNAUTHORIZED &&
 897           fetch->oauth2_attempt_count <= kMaxOAuth2Attempts) {
 898         DCHECK(identity_provider_.get());
 899         OAuth2TokenService::ScopeSet webstore_scopes;
 900         webstore_scopes.insert(kWebstoreOAuth2Scope);
 901         identity_provider_->GetTokenService()->InvalidateToken(
 902             identity_provider_->GetActiveAccountId(),
 903             webstore_scopes,
 904             access_token_);
 905         access_token_.clear();
 906         return true;
 907       }
 908       // Either there is no Gaia identity available, the active identity
 909       // doesn't have access to this resource, or the server keeps returning
 910       // 401s and we've retried too many times. Fall back on cookies.
 911       if (access_token_.empty() || response_code == net::HTTP_FORBIDDEN ||
 912           fetch->oauth2_attempt_count > kMaxOAuth2Attempts) {
 913         fetch->credentials = ExtensionFetch::CREDENTIALS_COOKIES;
 914         return true;
 915       }
 916       // Something else is wrong. Time to give up.
 917       return false;
 918     case ExtensionFetch::CREDENTIALS_COOKIES:
 919       if (response_code == net::HTTP_FORBIDDEN) {
 920         // Try the next session identity, up to some maximum.
 921         return IncrementAuthUserIndex(&fetch->url);
 922       }
 923       return false;
 924     default:
 925       NOTREACHED();
 926   }
 927   NOTREACHED();
 928   return false;
 929 }
 930
 931 void ExtensionDownloader::OnGetTokenSuccess(
 932     const OAuth2TokenService::Request* request,
 933     const std::string& access_token,
 934     const base::Time& expiration_time) {
 935   access_token_ = access_token;
 936   extension_fetcher_->AddExtraRequestHeader(
 937       base::StringPrintf("%s: Bearer %s",
 938                          net::HttpRequestHeaders::kAuthorization,
 939                          access_token_.c_str()));
 940   extension_fetcher_->Start();
 941 }
 942
 943 void ExtensionDownloader::OnGetTokenFailure(
 944     const OAuth2TokenService::Request* request,
 945     const GoogleServiceAuthError& error) {
 946   // If we fail to get an access token, kick the pending fetch and let it fall
 947   // back on cookies.
 948   extension_fetcher_->Start();
 949 }
 950
 951 ManifestFetchData* ExtensionDownloader::CreateManifestFetchData(
 952     const GURL& update_url,
 953     int request_id) {
 954   ManifestFetchData::PingMode ping_mode = ManifestFetchData::NO_PING;
 955   if (update_url.DomainIs(ping_enabled_domain_.c_str()))
 956     ping_mode = ManifestFetchData::PING_WITH_ENABLED_STATE;
 957   return new ManifestFetchData(
 958       update_url, request_id, brand_code_, manifest_query_params_, ping_mode);
 959 }
 960
 961 }  // namespace extensions