extensions/browser/extension_protocols.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 "extensions/browser/extension_protocols.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/base64.h"
  12 #include "base/compiler_specific.h"
  13 #include "base/files/file_path.h"
  14 #include "base/files/file_util.h"
  15 #include "base/format_macros.h"
  16 #include "base/logging.h"
  17 #include "base/memory/weak_ptr.h"
  18 #include "base/message_loop/message_loop.h"
  19 #include "base/metrics/field_trial.h"
  20 #include "base/metrics/histogram.h"
  21 #include "base/metrics/sparse_histogram.h"
  22 #include "base/sha1.h"
  23 #include "base/strings/string_number_conversions.h"
  24 #include "base/strings/string_util.h"
  25 #include "base/strings/stringprintf.h"
  26 #include "base/strings/utf_string_conversions.h"
  27 #include "base/threading/sequenced_worker_pool.h"
  28 #include "base/threading/thread_restrictions.h"
  29 #include "base/timer/elapsed_timer.h"
  30 #include "build/build_config.h"
  31 #include "content/public/browser/browser_thread.h"
  32 #include "content/public/browser/resource_request_info.h"
  33 #include "crypto/secure_hash.h"
  34 #include "crypto/sha2.h"
  35 #include "extensions/browser/content_verifier.h"
  36 #include "extensions/browser/content_verify_job.h"
  37 #include "extensions/browser/extensions_browser_client.h"
  38 #include "extensions/browser/info_map.h"
  39 #include "extensions/browser/url_request_util.h"
  40 #include "extensions/common/constants.h"
  41 #include "extensions/common/extension.h"
  42 #include "extensions/common/extension_resource.h"
  43 #include "extensions/common/file_util.h"
  44 #include "extensions/common/manifest_handlers/background_info.h"
  45 #include "extensions/common/manifest_handlers/csp_info.h"
  46 #include "extensions/common/manifest_handlers/icons_handler.h"
  47 #include "extensions/common/manifest_handlers/incognito_info.h"
  48 #include "extensions/common/manifest_handlers/shared_module_info.h"
  49 #include "extensions/common/manifest_handlers/web_accessible_resources_info.h"
  50 #include "net/base/io_buffer.h"
  51 #include "net/base/net_errors.h"
  52 #include "net/http/http_request_headers.h"
  53 #include "net/http/http_response_headers.h"
  54 #include "net/http/http_response_info.h"
  55 #include "net/url_request/url_request_error_job.h"
  56 #include "net/url_request/url_request_file_job.h"
  57 #include "net/url_request/url_request_simple_job.h"
  58 #include "url/url_util.h"
  59
  60 using content::BrowserThread;
  61 using content::ResourceRequestInfo;
  62 using content::ResourceType;
  63 using extensions::Extension;
  64 using extensions::SharedModuleInfo;
  65
  66 namespace extensions {
  67 namespace {
  68
  69 class GeneratedBackgroundPageJob : public net::URLRequestSimpleJob {
  70  public:
  71   GeneratedBackgroundPageJob(net::URLRequest* request,
  72                              net::NetworkDelegate* network_delegate,
  73                              const scoped_refptr<const Extension> extension,
  74                              const std::string& content_security_policy)
  75       : net::URLRequestSimpleJob(request, network_delegate),
  76         extension_(extension) {
  77     const bool send_cors_headers = false;
  78     // Leave cache headers out of generated background page jobs.
  79     response_info_.headers = BuildHttpHeaders(content_security_policy,
  80                                               send_cors_headers,
  81                                               base::Time());
  82   }
  83
  84   // Overridden from URLRequestSimpleJob:
  85   int GetData(std::string* mime_type,
  86               std::string* charset,
  87               std::string* data,
  88               const net::CompletionCallback& callback) const override {
  89     *mime_type = "text/html";
  90     *charset = "utf-8";
  91
  92     *data = "<!DOCTYPE html>\n<body>\n";
  93     const std::vector<std::string>& background_scripts =
  94         extensions::BackgroundInfo::GetBackgroundScripts(extension_.get());
  95     for (size_t i = 0; i < background_scripts.size(); ++i) {
  96       *data += "<script src=\"";
  97       *data += background_scripts[i];
  98       *data += "\"></script>\n";
  99     }
 100
 101     return net::OK;
 102   }
 103
 104   void GetResponseInfo(net::HttpResponseInfo* info) override {
 105     *info = response_info_;
 106   }
 107
 108  private:
 109   ~GeneratedBackgroundPageJob() override {}
 110
 111   scoped_refptr<const Extension> extension_;
 112   net::HttpResponseInfo response_info_;
 113 };
 114
 115 base::Time GetFileLastModifiedTime(const base::FilePath& filename) {
 116   if (base::PathExists(filename)) {
 117     base::File::Info info;
 118     if (base::GetFileInfo(filename, &info))
 119       return info.last_modified;
 120   }
 121   return base::Time();
 122 }
 123
 124 base::Time GetFileCreationTime(const base::FilePath& filename) {
 125   if (base::PathExists(filename)) {
 126     base::File::Info info;
 127     if (base::GetFileInfo(filename, &info))
 128       return info.creation_time;
 129   }
 130   return base::Time();
 131 }
 132
 133 void ReadResourceFilePathAndLastModifiedTime(
 134     const extensions::ExtensionResource& resource,
 135     const base::FilePath& directory,
 136     base::FilePath* file_path,
 137     base::Time* last_modified_time) {
 138   *file_path = resource.GetFilePath();
 139   *last_modified_time = GetFileLastModifiedTime(*file_path);
 140   // While we're here, log the delta between extension directory
 141   // creation time and the resource's last modification time.
 142   base::ElapsedTimer query_timer;
 143   base::Time dir_creation_time = GetFileCreationTime(directory);
 144   UMA_HISTOGRAM_TIMES("Extensions.ResourceDirectoryTimestampQueryLatency",
 145                       query_timer.Elapsed());
 146   int64 delta_seconds = (*last_modified_time - dir_creation_time).InSeconds();
 147   if (delta_seconds >= 0) {
 148     UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions.ResourceLastModifiedDelta",
 149                                 delta_seconds,
 150                                 0,
 151                                 base::TimeDelta::FromDays(30).InSeconds(),
 152                                 50);
 153   } else {
 154     UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions.ResourceLastModifiedNegativeDelta",
 155                                 -delta_seconds,
 156                                 1,
 157                                 base::TimeDelta::FromDays(30).InSeconds(),
 158                                 50);
 159   }
 160 }
 161
 162 class URLRequestExtensionJob : public net::URLRequestFileJob {
 163  public:
 164   URLRequestExtensionJob(net::URLRequest* request,
 165                          net::NetworkDelegate* network_delegate,
 166                          const std::string& extension_id,
 167                          const base::FilePath& directory_path,
 168                          const base::FilePath& relative_path,
 169                          const std::string& content_security_policy,
 170                          bool send_cors_header,
 171                          bool follow_symlinks_anywhere,
 172                          ContentVerifyJob* verify_job)
 173       : net::URLRequestFileJob(
 174             request,
 175             network_delegate,
 176             base::FilePath(),
 177             BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
 178                 base::SequencedWorkerPool::SKIP_ON_SHUTDOWN)),
 179         verify_job_(verify_job),
 180         seek_position_(0),
 181         bytes_read_(0),
 182         directory_path_(directory_path),
 183         // TODO(tc): Move all of these files into resources.pak so we don't
 184         // break when updating on Linux.
 185         resource_(extension_id, directory_path, relative_path),
 186         content_security_policy_(content_security_policy),
 187         send_cors_header_(send_cors_header),
 188         weak_factory_(this) {
 189     if (follow_symlinks_anywhere) {
 190       resource_.set_follow_symlinks_anywhere();
 191     }
 192   }
 193
 194   void GetResponseInfo(net::HttpResponseInfo* info) override {
 195     *info = response_info_;
 196   }
 197
 198   // This always returns 200 because a URLRequestExtensionJob will only get
 199   // created in MaybeCreateJob() if the file exists.
 200   int GetResponseCode() const override { return 200; }
 201
 202   void Start() override {
 203     request_timer_.reset(new base::ElapsedTimer());
 204     base::FilePath* read_file_path = new base::FilePath;
 205     base::Time* last_modified_time = new base::Time();
 206     bool posted = BrowserThread::PostBlockingPoolTaskAndReply(
 207         FROM_HERE,
 208         base::Bind(&ReadResourceFilePathAndLastModifiedTime,
 209                    resource_,
 210                    directory_path_,
 211                    base::Unretained(read_file_path),
 212                    base::Unretained(last_modified_time)),
 213         base::Bind(&URLRequestExtensionJob::OnFilePathAndLastModifiedTimeRead,
 214                    weak_factory_.GetWeakPtr(),
 215                    base::Owned(read_file_path),
 216                    base::Owned(last_modified_time)));
 217     DCHECK(posted);
 218   }
 219
 220   bool IsRedirectResponse(GURL* location, int* http_status_code) override {
 221     return false;
 222   }
 223
 224   void SetExtraRequestHeaders(const net::HttpRequestHeaders& headers) override {
 225     // TODO(asargent) - we'll need to add proper support for range headers.
 226     // crbug.com/369895.
 227     std::string range_header;
 228     if (headers.GetHeader(net::HttpRequestHeaders::kRange, &range_header)) {
 229       if (verify_job_.get())
 230         verify_job_ = NULL;
 231     }
 232     URLRequestFileJob::SetExtraRequestHeaders(headers);
 233   }
 234
 235   void OnSeekComplete(int64 result) override {
 236     DCHECK_EQ(seek_position_, 0);
 237     seek_position_ = result;
 238     // TODO(asargent) - we'll need to add proper support for range headers.
 239     // crbug.com/369895.
 240     if (result > 0 && verify_job_.get())
 241       verify_job_ = NULL;
 242   }
 243
 244   void OnReadComplete(net::IOBuffer* buffer, int result) override {
 245     if (result >= 0)
 246       UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.OnReadCompleteResult", result);
 247     else
 248       UMA_HISTOGRAM_SPARSE_SLOWLY("ExtensionUrlRequest.OnReadCompleteError",
 249                                   -result);
 250     if (result > 0) {
 251       bytes_read_ += result;
 252       if (verify_job_.get()) {
 253         verify_job_->BytesRead(result, buffer->data());
 254         if (!remaining_bytes())
 255           verify_job_->DoneReading();
 256       }
 257     }
 258   }
 259
 260  private:
 261   ~URLRequestExtensionJob() override {
 262     UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.TotalKbRead", bytes_read_ / 1024);
 263     UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.SeekPosition", seek_position_);
 264     if (request_timer_.get())
 265       UMA_HISTOGRAM_TIMES("ExtensionUrlRequest.Latency",
 266                           request_timer_->Elapsed());
 267   }
 268
 269   void OnFilePathAndLastModifiedTimeRead(base::FilePath* read_file_path,
 270                                          base::Time* last_modified_time) {
 271     file_path_ = *read_file_path;
 272     response_info_.headers = BuildHttpHeaders(
 273         content_security_policy_,
 274         send_cors_header_,
 275         *last_modified_time);
 276     URLRequestFileJob::Start();
 277   }
 278
 279   scoped_refptr<ContentVerifyJob> verify_job_;
 280
 281   scoped_ptr<base::ElapsedTimer> request_timer_;
 282
 283   // The position we seeked to in the file.
 284   int64 seek_position_;
 285
 286   // The number of bytes of content we read from the file.
 287   int bytes_read_;
 288
 289   net::HttpResponseInfo response_info_;
 290   base::FilePath directory_path_;
 291   extensions::ExtensionResource resource_;
 292   std::string content_security_policy_;
 293   bool send_cors_header_;
 294   base::WeakPtrFactory<URLRequestExtensionJob> weak_factory_;
 295 };
 296
 297 bool ExtensionCanLoadInIncognito(const ResourceRequestInfo* info,
 298                                  const std::string& extension_id,
 299                                  extensions::InfoMap* extension_info_map) {
 300   if (!extension_info_map->IsIncognitoEnabled(extension_id))
 301     return false;
 302
 303   // Only allow incognito toplevel navigations to extension resources in
 304   // split mode. In spanning mode, the extension must run in a single process,
 305   // and an incognito tab prevents that.
 306   if (info->GetResourceType() == content::RESOURCE_TYPE_MAIN_FRAME) {
 307     const Extension* extension =
 308         extension_info_map->extensions().GetByID(extension_id);
 309     return extension && extensions::IncognitoInfo::IsSplitMode(extension);
 310   }
 311
 312   return true;
 313 }
 314
 315 // Returns true if an chrome-extension:// resource should be allowed to load.
 316 // Pass true for |is_incognito| only for incognito profiles and not Chrome OS
 317 // guest mode profiles.
 318 // TODO(aa): This should be moved into ExtensionResourceRequestPolicy, but we
 319 // first need to find a way to get CanLoadInIncognito state into the renderers.
 320 bool AllowExtensionResourceLoad(net::URLRequest* request,
 321                                 bool is_incognito,
 322                                 const Extension* extension,
 323                                 extensions::InfoMap* extension_info_map) {
 324   const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request);
 325
 326   // We have seen crashes where info is NULL: crbug.com/52374.
 327   if (!info) {
 328     LOG(ERROR) << "Allowing load of " << request->url().spec()
 329                << "from unknown origin. Could not find user data for "
 330                << "request.";
 331     return true;
 332   }
 333
 334   if (is_incognito && !ExtensionCanLoadInIncognito(
 335                           info, request->url().host(), extension_info_map)) {
 336     return false;
 337   }
 338
 339   // The following checks are meant to replicate similar set of checks in the
 340   // renderer process, performed by ResourceRequestPolicy::CanRequestResource.
 341   // These are not exactly equivalent, because we don't have the same bits of
 342   // information. The two checks need to be kept in sync as much as possible, as
 343   // an exploited renderer can bypass the checks in ResourceRequestPolicy.
 344
 345   // Check if the extension for which this request is made is indeed loaded in
 346   // the process sending the request. If not, we need to explicitly check if
 347   // the resource is explicitly accessible or fits in a set of exception cases.
 348   // Note: This allows a case where two extensions execute in the same renderer
 349   // process to request each other's resources. We can't do a more precise
 350   // check, since the renderer can lie about which extension has made the
 351   // request.
 352   if (extension_info_map->process_map().Contains(
 353       request->url().host(), info->GetChildID())) {
 354     return true;
 355   }
 356
 357   // Allow the extension module embedder to grant permission for loads.
 358   if (ExtensionsBrowserClient::Get()->AllowCrossRendererResourceLoad(
 359           request, is_incognito, extension, extension_info_map)) {
 360     return true;
 361   }
 362
 363   // No special exceptions for cross-process loading. Block the load.
 364   return false;
 365 }
 366
 367 // Returns true if the given URL references an icon in the given extension.
 368 bool URLIsForExtensionIcon(const GURL& url, const Extension* extension) {
 369   DCHECK(url.SchemeIs(extensions::kExtensionScheme));
 370
 371   if (!extension)
 372     return false;
 373
 374   std::string path = url.path();
 375   DCHECK_EQ(url.host(), extension->id());
 376   DCHECK(path.length() > 0 && path[0] == '/');
 377   path = path.substr(1);
 378   return extensions::IconsInfo::GetIcons(extension).ContainsPath(path);
 379 }
 380
 381 class ExtensionProtocolHandler
 382     : public net::URLRequestJobFactory::ProtocolHandler {
 383  public:
 384   ExtensionProtocolHandler(bool is_incognito,
 385                            extensions::InfoMap* extension_info_map)
 386       : is_incognito_(is_incognito), extension_info_map_(extension_info_map) {}
 387
 388   ~ExtensionProtocolHandler() override {}
 389
 390   net::URLRequestJob* MaybeCreateJob(
 391       net::URLRequest* request,
 392       net::NetworkDelegate* network_delegate) const override;
 393
 394  private:
 395   const bool is_incognito_;
 396   extensions::InfoMap* const extension_info_map_;
 397   DISALLOW_COPY_AND_ASSIGN(ExtensionProtocolHandler);
 398 };
 399
 400 // Creates URLRequestJobs for extension:// URLs.
 401 net::URLRequestJob*
 402 ExtensionProtocolHandler::MaybeCreateJob(
 403     net::URLRequest* request, net::NetworkDelegate* network_delegate) const {
 404   // chrome-extension://extension-id/resource/path.js
 405   std::string extension_id = request->url().host();
 406   const Extension* extension =
 407       extension_info_map_->extensions().GetByID(extension_id);
 408
 409   // TODO(mpcomplete): better error code.
 410   if (!AllowExtensionResourceLoad(
 411           request, is_incognito_, extension, extension_info_map_)) {
 412     return new net::URLRequestErrorJob(
 413         request, network_delegate, net::ERR_ADDRESS_UNREACHABLE);
 414   }
 415
 416   // If this is a disabled extension only allow the icon to load.
 417   base::FilePath directory_path;
 418   if (extension)
 419     directory_path = extension->path();
 420   if (directory_path.value().empty()) {
 421     const Extension* disabled_extension =
 422         extension_info_map_->disabled_extensions().GetByID(extension_id);
 423     if (URLIsForExtensionIcon(request->url(), disabled_extension))
 424       directory_path = disabled_extension->path();
 425     if (directory_path.value().empty()) {
 426       LOG(WARNING) << "Failed to GetPathForExtension: " << extension_id;
 427       return NULL;
 428     }
 429   }
 430
 431   // Set up content security policy.
 432   std::string content_security_policy;
 433   bool send_cors_header = false;
 434   bool follow_symlinks_anywhere = false;
 435
 436   if (extension) {
 437     std::string resource_path = request->url().path();
 438
 439     // Use default CSP for <webview>.
 440     if (!url_request_util::IsWebViewRequest(request)) {
 441       content_security_policy =
 442           extensions::CSPInfo::GetResourceContentSecurityPolicy(extension,
 443                                                                 resource_path);
 444     }
 445
 446     if ((extension->manifest_version() >= 2 ||
 447          extensions::WebAccessibleResourcesInfo::HasWebAccessibleResources(
 448              extension)) &&
 449         extensions::WebAccessibleResourcesInfo::IsResourceWebAccessible(
 450             extension, resource_path)) {
 451       send_cors_header = true;
 452     }
 453
 454     follow_symlinks_anywhere =
 455         (extension->creation_flags() & Extension::FOLLOW_SYMLINKS_ANYWHERE)
 456         != 0;
 457   }
 458
 459   // Create a job for a generated background page.
 460   std::string path = request->url().path();
 461   if (path.size() > 1 &&
 462       path.substr(1) == extensions::kGeneratedBackgroundPageFilename) {
 463     return new GeneratedBackgroundPageJob(
 464         request, network_delegate, extension, content_security_policy);
 465   }
 466
 467   // Component extension resources may be part of the embedder's resource files,
 468   // for example component_extension_resources.pak in Chrome.
 469   net::URLRequestJob* resource_bundle_job =
 470       extensions::ExtensionsBrowserClient::Get()
 471           ->MaybeCreateResourceBundleRequestJob(request,
 472                                                 network_delegate,
 473                                                 directory_path,
 474                                                 content_security_policy,
 475                                                 send_cors_header);
 476   if (resource_bundle_job)
 477     return resource_bundle_job;
 478
 479   base::FilePath relative_path =
 480       extensions::file_util::ExtensionURLToRelativeFilePath(request->url());
 481
 482   // Handle shared resources (extension A loading resources out of extension B).
 483   if (SharedModuleInfo::IsImportedPath(path)) {
 484     std::string new_extension_id;
 485     std::string new_relative_path;
 486     SharedModuleInfo::ParseImportedPath(path, &new_extension_id,
 487                                         &new_relative_path);
 488     const Extension* new_extension =
 489         extension_info_map_->extensions().GetByID(new_extension_id);
 490
 491     if (SharedModuleInfo::ImportsExtensionById(extension, new_extension_id) &&
 492         new_extension) {
 493       directory_path = new_extension->path();
 494       extension_id = new_extension_id;
 495       relative_path = base::FilePath::FromUTF8Unsafe(new_relative_path);
 496     } else {
 497       return NULL;
 498     }
 499   }
 500   ContentVerifyJob* verify_job = NULL;
 501   ContentVerifier* verifier = extension_info_map_->content_verifier();
 502   if (verifier) {
 503     verify_job =
 504         verifier->CreateJobFor(extension_id, directory_path, relative_path);
 505     if (verify_job)
 506       verify_job->Start();
 507   }
 508
 509   return new URLRequestExtensionJob(request,
 510                                     network_delegate,
 511                                     extension_id,
 512                                     directory_path,
 513                                     relative_path,
 514                                     content_security_policy,
 515                                     send_cors_header,
 516                                     follow_symlinks_anywhere,
 517                                     verify_job);
 518 }
 519
 520 }  // namespace
 521
 522 net::HttpResponseHeaders* BuildHttpHeaders(
 523     const std::string& content_security_policy,
 524     bool send_cors_header,
 525     const base::Time& last_modified_time) {
 526   std::string raw_headers;
 527   raw_headers.append("HTTP/1.1 200 OK");
 528   if (!content_security_policy.empty()) {
 529     raw_headers.append(1, '\0');
 530     raw_headers.append("Content-Security-Policy: ");
 531     raw_headers.append(content_security_policy);
 532   }
 533
 534   if (send_cors_header) {
 535     raw_headers.append(1, '\0');
 536     raw_headers.append("Access-Control-Allow-Origin: *");
 537   }
 538
 539   if (!last_modified_time.is_null()) {
 540     // Hash the time and make an etag to avoid exposing the exact
 541     // user installation time of the extension.
 542     std::string hash =
 543         base::StringPrintf("%" PRId64, last_modified_time.ToInternalValue());
 544     hash = base::SHA1HashString(hash);
 545     std::string etag;
 546     base::Base64Encode(hash, &etag);
 547     raw_headers.append(1, '\0');
 548     raw_headers.append("ETag: \"");
 549     raw_headers.append(etag);
 550     raw_headers.append("\"");
 551     // Also force revalidation.
 552     raw_headers.append(1, '\0');
 553     raw_headers.append("cache-control: no-cache");
 554   }
 555
 556   raw_headers.append(2, '\0');
 557   return new net::HttpResponseHeaders(raw_headers);
 558 }
 559
 560 net::URLRequestJobFactory::ProtocolHandler* CreateExtensionProtocolHandler(
 561     bool is_incognito,
 562     extensions::InfoMap* extension_info_map) {
 563   return new ExtensionProtocolHandler(is_incognito, extension_info_map);
 564 }
 565
 566 }  // namespace extensions