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      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 // Helper class which handles communication with the SafeBrowsing servers for
      6 // improved binary download protection.
      7 
      8 #ifndef CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_
      9 #define CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_
     10 
     11 #include <set>
     12 #include <string>
     13 #include <vector>
     14 
     15 #include "base/basictypes.h"
     16 #include "base/callback.h"
     17 #include "base/files/file_path.h"
     18 #include "base/gtest_prod_util.h"
     19 #include "base/memory/ref_counted.h"
     20 #include "chrome/browser/safe_browsing/database_manager.h"
     21 #include "chrome/browser/safe_browsing/ui_manager.h"
     22 #include "url/gurl.h"
     23 
     24 
     25 namespace content {
     26 class DownloadItem;
     27 class PageNavigator;
     28 }
     29 
     30 namespace net {
     31 class URLRequestContextGetter;
     32 class X509Certificate;
     33 }  // namespace net
     34 
     35 namespace safe_browsing {
     36 class DownloadFeedbackService;
     37 class BinaryFeatureExtractor;
     38 
     39 // This class provides an asynchronous API to check whether a particular
     40 // client download is malicious or not.
     41 class DownloadProtectionService {
     42  public:
     43   enum DownloadCheckResult {
     44     SAFE,
     45     DANGEROUS,
     46     UNCOMMON,
     47     DANGEROUS_HOST,
     48     POTENTIALLY_UNWANTED
     49   };
     50 
     51   // Callback type which is invoked once the download request is done.
     52   typedef base::Callback<void(DownloadCheckResult)> CheckDownloadCallback;
     53 
     54   // Creates a download service.  The service is initially disabled.  You need
     55   // to call SetEnabled() to start it.  |sb_service| owns this object; we
     56   // keep a reference to |request_context_getter|.
     57   DownloadProtectionService(
     58       SafeBrowsingService* sb_service,
     59       net::URLRequestContextGetter* request_context_getter);
     60 
     61   virtual ~DownloadProtectionService();
     62 
     63   // Checks whether the given client download is likely to be malicious or not.
     64   // The result is delivered asynchronously via the given callback.  This
     65   // method must be called on the UI thread, and the callback will also be
     66   // invoked on the UI thread.  This method must be called once the download
     67   // is finished and written to disk.
     68   virtual void CheckClientDownload(content::DownloadItem* item,
     69                                    const CheckDownloadCallback& callback);
     70 
     71   // Checks whether any of the URLs in the redirect chain of the
     72   // download match the SafeBrowsing bad binary URL list.  The result is
     73   // delivered asynchronously via the given callback.  This method must be
     74   // called on the UI thread, and the callback will also be invoked on the UI
     75   // thread.  Pre-condition: !info.download_url_chain.empty().
     76   virtual void CheckDownloadUrl(const content::DownloadItem& item,
     77                                 const CheckDownloadCallback& callback);
     78 
     79   // Returns true iff the download specified by |info| should be scanned by
     80   // CheckClientDownload() for malicious content.
     81   virtual bool IsSupportedDownload(const content::DownloadItem& item,
     82                                    const base::FilePath& target_path) const;
     83 
     84   // Display more information to the user regarding the download specified by
     85   // |info|. This method is invoked when the user requests more information
     86   // about a download that was marked as malicious.
     87   void ShowDetailsForDownload(const content::DownloadItem& item,
     88                               content::PageNavigator* navigator);
     89 
     90   // Enables or disables the service.  This is usually called by the
     91   // SafeBrowsingService, which tracks whether any profile uses these services
     92   // at all.  Disabling causes any pending and future requests to have their
     93   // callbacks called with "SAFE" results.
     94   void SetEnabled(bool enabled);
     95 
     96   bool enabled() const {
     97     return enabled_;
     98   }
     99 
    100   // Returns the timeout that is used by CheckClientDownload().
    101   int64 download_request_timeout_ms() const {
    102     return download_request_timeout_ms_;
    103   }
    104 
    105   DownloadFeedbackService* feedback_service() {
    106     return feedback_service_.get();
    107   }
    108 
    109  protected:
    110   // Enum to keep track why a particular download verdict was chosen.
    111   // This is used to keep some stats around.
    112   enum DownloadCheckResultReason {
    113     REASON_INVALID_URL,
    114     REASON_SB_DISABLED,
    115     REASON_WHITELISTED_URL,
    116     REASON_WHITELISTED_REFERRER,
    117     REASON_INVALID_REQUEST_PROTO,
    118     REASON_SERVER_PING_FAILED,
    119     REASON_INVALID_RESPONSE_PROTO,
    120     REASON_NOT_BINARY_FILE,
    121     REASON_REQUEST_CANCELED,
    122     REASON_DOWNLOAD_DANGEROUS,
    123     REASON_DOWNLOAD_SAFE,
    124     REASON_EMPTY_URL_CHAIN,
    125     DEPRECATED_REASON_HTTPS_URL,
    126     REASON_PING_DISABLED,
    127     REASON_TRUSTED_EXECUTABLE,
    128     REASON_OS_NOT_SUPPORTED,
    129     REASON_DOWNLOAD_UNCOMMON,
    130     REASON_DOWNLOAD_NOT_SUPPORTED,
    131     REASON_INVALID_RESPONSE_VERDICT,
    132     REASON_ARCHIVE_WITHOUT_BINARIES,
    133     REASON_DOWNLOAD_DANGEROUS_HOST,
    134     REASON_DOWNLOAD_POTENTIALLY_UNWANTED,
    135     REASON_MAX  // Always add new values before this one.
    136   };
    137 
    138  private:
    139   class CheckClientDownloadRequest;  // Per-request state
    140   friend class DownloadProtectionServiceTest;
    141   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    142                            CheckClientDownloadWhitelistedUrl);
    143   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    144                            CheckClientDownloadValidateRequest);
    145   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    146                            CheckClientDownloadSuccess);
    147   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    148                            CheckClientDownloadHTTPS);
    149   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    150                            CheckClientDownloadZip);
    151   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    152                            CheckClientDownloadFetchFailed);
    153   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    154                            TestDownloadRequestTimeout);
    155   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
    156                            CheckClientCrxDownloadSuccess);
    157   static const char kDownloadRequestUrl[];
    158 
    159   // Cancels all requests in |download_requests_|, and empties it, releasing
    160   // the references to the requests.
    161   void CancelPendingRequests();
    162 
    163   // Called by a CheckClientDownloadRequest instance when it finishes, to
    164   // remove it from |download_requests_|.
    165   void RequestFinished(CheckClientDownloadRequest* request);
    166 
    167   // Given a certificate and its immediate issuer certificate, generates the
    168   // list of strings that need to be checked against the download whitelist to
    169   // determine whether the certificate is whitelisted.
    170   static void GetCertificateWhitelistStrings(
    171       const net::X509Certificate& certificate,
    172       const net::X509Certificate& issuer,
    173       std::vector<std::string>* whitelist_strings);
    174 
    175   // Returns the URL that will be used for download requests.
    176   static GURL GetDownloadRequestUrl();
    177 
    178   // These pointers may be NULL if SafeBrowsing is disabled.
    179   scoped_refptr<SafeBrowsingUIManager> ui_manager_;
    180   scoped_refptr<SafeBrowsingDatabaseManager> database_manager_;
    181 
    182   // The context we use to issue network requests.
    183   scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
    184 
    185   // Map of client download request to the corresponding callback that
    186   // has to be invoked when the request is done.  This map contains all
    187   // pending server requests.
    188   std::set<scoped_refptr<CheckClientDownloadRequest> > download_requests_;
    189 
    190   // Keeps track of the state of the service.
    191   bool enabled_;
    192 
    193   // BinaryFeatureExtractor object, may be overridden for testing.
    194   scoped_refptr<BinaryFeatureExtractor> binary_feature_extractor_;
    195 
    196   int64 download_request_timeout_ms_;
    197 
    198   scoped_ptr<DownloadFeedbackService> feedback_service_;
    199 
    200   DISALLOW_COPY_AND_ASSIGN(DownloadProtectionService);
    201 };
    202 }  // namespace safe_browsing
    203 
    204 #endif  // CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_
    205