extensions/browser/content_hash_fetcher.h

   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 #ifndef EXTENSIONS_BROWSER_CONTENT_HASH_FETCHER_H_
   6 #define EXTENSIONS_BROWSER_CONTENT_HASH_FETCHER_H_
   7
   8 #include <set>
   9 #include <string>
  10
  11 #include "base/callback.h"
  12 #include "base/files/file_path.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "extensions/common/extension.h"
  15
  16 namespace content {
  17 class BrowserContext;
  18 }
  19
  20 namespace extensions {
  21
  22 class ExtensionRegistry;
  23 class ContentHashFetcherJob;
  24 class ContentVerifierDelegate;
  25
  26 // This class is responsible for getting signed expected hashes for use in
  27 // extension content verification. As extensions are loaded it will fetch and
  28 // parse/validate/cache this data as needed, including calculating expected
  29 // hashes for each block of each file within an extension. (These unsigned leaf
  30 // node block level hashes will always be checked at time of use use to make
  31 // sure they match the signed treehash root hash).
  32 class ContentHashFetcher {
  33  public:
  34   // A callback for when a fetch is complete. This reports back:
  35   // -extension id
  36   // -whether we were successful or not (have verified_contents.json and
  37   // -computed_hashes.json files)
  38   // -was it a forced check?
  39   // -a set of paths whose contents didn't match expected values
  40   typedef base::Callback<
  41       void(const std::string&, bool, bool, const std::set<base::FilePath>&)>
  42       FetchCallback;
  43
  44   // The consumer of this class needs to ensure that context and delegate
  45   // outlive this object.
  46   ContentHashFetcher(content::BrowserContext* context,
  47                      ContentVerifierDelegate* delegate,
  48                      const FetchCallback& callback);
  49   virtual ~ContentHashFetcher();
  50
  51   // Explicitly ask to fetch hashes for |extension|. If |force| is true,
  52   // we will always check the validity of the verified_contents.json and
  53   // re-check the contents of the files in the filesystem.
  54   void DoFetch(const Extension* extension, bool force);
  55
  56   // These should be called when an extension is loaded or unloaded.
  57   virtual void ExtensionLoaded(const Extension* extension);
  58   virtual void ExtensionUnloaded(const Extension* extension);
  59
  60  private:
  61   // Callback for when a job getting content hashes has completed.
  62   void JobFinished(ContentHashFetcherJob* job);
  63
  64   content::BrowserContext* context_;
  65   ContentVerifierDelegate* delegate_;
  66   FetchCallback fetch_callback_;
  67
  68   // We keep around pointers to in-progress jobs, both so we can avoid
  69   // scheduling duplicate work if fetching is already in progress, and so that
  70   // we can cancel in-progress work at shutdown time.
  71   typedef std::pair<ExtensionId, std::string> IdAndVersion;
  72   typedef std::map<IdAndVersion, scoped_refptr<ContentHashFetcherJob> > JobMap;
  73   JobMap jobs_;
  74
  75   // Used for binding callbacks passed to jobs.
  76   base::WeakPtrFactory<ContentHashFetcher> weak_ptr_factory_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(ContentHashFetcher);
  79 };
  80
  81 }  // namespace extensions
  82
  83 #endif  // EXTENSIONS_BROWSER_CONTENT_HASH_FETCHER_H_