chrome/browser/component_updater/component_unpacker.h

   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 #ifndef CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_
   6 #define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "base/files/file_path.h"
  14 #include "base/json/json_file_value_serializer.h"
  15 #include "base/memory/ref_counted.h"
  16 #include "base/memory/scoped_ptr.h"
  17 #include "base/sequenced_task_runner.h"
  18
  19 namespace component_updater {
  20
  21 class ComponentInstaller;
  22 class ComponentPatcher;
  23
  24 // Deserializes the CRX manifest. The top level must be a dictionary.
  25 scoped_ptr<base::DictionaryValue> ReadManifest(
  26     const base::FilePath& unpack_path);
  27
  28 // In charge of unpacking the component CRX package and verifying that it is
  29 // well formed and the cryptographic signature is correct. If there is no
  30 // error the component specific installer will be invoked to proceed with
  31 // the component installation or update.
  32 //
  33 // This class should be used only by the component updater. It is inspired by
  34 // and overlaps with code in the extension's SandboxedUnpacker.
  35 // The main differences are:
  36 // - The public key hash is full SHA256.
  37 // - Does not use a sandboxed unpacker. A valid component is fully trusted.
  38 // - The manifest can have different attributes and resources are not
  39 //   transcoded.
  40 //
  41 // If the CRX is a delta CRX, the flow is:
  42 //   [ComponentUpdater]      [ComponentPatcher]
  43 //   Unpack
  44 //     \_ Verify
  45 //     \_ Unzip
  46 //     \_ BeginPatching ---> DifferentialUpdatePatch
  47 //                             ...
  48 //   EndPatching <------------ ...
  49 //     \_ Install
  50 //     \_ Finish
  51 //
  52 // For a full CRX, the flow is:
  53 //   [ComponentUpdater]
  54 //   Unpack
  55 //     \_ Verify
  56 //     \_ Unzip
  57 //     \_ BeginPatching
  58 //          |
  59 //          V
  60 //   EndPatching
  61 //     \_ Install
  62 //     \_ Finish
  63 //
  64 // In both cases, if there is an error at any point, the remaining steps will
  65 // be skipped and Finish will be called.
  66 class ComponentUnpacker : public base::RefCountedThreadSafe<ComponentUnpacker> {
  67  public:
  68   // Possible error conditions.
  69   // Add only to the bottom of this enum; the order must be kept stable.
  70   enum Error {
  71     kNone,
  72     kInvalidParams,
  73     kInvalidFile,
  74     kUnzipPathError,
  75     kUnzipFailed,
  76     kNoManifest,
  77     kBadManifest,
  78     kBadExtension,
  79     kInvalidId,
  80     kInstallerError,
  81     kIoError,
  82     kDeltaVerificationFailure,
  83     kDeltaBadCommands,
  84     kDeltaUnsupportedCommand,
  85     kDeltaOperationFailure,
  86     kDeltaPatchProcessFailure,
  87     kDeltaMissingExistingFile,
  88     kFingerprintWriteFailed,
  89   };
  90
  91   typedef base::Callback<void(Error, int)> Callback;
  92
  93   // Constructs an unpacker for a specific component unpacking operation.
  94   // |pk_hash| is the expected/ public key SHA256 hash. |path| is the current
  95   // location of the CRX.
  96   ComponentUnpacker(const std::vector<uint8>& pk_hash,
  97                     const base::FilePath& path,
  98                     const std::string& fingerprint,
  99                     ComponentInstaller* installer,
 100                     bool in_process,
 101                     scoped_refptr<base::SequencedTaskRunner> task_runner);
 102
 103   // Begins the actual unpacking of the files. May invoke a patcher if the
 104   // package is a differential update. Calls |callback| with the result.
 105   void Unpack(const Callback& callback);
 106
 107  private:
 108   friend class base::RefCountedThreadSafe<ComponentUnpacker>;
 109
 110   virtual ~ComponentUnpacker();
 111
 112   bool UnpackInternal();
 113
 114   // The first step of unpacking is to verify the file. Returns false if an
 115   // error is encountered, the file is malformed, or the file is incorrectly
 116   // signed.
 117   bool Verify();
 118
 119   // The second step of unpacking is to unzip. Returns false if an error
 120   // occurs as part of unzipping.
 121   bool Unzip();
 122
 123   // The third step is to optionally patch files - this is a no-op for full
 124   // (non-differential) updates. This step is asynchronous. Returns false if an
 125   // error is encountered.
 126   bool BeginPatching();
 127
 128   // When patching is complete, EndPatching is called before moving on to step
 129   // four.
 130   void EndPatching(Error error, int extended_error);
 131
 132   // The fourth step is to install the unpacked component.
 133   void Install();
 134
 135   // The final step is to do clean-up for things that can't be tidied as we go.
 136   // If there is an error at any step, the remaining steps are skipped and
 137   // and Finish is called.
 138   // Finish is responsible for calling the callback provided in Start().
 139   void Finish();
 140
 141   std::vector<uint8> pk_hash_;
 142   base::FilePath path_;
 143   base::FilePath unpack_path_;
 144   base::FilePath unpack_diff_path_;
 145   bool is_delta_;
 146   std::string fingerprint_;
 147   scoped_refptr<ComponentPatcher> patcher_;
 148   ComponentInstaller* installer_;
 149   Callback callback_;
 150   const bool in_process_;
 151   Error error_;
 152   int extended_error_;
 153   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 154
 155   DISALLOW_COPY_AND_ASSIGN(ComponentUnpacker);
 156 };
 157
 158 }  // namespace component_updater
 159
 160 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_