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