components/update_client/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_UPDATE_CLIENT_COMPONENT_UNPACKER_H_
   6 #define COMPONENTS_UPDATE_CLIENT_COMPONENT_UNPACKER_H_
   7
   8 #include <stdint.h>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/callback.h"
  13 #include "base/files/file_path.h"
  14 #include "base/json/json_file_value_serializer.h"
  15 #include "base/macros.h"
  16 #include "base/memory/ref_counted.h"
  17 #include "base/memory/scoped_ptr.h"
  18 #include "base/sequenced_task_runner.h"
  19
  20 namespace update_client {
  21
  22 class CrxInstaller;
  23 class ComponentPatcher;
  24 class OutOfProcessPatcher;
  25
  26 // Deserializes the CRX manifest. The top level must be a dictionary.
  27 scoped_ptr<base::DictionaryValue> ReadManifest(
  28     const base::FilePath& unpack_path);
  29
  30 // In charge of unpacking the component CRX package and verifying that it is
  31 // well formed and the cryptographic signature is correct. If there is no
  32 // error the component specific installer will be invoked to proceed with
  33 // the component installation or update.
  34 //
  35 // This class should be used only by the component updater. It is inspired by
  36 // and overlaps with code in the extension's SandboxedUnpacker.
  37 // The main differences are:
  38 // - The public key hash is full SHA256.
  39 // - Does not use a sandboxed unpacker. A valid component is fully trusted.
  40 // - The manifest can have different attributes and resources are not
  41 //   transcoded.
  42 //
  43 // If the CRX is a delta CRX, the flow is:
  44 //   [ComponentUpdater]      [ComponentPatcher]
  45 //   Unpack
  46 //     \_ Verify
  47 //     \_ Unzip
  48 //     \_ BeginPatching ---> DifferentialUpdatePatch
  49 //                             ...
  50 //   EndPatching <------------ ...
  51 //     \_ Install
  52 //     \_ Finish
  53 //
  54 // For a full CRX, the flow is:
  55 //   [ComponentUpdater]
  56 //   Unpack
  57 //     \_ Verify
  58 //     \_ Unzip
  59 //     \_ BeginPatching
  60 //          |
  61 //          V
  62 //   EndPatching
  63 //     \_ Install
  64 //     \_ Finish
  65 //
  66 // In both cases, if there is an error at any point, the remaining steps will
  67 // be skipped and Finish will be called.
  68 class ComponentUnpacker : public base::RefCountedThreadSafe<ComponentUnpacker> {
  69  public:
  70   // Possible error conditions.
  71   // Add only to the bottom of this enum; the order must be kept stable.
  72   enum Error {
  73     kNone,
  74     kInvalidParams,
  75     kInvalidFile,
  76     kUnzipPathError,
  77     kUnzipFailed,
  78     kNoManifest,
  79     kBadManifest,
  80     kBadExtension,
  81     kInvalidId,
  82     kInstallerError,
  83     kIoError,
  84     kDeltaVerificationFailure,
  85     kDeltaBadCommands,
  86     kDeltaUnsupportedCommand,
  87     kDeltaOperationFailure,
  88     kDeltaPatchProcessFailure,
  89     kDeltaMissingExistingFile,
  90     kFingerprintWriteFailed,
  91   };
  92
  93   typedef base::Callback<void(Error, int)> Callback;
  94
  95   // Constructs an unpacker for a specific component unpacking operation.
  96   // |pk_hash| is the expected/ public key SHA256 hash. |path| is the current
  97   // location of the CRX.
  98   ComponentUnpacker(
  99       const std::vector<uint8_t>& pk_hash,
 100       const base::FilePath& path,
 101       const std::string& fingerprint,
 102       const scoped_refptr<CrxInstaller>& installer,
 103       const scoped_refptr<OutOfProcessPatcher>& oop_patcher,
 104       const scoped_refptr<base::SequencedTaskRunner>& task_runner);
 105
 106   // Begins the actual unpacking of the files. May invoke a patcher if the
 107   // package is a differential update. Calls |callback| with the result.
 108   void Unpack(const Callback& callback);
 109
 110  private:
 111   friend class base::RefCountedThreadSafe<ComponentUnpacker>;
 112
 113   virtual ~ComponentUnpacker();
 114
 115   bool UnpackInternal();
 116
 117   // The first step of unpacking is to verify the file. Returns false if an
 118   // error is encountered, the file is malformed, or the file is incorrectly
 119   // signed.
 120   bool Verify();
 121
 122   // The second step of unpacking is to unzip. Returns false if an error
 123   // occurs as part of unzipping.
 124   bool Unzip();
 125
 126   // The third step is to optionally patch files - this is a no-op for full
 127   // (non-differential) updates. This step is asynchronous. Returns false if an
 128   // error is encountered.
 129   bool BeginPatching();
 130
 131   // When patching is complete, EndPatching is called before moving on to step
 132   // four.
 133   void EndPatching(Error error, int extended_error);
 134
 135   // The fourth step is to install the unpacked component.
 136   void Install();
 137
 138   // The final step is to do clean-up for things that can't be tidied as we go.
 139   // If there is an error at any step, the remaining steps are skipped and
 140   // and Finish is called.
 141   // Finish is responsible for calling the callback provided in Start().
 142   void Finish();
 143
 144   std::vector<uint8_t> pk_hash_;
 145   base::FilePath path_;
 146   base::FilePath unpack_path_;
 147   base::FilePath unpack_diff_path_;
 148   bool is_delta_;
 149   std::string fingerprint_;
 150   scoped_refptr<ComponentPatcher> patcher_;
 151   scoped_refptr<CrxInstaller> installer_;
 152   Callback callback_;
 153   scoped_refptr<OutOfProcessPatcher> oop_patcher_;
 154   Error error_;
 155   int extended_error_;
 156   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 157
 158   DISALLOW_COPY_AND_ASSIGN(ComponentUnpacker);
 159 };
 160
 161 }  // namespace update_client
 162
 163 #endif  // COMPONENTS_UPDATE_CLIENT_COMPONENT_UNPACKER_H_