Home | History | Annotate | Download | only in component_updater 
      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_
    161