chrome/browser/extensions/sandboxed_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_EXTENSIONS_SANDBOXED_UNPACKER_H_
   6 #define CHROME_BROWSER_EXTENSIONS_SANDBOXED_UNPACKER_H_
   7
   8 #include <string>
   9
  10 #include "base/files/file_path.h"
  11 #include "base/files/scoped_temp_dir.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/time/time.h"
  14 #include "content/public/browser/utility_process_host_client.h"
  15 #include "extensions/common/manifest.h"
  16
  17 class SkBitmap;
  18
  19 namespace base {
  20 class DictionaryValue;
  21 class SequencedTaskRunner;
  22 }
  23
  24 namespace extensions {
  25 class Extension;
  26
  27 class SandboxedUnpackerClient
  28     : public base::RefCountedThreadSafe<SandboxedUnpackerClient> {
  29  public:
  30   // temp_dir - A temporary directory containing the results of the extension
  31   // unpacking. The client is responsible for deleting this directory.
  32   //
  33   // extension_root - The path to the extension root inside of temp_dir.
  34   //
  35   // original_manifest - The parsed but unmodified version of the manifest,
  36   // with no modifications such as localization, etc.
  37   //
  38   // extension - The extension that was unpacked. The client is responsible
  39   // for deleting this memory.
  40   //
  41   // install_icon - The icon we will display in the installation UI, if any.
  42   virtual void OnUnpackSuccess(const base::FilePath& temp_dir,
  43                                const base::FilePath& extension_root,
  44                                const base::DictionaryValue* original_manifest,
  45                                const Extension* extension,
  46                                const SkBitmap& install_icon) = 0;
  47   virtual void OnUnpackFailure(const base::string16& error) = 0;
  48
  49  protected:
  50   friend class base::RefCountedThreadSafe<SandboxedUnpackerClient>;
  51
  52   virtual ~SandboxedUnpackerClient() {}
  53 };
  54
  55 // SandboxedUnpacker unpacks extensions from the CRX format into a
  56 // directory. This is done in a sandboxed subprocess to protect the browser
  57 // process from parsing complex formats like JPEG or JSON from untrusted
  58 // sources.
  59 //
  60 // Unpacking an extension using this class makes minor changes to its source,
  61 // such as transcoding all images to PNG, parsing all message catalogs
  62 // and rewriting the manifest JSON. As such, it should not be used when the
  63 // output is not intended to be given back to the author.
  64 //
  65 //
  66 // Lifetime management:
  67 //
  68 // This class is ref-counted by each call it makes to itself on another thread,
  69 // and by UtilityProcessHost.
  70 //
  71 // Additionally, we hold a reference to our own client so that it lives at least
  72 // long enough to receive the result of unpacking.
  73 //
  74 //
  75 // NOTE: This class should only be used on the file thread.
  76 class SandboxedUnpacker : public content::UtilityProcessHostClient {
  77  public:
  78   // Unpacks the extension in |crx_path| into a temporary directory and calls
  79   // |client| with the result. If |run_out_of_process| is provided, unpacking
  80   // is done in a sandboxed subprocess. Otherwise, it is done in-process.
  81   SandboxedUnpacker(const base::FilePath& crx_path,
  82                     Manifest::Location location,
  83                     int creation_flags,
  84                     const base::FilePath& extensions_dir,
  85                     base::SequencedTaskRunner* unpacker_io_task_runner,
  86                     SandboxedUnpackerClient* client);
  87
  88   // Start unpacking the extension. The client is called with the results.
  89   void Start();
  90
  91  private:
  92   class ProcessHostClient;
  93
  94   // Enumerate all the ways unpacking can fail.  Calls to ReportFailure()
  95   // take a failure reason as an argument, and put it in histogram
  96   // Extensions.SandboxUnpackFailureReason.
  97   enum FailureReason {
  98     // SandboxedUnpacker::CreateTempDirectory()
  99     COULD_NOT_GET_TEMP_DIRECTORY,
 100     COULD_NOT_CREATE_TEMP_DIRECTORY,
 101
 102     // SandboxedUnpacker::Start()
 103     FAILED_TO_COPY_EXTENSION_FILE_TO_TEMP_DIRECTORY,
 104     COULD_NOT_GET_SANDBOX_FRIENDLY_PATH,
 105
 106     // SandboxedUnpacker::OnUnpackExtensionSucceeded()
 107     COULD_NOT_LOCALIZE_EXTENSION,
 108     INVALID_MANIFEST,
 109
 110     // SandboxedUnpacker::OnUnpackExtensionFailed()
 111     UNPACKER_CLIENT_FAILED,
 112
 113     // SandboxedUnpacker::OnProcessCrashed()
 114     UTILITY_PROCESS_CRASHED_WHILE_TRYING_TO_INSTALL,
 115
 116     // SandboxedUnpacker::ValidateSignature()
 117     CRX_FILE_NOT_READABLE,
 118     CRX_HEADER_INVALID,
 119     CRX_MAGIC_NUMBER_INVALID,
 120     CRX_VERSION_NUMBER_INVALID,
 121     CRX_EXCESSIVELY_LARGE_KEY_OR_SIGNATURE,
 122     CRX_ZERO_KEY_LENGTH,
 123     CRX_ZERO_SIGNATURE_LENGTH,
 124     CRX_PUBLIC_KEY_INVALID,
 125     CRX_SIGNATURE_INVALID,
 126     CRX_SIGNATURE_VERIFICATION_INITIALIZATION_FAILED,
 127     CRX_SIGNATURE_VERIFICATION_FAILED,
 128
 129     // SandboxedUnpacker::RewriteManifestFile()
 130     ERROR_SERIALIZING_MANIFEST_JSON,
 131     ERROR_SAVING_MANIFEST_JSON,
 132
 133     // SandboxedUnpacker::RewriteImageFiles()
 134     COULD_NOT_READ_IMAGE_DATA_FROM_DISK,
 135     DECODED_IMAGES_DO_NOT_MATCH_THE_MANIFEST,
 136     INVALID_PATH_FOR_BROWSER_IMAGE,
 137     ERROR_REMOVING_OLD_IMAGE_FILE,
 138     INVALID_PATH_FOR_BITMAP_IMAGE,
 139     ERROR_RE_ENCODING_THEME_IMAGE,
 140     ERROR_SAVING_THEME_IMAGE,
 141     ABORTED_DUE_TO_SHUTDOWN,
 142
 143     // SandboxedUnpacker::RewriteCatalogFiles()
 144     COULD_NOT_READ_CATALOG_DATA_FROM_DISK,
 145     INVALID_CATALOG_DATA,
 146     INVALID_PATH_FOR_CATALOG,
 147     ERROR_SERIALIZING_CATALOG,
 148     ERROR_SAVING_CATALOG,
 149
 150     NUM_FAILURE_REASONS
 151   };
 152
 153   friend class ProcessHostClient;
 154   friend class SandboxedUnpackerTest;
 155
 156   virtual ~SandboxedUnpacker();
 157
 158   // Set |temp_dir_| as a temporary directory to unpack the extension in.
 159   // Return true on success.
 160   virtual bool CreateTempDirectory();
 161
 162   // Validates the signature of the extension and extract the key to
 163   // |public_key_|. Returns true if the signature validates, false otherwise.
 164   //
 165   // NOTE: Having this method here is a bit ugly. This code should really live
 166   // in extensions::Unpacker as it is not specific to sandboxed unpacking. It
 167   // was put here because we cannot run windows crypto code in the sandbox. But
 168   // we could still have this method statically on extensions::Unpacker so that
 169   // code just for unpacking is there and code just for sandboxing of unpacking
 170   // is here.
 171   bool ValidateSignature();
 172
 173   // Starts the utility process that unpacks our extension.
 174   void StartProcessOnIOThread(const base::FilePath& temp_crx_path);
 175
 176   // UtilityProcessHostClient
 177   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 178   virtual void OnProcessCrashed(int exit_code) OVERRIDE;
 179
 180   // IPC message handlers.
 181   void OnUnpackExtensionSucceeded(const base::DictionaryValue& manifest);
 182   void OnUnpackExtensionFailed(const base::string16& error_message);
 183
 184   void ReportFailure(FailureReason reason, const base::string16& message);
 185   void ReportSuccess(const base::DictionaryValue& original_manifest,
 186                      const SkBitmap& install_icon);
 187
 188   // Overwrites original manifest with safe result from utility process.
 189   // Returns NULL on error. Caller owns the returned object.
 190   base::DictionaryValue* RewriteManifestFile(
 191       const base::DictionaryValue& manifest);
 192
 193   // Overwrites original files with safe results from utility process.
 194   // Reports error and returns false if it fails.
 195   bool RewriteImageFiles(SkBitmap* install_icon);
 196   bool RewriteCatalogFiles();
 197
 198   // Cleans up temp directory artifacts.
 199   void Cleanup();
 200
 201   // The path to the CRX to unpack.
 202   base::FilePath crx_path_;
 203
 204   // Our client.
 205   scoped_refptr<SandboxedUnpackerClient> client_;
 206
 207   // The Extensions directory inside the profile.
 208   base::FilePath extensions_dir_;
 209
 210   // A temporary directory to use for unpacking.
 211   base::ScopedTempDir temp_dir_;
 212
 213   // The root directory of the unpacked extension. This is a child of temp_dir_.
 214   base::FilePath extension_root_;
 215
 216   // Represents the extension we're unpacking.
 217   scoped_refptr<Extension> extension_;
 218
 219   // Whether we've received a response from the utility process yet.
 220   bool got_response_;
 221
 222   // The public key that was extracted from the CRX header.
 223   std::string public_key_;
 224
 225   // The extension's ID. This will be calculated from the public key in the crx
 226   // header.
 227   std::string extension_id_;
 228
 229   // Time at which unpacking started. Used to compute the time unpacking takes.
 230   base::TimeTicks unpack_start_time_;
 231
 232   // Location to use for the unpacked extension.
 233   Manifest::Location location_;
 234
 235   // Creation flags to use for the extension.  These flags will be used
 236   // when calling Extenion::Create() by the crx installer.
 237   int creation_flags_;
 238
 239   // Sequenced task runner where file I/O operations will be performed at.
 240   scoped_refptr<base::SequencedTaskRunner> unpacker_io_task_runner_;
 241 };
 242
 243 }  // namespace extensions
 244
 245 #endif  // CHROME_BROWSER_EXTENSIONS_SANDBOXED_UNPACKER_H_