extensions/browser/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/browser/crx_file_info.h"
  16 #include "extensions/browser/install/crx_install_error.h"
  17 #include "extensions/common/manifest.h"
  18
  19 class SkBitmap;
  20
  21 namespace base {
  22 class DictionaryValue;
  23 class SequencedTaskRunner;
  24 }
  25
  26 namespace crypto {
  27 class SecureHash;
  28 }
  29
  30 namespace extensions {
  31 class Extension;
  32
  33 class SandboxedUnpackerClient
  34     : public base::RefCountedThreadSafe<SandboxedUnpackerClient> {
  35  public:
  36   // temp_dir - A temporary directory containing the results of the extension
  37   // unpacking. The client is responsible for deleting this directory.
  38   //
  39   // extension_root - The path to the extension root inside of temp_dir.
  40   //
  41   // original_manifest - The parsed but unmodified version of the manifest,
  42   // with no modifications such as localization, etc.
  43   //
  44   // extension - The extension that was unpacked. The client is responsible
  45   // for deleting this memory.
  46   //
  47   // install_icon - The icon we will display in the installation UI, if any.
  48   virtual void OnUnpackSuccess(const base::FilePath& temp_dir,
  49                                const base::FilePath& extension_root,
  50                                const base::DictionaryValue* original_manifest,
  51                                const Extension* extension,
  52                                const SkBitmap& install_icon) = 0;
  53   virtual void OnUnpackFailure(const CrxInstallError& error) = 0;
  54
  55  protected:
  56   friend class base::RefCountedThreadSafe<SandboxedUnpackerClient>;
  57
  58   virtual ~SandboxedUnpackerClient() {}
  59 };
  60
  61 // SandboxedUnpacker unpacks extensions from the CRX format into a
  62 // directory. This is done in a sandboxed subprocess to protect the browser
  63 // process from parsing complex formats like JPEG or JSON from untrusted
  64 // sources.
  65 //
  66 // Unpacking an extension using this class makes minor changes to its source,
  67 // such as transcoding all images to PNG, parsing all message catalogs
  68 // and rewriting the manifest JSON. As such, it should not be used when the
  69 // output is not intended to be given back to the author.
  70 //
  71 //
  72 // Lifetime management:
  73 //
  74 // This class is ref-counted by each call it makes to itself on another thread,
  75 // and by UtilityProcessHost.
  76 //
  77 // Additionally, we hold a reference to our own client so that it lives at least
  78 // long enough to receive the result of unpacking.
  79 //
  80 //
  81 // NOTE: This class should only be used on the file thread.
  82 class SandboxedUnpacker : public content::UtilityProcessHostClient {
  83  public:
  84   // Unpacks the extension in |crx_path| into a temporary directory and calls
  85   // |client| with the result. If |run_out_of_process| is provided, unpacking
  86   // is done in a sandboxed subprocess. Otherwise, it is done in-process.
  87   SandboxedUnpacker(
  88       const CRXFileInfo& file,
  89       Manifest::Location location,
  90       int creation_flags,
  91       const base::FilePath& extensions_dir,
  92       const scoped_refptr<base::SequencedTaskRunner>& unpacker_io_task_runner,
  93       SandboxedUnpackerClient* client);
  94
  95   // Start unpacking the extension. The client is called with the results.
  96   void Start();
  97
  98  private:
  99   class ProcessHostClient;
 100
 101   // Enumerate all the ways unpacking can fail.  Calls to ReportFailure()
 102   // take a failure reason as an argument, and put it in histogram
 103   // Extensions.SandboxUnpackFailureReason.
 104   enum FailureReason {
 105     // SandboxedUnpacker::CreateTempDirectory()
 106     COULD_NOT_GET_TEMP_DIRECTORY,
 107     COULD_NOT_CREATE_TEMP_DIRECTORY,
 108
 109     // SandboxedUnpacker::Start()
 110     FAILED_TO_COPY_EXTENSION_FILE_TO_TEMP_DIRECTORY,
 111     COULD_NOT_GET_SANDBOX_FRIENDLY_PATH,
 112
 113     // SandboxedUnpacker::OnUnpackExtensionSucceeded()
 114     COULD_NOT_LOCALIZE_EXTENSION,
 115     INVALID_MANIFEST,
 116
 117     // SandboxedUnpacker::OnUnpackExtensionFailed()
 118     UNPACKER_CLIENT_FAILED,
 119
 120     // SandboxedUnpacker::OnProcessCrashed()
 121     UTILITY_PROCESS_CRASHED_WHILE_TRYING_TO_INSTALL,
 122
 123     // SandboxedUnpacker::ValidateSignature()
 124     CRX_FILE_NOT_READABLE,
 125     CRX_HEADER_INVALID,
 126     CRX_MAGIC_NUMBER_INVALID,
 127     CRX_VERSION_NUMBER_INVALID,
 128     CRX_EXCESSIVELY_LARGE_KEY_OR_SIGNATURE,
 129     CRX_ZERO_KEY_LENGTH,
 130     CRX_ZERO_SIGNATURE_LENGTH,
 131     CRX_PUBLIC_KEY_INVALID,
 132     CRX_SIGNATURE_INVALID,
 133     CRX_SIGNATURE_VERIFICATION_INITIALIZATION_FAILED,
 134     CRX_SIGNATURE_VERIFICATION_FAILED,
 135
 136     // SandboxedUnpacker::RewriteManifestFile()
 137     ERROR_SERIALIZING_MANIFEST_JSON,
 138     ERROR_SAVING_MANIFEST_JSON,
 139
 140     // SandboxedUnpacker::RewriteImageFiles()
 141     COULD_NOT_READ_IMAGE_DATA_FROM_DISK,
 142     DECODED_IMAGES_DO_NOT_MATCH_THE_MANIFEST,
 143     INVALID_PATH_FOR_BROWSER_IMAGE,
 144     ERROR_REMOVING_OLD_IMAGE_FILE,
 145     INVALID_PATH_FOR_BITMAP_IMAGE,
 146     ERROR_RE_ENCODING_THEME_IMAGE,
 147     ERROR_SAVING_THEME_IMAGE,
 148     ABORTED_DUE_TO_SHUTDOWN,
 149
 150     // SandboxedUnpacker::RewriteCatalogFiles()
 151     COULD_NOT_READ_CATALOG_DATA_FROM_DISK,
 152     INVALID_CATALOG_DATA,
 153     INVALID_PATH_FOR_CATALOG,
 154     ERROR_SERIALIZING_CATALOG,
 155     ERROR_SAVING_CATALOG,
 156
 157     // SandboxedUnpacker::ValidateSignature()
 158     CRX_HASH_VERIFICATION_FAILED,
 159
 160     NUM_FAILURE_REASONS
 161   };
 162
 163   friend class ProcessHostClient;
 164   friend class SandboxedUnpackerTest;
 165
 166   ~SandboxedUnpacker() override;
 167
 168   // Set |temp_dir_| as a temporary directory to unpack the extension in.
 169   // Return true on success.
 170   virtual bool CreateTempDirectory();
 171
 172   // Finalizes hash calculation and checks the result against the expected
 173   // package hash. In case of mismatch, depending on the command-line option,
 174   // we will either fail installation, or just update histograms.
 175   bool FinalizeHash(scoped_ptr<crypto::SecureHash>& hash);
 176
 177   // Validates the signature of the extension and extract the key to
 178   // |public_key_|. Returns true if the signature validates, false otherwise.
 179   //
 180   // NOTE: Having this method here is a bit ugly. This code should really live
 181   // in extensions::Unpacker as it is not specific to sandboxed unpacking. It
 182   // was put here because we cannot run windows crypto code in the sandbox. But
 183   // we could still have this method statically on extensions::Unpacker so that
 184   // code just for unpacking is there and code just for sandboxing of unpacking
 185   // is here.
 186   bool ValidateSignature();
 187
 188   // Starts the utility process that unpacks our extension.
 189   void StartProcessOnIOThread(const base::FilePath& temp_crx_path);
 190
 191   // UtilityProcessHostClient
 192   bool OnMessageReceived(const IPC::Message& message) override;
 193   void OnProcessCrashed(int exit_code) override;
 194
 195   // IPC message handlers.
 196   void OnUnpackExtensionSucceeded(const base::DictionaryValue& manifest);
 197   void OnUnpackExtensionFailed(const base::string16& error_message);
 198
 199   void ReportFailure(FailureReason reason, const base::string16& message);
 200   void ReportSuccess(const base::DictionaryValue& original_manifest,
 201                      const SkBitmap& install_icon);
 202
 203   // Overwrites original manifest with safe result from utility process.
 204   // Returns NULL on error. Caller owns the returned object.
 205   base::DictionaryValue* RewriteManifestFile(
 206       const base::DictionaryValue& manifest);
 207
 208   // Overwrites original files with safe results from utility process.
 209   // Reports error and returns false if it fails.
 210   bool RewriteImageFiles(SkBitmap* install_icon);
 211   bool RewriteCatalogFiles();
 212
 213   // Cleans up temp directory artifacts.
 214   void Cleanup();
 215
 216   // The path to the CRX to unpack.
 217   base::FilePath crx_path_;
 218
 219   // The package SHA256 hash sum that was reported from the Web Store.
 220   std::string package_hash_;
 221
 222   // Whether we need to check the .crx hash sum.
 223   bool check_crx_hash_;
 224
 225   // Our client.
 226   scoped_refptr<SandboxedUnpackerClient> client_;
 227
 228   // The Extensions directory inside the profile.
 229   base::FilePath extensions_dir_;
 230
 231   // A temporary directory to use for unpacking.
 232   base::ScopedTempDir temp_dir_;
 233
 234   // The root directory of the unpacked extension. This is a child of temp_dir_.
 235   base::FilePath extension_root_;
 236
 237   // Represents the extension we're unpacking.
 238   scoped_refptr<Extension> extension_;
 239
 240   // Whether we've received a response from the utility process yet.
 241   bool got_response_;
 242
 243   // The public key that was extracted from the CRX header.
 244   std::string public_key_;
 245
 246   // The extension's ID. This will be calculated from the public key in the crx
 247   // header.
 248   std::string extension_id_;
 249
 250   // Time at which unpacking started. Used to compute the time unpacking takes.
 251   base::TimeTicks unpack_start_time_;
 252
 253   // Location to use for the unpacked extension.
 254   Manifest::Location location_;
 255
 256   // Creation flags to use for the extension.  These flags will be used
 257   // when calling Extenion::Create() by the crx installer.
 258   int creation_flags_;
 259
 260   // Sequenced task runner where file I/O operations will be performed at.
 261   scoped_refptr<base::SequencedTaskRunner> unpacker_io_task_runner_;
 262 };
 263
 264 }  // namespace extensions
 265
 266 #endif  // CHROME_BROWSER_EXTENSIONS_SANDBOXED_UNPACKER_H_