components/update_client/component_unpacker.cc

   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 #include "components/update_client/component_unpacker.h"
   6
   7 #include <stdint.h>
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/bind.h"
  12 #include "base/files/file_path.h"
  13 #include "base/files/file_util.h"
  14 #include "base/files/scoped_file.h"
  15 #include "base/json/json_file_value_serializer.h"
  16 #include "base/location.h"
  17 #include "base/logging.h"
  18 #include "base/numerics/safe_conversions.h"
  19 #include "base/strings/string_number_conversions.h"
  20 #include "base/strings/stringprintf.h"
  21 #include "base/values.h"
  22 #include "components/crx_file/constants.h"
  23 #include "components/crx_file/crx_file.h"
  24 #include "components/update_client/component_patcher.h"
  25 #include "components/update_client/component_patcher_operation.h"
  26 #include "components/update_client/update_client.h"
  27 #include "crypto/secure_hash.h"
  28 #include "crypto/signature_verifier.h"
  29 #include "third_party/zlib/google/zip.h"
  30
  31 using crypto::SecureHash;
  32
  33 namespace update_client {
  34
  35 namespace {
  36
  37 // This class makes sure that the CRX digital signature is valid
  38 // and well formed.
  39 class CRXValidator {
  40  public:
  41   explicit CRXValidator(FILE* crx_file) : valid_(false), is_delta_(false) {
  42     crx_file::CrxFile::Header header;
  43     size_t len = fread(&header, 1, sizeof(header), crx_file);
  44     if (len < sizeof(header))
  45       return;
  46
  47     crx_file::CrxFile::Error error;
  48     scoped_ptr<crx_file::CrxFile> crx(crx_file::CrxFile::Parse(header, &error));
  49     if (!crx.get())
  50       return;
  51     is_delta_ = crx_file::CrxFile::HeaderIsDelta(header);
  52
  53     std::vector<uint8_t> key(header.key_size);
  54     len = fread(&key[0], sizeof(uint8_t), header.key_size, crx_file);
  55     if (len < header.key_size)
  56       return;
  57
  58     std::vector<uint8_t> signature(header.signature_size);
  59     len =
  60         fread(&signature[0], sizeof(uint8_t), header.signature_size, crx_file);
  61     if (len < header.signature_size)
  62       return;
  63
  64     crypto::SignatureVerifier verifier;
  65     if (!verifier.VerifyInit(
  66             crx_file::kSignatureAlgorithm,
  67             base::checked_cast<int>(sizeof(crx_file::kSignatureAlgorithm)),
  68             &signature[0], base::checked_cast<int>(signature.size()), &key[0],
  69             base::checked_cast<int>(key.size()))) {
  70       // Signature verification initialization failed. This is most likely
  71       // caused by a public key in the wrong format (should encode algorithm).
  72       return;
  73     }
  74
  75     const size_t kBufSize = 8 * 1024;
  76     scoped_ptr<uint8_t[]> buf(new uint8_t[kBufSize]);
  77     while ((len = fread(buf.get(), 1, kBufSize, crx_file)) > 0)
  78       verifier.VerifyUpdate(buf.get(), base::checked_cast<int>(len));
  79
  80     if (!verifier.VerifyFinal())
  81       return;
  82
  83     public_key_.swap(key);
  84     valid_ = true;
  85   }
  86
  87   bool valid() const { return valid_; }
  88
  89   bool is_delta() const { return is_delta_; }
  90
  91   const std::vector<uint8_t>& public_key() const { return public_key_; }
  92
  93  private:
  94   bool valid_;
  95   bool is_delta_;
  96   std::vector<uint8_t> public_key_;
  97 };
  98
  99 }  // namespace
 100
 101 ComponentUnpacker::ComponentUnpacker(
 102     const std::vector<uint8_t>& pk_hash,
 103     const base::FilePath& path,
 104     const std::string& fingerprint,
 105     const scoped_refptr<CrxInstaller>& installer,
 106     const scoped_refptr<OutOfProcessPatcher>& oop_patcher,
 107     const scoped_refptr<base::SequencedTaskRunner>& task_runner)
 108     : pk_hash_(pk_hash),
 109       path_(path),
 110       is_delta_(false),
 111       fingerprint_(fingerprint),
 112       installer_(installer),
 113       oop_patcher_(oop_patcher),
 114       error_(kNone),
 115       extended_error_(0),
 116       task_runner_(task_runner) {
 117 }
 118
 119 // TODO(cpu): add a specific attribute check to a component json that the
 120 // extension unpacker will reject, so that a component cannot be installed
 121 // as an extension.
 122 scoped_ptr<base::DictionaryValue> ReadManifest(
 123     const base::FilePath& unpack_path) {
 124   base::FilePath manifest =
 125       unpack_path.Append(FILE_PATH_LITERAL("manifest.json"));
 126   if (!base::PathExists(manifest))
 127     return scoped_ptr<base::DictionaryValue>();
 128   JSONFileValueDeserializer deserializer(manifest);
 129   std::string error;
 130   scoped_ptr<base::Value> root(deserializer.Deserialize(NULL, &error));
 131   if (!root.get())
 132     return scoped_ptr<base::DictionaryValue>();
 133   if (!root->IsType(base::Value::TYPE_DICTIONARY))
 134     return scoped_ptr<base::DictionaryValue>();
 135   return scoped_ptr<base::DictionaryValue>(
 136              static_cast<base::DictionaryValue*>(root.release())).Pass();
 137 }
 138
 139 bool ComponentUnpacker::UnpackInternal() {
 140   return Verify() && Unzip() && BeginPatching();
 141 }
 142
 143 void ComponentUnpacker::Unpack(const Callback& callback) {
 144   callback_ = callback;
 145   if (!UnpackInternal())
 146     Finish();
 147 }
 148
 149 bool ComponentUnpacker::Verify() {
 150   VLOG(1) << "Verifying component: " << path_.value();
 151   if (pk_hash_.empty() || path_.empty()) {
 152     error_ = kInvalidParams;
 153     return false;
 154   }
 155   // First, validate the CRX header and signature. As of today
 156   // this is SHA1 with RSA 1024.
 157   base::ScopedFILE file(base::OpenFile(path_, "rb"));
 158   if (!file.get()) {
 159     error_ = kInvalidFile;
 160     return false;
 161   }
 162   CRXValidator validator(file.get());
 163   file.reset();
 164   if (!validator.valid()) {
 165     error_ = kInvalidFile;
 166     return false;
 167   }
 168   is_delta_ = validator.is_delta();
 169
 170   // File is valid and the digital signature matches. Now make sure
 171   // the public key hash matches the expected hash. If they do we fully
 172   // trust this CRX.
 173   uint8_t hash[32] = {};
 174   scoped_ptr<SecureHash> sha256(SecureHash::Create(SecureHash::SHA256));
 175   sha256->Update(&(validator.public_key()[0]), validator.public_key().size());
 176   sha256->Finish(hash, arraysize(hash));
 177
 178   if (!std::equal(pk_hash_.begin(), pk_hash_.end(), hash)) {
 179     VLOG(1) << "Hash mismatch: " << path_.value();
 180     error_ = kInvalidId;
 181     return false;
 182   }
 183   VLOG(1) << "Verification successful: " << path_.value();
 184   return true;
 185 }
 186
 187 bool ComponentUnpacker::Unzip() {
 188   base::FilePath& destination = is_delta_ ? unpack_diff_path_ : unpack_path_;
 189   VLOG(1) << "Unpacking in: " << destination.value();
 190   if (!base::CreateNewTempDirectory(base::FilePath::StringType(),
 191                                     &destination)) {
 192     VLOG(1) << "Unable to create temporary directory for unpacking.";
 193     error_ = kUnzipPathError;
 194     return false;
 195   }
 196   if (!zip::Unzip(path_, destination)) {
 197     VLOG(1) << "Unzipping failed.";
 198     error_ = kUnzipFailed;
 199     return false;
 200   }
 201   VLOG(1) << "Unpacked successfully";
 202   return true;
 203 }
 204
 205 bool ComponentUnpacker::BeginPatching() {
 206   if (is_delta_) {  // Package is a diff package.
 207     // Use a different temp directory for the patch output files.
 208     if (!base::CreateNewTempDirectory(base::FilePath::StringType(),
 209                                       &unpack_path_)) {
 210       error_ = kUnzipPathError;
 211       return false;
 212     }
 213     patcher_ = new ComponentPatcher(unpack_diff_path_, unpack_path_, installer_,
 214                                     oop_patcher_, task_runner_);
 215     task_runner_->PostTask(
 216         FROM_HERE,
 217         base::Bind(&ComponentPatcher::Start, patcher_,
 218                    base::Bind(&ComponentUnpacker::EndPatching,
 219                               scoped_refptr<ComponentUnpacker>(this))));
 220   } else {
 221     task_runner_->PostTask(
 222         FROM_HERE,
 223         base::Bind(&ComponentUnpacker::EndPatching,
 224                    scoped_refptr<ComponentUnpacker>(this), kNone, 0));
 225   }
 226   return true;
 227 }
 228
 229 void ComponentUnpacker::EndPatching(Error error, int extended_error) {
 230   error_ = error;
 231   extended_error_ = extended_error;
 232   patcher_ = NULL;
 233   if (error_ != kNone) {
 234     Finish();
 235     return;
 236   }
 237   // Optimization: clean up patch files early, in case disk space is too low to
 238   // install otherwise.
 239   if (!unpack_diff_path_.empty()) {
 240     base::DeleteFile(unpack_diff_path_, true);
 241     unpack_diff_path_.clear();
 242   }
 243   Install();
 244   Finish();
 245 }
 246
 247 void ComponentUnpacker::Install() {
 248   // Write the fingerprint to disk.
 249   if (static_cast<int>(fingerprint_.size()) !=
 250       base::WriteFile(
 251           unpack_path_.Append(FILE_PATH_LITERAL("manifest.fingerprint")),
 252           fingerprint_.c_str(), base::checked_cast<int>(fingerprint_.size()))) {
 253     error_ = kFingerprintWriteFailed;
 254     return;
 255   }
 256   scoped_ptr<base::DictionaryValue> manifest(ReadManifest(unpack_path_));
 257   if (!manifest.get()) {
 258     error_ = kBadManifest;
 259     return;
 260   }
 261   DCHECK(error_ == kNone);
 262   if (!installer_->Install(*manifest, unpack_path_)) {
 263     error_ = kInstallerError;
 264     return;
 265   }
 266 }
 267
 268 void ComponentUnpacker::Finish() {
 269   if (!unpack_diff_path_.empty())
 270     base::DeleteFile(unpack_diff_path_, true);
 271   if (!unpack_path_.empty())
 272     base::DeleteFile(unpack_path_, true);
 273   task_runner_->PostTask(FROM_HERE,
 274                          base::Bind(callback_, error_, extended_error_));
 275 }
 276
 277 ComponentUnpacker::~ComponentUnpacker() {
 278 }
 279
 280 }  // namespace update_client