Differential updates for components.

chrome/browser/component_updater/component_unpacker.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/component_updater/component_unpacker.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_util.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/memory/scoped_handle.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
+#include "chrome/browser/component_updater/component_patcher.h"
 #include "chrome/browser/component_updater/component_updater_service.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "crypto/secure_hash.h"
 #include "crypto/signature_verifier.h"
 #include "extensions/common/crx_file.h"
 #include "third_party/zlib/google/zip.h"
 
 using crypto::SecureHash;
 
 namespace {
+
 // This class makes sure that the CRX digital signature is valid
 // and well formed.
 class CRXValidator {
  public:
-  explicit CRXValidator(FILE* crx_file) : valid_(false) {
+  explicit CRXValidator(FILE* crx_file) : valid_(false), delta_(false) {
     extensions::CrxFile::Header header;
     size_t len = fread(&header, 1, sizeof(header), crx_file);
     if (len < sizeof(header))
       return;
 
     extensions::CrxFile::Error error;
     scoped_ptr<extensions::CrxFile> crx(
         extensions::CrxFile::Parse(header, &error));
     if (!crx.get())
       return;
+    delta_ = extensions::CrxFile::HeaderIsDelta(header);
 
     std::vector<uint8> key(header.key_size);
     len = fread(&key[0], sizeof(uint8), header.key_size, crx_file);
     if (len < header.key_size)
       return;
 
     std::vector<uint8> signature(header.signature_size);
     len = fread(&signature[0], sizeof(uint8), header.signature_size, crx_file);
     if (len < header.signature_size)
       return;
@@ skipping 15 matching lines @@
 
     if (!verifier.VerifyFinal())
       return;
 
     public_key_.swap(key);
     valid_ = true;
   }
 
   bool valid() const { return valid_; }
 
+  bool delta() const { return delta_; }
+
   const std::vector<uint8>& public_key() const { return public_key_; }
 
  private:
   bool valid_;
+  bool delta_;
   std::vector<uint8> public_key_;
 };
 
 // Deserialize the CRX manifest. The top level must be a dictionary.
 // TODO(cpu): add a specific attribute check to a component json that the
 // extension unpacker will reject, so that a component cannot be installed
 // as an extension.
 base::DictionaryValue* ReadManifest(const base::FilePath& unpack_path) {
   base::FilePath manifest =
       unpack_path.Append(FILE_PATH_LITERAL("manifest.json"));
   if (!file_util::PathExists(manifest))
     return NULL;
   JSONFileValueSerializer serializer(manifest);
   std::string error;
   scoped_ptr<base::Value> root(serializer.Deserialize(NULL, &error));
   if (!root.get())
     return NULL;
   if (!root->IsType(base::Value::TYPE_DICTIONARY))
     return NULL;
   return static_cast<base::DictionaryValue*>(root.release());
 }
 
+// Deletes a path if it exists, and then creates a directory there.
+// Returns true if and only if these operations were successful.
+// This method doesn't take any special steps to prevent files from
+// being inserted into the target directory by another process or thread.
+bool MakeEmptyDirectory(const base::FilePath& path) {
+  if (file_util::PathExists(path)) {
+    if (!file_util::Delete(path, true))
+      return false;
+  }
+  if (!file_util::CreateDirectory(path))
+    return false;
+  return true;
+}
+
 }  // namespace.
 
 ComponentUnpacker::ComponentUnpacker(const std::vector<uint8>& pk_hash,
                                      const base::FilePath& path,
+                                     const std::string& fingerprint,
+                                     ComponentPatcher* patcher,
                                      ComponentInstaller* installer)
-  : error_(kNone) {
+    : error_(kNone),
+      extended_error_(0) {
   if (pk_hash.empty() || path.empty()) {
     error_ = kInvalidParams;
     return;
   }
   // First, validate the CRX header and signature. As of today
   // this is SHA1 with RSA 1024.
   ScopedStdioHandle file(file_util::OpenFile(path, "rb"));
   if (!file.get()) {
     error_ = kInvalidFile;
     return;
@@ skipping 11 matching lines @@
   uint8 hash[32];
   scoped_ptr<SecureHash> sha256(SecureHash::Create(SecureHash::SHA256));
   sha256->Update(&(validator.public_key()[0]), validator.public_key().size());
   sha256->Finish(hash, arraysize(hash));
 
   if (!std::equal(pk_hash.begin(), pk_hash.end(), hash)) {
     error_ = kInvalidId;
     return;
   }
   // We want the temporary directory to be unique and yet predictable, so
-  // we can easily find the package in a end user machine.
-  std::string dir(
+  // we can easily find the package in an end user machine.
+  const std::string dir(
       base::StringPrintf("CRX_%s", base::HexEncode(hash, 6).c_str()));
   unpack_path_ = path.DirName().AppendASCII(dir.c_str());
-  if (file_util::DirectoryExists(unpack_path_)) {
-    if (!file_util::Delete(unpack_path_, true)) {
-      unpack_path_.clear();
-      error_ = kUzipPathError;
+  if (!MakeEmptyDirectory(unpack_path_)) {
+    unpack_path_.clear();
+    error_ = kUnzipPathError;
+    return;
+  }
+  if (validator.delta()) {  // Package is a diff package.
+    // We want a different temp directory for the delta files; we'll put the
+    // patch output into unpack_path_.
+    std::string dir(
+        base::StringPrintf("CRX_%s_diff", base::HexEncode(hash, 6).c_str()));
+    base::FilePath unpack_diff_path = path.DirName().AppendASCII(dir.c_str());
+    if (!MakeEmptyDirectory(unpack_diff_path)) {
+      error_ = kUnzipPathError;
       return;
     }
-  }
-  if (!file_util::CreateDirectory(unpack_path_)) {
-    unpack_path_.clear();
-    error_ = kUzipPathError;
-    return;
-  }
-  if (!zip::Unzip(path, unpack_path_)) {
-    error_ = kUnzipFailed;
-    return;
+    if (!zip::Unzip(path, unpack_diff_path)) {
+      error_ = kUnzipFailed;
+      return;
+    }
+    ComponentUnpacker::Error result = DifferentialUpdatePatch(unpack_diff_path,
+                                                              unpack_path_,
+                                                              patcher,
+                                                              installer,
+                                                              &extended_error_);
+    file_util::Delete(unpack_diff_path, true);
+    unpack_diff_path.clear();
+    error_ = result;
+    if (error_ != kNone) {
+      return;
+    }
+  } else {
+    // Package is a normal update/install; unzip it into unpack_path_ directly.
+    if (!zip::Unzip(path, unpack_path_)) {
+      error_ = kUnzipFailed;
+      return;
+    }
   }
   scoped_ptr<base::DictionaryValue> manifest(ReadManifest(unpack_path_));
   if (!manifest.get()) {
     error_ = kBadManifest;
     return;
   }
+  // Write the fingerprint to disk.
+  if (static_cast<int>(fingerprint.size()) !=
+      file_util::WriteFile(
+          unpack_path_.Append(FILE_PATH_LITERAL("manifest.fingerprint")),
+          fingerprint.c_str(),
+          fingerprint.size())) {
+    error_ = kFingerprintWriteFailed;
+    return;
+  }
   if (!installer->Install(*manifest, unpack_path_)) {
     error_ = kInstallerError;
     return;
   }
   // Installation successful. The directory is not our concern now.
   unpack_path_.clear();
 }
 
 ComponentUnpacker::~ComponentUnpacker() {
-  if (!unpack_path_.empty()) {
+  if (!unpack_path_.empty())
     file_util::Delete(unpack_path_, true);
-  }
 }