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Unified Diff: chrome/common/component_flash_hint_file_linux.cc

Issue 1261333004: Add support for Flash Player Component updates on Linux (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Use SecureHash, fix up unit tests, general cleanup Created 5 years, 4 months ago
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Index: chrome/common/component_flash_hint_file_linux.cc
diff --git a/chrome/common/component_flash_hint_file_linux.cc b/chrome/common/component_flash_hint_file_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..77616bee66663f91c9e37ec369057ad470c0906b
--- /dev/null
+++ b/chrome/common/component_flash_hint_file_linux.cc
@@ -0,0 +1,222 @@
+// Copyright 2015 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/common/component_flash_hint_file.h"
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "base/base64.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/important_file_writer.h"
+#include "base/files/memory_mapped_file.h"
+#include "base/files/scoped_file.h"
+#include "base/json/json_string_value_serializer.h"
+#include "base/path_service.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/stl_util.h"
+#include "base/values.h"
+#include "chrome/common/chrome_paths.h"
+#include "crypto/secure_hash.h"
+#include "crypto/sha2.h"
+
+namespace chrome {
+
+namespace {
+// The current version of the hints file.
+const int kCurrentHintFileVersion = 0x10;
+// The earliest version of the hints file.
+const int kEarliestHintFileVersion = 0x10;
+// The Version field in the JSON encoded file.
+const char kVersionField[] = "Version";
+// The HashAlgorithm field in the JSON encoded file.
+const char kHashAlgoField[] = "HashAlgorithm";
+// The Hash field in the JSON encoded file.
+const char kHashField[] = "Hash";
+// The PluginPath field in the JSON encoded file.
+const char kPluginPath[] = "PluginPath";
+// The PluginVersion field in the JSON encoded file.
+const char kPluginVersion[] = "PluginVersion";
+// For use with the scoped_ptr of an mmap-ed buffer
+struct MmapDeleter {
+ size_t map_size;
+ inline void operator()(uint8_t* ptr) const {
+ if (ptr != MAP_FAILED)
+ munmap(ptr, map_size);
+ }
+};
+
+// Hashes the plugin file and returns the result in the out params.
+void SHA256Hash(const base::MemoryMappedFile& mapped_file,
+ void* result,
+ size_t len) {
+ CHECK(len == crypto::kSHA256Length);
jln (very slow on Chromium) 2015/08/06 18:48:15 CHECK_EQ()
Greg K 2015/08/07 21:15:29 Done.
+ scoped_ptr<crypto::SecureHash> secure_hash(
+ crypto::SecureHash::Create(crypto::SecureHash::SHA256));
+ size_t bytes_remaining = mapped_file.length(), bytes_read = 0;
jln (very slow on Chromium) 2015/08/06 18:48:15 Style: one line per variable (can't find where tha
Greg K 2015/08/07 21:15:29 Done.
+ const size_t page_size = sysconf(_SC_PAGE_SIZE);
+
+ while (bytes_remaining > 0) {
+ const size_t len =
+ bytes_remaining >= page_size ? page_size : bytes_remaining;
+ CHECK(bytes_remaining >= len);
jln (very slow on Chromium) 2015/08/06 18:48:14 CHECK_GE()
Greg K 2015/08/07 21:15:29 Acknowledged.
+ secure_hash->Update(mapped_file.data() + bytes_read, len);
jln (very slow on Chromium) 2015/08/06 18:48:14 Why force this page by page? Why not ask update to
Greg K 2015/08/07 21:15:29 Done.
+ bytes_remaining -= len;
+ bytes_read += len;
+ }
+ secure_hash->Finish(result, len);
+}
+
+} // namespace
+
+// static
+bool ComponentFlashHintFile::TestExecutableMapping(const base::FilePath& path) {
+ const base::ScopedFD fd(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
jln (very slow on Chromium) 2015/08/06 18:48:15 Do CLOEXEC while you're at it.
Greg K 2015/08/07 21:15:29 Done.
+ if (!fd.is_valid())
+ return false;
+ const MmapDeleter deleter = {.map_size = sizeof(uint8_t)};
jln (very slow on Chromium) 2015/08/06 18:48:14 Style: I don't think we allow designed initializer
Greg K 2015/08/07 21:15:29 Done.
+ scoped_ptr<uint8_t, MmapDeleter> buf_ptr(
+ reinterpret_cast<uint8_t*>(mmap(NULL, deleter.map_size,
jln (very slow on Chromium) 2015/08/06 18:48:14 Given the simplicity here, I would not use the Mma
Greg K 2015/08/07 21:15:29 Makes sense, but I will leave it there in case som
+ PROT_READ | PROT_EXEC, MAP_PRIVATE,
+ fd.get(), 0)),
+ deleter);
+ return buf_ptr.get() != MAP_FAILED;
+}
+
+// static
+bool ComponentFlashHintFile::RecordFlashUpdate(
+ const base::FilePath& unpacked_plugin,
+ const base::FilePath& moved_plugin,
+ const std::string& version) {
+ base::MemoryMappedFile mapped_file;
+ if (!mapped_file.Initialize(unpacked_plugin))
+ return false;
+
+ std::string hash(crypto::kSHA256Length, 0);
+ SHA256Hash(mapped_file, string_as_array(&hash), hash.size());
+
+ return WriteToDisk(kCurrentHintFileVersion,
+ crypto::SecureHash::Algorithm::SHA256, hash, moved_plugin,
+ version);
+}
+
+// static
+bool ComponentFlashHintFile::DoesHintFileExist() {
+ base::FilePath hint_file_path;
+ if (!PathService::Get(chrome::FILE_COMPONENT_FLASH_HINT, &hint_file_path))
+ return false;
+ return base::PathExists(hint_file_path);
+}
+
+// static
+bool ComponentFlashHintFile::WriteToDisk(
+ const int version,
+ const crypto::SecureHash::Algorithm algorithm,
+ const std::string& hash,
+ const base::FilePath& plugin_path,
+ const std::string& flash_version) {
+ base::FilePath hint_file_path;
+ if (!PathService::Get(chrome::FILE_COMPONENT_FLASH_HINT, &hint_file_path))
+ return false;
+
+ std::string encoded_hash;
+ base::Base64Encode(hash, &encoded_hash);
+
+ // Now construct a Value object to convert to JSON.
+ base::DictionaryValue dict;
+ dict.SetInteger(kVersionField, version);
+ dict.SetInteger(kHashAlgoField, crypto::SecureHash::SHA256);
+ dict.SetString(kHashField, encoded_hash);
+ dict.SetString(kPluginPath, plugin_path.value());
+ dict.SetString(kPluginVersion, flash_version);
+ // Do the serialization of the DictionaryValue to JSON.
+ std::string json_string;
+ JSONStringValueSerializer serializer(&json_string);
+ if (!serializer.Serialize(dict))
+ return false;
+
+ return base::ImportantFileWriter::WriteFileAtomically(hint_file_path,
+ json_string);
+}
+
+// static
+bool ComponentFlashHintFile::VerifyAndReturnFlashLocation(
+ base::FilePath* path,
+ std::string* flash_version) {
+ base::FilePath hint_file_path;
+ if (!PathService::Get(chrome::FILE_COMPONENT_FLASH_HINT, &hint_file_path))
+ return false;
+
+ std::string json_string;
+ if (!base::ReadFileToString(hint_file_path, &json_string))
+ return false;
+
+ int error_code;
+ std::string error_message;
+ JSONStringValueDeserializer deserializer(json_string);
+ const scoped_ptr<base::Value> value(
+ deserializer.Deserialize(&error_code, &error_message));
+
+ if (value == nullptr) {
+ LOG(ERROR)
+ << "Could not deserialize the component updated flash hint file. Error "
+ << error_code << ": " << error_message;
+ return false;
+ }
+
+ base::DictionaryValue* dict = nullptr;
+ if (!value->GetAsDictionary(&dict))
+ return false;
+
+ int version;
+ if (!dict->GetInteger(kVersionField, &version))
+ return false;
+ if (version < kEarliestHintFileVersion || version > kCurrentHintFileVersion)
+ return false;
+
+ int hash_algorithm;
+ if (!dict->GetInteger(kHashAlgoField, &hash_algorithm))
+ return false;
+ if (hash_algorithm != crypto::SecureHash::SHA256)
+ return false;
+
+ std::string hash;
+ if (!dict->GetString(kHashField, &hash))
+ return false;
+
+ std::string plugin_path_str;
+ if (!dict->GetString(kPluginPath, &plugin_path_str))
+ return false;
+
+ std::string plugin_version_str;
+ if (!dict->GetString(kPluginVersion, &plugin_version_str))
+ return false;
+
+ std::string decoded_hash;
+ if (!base::Base64Decode(hash, &decoded_hash))
+ return false;
+
+ const base::FilePath plugin_path(plugin_path_str);
+ base::MemoryMappedFile plugin_file;
+ if (!plugin_file.Initialize(plugin_path))
+ return false;
+
+ std::vector<uint8_t> file_hash(crypto::kSHA256Length, 0);
+ SHA256Hash(plugin_file, &file_hash[0], file_hash.size());
+ if (memcmp(&file_hash[0], string_as_array(&decoded_hash),
jln (very slow on Chromium) 2015/08/06 18:48:15 So there is nothing better than memcmp in crypto/
Greg K 2015/08/07 21:15:29 Turns out there is SecureEqualMem.
+ crypto::kSHA256Length) != 0) {
+ LOG(ERROR)
+ << "The hash recorded in the component flash hint file does not "
+ "match the actual hash of the flash plugin found on disk. The "
+ "component flash plugin will not be loaded.";
+ return false;
+ }
+
+ *path = plugin_path;
+ flash_version->assign(plugin_version_str);
+ return true;
+}
+
+} // namespace chrome

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