44a4328ea8
refactor: take a uint8_t span in ValidateIntegrityOrDie() Doing some groundwork for fixing unsafe base::File() APIs: - Change ValidateIntegrityOrDie() to take a span<const uint8_t> arg. We'll need this to migrate asar's base::File API calls away from the ones tagged `UNSAFE_BUFFER_USAGE` because the safe counterparts use span<uint8_t> too. - Simplify ValidateIntegrityOrDie()'s implementation by using crypto::SHA256Hash() instead of reinventing the wheel.
155 lines
4.4 KiB
C++
155 lines
4.4 KiB
C++
// Copyright (c) 2015 GitHub, Inc.
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// Use of this source code is governed by the MIT license that can be
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// found in the LICENSE file.
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#include "shell/common/asar/asar_util.h"
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#include <map>
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#include <memory>
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#include <string>
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#include "base/files/file_path.h"
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#include "base/files/file_util.h"
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#include "base/logging.h"
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#include "base/no_destructor.h"
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#include "base/strings/string_number_conversions.h"
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#include "base/strings/string_util.h"
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#include "base/synchronization/lock.h"
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#include "base/threading/thread_local.h"
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#include "crypto/secure_hash.h"
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#include "crypto/sha2.h"
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#include "shell/common/asar/archive.h"
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#include "shell/common/thread_restrictions.h"
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namespace asar {
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namespace {
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typedef std::map<base::FilePath, std::shared_ptr<Archive>> ArchiveMap;
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const base::FilePath::CharType kAsarExtension[] = FILE_PATH_LITERAL(".asar");
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bool IsDirectoryCached(const base::FilePath& path) {
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static base::NoDestructor<std::map<base::FilePath, bool>>
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s_is_directory_cache;
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static base::NoDestructor<base::Lock> lock;
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base::AutoLock auto_lock(*lock);
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auto& is_directory_cache = *s_is_directory_cache;
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auto it = is_directory_cache.find(path);
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if (it != is_directory_cache.end()) {
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return it->second;
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}
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electron::ScopedAllowBlockingForElectron allow_blocking;
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return is_directory_cache[path] = base::DirectoryExists(path);
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}
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ArchiveMap& GetArchiveCache() {
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static base::NoDestructor<ArchiveMap> s_archive_map;
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return *s_archive_map;
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}
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base::Lock& GetArchiveCacheLock() {
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static base::NoDestructor<base::Lock> lock;
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return *lock;
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}
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} // namespace
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std::shared_ptr<Archive> GetOrCreateAsarArchive(const base::FilePath& path) {
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base::AutoLock auto_lock(GetArchiveCacheLock());
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ArchiveMap& map = GetArchiveCache();
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// if we have it, return it
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const auto lower = map.lower_bound(path);
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if (lower != std::end(map) && !map.key_comp()(path, lower->first))
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return lower->second;
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// if we can create it, return it
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auto archive = std::make_shared<Archive>(path);
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if (archive->Init()) {
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map.try_emplace(lower, path, archive);
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return archive;
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}
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// didn't have it, couldn't create it
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return nullptr;
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}
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bool GetAsarArchivePath(const base::FilePath& full_path,
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base::FilePath* asar_path,
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base::FilePath* relative_path,
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bool allow_root) {
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base::FilePath iter = full_path;
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while (true) {
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base::FilePath dirname = iter.DirName();
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if (iter.MatchesExtension(kAsarExtension) && !IsDirectoryCached(iter))
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break;
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else if (iter == dirname)
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return false;
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iter = dirname;
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}
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base::FilePath tail;
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if (!((allow_root && iter == full_path) ||
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iter.AppendRelativePath(full_path, &tail)))
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return false;
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*asar_path = iter;
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*relative_path = tail;
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return true;
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}
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bool ReadFileToString(const base::FilePath& path, std::string* contents) {
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base::FilePath asar_path, relative_path;
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if (!GetAsarArchivePath(path, &asar_path, &relative_path))
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return base::ReadFileToString(path, contents);
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std::shared_ptr<Archive> archive = GetOrCreateAsarArchive(asar_path);
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if (!archive)
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return false;
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Archive::FileInfo info;
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if (!archive->GetFileInfo(relative_path, &info))
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return false;
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if (info.unpacked) {
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base::FilePath real_path;
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// For unpacked file it will return the real path instead of doing the copy.
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archive->CopyFileOut(relative_path, &real_path);
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return base::ReadFileToString(real_path, contents);
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}
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base::File src(asar_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
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if (!src.IsValid())
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return false;
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contents->resize(info.size);
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if (static_cast<int>(info.size) !=
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src.Read(info.offset, const_cast<char*>(contents->data()),
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contents->size())) {
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return false;
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}
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if (info.integrity)
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ValidateIntegrityOrDie(base::as_byte_span(*contents), *info.integrity);
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return true;
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}
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void ValidateIntegrityOrDie(base::span<const uint8_t> input,
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const IntegrityPayload& integrity) {
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if (integrity.algorithm == HashAlgorithm::kSHA256) {
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const std::string hex_hash =
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base::ToLowerASCII(base::HexEncode(crypto::SHA256Hash(input)));
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if (integrity.hash != hex_hash) {
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LOG(FATAL) << "Integrity check failed for asar archive ("
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<< integrity.hash << " vs " << hex_hash << ")";
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}
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} else {
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LOG(FATAL) << "Unsupported hashing algorithm in ValidateIntegrityOrDie";
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}
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}
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} // namespace asar
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