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// Copyright 2014 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.
#ifndef EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
#define EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
#include <stddef.h>
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "base/callback.h"
#include "base/files/file_path.h"
#include "extensions/browser/content_verifier/content_verifier_utils.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
namespace extensions {
using IsCancelledCallback = base::RepeatingCallback<bool(void)>;
using ShouldComputeHashesCallback =
base::RepeatingCallback<bool(const base::FilePath& relative_path)>;
using CanonicalRelativePath = content_verifier_utils::CanonicalRelativePath;
// A class for storage and serialization of a set of SHA256 block hashes
// computed over the files inside an extension.
class ComputedHashes {
public:
// Status of reading computed hashes from file: either success or error type.
enum class Status {
// Status is undefined.
UNKNOWN,
// Failed to read file.
READ_FAILED,
// File read successfully, but failed to parse the contents.
PARSE_FAILED,
// No error.
SUCCESS,
};
// Hashes data for relative paths.
// System specific path canonicalization is taken care of inside this class.
class Data {
public:
struct HashInfo {
int block_size;
std::vector<std::string> hashes;
// The relative unix style path.
// Note that we use canonicalized paths as keys to HashInfo's container
// |items_|.
//
// TODO(http://crbug.com/796395#c28): Consider removing this once
// ContentVerifier::ShouldVerifyAnyPaths works with canonicalized relative
// paths.
base::FilePath relative_unix_path;
HashInfo(int block_size,
std::vector<std::string> hashes,
base::FilePath relative_unix_path);
~HashInfo();
HashInfo(const HashInfo&) = delete;
HashInfo& operator=(const HashInfo&) = delete;
HashInfo(HashInfo&&);
HashInfo& operator=(HashInfo&&);
};
using Items = std::map<CanonicalRelativePath, HashInfo>;
Data();
~Data();
Data(const Data&) = delete;
Data& operator=(const Data&) = delete;
Data(Data&&);
Data& operator=(Data&&);
// For |relative_path|, adds hash information with |block_size| and
// |hashes|.
// Note that |relative_path| will be canonicalized.
void Add(const base::FilePath& relative_path,
int block_size,
std::vector<std::string> hashes);
// Removes the item that corresponds to |relative_path|.
void Remove(const base::FilePath& relative_path);
// Returns HashInfo* for |relative_path| or nullptr if not found.
const HashInfo* GetItem(const base::FilePath& relative_path) const;
const Items& items() const;
private:
// All items, stored by canonicalized FilePath::StringType key.
Items items_;
};
explicit ComputedHashes(Data&& data);
ComputedHashes(const ComputedHashes&) = delete;
ComputedHashes& operator=(const ComputedHashes&) = delete;
ComputedHashes(ComputedHashes&&);
ComputedHashes& operator=(ComputedHashes&&);
~ComputedHashes();
// Reads computed hashes from the computed_hashes.json file, stores read
// success/failure status to |status|. Returns nullopt upon any failure (i.e.
// |status| != Status::SUCCESS).
static absl::optional<ComputedHashes> CreateFromFile(
const base::FilePath& path,
Status* status);
// Computes hashes for files in |extension_root|. Returns nullopt upon any
// failure. Callback |should_compute_hashes_for| is used to determine whether
// we need hashes for a resource or not.
// TODO(https://crbug.com/796395#c24) To support per-file block size instead
// of passing |block_size| as an argument make callback
// |should_compute_hashes_for| return optional<int>: nullopt if hashes are not
// needed for this file, block size for this file otherwise.
static absl::optional<ComputedHashes::Data> Compute(
const base::FilePath& extension_root,
int block_size,
const IsCancelledCallback& is_cancelled,
const ShouldComputeHashesCallback& should_compute_hashes_for_resource);
// Saves computed hashes to given file, returns false upon any failure (and
// true on success).
bool WriteToFile(const base::FilePath& path) const;
// Gets hash info for |relative_path|. The block size and hashes for
// |relative_path| will be copied into the out parameters. Returns false if
// resource was not found (and true on success).
bool GetHashes(const base::FilePath& relative_path,
int* block_size,
std::vector<std::string>* hashes) const;
// Returns the SHA256 hash of each |block_size| chunk in |contents|.
static std::vector<std::string> GetHashesForContent(
const std::string& contents,
size_t block_size);
private:
// Builds hashes for one resource and checks them against
// verified_contents.json if needed. Returns nullopt if nothing should be
// added to computed_hashes.json for this resource.
static absl::optional<std::vector<std::string>> ComputeAndCheckResourceHash(
const base::FilePath& full_path,
int block_size);
Data data_;
};
} // namespace extensions
#endif // EXTENSIONS_BROWSER_COMPUTED_HASHES_H_
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