[Passwords] Introduce GaiaIdHash

This CL introduces the GaiaIdHash class. Follow up CLs will make use of
this class.

Bug: 1032992
Change-Id: Ic42333864260e22fb2fcd7aadbf8beb0c38dc95c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2126997
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754874}

components/password_manager/core/browser/BUILD.gn

@@ -98,6 +98,8 @@ jumbo_static_library("browser") {
     "form_saver_impl.cc",
     "form_saver_impl.h",
     "form_submission_observer.h",
+    "gaia_id_hash.cc",
+    "gaia_id_hash.h",
     "generation/password_requirements_spec_fetcher.h",
     "generation/password_requirements_spec_fetcher_impl.cc",
     "generation/password_requirements_spec_fetcher_impl.h",
@@ -531,6 +533,7 @@ source_set("unit_tests") {
     "field_info_table_unittest.cc",
     "form_fetcher_impl_unittest.cc",
     "form_saver_impl_unittest.cc",
+    "gaia_id_hash_unittest.cc",
     "generation/password_generator_unittest.cc",
     "generation/password_requirements_spec_fetcher_unittest.cc",
     "http_auth_manager_unittest.cc",

components/password_manager/core/browser/gaia_id_hash.cc

+// Copyright 2020 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 "components/password_manager/core/browser/gaia_id_hash.h"
+
+#include "base/base64.h"
+#include "crypto/sha2.h"
+
+namespace password_manager {
+
+// static
+GaiaIdHash GaiaIdHash::FromGaiaId(const std::string& gaia_id) {
+  return FromBinary(crypto::SHA256HashString(gaia_id));
+}
+
+// static
+GaiaIdHash GaiaIdHash::FromBinary(const std::string& gaia_id_hash) {
+  return GaiaIdHash(gaia_id_hash);
+}
+
+// static
+GaiaIdHash GaiaIdHash::FromBase64(const std::string& gaia_id_base64_hash) {
+  std::string gaia_id_hash;
+  base::Base64Decode(gaia_id_base64_hash, &gaia_id_hash);
+  return FromBinary(gaia_id_hash);
+}
+
+GaiaIdHash::GaiaIdHash() = default;
+
+GaiaIdHash::GaiaIdHash(const GaiaIdHash& other) = default;
+
+GaiaIdHash::GaiaIdHash(GaiaIdHash&& other) = default;
+
+GaiaIdHash::~GaiaIdHash() = default;
+
+GaiaIdHash::GaiaIdHash(const std::string& gaia_id_hash)
+    : gaia_id_hash_(gaia_id_hash) {}
+
+std::string GaiaIdHash::ToBinary() const {
+  return gaia_id_hash_;
+}
+
+std::string GaiaIdHash::ToBase64() const {
+  std::string gaia_id_base64_hash;
+  base::Base64Encode(gaia_id_hash_, &gaia_id_base64_hash);
+  return gaia_id_base64_hash;
+}
+
+bool GaiaIdHash::IsValid() const {
+  return gaia_id_hash_.size() == crypto::kSHA256Length;
+}
+
+bool operator==(const GaiaIdHash& lhs, const GaiaIdHash& rhs) {
+  return lhs.gaia_id_hash_ == rhs.gaia_id_hash_;
+}
+
+bool operator!=(const GaiaIdHash& lhs, const GaiaIdHash& rhs) {
+  return !(lhs == rhs);
+}
+
+}  // namespace password_manager

components/password_manager/core/browser/gaia_id_hash.h

+// Copyright 2020 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 COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_GAIA_ID_HASH_H_
+#define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_GAIA_ID_HASH_H_
+
+#include <string>
+
+namespace password_manager {
+
+// Represents the hash of the Gaia ID of a signed-in user. This is useful for
+// storing Gaia-keyed information without storing sensitive information (like
+// the email address).
+class GaiaIdHash {
+ public:
+  static GaiaIdHash FromGaiaId(const std::string& gaia_id);
+  // |gaia_id_hash| is a string representing the binary hash of the gaia id. If
+  // the input isn't of length crypto::kSHA256Length, it returns an invalid
+  // GaiaIdHash object.
+  static GaiaIdHash FromBinary(const std::string& gaia_id_hash);
+  // If |gaia_id_base64_hash| isn't well-formed Base64 string, or doesn't decode
+  // to a hash of the correct length, it returns an invalid GaiaIdHash object.
+  static GaiaIdHash FromBase64(const std::string& gaia_id_base64_hash);
+
+  GaiaIdHash();
+  GaiaIdHash(const GaiaIdHash& other);
+  GaiaIdHash(GaiaIdHash&& other);
+  ~GaiaIdHash();
+
+  std::string ToBinary() const;
+  std::string ToBase64() const;
+
+  bool IsValid() const;
+
+  friend bool operator==(const GaiaIdHash& lhs, const GaiaIdHash& rhs);
+  friend bool operator!=(const GaiaIdHash& lhs, const GaiaIdHash& rhs);
+
+ private:
+  explicit GaiaIdHash(const std::string& gaia_id_hash);
+  const std::string gaia_id_hash_;
+};
+
+}  // namespace password_manager
+
+#endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_GAIA_ID_HASH_H_

components/password_manager/core/browser/gaia_id_hash_unittest.cc

+// Copyright 2020 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 "components/password_manager/core/browser/gaia_id_hash.h"
+
+#include "base/base64.h"
+#include "crypto/sha2.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace password_manager {
+
+TEST(GaiaIdHashTest, ShouldBeDeterministic) {
+  const std::string gaia_id = "user_gaia_id";
+  GaiaIdHash gaia_id_hash1 = GaiaIdHash::FromGaiaId(gaia_id);
+  GaiaIdHash gaia_id_hash2 = GaiaIdHash::FromGaiaId(gaia_id);
+  EXPECT_EQ(gaia_id_hash1.ToBinary(), gaia_id_hash2.ToBinary());
+  EXPECT_EQ(gaia_id_hash1.ToBase64(), gaia_id_hash2.ToBase64());
+  EXPECT_EQ(gaia_id_hash1, gaia_id_hash2);
+}
+
+TEST(GaiaIdHashTest, ShouldHash) {
+  const std::string gaia_id = "user_gaia_id";
+  const std::string gaia_id_hash = crypto::SHA256HashString(gaia_id);
+  std::string gaia_id_base64_hash;
+  base::Base64Encode(gaia_id_hash, &gaia_id_base64_hash);
+
+  GaiaIdHash hash = GaiaIdHash::FromGaiaId(gaia_id);
+  EXPECT_EQ(gaia_id_hash, hash.ToBinary());
+  EXPECT_EQ(gaia_id_base64_hash, hash.ToBase64());
+}
+
+TEST(GaiaIdHashTest, ShouldBase64EncodeDecode) {
+  const std::string gaia_id = "user_gaia_id";
+  GaiaIdHash hash1 = GaiaIdHash::FromGaiaId(gaia_id);
+  GaiaIdHash hash2 = GaiaIdHash::FromBase64(hash1.ToBase64());
+  EXPECT_EQ(hash1, hash2);
+}
+
+TEST(GaiaIdHashTest, ShouldBeInvalid) {
+  // Hash must be of length crypto::kSHA256Length.
+  GaiaIdHash hash1 = GaiaIdHash::FromBinary("too_short_hash");
+  EXPECT_FALSE(hash1.IsValid());
+
+  GaiaIdHash hash2 = GaiaIdHash::FromBase64("invalid_base64");
+  EXPECT_FALSE(hash2.IsValid());
+}
+
+}  // namespace password_manager