libchrome_tools/patches/Add-base-Token-class.patch

From bd984b07c2672500cf1344ee16807e52a42cfe0c Mon Sep 17 00:00:00 2001
From: Soshun Naito <[email protected]>
Date: Tue, 6 Aug 2024 08:37:44 +0000
Subject: [PATCH] base: Add base::Token class

This CL is a cherry-pick of the following CL: https://crrev.com/c/1320190
It adds token.h and token.cc introduced in the CL above. These files are
requried to build ARC with [Uuid] attribute in Mojo enabled.
This CL also replaces unguessable_token.h and unguessable_token.cc with
those in the original CL to let base::UnguessableToken to inherit
base::Token.

Bug: b:357737923, b:41420830
Test: m

Change-Id: I93cc0a588a4268416d3a3ba28e170992794e479d
---
 Android.bp                |  2 ++
 base/token.cc             | 28 +++++++++++++++
 base/token.h              | 72 +++++++++++++++++++++++++++++++++++++++
 base/unguessable_token.cc | 20 +++++------
 base/unguessable_token.h  | 36 ++++++++++++--------
 5 files changed, 132 insertions(+), 26 deletions(-)
 create mode 100644 base/token.cc
 create mode 100644 base/token.h

diff --git a/Android.bp b/Android.bp
index 340a194ac..c9b031519 100644
--- a/Android.bp
+++ b/Android.bp
@@ -458,6 +458,7 @@ filegroup {
         "base/timer/hi_res_timer_manager.h",
         "base/timer/mock_timer.h",
         "base/timer/timer.h",
+        "base/token.h",
         "base/trace_event/common/trace_event_common.h",
         "base/trace_event/heap_profiler.h",
         "base/trace_event/trace_event.h",
@@ -736,6 +737,7 @@ libchromeCommonSrc = [
     "base/time/time_override.cc",
     "base/timer/elapsed_timer.cc",
     "base/timer/timer.cc",
+    "base/token.cc",
     "base/unguessable_token.cc",
     "base/value_iterators.cc",
     "base/values.cc",
diff --git a/base/token.cc b/base/token.cc
new file mode 100644
index 000000000..e7ad89671
--- /dev/null
+++ b/base/token.cc
@@ -0,0 +1,28 @@
+// Copyright 2018 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 "base/token.h"
+
+#include <inttypes.h>
+
+#include "base/rand_util.h"
+#include "base/strings/stringprintf.h"
+
+namespace base {
+
+// static
+Token Token::CreateRandom() {
+  Token token;
+
+  // Use base::RandBytes instead of crypto::RandBytes, because crypto calls the
+  // base version directly, and to prevent the dependency from base/ to crypto/.
+  base::RandBytes(&token, sizeof(token));
+  return token;
+}
+
+std::string Token::ToString() const {
+  return base::StringPrintf("%016" PRIX64 "%016" PRIX64, high_, low_);
+}
+
+}  // namespace base
diff --git a/base/token.h b/base/token.h
new file mode 100644
index 000000000..f12277e11
--- /dev/null
+++ b/base/token.h
@@ -0,0 +1,72 @@
+// Copyright 2018 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 BASE_TOKEN_H_
+#define BASE_TOKEN_H_
+
+#include <stdint.h>
+
+#include <iosfwd>
+#include <tuple>
+
+#include "base/base_export.h"
+#include "base/hash.h"
+
+namespace base {
+
+// A Token is a randomly chosen 128-bit integer. This class supports generation
+// from a cryptographically strong random source, or constexpr construction over
+// fixed values (e.g. to store a pre-generated constant value). Tokens are
+// similar in spirit and purpose to UUIDs, without many of the constraints and
+// expectations (such as byte layout and string representation) clasically
+// associated with UUIDs.
+class BASE_EXPORT Token {
+ public:
+  // Constructs a zero Token.
+  constexpr Token() : high_(0), low_(0) {}
+
+  // Constructs a Token with |high| and |low| as its contents.
+  constexpr Token(uint64_t high, uint64_t low) : high_(high), low_(low) {}
+
+  // Constructs a new Token with random |high| and |low| values taken from a
+  // cryptographically strong random source.
+  static Token CreateRandom();
+
+  // The high and low 64 bits of this Token.
+  uint64_t high() const { return high_; }
+  uint64_t low() const { return low_; }
+
+  bool is_zero() const { return high_ == 0 && low_ == 0; }
+
+  bool operator==(const Token& other) const {
+    return high_ == other.high_ && low_ == other.low_;
+  }
+
+  bool operator!=(const Token& other) const { return !(*this == other); }
+
+  bool operator<(const Token& other) const {
+    return std::tie(high_, low_) < std::tie(other.high_, other.low_);
+  }
+
+  // Generates a string representation of this Token useful for e.g. logging.
+  std::string ToString() const;
+
+ private:
+  // Note: Two uint64_t are used instead of uint8_t[16] in order to have a
+  // simpler implementation, paricularly for |ToString()|, |is_zero()|, and
+  // constexpr value construction.
+  uint64_t high_;
+  uint64_t low_;
+};
+
+// For use in std::unordered_map.
+struct TokenHash {
+  size_t operator()(const base::Token& token) const {
+    return base::HashInts64(token.high(), token.low());
+  }
+};
+
+}  // namespace base
+
+#endif  // BASE_TOKEN_H_
\ No newline at end of file
diff --git a/base/unguessable_token.cc b/base/unguessable_token.cc
index 0d8aad39c..973b4167b 100644
--- a/base/unguessable_token.cc
+++ b/base/unguessable_token.cc
@@ -5,25 +5,23 @@
 #include "base/unguessable_token.h"

 #include "base/format_macros.h"
+#include "base/no_destructor.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"

 namespace base {

-UnguessableToken::UnguessableToken(uint64_t high, uint64_t low)
-    : high_(high), low_(low) {}
+UnguessableToken::UnguessableToken(const base::Token& token) : token_(token) {}

-std::string UnguessableToken::ToString() const {
-  return base::StringPrintf("%016" PRIX64 "%016" PRIX64, high_, low_);
+// static
+UnguessableToken UnguessableToken::Create() {
+  return UnguessableToken(Token::CreateRandom());
 }

 // static
-UnguessableToken UnguessableToken::Create() {
-  UnguessableToken token;
-  // Use base::RandBytes instead of crypto::RandBytes, because crypto calls the
-  // base version directly, and to prevent the dependency from base/ to crypto/.
-  base::RandBytes(&token, sizeof(token));
-  return token;
+const UnguessableToken& UnguessableToken::Null() {
+  static const NoDestructor<UnguessableToken> null_token;
+  return *null_token;
 }

 // static
@@ -31,7 +29,7 @@ UnguessableToken UnguessableToken::Deserialize(uint64_t high, uint64_t low) {
   // Receiving a zeroed out UnguessableToken from another process means that it
   // was never initialized via Create(). Treat this case as a security issue.
   DCHECK(!(high == 0 && low == 0));
-  return UnguessableToken(high, low);
+  return UnguessableToken(Token{high, low});
 }

 std::ostream& operator<<(std::ostream& out, const UnguessableToken& token) {
diff --git a/base/unguessable_token.h b/base/unguessable_token.h
index 6858e22a4..7f7b59a3a 100644
--- a/base/unguessable_token.h
+++ b/base/unguessable_token.h
@@ -13,14 +13,17 @@
 #include "base/base_export.h"
 #include "base/hash.h"
 #include "base/logging.h"
+#include "base/token.h"

 namespace base {

 struct UnguessableTokenHash;

-// A UnguessableToken is an 128-bit token generated from a cryptographically
-// strong random source. It can be used as part of a larger aggregate type,
-// or as an ID in and of itself.
+// UnguessableToken is, like Token, a randomly chosen 128-bit value. Unlike
+// Token however, a new UnguessableToken must always be generated at runtime
+// from a cryptographically strong random source (or copied or serialized and
+// deserialized from another such UnguessableToken). It can be used as part of a
+// larger aggregate type, or as an ID in and of itself.
 //
 // UnguessableToken can be used to implement "Capability-Based Security".
 // In other words, UnguessableToken can be used when the resource associated
@@ -42,6 +45,12 @@ class BASE_EXPORT UnguessableToken {
   // Create a unique UnguessableToken.
   static UnguessableToken Create();

+  // Returns a reference to a global null UnguessableToken. This should only be
+  // used for functions that need to return a reference to an UnguessableToken,
+  // and should not be used as a general-purpose substitute for invoking the
+  // default constructor.
+  static const UnguessableToken& Null();
+
   // Return a UnguessableToken built from the high/low bytes provided.
   // It should only be used in deserialization scenarios.
   //
@@ -56,28 +65,28 @@ class BASE_EXPORT UnguessableToken {
   // NOTE: Serializing an empty UnguessableToken is an illegal operation.
   uint64_t GetHighForSerialization() const {
     DCHECK(!is_empty());
-    return high_;
+    return token_.high();
   }

   // NOTE: Serializing an empty UnguessableToken is an illegal operation.
   uint64_t GetLowForSerialization() const {
     DCHECK(!is_empty());
-    return low_;
+    return token_.low();
   }

-  bool is_empty() const { return high_ == 0 && low_ == 0; }
+  bool is_empty() const { return token_.is_zero(); }

   // Hex representation of the unguessable token.
-  std::string ToString() const;
+  std::string ToString() const { return token_.ToString(); }

   explicit operator bool() const { return !is_empty(); }

   bool operator<(const UnguessableToken& other) const {
-    return std::tie(high_, low_) < std::tie(other.high_, other.low_);
+    return token_ < other.token_;
   }

   bool operator==(const UnguessableToken& other) const {
-    return high_ == other.high_ && low_ == other.low_;
+    return token_ == other.token_;
   }

   bool operator!=(const UnguessableToken& other) const {
@@ -86,12 +95,9 @@ class BASE_EXPORT UnguessableToken {

  private:
   friend struct UnguessableTokenHash;
-  UnguessableToken(uint64_t high, uint64_t low);
+  explicit UnguessableToken(const Token& token);

-  // Note: Two uint64_t are used instead of uint8_t[16], in order to have a
-  // simpler ToString() and is_empty().
-  uint64_t high_ = 0;
-  uint64_t low_ = 0;
+  base::Token token_;
 };

 BASE_EXPORT std::ostream& operator<<(std::ostream& out,
@@ -101,7 +107,7 @@ BASE_EXPORT std::ostream& operator<<(std::ostream& out,
 struct UnguessableTokenHash {
   size_t operator()(const base::UnguessableToken& token) const {
     DCHECK(token);
-    return base::HashInts64(token.high_, token.low_);
+    return TokenHash()(token.token_);
   }
 };

--
2.46.0.rc2.264.g509ed76dc8-goog