From 80a47aa966f0b7febb981d389b644a16600f8181 Mon Sep 17 00:00:00 2001
From: Didactic Drunk <1479616+didactic-drunk@users.noreply.github.com>
Date: Wed, 11 May 2022 22:30:05 -0700
Subject: [PATCH] Switch Crypto::Secret from module to abstract class

---
 README.md                          |  6 +++---
 spec/crypto_secret_spec.cr         |  2 --
 src/crypto-secret/bidet.cr         |  6 +++---
 src/crypto-secret/config.cr        | 33 ++++++++++++++++--------------
 src/crypto-secret/crypto-secret.cr |  3 ---
 src/crypto-secret/lib.cr           |  2 +-
 src/crypto-secret/not.cr           |  6 +++---
 src/crypto-secret/secret.cr        | 21 ++++++++-----------
 src/crypto-secret/stateful.cr      |  8 +-------
 src/crypto-secret/stateless.cr     | 11 ++++------
 10 files changed, 41 insertions(+), 57 deletions(-)

diff --git a/README.md b/README.md
index 4b6d468..3f06613 100644
--- a/README.md
+++ b/README.md
@@ -192,12 +192,12 @@ Each implementation may add additional protections
 **Only intended for use by crypto library authors**
 
 ```
-class MySecret
+class MySecret < Crypto::Secret
   # Choose one
   include Crypto::Secret::Stateless
   include Crypto::Secret::Stateful
 
-  def initialize(size)
+  def initialize(size : Int32)
     # allocate or reference storage
     # optionally mlock
   end
@@ -209,7 +209,7 @@ class MySecret
     # optionally reencrypt or signal HSM
   end
 
-  def bytesize : Int32
+  def buffer_bytesize : Int32
     # return the size
   end
 
diff --git a/spec/crypto_secret_spec.cr b/spec/crypto_secret_spec.cr
index 310702f..26bfff1 100644
--- a/spec/crypto_secret_spec.cr
+++ b/spec/crypto_secret_spec.cr
@@ -1,8 +1,6 @@
 require "./spec_helper"
 require "../src/crypto-secret/test"
 require "../src/crypto-secret"
-#require "../src/crypto-secret/not"
-#require "../src/crypto-secret/bidet"
 
 test_secret_class Crypto::Secret::Not
 test_secret_class Crypto::Secret::Bidet
diff --git a/src/crypto-secret/bidet.cr b/src/crypto-secret/bidet.cr
index cd31558..167d70b 100644
--- a/src/crypto-secret/bidet.cr
+++ b/src/crypto-secret/bidet.cr
@@ -1,6 +1,6 @@
 require "./stateless"
 
-module Crypto::Secret
+abstract class Crypto::Secret
   # Leaves less sh** around if you forget to wipe.  A safer default for large secrets that may stress mlock limits or low confidentiality secrets.
   #
   # * Wipes on finalize but should not be relied on
@@ -8,7 +8,7 @@ module Crypto::Secret
   # * Not access protected
   # * No guard pages
   # * Hours of fun
-  class Bidet < Base
+  class Bidet < Secret
     include Stateless
 
     def self.new(size : Int32)
@@ -20,6 +20,6 @@ module Crypto::Secret
     end
 
     delegate_to_slice @bytes
-    delegate_to_bytesize @bytes.bytesize
+    delegate_buffer_bytesize_to @bytes.bytesize
   end
 end
diff --git a/src/crypto-secret/config.cr b/src/crypto-secret/config.cr
index b06893e..7fd2de3 100644
--- a/src/crypto-secret/config.cr
+++ b/src/crypto-secret/config.cr
@@ -1,3 +1,6 @@
+require "./not"
+require "./bidet"
+
 {% if @type.has_constant?("Sodium") %}
   CRYPTO_SECRET_KEY_CLASS = Sodium::SecureBuffer
 {% else %}
@@ -12,23 +15,23 @@ module Crypto::Secret::Config
     Paranoid
     Default
     Lax
-    None
+    #    None
   end
 
-  def self.setup(how : SecurityLevel = SecurityLevel::Default) : Nil
-    case how
-      in SecurityLevel::Paranoid
-        register_use Bidet, :not
-        register_use CRYPTO_SECRET_KEY_CLASS, :kgk, :key, :data
-      in SecurityLevel::Default
-        register_use Not, :not
-        register_use Bidet, :data
-        register_use CRYPTO_SECRET_KEY_CLASS, :kgk, :key
-      in SecurityLevel::Lax
-        register_use Not, :not
-        register_use Bidet, :kgk, :key, :data
-      in SecurityLevel::None
-        register_use Not, :kgk, :key, :data, :not
+  def self.setup(level : SecurityLevel = SecurityLevel::Default) : Nil
+    register_use Not, :not
+
+    case level
+    in SecurityLevel::Paranoid
+      register_use Bidet, :not
+      register_use CRYPTO_SECRET_KEY_CLASS, :kgk, :key, :data
+    in SecurityLevel::Default
+      register_use Crypto::Secret::Bidet, :data
+      register_use CRYPTO_SECRET_KEY_CLASS, :kgk, :key
+    in SecurityLevel::Lax
+      register_use Bidet, :kgk, :key, :data
+      #      in SecurityLevel::None
+      #        register_use Not, :kgk, :key, :data
     end
   end
 
diff --git a/src/crypto-secret/crypto-secret.cr b/src/crypto-secret/crypto-secret.cr
index 3a0daf5..bb2e765 100644
--- a/src/crypto-secret/crypto-secret.cr
+++ b/src/crypto-secret/crypto-secret.cr
@@ -1,4 +1 @@
-#require "./not"
 require "./secret"
-# require "./large"
-# require "./key"
diff --git a/src/crypto-secret/lib.cr b/src/crypto-secret/lib.cr
index 491cbe2..d729092 100644
--- a/src/crypto-secret/lib.cr
+++ b/src/crypto-secret/lib.cr
@@ -1,5 +1,5 @@
 module Crypto
-  module Secret
+  abstract class Secret
     module Stateless
     end
 
diff --git a/src/crypto-secret/not.cr b/src/crypto-secret/not.cr
index e770913..c42f823 100644
--- a/src/crypto-secret/not.cr
+++ b/src/crypto-secret/not.cr
@@ -1,6 +1,6 @@
 require "./stateless"
 
-module Crypto::Secret
+abstract class Crypto::Secret
   # A not very secret `Secret`, but fast
   #
   # Suitable uses:
@@ -12,7 +12,7 @@ module Crypto::Secret
   # * Not access protected
   # * No guard pages
   # * No wiping
-  struct Not
+  class Not < Secret
     include Stateless
 
     def self.new(size : Int32)
@@ -25,7 +25,7 @@ module Crypto::Secret
     end
 
     delegate_to_slice @bytes
-    delegate_to_bytesize @bytes.bytesize
+    delegate_buffer_bytesize_to @bytes.bytesize
 
     def wipe
     end
diff --git a/src/crypto-secret/secret.cr b/src/crypto-secret/secret.cr
index af5562c..79eae42 100644
--- a/src/crypto-secret/secret.cr
+++ b/src/crypto-secret/secret.cr
@@ -10,7 +10,7 @@ require "./class_methods"
 #
 # Other shards may provide additional `Secret` types ([sodium.cr](https://github.com/didactic-drunk/sodium.cr))
 @[Experimental]
-module Crypto::Secret
+abstract class Crypto::Secret
   class Error < Exception
     class KeyWiped < Error
     end
@@ -162,7 +162,11 @@ module Crypto::Secret
   abstract def readonly(& : Bytes -> U) forall U
 
   protected abstract def to_slice(& : Bytes -> U) forall U
-  abstract def bytesize : Int32
+  abstract def buffer_bytesize : Int32
+
+  def bytesize : Int32
+    buffer_bytesize
+  end
 
   macro delegate_to_slice(to object)
     def to_slice(& : Bytes -> U) forall U
@@ -170,8 +174,8 @@ module Crypto::Secret
     end
   end
 
-  macro delegate_to_bytesize(to object)
-    def bytesize : Int32
+  macro delegate_buffer_bytesize_to(to object)
+    def buffer_bytesize : Int32
       {{object.id}}
     end
   end
@@ -181,13 +185,4 @@ module Crypto::Secret
   end
 end
 
-macro finished
-  {% for key, klass in Crypto::Secret::REGISTERED_USES %}
-#puts "{{key}}={{klass}}"
-puts "key=klass"
-    require {{ Crypto::Secret::REGISTERED_LOAD_PATHS[klass] }}
-    Crypto::Secret::REGISTERED[:{{key.id}}] = {{klass.id}}
-  {% end %}
-end
-
 require "./config"
diff --git a/src/crypto-secret/stateful.cr b/src/crypto-secret/stateful.cr
index 0c31fb4..0823e4c 100644
--- a/src/crypto-secret/stateful.cr
+++ b/src/crypto-secret/stateful.cr
@@ -1,6 +1,6 @@
 require "./secret"
 
-module Crypto::Secret
+abstract class Crypto::Secret
   # Development guide:
   # 1. Create your initialize method and optionally allocate memory
   # 2. Create a finalize method to deallocate memory if necessary
@@ -10,12 +10,6 @@ module Crypto::Secret
   #
   # When state changes are required (such as using #noaccess) and the buffer is accessed from multiple threads wrap each #readonly/#readwrite block in a lock.
   module Stateful
-    include Crypto::Secret
-
-    macro included
-      extend ClassMethods
-    end
-
     @state = State::Readwrite
     @pre_wipe_state = State::Readwrite
 
diff --git a/src/crypto-secret/stateless.cr b/src/crypto-secret/stateless.cr
index 3879d96..2fe86ad 100644
--- a/src/crypto-secret/stateless.cr
+++ b/src/crypto-secret/stateless.cr
@@ -2,14 +2,11 @@ require "./secret"
 
 # Provides a 0 overhead implementation of [#readwrite, #readonly, #noaccess, #reset] with no protection
 #
-# Data is erased when #wipe is out of scope, manual #wipe, or finalized except for `Not`
+# Data is erased when (except for `Crypto::Secret::Not`):
+# * #wipe(&block) goes out of scope
+# * manual #wipe
+# * finalized
 module Crypto::Secret::Stateless
-  include Crypto::Secret
-
-  macro included
-    extend ClassMethods
-  end
-
   # Not thread safe
   def readwrite : Secret
     self