Merge pull request #189 from valthon/master

add fallback constants for Argon2
RubyCrypto · Jan 14, 2019 · 2084365 · 2084365
2 parents f72fdca + 0242903
commit 2084365
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Showing 5 changed files with 80 additions and 24 deletions.
diff --git a/lib/rbnacl/boxes/curve25519xsalsa20poly1305.rb b/lib/rbnacl/boxes/curve25519xsalsa20poly1305.rb
@@ -73,7 +73,7 @@ class Curve25519XSalsa20Poly1305
       sodium_constant  :BOXZEROBYTES
       sodium_constant  :BEFORENMBYTES
       sodium_constant  :PUBLICKEYBYTES
-      sodium_constant  :SECRETKEYBYTES, :PRIVATEKEYBYTES
+      sodium_constant  :SECRETKEYBYTES, name: :PRIVATEKEYBYTES
 
       sodium_function :box_curve25519xsalsa20poly1305_beforenm,
                       :crypto_box_curve25519xsalsa20poly1305_beforenm,

diff --git a/lib/rbnacl/password_hash/argon2.rb b/lib/rbnacl/password_hash/argon2.rb
@@ -18,18 +18,18 @@ class Argon2
       sodium_constant :ALG_ARGON2I13
       sodium_constant :ALG_ARGON2ID13 if Sodium::Version::ARGON2ID_SUPPORTED
 
-      sodium_constant :SALTBYTES             # 16
-      sodium_constant :STRBYTES              # 128
-      sodium_constant :OPSLIMIT_INTERACTIVE  # 4
-      sodium_constant :MEMLIMIT_INTERACTIVE  # 2 ** 25 (32mb)
-      sodium_constant :OPSLIMIT_MODERATE     # 6
-      sodium_constant :MEMLIMIT_MODERATE     # 2 ** 27 (128mb)
-      sodium_constant :OPSLIMIT_SENSITIVE    # 8
-      sodium_constant :MEMLIMIT_SENSITIVE    # 2 ** 29 (512mb)
-      sodium_constant :MEMLIMIT_MIN          # 8192
-      sodium_constant :MEMLIMIT_MAX          # 4_294_967_296
-      sodium_constant :OPSLIMIT_MIN          # 3
-      sodium_constant :OPSLIMIT_MAX          # 10
+      sodium_constant :SALTBYTES, fallback: 16
+      sodium_constant :STRBYTES, fallback: 128
+      sodium_constant :OPSLIMIT_INTERACTIVE, fallback: 4
+      sodium_constant :MEMLIMIT_INTERACTIVE, fallback: 2**25 # (32mb)
+      sodium_constant :OPSLIMIT_MODERATE, fallback: 6
+      sodium_constant :MEMLIMIT_MODERATE, fallback: 2**27 # (128mb)
+      sodium_constant :OPSLIMIT_SENSITIVE, fallback: 8
+      sodium_constant :MEMLIMIT_SENSITIVE, fallback: 2**29 # (512mb)
+      sodium_constant :MEMLIMIT_MIN, fallback: 8192
+      sodium_constant :MEMLIMIT_MAX, fallback: 4_294_967_296
+      sodium_constant :OPSLIMIT_MIN, fallback: 3
+      sodium_constant :OPSLIMIT_MAX, fallback: 10
 
       ARGON2_MIN_OUTLEN = 16
       ARGON2_MAX_OUTLEN = 0xFFFFFFFF

diff --git a/lib/rbnacl/signatures/ed25519.rb b/lib/rbnacl/signatures/ed25519.rb
@@ -10,9 +10,9 @@ module Ed25519
       sodium_type      :sign
       sodium_primitive :ed25519
       sodium_constant  :SEEDBYTES
-      sodium_constant  :PUBLICKEYBYTES, :VERIFYKEYBYTES
-      sodium_constant  :SECRETKEYBYTES, :SIGNINGKEYBYTES
-      sodium_constant  :BYTES,          :SIGNATUREBYTES
+      sodium_constant  :PUBLICKEYBYTES, name: :VERIFYKEYBYTES
+      sodium_constant  :SECRETKEYBYTES, name: :SIGNINGKEYBYTES
+      sodium_constant  :BYTES,          name: :SIGNATUREBYTES
     end
   end
 end
diff --git a/lib/rbnacl/sodium.rb b/lib/rbnacl/sodium.rb
@@ -29,14 +29,19 @@ def primitive
       sodium_primitive
     end
 
-    def sodium_constant(constant, name = constant)
-      fn = if sodium_primitive
-             "crypto_#{sodium_type}_#{sodium_primitive}_#{constant.to_s.downcase}"
-           else
-             "crypto_#{sodium_type}_#{constant.to_s.downcase}"
-           end
-      attach_function fn, [], :size_t
-      const_set(name, public_send(fn))
+    def sodium_constant(constant, name: constant, fallback: nil)
+      fn_name_components = ["crypto", sodium_type, sodium_primitive, constant.to_s.downcase]
+      fn_name = fn_name_components.compact.join("_")
+
+      begin
+        attach_function fn_name, [], :size_t
+      rescue FFI::NotFoundError
+        raise if fallback.nil?
+
+        define_singleton_method fn_name, -> { fallback }
+      end
+
+      const_set(name, public_send(fn_name))
     end
 
     def sodium_function(name, function, arguments)

diff --git a/spec/rbnacl/sodium_spec.rb b/spec/rbnacl/sodium_spec.rb
@@ -0,0 +1,51 @@
+RSpec.describe RbNaCl::Sodium do
+  subject(:sodium_class) do
+    class SodiumExtendedClass
+      extend RbNaCl::Sodium
+
+      sodium_type :auth
+      sodium_primitive :hmacsha512
+      # sodium_constant :BYTES
+      # sodium_constant :KEYBYTES
+    end
+    SodiumExtendedClass
+  end
+
+  context ".sodium_constant" do
+    it "retrieves the libsodium constant" do
+      sodium_class.sodium_constant :BYTES
+      expect(sodium_class::BYTES).to eq(64)
+    end
+
+    context "with alternate constant name" do
+      it "sets the alternate constant name" do
+        sodium_class.sodium_constant :BYTES, name: :COOL_BYTES
+        expect(sodium_class::COOL_BYTES).to eq(64)
+      end
+    end
+
+    context "when libsodium does not define the constant" do
+      it "raises an exception" do
+        expect do
+          sodium_class.sodium_constant :MIN_DANCING_PARTNERS
+        end.to raise_error(FFI::NotFoundError)
+      end
+    end
+
+    context "with fallback" do
+      context "when libsodium defines the constant" do
+        it "return the libsodium value" do
+          sodium_class.sodium_constant :BYTES, fallback: 888
+          expect(sodium_class::BYTES).to eq(64)
+        end
+      end
+
+      context "when libsodium does not define the constant" do
+        it "uses the fallback" do
+          sodium_class.sodium_constant :MAX_PANDAS, fallback: 24
+          expect(sodium_class::MAX_PANDAS).to eq(24)
+        end
+      end
+    end
+  end
+end