feat(Signature): refactor and expand public-key signature API

.github/workflows/ci.yaml

@@ -91,7 +91,7 @@ jobs:
         id: setup-haskell
         uses: haskell-actions/setup@v2
         with:
-          ghc-version: '9.8.2'
+          ghc-version: '9.10.1'
           cabal-version: 'latest'
 
       - name: Freeze

sel/sel.cabal

@@ -54,6 +54,7 @@ library
     Sel.HMAC.SHA256
     Sel.HMAC.SHA512
     Sel.HMAC.SHA512_256
+    Sel.KeyMaterialDecodeError
     Sel.PublicKey.Cipher
     Sel.PublicKey.Seal
     Sel.PublicKey.Signature
@@ -66,6 +67,7 @@ library
     Sel.Internal
     Sel.Internal.Scoped
     Sel.Internal.Scoped.Foreign
+    Sel.PublicKey.Internal.Signature
 
   build-depends:
     , base                >=4.14   && <5

sel/src/Sel/Hashing/Short.hs

@@ -53,9 +53,8 @@ import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Text
 import qualified Data.Text.Lazy.Builder as Builder
 import Foreign hiding (void)
-import Foreign.C (CSize, CUChar, CULLong)
+import Foreign.C (CChar, CSize, CUChar, CULLong)
 import GHC.Exception (Exception)
-import GHC.IO.Handle.Text (memcpy)
 import System.IO.Unsafe (unsafeDupablePerformIO)
 
 import qualified Data.Base16.Types as Base16
@@ -250,7 +249,10 @@ binaryToShortHashKey binaryKey =
       BS.unsafeUseAsCString binaryKey $ \cString -> do
         shortHashKeyFPtr <- Foreign.mallocForeignPtrBytes (fromIntegral cryptoShortHashSipHashX24KeyBytes)
         Foreign.withForeignPtr shortHashKeyFPtr $ \shortHashKeyPtr ->
-          memcpy shortHashKeyPtr (Foreign.castPtr cString) cryptoShortHashSipHashX24KeyBytes
+          Foreign.copyBytes
+            shortHashKeyPtr
+            (Foreign.castPtr @CChar @CUChar cString)
+            (fromIntegral cryptoShortHashSipHashX24KeyBytes)
         pure $ Just $ ShortHashKey shortHashKeyFPtr
 
 -- | Convert a strict hexadecimal-encoded 'Text' to a 'ShortHashKey'.

sel/src/Sel/KeyMaterialDecodeError.hs

@@ -0,0 +1,91 @@
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DerivingVia #-}
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE ViewPatterns #-}
+
+-- |
+-- Module      : Sel.KeyMaterialDecodeError
+-- Description : Key material utilities
+-- Copyright   : (c) Jack Henahan, 2024
+-- License     : BSD-3-Clause
+-- Maintainer  : The Haskell Cryptography Group
+-- Portability : GHC only
+module Sel.KeyMaterialDecodeError
+  ( -- * Key material utilities
+    KeyMaterialDecodeError (..)
+  , RequiredLength (..)
+  , InputLength (..)
+  , validKeyMaterial
+  )
+where
+
+import Control.Exception (Exception)
+import Data.Bifunctor (first)
+import Data.ByteString (StrictByteString)
+import Data.ByteString qualified as ByteString
+import Data.ByteString.Base16 qualified as Base16
+import Data.Coerce (coerce)
+import Data.Text (Text)
+import Data.Text.Display (Display, ShowInstance (..))
+import Foreign.C (CSize (..))
+
+-- | Errors arising from decoding key material from bytes.
+--
+-- @since 0.0.3.0
+data KeyMaterialDecodeError
+  = -- | Input length does not match the length required for the target pointer.
+    --
+    -- @since 0.0.3.0
+    ByteLengthMismatch RequiredLength InputLength
+  | -- | Input bytes did not decode to hexadecimal.
+    --
+    -- @since 0.0.3.0
+    DecodingFailure Text
+  deriving stock
+    ( Show
+      -- ^ @since 0.0.3.0
+    , Eq
+      -- ^ @since 0.0.3.0
+    )
+  deriving
+    ( Display
+      -- ^ @since 0.0.3.0
+    )
+    via (ShowInstance KeyMaterialDecodeError)
+  deriving anyclass
+    ( Exception
+      -- ^ @since 0.0.3.0
+    )
+
+-- | The length of the target pointer for some key material.
+--
+-- @since 0.0.3.0
+newtype RequiredLength = RequiredLength Int
+  deriving stock
+    ( Show
+      -- ^ @since 0.0.3.0
+    , Eq
+      -- ^ @since 0.0.3.0
+    )
+
+-- | The length of some input bytes.
+--
+-- @since 0.0.3.0
+newtype InputLength = InputLength Int
+  deriving stock
+    ( Show
+      -- ^ @since 0.0.3.0
+    , Eq
+      -- ^ @since 0.0.3.0
+    )
+
+-- | Attempt to decode a hexadecimal-encoded 'StrictByteString' with an expected length.
+--
+-- @since 0.0.3.0
+validKeyMaterial :: CSize -> StrictByteString -> Either KeyMaterialDecodeError StrictByteString
+validKeyMaterial (fromIntegral -> requiredLength) bytes = do
+  decoded@(ByteString.length -> inputLength) <-
+    first DecodingFailure (Base16.decodeBase16Untyped bytes)
+  if requiredLength == inputLength
+    then Right decoded
+    else Left $ ByteLengthMismatch (coerce requiredLength) (coerce inputLength)

sel/src/Sel/PublicKey/Cipher.hs

@@ -64,7 +64,6 @@ import Foreign (ForeignPtr, Ptr)
 import qualified Foreign
 import Foreign.C (CChar, CSize, CUChar, CULLong)
 import qualified Foreign.C as Foreign
-import GHC.IO.Handle.Text (memcpy)
 import System.IO.Unsafe (unsafeDupablePerformIO)
 
 import Control.Exception
@@ -496,10 +495,10 @@ decrypt
               (-1) -> pure Nothing
               _ -> do
                 bsPtr <- Foreign.mallocBytes (fromIntegral messageLength)
-                memcpy bsPtr (Foreign.castPtr messagePtr) (fromIntegral messageLength)
+                Foreign.copyBytes bsPtr messagePtr (fromIntegral messageLength)
                 Just
                   <$> BS.unsafePackMallocCStringLen
-                    (Foreign.castPtr @CChar bsPtr, fromIntegral messageLength)
+                    (Foreign.castPtr @CUChar @CChar bsPtr, fromIntegral messageLength)
 
 -- | Exception thrown upon error during the generation of
 -- the key pair by 'newKeyPair'.