From e74149a7569afd1ea7d67c77f40c37471e7e3e58 Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@google.com>
Date: Fri, 28 Sep 2018 18:33:35 -0400
Subject: Begin implementing symmetric encryption

Support RC4. Future commits will add support for more modern algorithms.
---
 src/BTLS/BoringSSL/Cipher.chs | 92 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 src/BTLS/BoringSSL/Cipher.chs

(limited to 'src/BTLS/BoringSSL/Cipher.chs')

diff --git a/src/BTLS/BoringSSL/Cipher.chs b/src/BTLS/BoringSSL/Cipher.chs
new file mode 100644
index 0000000..ac966d9
--- /dev/null
+++ b/src/BTLS/BoringSSL/Cipher.chs
@@ -0,0 +1,92 @@
+-- Copyright 2018 Google LLC
+--
+-- Licensed under the Apache License, Version 2.0 (the "License"); you may not
+-- use this file except in compliance with the License. You may obtain a copy of
+-- the License at
+--
+--     https://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+-- License for the specific language governing permissions and limitations under
+-- the License.
+
+{-# OPTIONS_GHC -Wno-missing-methods #-}
+
+module BTLS.BoringSSL.Cipher
+  ( evpRC4
+  , mallocEVPCipherCtx
+  , evpCipherInitEx, evpCipherUpdate, evpCipherFinalEx
+  , evpCipherCtxSetKeyLength
+  , evpCipherNID, evpCipherBlockSize, evpCipherKeyLength, evpCipherIVLength
+  , CipherDirection(ReuseDirection, Decrypt, Encrypt)
+  ) where
+
+import Data.ByteString (ByteString)
+import Foreign (FinalizerPtr, ForeignPtr, Ptr, Storable(alignment, sizeOf), withForeignPtr)
+import Foreign.C.Types
+
+{#import BTLS.BoringSSL.Base#}
+import BTLS.Buffer (unsafeUseAsCBuffer)
+import BTLS.CreateWithFinalizer (createWithFinalizer)
+
+#include <openssl/cipher.h>
+
+data CipherDirection = ReuseDirection | Decrypt | Encrypt
+  deriving (Eq, Show)
+
+instance Enum CipherDirection where
+  fromEnum ReuseDirection = -1
+  fromEnum Decrypt = 0
+  fromEnum Encrypt = 1
+
+{#fun pure EVP_rc4 as evpRC4 {} -> `Ptr EVPCipher'#}
+
+-- | Memory-safe allocator for 'EVPCipherCtx'.
+mallocEVPCipherCtx :: IO (ForeignPtr EVPCipherCtx)
+mallocEVPCipherCtx =
+  createWithFinalizer {#call EVP_CIPHER_CTX_init as ^#} btlsFinalizeEVPCipherCtxPtr
+
+foreign import ccall "&btlsFinalizeEVPCipherCtx"
+  btlsFinalizeEVPCipherCtxPtr :: FinalizerPtr EVPCipherCtx
+
+{#fun EVP_CipherInit_ex as evpCipherInitEx
+  { withForeignPtr* `ForeignPtr EVPCipherCtx'
+  , `Ptr EVPCipher'
+  , `Ptr Engine'
+  , id `Ptr CUChar'
+  , id `Ptr CUChar'
+  , 'fromIntegral . fromEnum' `CipherDirection'
+  } -> `Int'#}
+
+{#fun EVP_CipherUpdate as evpCipherUpdate
+  { withForeignPtr* `ForeignPtr EVPCipherCtx'
+  , id `Ptr CUChar'
+  , id `Ptr CInt'
+  , unsafeUseAsCBuffer* `ByteString'&
+  } -> `Int'#}
+
+{#fun EVP_CipherFinal_ex as evpCipherFinalEx
+  { withForeignPtr* `ForeignPtr EVPCipherCtx'
+  , id `Ptr CUChar'
+  , id `Ptr CInt'
+  } -> `Int'#}
+
+{#fun EVP_CIPHER_CTX_set_key_length as evpCipherCtxSetKeyLength
+  {withForeignPtr* `ForeignPtr EVPCipherCtx', `Int'} -> `Int'#}
+
+{#fun pure EVP_CIPHER_nid as evpCipherNID {`Ptr EVPCipher'} -> `Int'#}
+
+{#fun pure EVP_CIPHER_block_size as evpCipherBlockSize
+  {`Ptr EVPCipher'} -> `Int'#}
+
+{#fun pure EVP_CIPHER_key_length as evpCipherKeyLength
+  {`Ptr EVPCipher'} -> `Int'#}
+
+{#fun pure EVP_CIPHER_iv_length as evpCipherIVLength
+  {`Ptr EVPCipher'} -> `Int'#}
+
+instance Storable EVPCipherCtx where
+  sizeOf _ = {#sizeof EVP_CIPHER_CTX#}
+  alignment _ = {#alignof EVP_CIPHER_CTX#}
-- 
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