From d1a85eb87934d348c9789aec59c751fa615ec363 Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@google.com>
Date: Thu, 23 Aug 2018 17:24:47 -0400
Subject: Clean up casts

Use unsigned char buffers more pervasively throughout the code. This
removes most calls to `asCUCharBuf`, isolating `unsafeCoerce` further.
By making some type signatures slightly more flexible, also eliminate
most explicit integer conversions.
---
 src/Data/Digest.hs | 13 ++-----------
 src/Data/HMAC.hs   | 14 ++++----------
 2 files changed, 6 insertions(+), 21 deletions(-)

(limited to 'src/Data')

diff --git a/src/Data/Digest.hs b/src/Data/Digest.hs
index 0587d2b..3e6f263 100644
--- a/src/Data/Digest.hs
+++ b/src/Data/Digest.hs
@@ -27,7 +27,6 @@ import Foreign.Marshal.Unsafe (unsafeLocalState)
 import BTLS.BoringSSL.Base
 import BTLS.BoringSSL.Digest
 import BTLS.BoringSSLPatterns (initUpdateFinalize)
-import BTLS.Cast (asCUCharBuf)
 import BTLS.Types (Algorithm(Algorithm), Digest(Digest))
 
 type LazyByteString = ByteString.Lazy.ByteString
@@ -45,13 +44,5 @@ hash :: Algorithm -> LazyByteString -> Digest
 hash (Algorithm md) =
   Digest
     . unsafeLocalState
-    . initUpdateFinalize mallocEVPMDCtx initialize evpDigestUpdate finalize
-  where
-    initialize ctx = evpDigestInitEx ctx md noEngine
-
-    finalize ctx mdOut pOutSize =
-      -- 'mdOut' is a 'Ptr CChar'. However, to make life more interesting,
-      -- 'evpDigestFinalEx' requires a 'Ptr CUChar'. To work around this,
-      -- we're going to cheat and let Haskell reinterpret-cast 'mdOut' to 'Ptr
-      -- CUChar.
-      evpDigestFinalEx ctx (asCUCharBuf mdOut) pOutSize
+    . initUpdateFinalize mallocEVPMDCtx initialize evpDigestUpdate evpDigestFinalEx
+  where initialize ctx = evpDigestInitEx ctx md noEngine
diff --git a/src/Data/HMAC.hs b/src/Data/HMAC.hs
index 8697c20..1850103 100644
--- a/src/Data/HMAC.hs
+++ b/src/Data/HMAC.hs
@@ -27,7 +27,7 @@ import BTLS.BoringSSL.Base
 import BTLS.BoringSSL.HMAC
 import BTLS.BoringSSL.Mem (cryptoMemcmp)
 import BTLS.BoringSSLPatterns (initUpdateFinalize)
-import BTLS.Cast (asCUCharBuf)
+import BTLS.Buffer (unsafeUseAsCUStringLen)
 import BTLS.Types (Algorithm(Algorithm), Digest(Digest), SecretKey(SecretKey))
 
 type LazyByteString = ByteString.Lazy.ByteString
@@ -51,14 +51,8 @@ hmac :: Algorithm -> SecretKey -> LazyByteString -> HMAC
 hmac (Algorithm md) (SecretKey key) =
   HMAC
     . unsafeLocalState
-    . initUpdateFinalize mallocHMACCtx initialize update finalize
+    . initUpdateFinalize mallocHMACCtx initialize hmacUpdate hmacFinal
   where
     initialize ctx =
-      ByteString.unsafeUseAsCStringLen key $ \(keyBytes, keySize) ->
-        hmacInitEx ctx keyBytes (fromIntegral keySize) md noEngine
-
-    -- initUpdateFinalize deals with buffers that are 'Ptr CChar'. However,
-    -- BoringSSL's HMAC functions deal with buffers that are 'Ptr CUChar'. As
-    -- in Data.Digest, we'll let Haskell reinterpret-cast the buffers.
-    update ctx buf len = hmacUpdate ctx (asCUCharBuf buf) len
-    finalize ctx hmacOut pOutSize = hmacFinal ctx (asCUCharBuf hmacOut) pOutSize
+      unsafeUseAsCUStringLen key $ \(keyBytes, keySize) ->
+        hmacInitEx ctx keyBytes keySize md noEngine
-- 
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