From c6b4149a73d71e1b86575bae9c2615a2296c3091 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Tue, 7 May 2019 21:40:53 +0200
Subject: Verify signatures when loading from storage

---
 src/PubKey.hs | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/PubKey.hs b/src/PubKey.hs
index af4d03b..787ada3 100644
--- a/src/PubKey.hs
+++ b/src/PubKey.hs
@@ -1,6 +1,6 @@
 module PubKey (
     PublicKey, SecretKey,
-    Signature(sigKey), Signed(..),
+    Signature(sigKey), Signed, signedData, signedSignature,
     generateKeys,
     sign, signAdd,
 ) where
@@ -28,11 +28,17 @@ data Signature = Signature
     deriving (Show)
 
 data Signed a = Signed
-    { signedData :: Stored a
-    , signedSignature :: [Stored Signature]
+    { signedData_ :: Stored a
+    , signedSignature_ :: [Stored Signature]
     }
     deriving (Show)
 
+signedData :: Signed a -> Stored a
+signedData = signedData_
+
+signedSignature :: Signed a -> [Stored Signature]
+signedSignature = signedSignature_
+
 instance Storable PublicKey where
     store' (PublicKey pk) = storeRec $ do
         storeText "type" $ T.pack "ed25519"
@@ -61,9 +67,14 @@ instance Storable a => Storable (Signed a) where
         storeRef "data" $ signedData sig
         mapM_ (storeRef "sig") $ signedSignature sig
 
-    load' = loadRec $ Signed
-        <$> loadRef "data"
-        <*> loadRefs "sig"
+    load' = loadRec $ do
+        sdata <- loadRef "data"
+        sigs <- loadRefs "sig"
+        forM_ sigs $ \sig -> do
+            let PublicKey pubkey = fromStored $ sigKey $ fromStored sig
+            when (not $ ED.verify pubkey (storedRef sdata) $ sigSignature $ fromStored sig) $
+                throwError "signature verification failed"
+        return $ Signed sdata sigs
 
 
 generateKeys :: Storage -> IO (SecretKey, Stored PublicKey)
-- 
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