Commit 21dc8694 authored by Iustin Pop's avatar Iustin Pop

htools: add a small module for crypto functions

This adds a dependency on the following new libraries:

- Data.HMAC module from the 'crypto' library
- Data.Text from the 'text' library
- Data.ByteString from the 'bytestring' library

In Debian, the bytestring library comes with the ghc compiler, whereas
the other two are available separately in wheezy/unstable.
Signed-off-by: default avatarIustin Pop <iustin@google.com>
Reviewed-by: default avatarGuido Trotter <ultrotter@google.com>
parent 417cc253
......@@ -397,6 +397,7 @@ HS_LIB_SRCS = \
htools/Ganeti/BasicTypes.hs \
htools/Ganeti/Confd.hs \
htools/Ganeti/Config.hs \
htools/Ganeti/Hash.hs \
htools/Ganeti/Jobs.hs \
htools/Ganeti/Luxi.hs \
htools/Ganeti/Objects.hs \
......
{-| Crypto-related helper functions.
-}
{-
Copyright (C) 2011, 2012 Google Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.
-}
module Ganeti.Hash
( computeMac
, verifyMac
, HashKey
) where
import qualified Data.ByteString as B
import Data.Char
import Data.HMAC (hmac_sha1)
import qualified Data.Text as T
import Data.Text.Encoding (encodeUtf8)
import Data.Word
import Text.Printf (printf)
-- | Type alias for the hash key. This depends on the library being
-- used.
type HashKey = [Word8]
-- | Converts a string to a list of bytes.
stringToWord8 :: String -> HashKey
stringToWord8 = B.unpack . encodeUtf8 . T.pack
-- | Converts a list of bytes to a string.
word8ToString :: HashKey -> String
word8ToString = concat . map (printf "%02x")
-- | Computes the HMAC for a given key/test and salt.
computeMac :: HashKey -> Maybe String -> String -> String
computeMac key salt text =
word8ToString . hmac_sha1 key . stringToWord8 $ maybe text (++ text) salt
-- | Verifies the HMAC for a given message.
verifyMac :: HashKey -> Maybe String -> String -> String -> Bool
verifyMac key salt text digest =
map toLower digest == computeMac key salt text
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