root / htools / Ganeti / Hash.hs @ cd67e337
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{-| Crypto-related helper functions. |
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-} |
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{- |
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Copyright (C) 2011, 2012 Google Inc. |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, but |
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WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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02110-1301, USA. |
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-} |
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module Ganeti.Hash |
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( computeMac |
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, verifyMac |
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, HashKey |
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) where |
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import qualified Data.ByteString as B |
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import Data.Char |
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import Data.HMAC (hmac_sha1) |
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import qualified Data.Text as T |
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import Data.Text.Encoding (encodeUtf8) |
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import Data.Word |
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import Text.Printf (printf) |
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-- | Type alias for the hash key. This depends on the library being |
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-- used. |
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type HashKey = [Word8] |
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-- | Converts a string to a list of bytes. |
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stringToWord8 :: String -> HashKey |
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stringToWord8 = B.unpack . encodeUtf8 . T.pack |
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-- | Converts a list of bytes to a string. |
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word8ToString :: HashKey -> String |
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word8ToString = concatMap (printf "%02x") |
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-- | Computes the HMAC for a given key/test and salt. |
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computeMac :: HashKey -> Maybe String -> String -> String |
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computeMac key salt text = |
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word8ToString . hmac_sha1 key . stringToWord8 $ maybe text (++ text) salt |
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-- | Verifies the HMAC for a given message. |
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verifyMac :: HashKey -> Maybe String -> String -> String -> Bool |
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verifyMac key salt text digest = |
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map toLower digest == computeMac key salt text |