130 lines
3.4 KiB
Haskell
130 lines
3.4 KiB
Haskell
{-|
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Module: Password
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Description: a simple password manager
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Copyright: (C) 2018 Jonathan Lamothe
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License: LGPLv3 (or later)
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Maintainer: jlamothe1980@gmail.com
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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 Lesser General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this program. If not, see
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<https://www.gnu.org/licenses/>.
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-}
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{-# LANGUAGE TemplateHaskell #-}
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module Password (
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-- * Data Types
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PWDatabase, PWData(..), PWPolicy (..), PWSalt,
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-- ** Lenses
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-- $lenses
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-- *** PWData
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pwPolicy, pwSalt,
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-- *** PWPolicy
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pwLength, pwUpper, pwLower, pwDigits, pwSpecial,
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-- ** Default Instances
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newPWData, newPWPolicy, newPWSalt,
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-- * Functions
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validatePWPolicy
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) where
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import Control.Lens (makeLenses, (^.))
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import Data.Char (isUpper, isLower, isDigit, isAlphaNum)
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import qualified Data.ByteString as B
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import qualified Data.Map as M
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import Data.Maybe (fromMaybe)
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import System.Random (RandomGen, randoms, split)
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-- | a mapping of service names to password data
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type PWDatabase = M.Map String PWData
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-- | data necessary to construct a password
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data PWData = PWData
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{ _pwPolicy :: PWPolicy
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-- ^ the password policy
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, _pwSalt :: B.ByteString
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-- ^ random data used to generate the password
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} deriving (Eq, Show)
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-- | defines a password policy
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data PWPolicy = PWPolicy
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{ _pwLength :: Int
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-- ^ password length
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, _pwUpper :: Int
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-- ^ the minimum number of upper case characters
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, _pwLower :: Int
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-- ^ the minimum number of lower case characters
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, _pwDigits :: Int
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-- ^ the minimum number of digits
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, _pwSpecial :: Maybe Int
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-- ^ the minimum number of non-alphanumeric characters (not allowed
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-- if @"Nothing"@)
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} deriving (Eq, Show)
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-- | the "salt" used to generate a password
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type PWSalt = B.ByteString
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-- $lenses The following functions are automatically generated by
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-- @makeLenses@. See the
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-- [lens](http://hackage.haskell.org/package/lens) package for further
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-- details.
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makeLenses ''PWPolicy
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makeLenses ''PWData
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-- | builds a new @'PWData'@
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newPWData
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:: RandomGen g
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=> g
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-- ^ the random generator to use
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-> (PWData, g)
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-- ^ the result and new random generator
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newPWData g = (result, g') where
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result = PWData newPWPolicy salt
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(salt, g') = newPWSalt g
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-- | default password policy
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newPWPolicy :: PWPolicy
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newPWPolicy = PWPolicy 16 0 0 0 (Just 0)
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-- | builds a new salt
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newPWSalt
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:: RandomGen g
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=> g
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-- ^ the random generator to use
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-> (PWSalt, g)
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-- ^ the result and new random generator
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newPWSalt g = (result, g2) where
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result = B.pack $ take 256 $ randoms g1
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(g1, g2) = split g
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-- | validates a password policy
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validatePWPolicy
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:: PWPolicy
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-- ^ the policy being validated
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-> Bool
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-- ^ indicates whether or not the policy is valid
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validatePWPolicy x = and
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[ needed <= x^.pwLength
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, x^.pwLength >= 0
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, x^.pwUpper >= 0
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, x^.pwLower >= 0
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, x^.pwDigits >= 0
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, fromMaybe 0 (x^.pwSpecial) >= 0
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] where
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needed = x^.pwUpper + x^.pwLower + x^.pwDigits + special
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special = fromMaybe 0 $ x^.pwSpecial
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--jl
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