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{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FlexibleContexts #-}
--------------------------------------------------------------------------------
-- | Get a certificate from Let's Encrypt using the ACME protocol.
module Main where
import Control.Lens hiding ((.=))
import Control.Monad
import Crypto.Number.Serialize (i2osp)
import Data.Aeson (ToJSON (..), encode, object, (.=))
import Data.Aeson.Lens hiding (key)
import qualified Data.Aeson.Lens as JSON
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import qualified Data.ByteString.Base64.URL as Base64
import qualified Data.ByteString.Char8 as BC
import qualified Data.ByteString.Lazy as LB
import qualified Data.ByteString.Lazy.Char8 as LC
import Data.Digest.Pure.SHA (bytestringDigest, sha256)
import Data.Maybe
import qualified Data.Text as T
import Data.Text.Encoding (decodeUtf8)
import Network.Wreq (Response, responseHeader, responseBody, responseStatus, statusCode, statusMessage, defaults, checkStatus)
import qualified Network.Wreq.Session as WS
import OpenSSL
import OpenSSL.EVP.Digest
import OpenSSL.EVP.PKey
import OpenSSL.EVP.Sign
import OpenSSL.PEM
import OpenSSL.RSA
import Options.Applicative hiding (header)
import qualified Options.Applicative as Opt
import System.Directory
import System.Process (readProcess)
import Control.Monad.RWS.Strict
import Data.Coerce
directoryUrl :: String
directoryUrl = "https://acme-v01.api.letsencrypt.org/directory"
main :: IO ()
main = execParser opts >>= go
where
opts = info (helper <*> cmdopts) (fullDesc <> progDesc detailedDescription <> Opt.header "Let's Encrypt! ACME client")
detailedDescription = "This is a work in progress."
data CmdOpts = CmdOpts {
optKeyFile :: String,
optDomain :: String,
optEmail :: Maybe String,
optTerms :: Maybe String
}
defaultTerms :: String
defaultTerms = "https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf"
cmdopts :: Parser CmdOpts
cmdopts = CmdOpts <$> strOption (long "key" <> metavar "FILE" <> help "filename of your private RSA key")
<*> strOption (long "domain" <> metavar "DOMAIN" <> help "the domain name to certify")
<*> optional (strOption (long "email" <> metavar "ADDRESS" <> help "an email address with which to register an account"))
<*> optional (strOption (long "terms" <> metavar "URL" <> help "the terms param of the registration request"))
genKey :: String -> IO ()
genKey privKeyFile = readProcess "openssl" (words "genrsa 4096 -out" ++ [privKeyFile]) "" >>= writeFile privKeyFile
data Keys = Keys SomeKeyPair RSAPubKey
readKeys :: String -> IO Keys
readKeys privKeyFile = do
priv <- readFile privKeyFile >>= flip readPrivateKey PwTTY
pub <- rsaCopyPublic $ fromMaybe (error "Error: failed to parse RSA key.") (toKeyPair priv :: Maybe RSAKeyPair)
return $ Keys priv pub
go :: CmdOpts -> IO ()
go (CmdOpts privKeyFile domain email termOverride) = do
doesFileExist privKeyFile >>= flip unless (genKey privKeyFile)
keys@(Keys _ pub) <- readKeys privKeyFile
let terms = fromMaybe defaultTerms termOverride
nonce_ = undefined
-- Create user account
forM_ email $ \m ->
LB.writeFile "registration.body" =<< signPayload keys nonce_ (registration m terms)
-- Obtain a challenge
LB.writeFile "challenge-request.body" =<< signPayload keys nonce_ (authz domain)
-- Answser the challenge
let thumb = thumbprint (JWK (rsaE pub) "RSA" (rsaN pub))
-- Extracted from POST response above.
token = "DjyJpI3HVWAmsAwMT5ZFpW8dj19cel6ml6qaBUeGpCg"
thumbtoken = toStrict (LB.fromChunks [token, ".", thumb])
putStrLn ("Serve http://" ++ domain ++ "/.well-known/acme-challenge/" ++ BC.unpack token)
putStrLn ("With content:\n" ++ BC.unpack thumbtoken)
-- Notify Let's Encrypt we answsered the challenge
LB.writeFile "challenge-response.body" =<< signPayload keys nonce_ (challenge thumbtoken)
-- Wait for challenge validation Send a CSR and get a certificate
csr_ <- B.readFile (domain ++ ".csr.der")
LB.writeFile "csr-request.body" =<< signPayload keys nonce_ (csr csr_)
return ()
data Env = Env { getDir :: Directory, getKeys :: Keys, getSession :: WS.Session }
type ACME a = RWST Env () Nonce IO a
runACME :: String -> Keys -> ACME a -> IO a
runACME url keys f = WS.withSession $ \sess -> do
Just (dir, nonce) <- getDirectory sess url
fst <$> evalRWST f (Env dir keys sess) nonce
data Directory = Directory {
_newCert :: String,
_newAuthz :: String,
_revokeCert :: String,
_newReg :: String
}
newtype Nonce = Nonce String
testRegister :: String -> IO (Response LC.ByteString)
testRegister email = readKeys "rsa.key" >>= flip (runACME directoryUrl) (register email defaultTerms) >>= statusReport
getDirectory :: WS.Session -> String -> IO (Maybe (Directory, Nonce))
getDirectory sess url = do
r <- WS.get sess url
let nonce = r ^? responseHeader "Replay-Nonce" . to (Nonce . T.unpack . decodeUtf8)
k x = r ^? responseBody . JSON.key x . _String . to T.unpack
return $ (,) <$> (Directory <$> k "new-cert" <*> k "new-authz" <*> k "revoke-cert" <*> k "new-reg") <*> nonce
register :: String -> String -> ACME (Response LC.ByteString)
register email terms = sendPayload _newReg (registration email terms)
statusLine :: Response body -> String
statusLine r = (r ^. responseStatus . statusCode . to show) ++ " " ++ r ^. responseStatus . statusMessage . to (T.unpack . decodeUtf8)
statusReport :: MonadIO m => Response body -> m (Response body)
statusReport r = do
liftIO $ putStrLn $ statusLine r
return r
sendPayload :: (MonadIO m, MonadState Nonce m, MonadReader Env m) => (Directory -> String) -> ByteString -> m (Response LC.ByteString)
sendPayload reqType payload = do
keys <- asks getKeys
dir <- asks getDir
nonce <- gets coerce
signed <- liftIO $ signPayload keys nonce payload
post (reqType dir) signed
-- post :: (MonadReader Env m, MonadState Nonce m, MonadIO m, Postable a) => String -> a -> m (Response LC.ByteString)
post url payload = do
sess <- asks getSession
r <- liftIO $ WS.postWith noStatusCheck sess url payload
put $ r ^?! responseHeader "Replay-Nonce" . to (Nonce . T.unpack . decodeUtf8)
return r
where
noStatusCheck = defaults & checkStatus .~ Just nullChecker
nullChecker _ _ _ = Nothing
--------------------------------------------------------------------------------
-- | Sign return a payload with a nonce-protected header.
signPayload :: Keys -> String -> ByteString -> IO LC.ByteString
signPayload (Keys priv pub) nonce_ payload = withOpenSSL $ do
let protected = b64 (header pub nonce_)
Just dig <- getDigestByName "SHA256"
sig <- b64 <$> signBS dig priv (B.concat [protected, ".", payload])
return $ encode (Request (header' pub) protected payload sig)
--------------------------------------------------------------------------------
-- | Base64URL encoding of Integer with padding '=' removed.
b64i :: Integer -> ByteString
b64i = b64 . i2osp
b64 :: ByteString -> ByteString
b64 = B.takeWhile (/= 61) . Base64.encode
toStrict :: LB.ByteString -> ByteString
toStrict = B.concat . LB.toChunks
header' :: RSAKey k => k -> Header
header' key = Header "RS256" (JWK (rsaE key) "RSA" (rsaN key)) Nothing
header :: RSAKey k => k -> String -> ByteString
header key nonce = (toStrict . encode)
(Header "RS256" (JWK (rsaE key) "RSA" (rsaN key)) (Just nonce))
-- | Registration payload to sign with user key.
registration :: String -> String -> ByteString
registration emailAddr terms = (b64 . toStrict . encode) (Reg emailAddr terms)
-- | Challenge request payload to sign with user key.
authz :: String -> ByteString
authz = b64. toStrict . encode . Authz
-- | Challenge response payload to sign with user key.
challenge :: ByteString -> ByteString
challenge = b64 . toStrict . encode . Challenge . BC.unpack
-- | CSR request payload to sign with user key.
csr :: ByteString -> ByteString
csr = b64 . toStrict . encode . CSR . b64
thumbprint :: JWK -> ByteString
thumbprint = b64 . toStrict .bytestringDigest . sha256 . encodeOrdered
-- | There is an `encodePretty'` in `aeson-pretty`, but do it by hand here.
encodeOrdered :: JWK -> LB.ByteString
encodeOrdered JWK{..} = LC.pack $
"{\"e\":\"" ++ hE' ++ "\",\"kty\":\"" ++ hKty ++ "\",\"n\":\"" ++ hN' ++ "\"}"
where
hE' = BC.unpack (b64i hE)
hN' = BC.unpack (b64i hN)
--------------------------------------------------------------------------------
data Header = Header
{ hAlg :: String
, hJwk :: JWK
, hNonce :: Maybe String
}
deriving Show
data JWK = JWK
{ hE :: Integer
, hKty :: String
, hN :: Integer
}
deriving Show
instance ToJSON Header where
toJSON Header{..} = object $
[ "alg" .= hAlg
, "jwk" .= toJSON hJwk
] ++ maybe [] ((:[]) . ("nonce" .=)) hNonce
instance ToJSON JWK where
toJSON JWK{..} = object
[ "e" .= decodeUtf8 (b64i hE)
, "kty" .= hKty
, "n" .= decodeUtf8 (b64i hN)
]
data Reg = Reg
{ rMail :: String
, rAgreement :: String
}
deriving Show
instance ToJSON Reg where
toJSON Reg{..} = object
[ "resource" .= ("new-reg" :: String)
, "contact" .= ["mailto:" ++ rMail]
, "agreement" .= rAgreement
]
data Request = Request
{ rHeader :: Header
, rProtected :: ByteString
, rPayload :: ByteString
, rSignature :: ByteString
}
deriving Show
instance ToJSON Request where
toJSON Request{..} = object
[ "header" .= toJSON rHeader
, "protected" .= decodeUtf8 rProtected
, "payload" .= decodeUtf8 rPayload
, "signature" .= decodeUtf8 rSignature
]
data Authz = Authz
{ aDomain :: String
}
instance ToJSON Authz where
toJSON Authz{..} = object
[ "resource" .= ("new-authz" :: String)
, "identifier" .= object
[ "type" .= ("dns" :: String)
, "value" .= aDomain
]
]
data Challenge = Challenge
{ cKeyAuth :: String
}
instance ToJSON Challenge where
toJSON Challenge{..} = object
[ "resource" .= ("challenge" :: String)
, "keyAuthorization" .= cKeyAuth
]
data CSR = CSR ByteString
deriving Show
instance ToJSON CSR where
toJSON (CSR s) = object
[ "resource" .= ("new-cert" :: String)
, "csr" .= decodeUtf8 s
]
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