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{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
--------------------------------------------------------------------------------
-- | Get a certificate from Let's Encrypt using the ACME protocol.
--
-- https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md
module Main where
import Control.Lens hiding ((.=), each)
import Control.Monad
import Control.Monad.RWS.Strict
import Crypto.Number.Serialize (i2osp)
import Data.Aeson (ToJSON (..), Value, 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.Coerce
import Data.Digest.Pure.SHA (bytestringDigest, sha256)
import Data.Maybe
import Data.String (fromString)
import qualified Data.Text as T
import Data.Text.Encoding (decodeUtf8, encodeUtf8)
import Data.Time.Clock.POSIX (getPOSIXTime)
import Network.Wreq (Response, checkStatus, defaults,
responseBody, responseHeader,
responseStatus, statusCode,
statusMessage)
import qualified Network.Wreq as W
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 OpenSSL.X509.Request
import Options.Applicative hiding (header)
import qualified Options.Applicative as Opt
import System.Directory
import Network.ACME
import Data.List
import Pipes
stagingDirectoryUrl, liveDirectoryUrl :: String
liveDirectoryUrl = "https://acme-v01.api.letsencrypt.org/directory"
stagingDirectoryUrl = "https://acme-staging.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 = unwords
[ "This program will generate a signed TLS certificate"
, "using the ACME protocol and the free Let's Encrypt! CA."
]
data CmdOpts = CmdOpts {
optKeyFile :: String,
optDomains :: [String],
optChallengeDir :: String,
optDomainDir :: Maybe String,
optEmail :: Maybe String,
optTerms :: Maybe String,
optStaging :: Bool
}
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")
<*> some
(strOption
(long "domain" <>
metavar "DOMAIN" <>
help
(unwords
[ "the domain name(s) to certify;"
, "specify more than once for a multi-domain certificate"
])))
<*> strOption (long "challenge-dir" <> metavar "DIR" <>
help "output directory for ACME challenges")
<*> optional
(strOption
(long "domain-dir" <>
metavar "DIR" <>
help
(unwords
[ "directory in which to domain certificates and keys are stored;"
, "the default is to use the (first) domain name as a directory name"
])))
<*> 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"))
<*> switch
(long "staging" <> help
(unwords
[ "use staging servers instead of live servers"
, "(generated certificates will not be trusted!)"
]))
genKey :: String -> IO ()
genKey privKeyFile = withOpenSSL $ do
kp <- generateRSAKey' 4096 65537
pem <- writePKCS8PrivateKey kp Nothing
writeFile privKeyFile pem
genReq :: FilePath -> [String] -> IO LC.ByteString
genReq _ [] = error "genReq called with zero domains"
genReq domainKeyFile domains@(domain:_) = withOpenSSL $ do
Just (Keys priv pub) <- readKeyFile domainKeyFile
Just dig <- getDigestByName "SHA256"
req <- newX509Req
setSubjectName req [("CN", domain)]
setVersion req 0
setPublicKey req pub
void $ addExtensions req [nidSubjectAltName %%% intercalate ", " (map ("DNS:" ++) domains)]
signX509Req req priv (Just dig)
writeX509ReqDER req
where
nidKeyUsage = 83
nidSubjectAltName = 85
(%%%) = (,)
infixr 0 %%%
readKeyFile :: FilePath -> IO (Maybe Keys)
readKeyFile = readFile >=> readKeys
data ChallengeRequest = ChallengeRequest { crUri :: String, crToken :: ByteString, crThumbToken :: ByteString }
otherwiseM :: Monad m => m Bool -> m () -> m ()
a `otherwiseM` b = a >>= flip unless b
infixl 0 `otherwiseM`
go :: CmdOpts -> IO ()
go CmdOpts { .. } = do
let terms = fromMaybe defaultTerms optTerms
directoryUrl = if optStaging then stagingDirectoryUrl else liveDirectoryUrl
domainKeyFile = domainDir </> "rsa.key"
domainCSRFile = domainDir </> "csr.der"
domainCertFile = domainDir </> "cert.der"
domainDir = fromMaybe (head optDomains) optDomainDir
privKeyFile = optKeyFile
requestDomains = optDomains
doesFileExist privKeyFile `otherwiseM` genKey privKeyFile
doesDirectoryExist domainDir `otherwiseM` createDirectory domainDir
doesFileExist domainKeyFile `otherwiseM` genKey domainKeyFile
Just keys <- readKeyFile privKeyFile
doesFileExist domainCSRFile `otherwiseM` genReq domainKeyFile requestDomains >>= LC.writeFile domainCSRFile
csrData <- B.readFile domainCSRFile
ensureWritable optChallengeDir "challenge directory"
ensureWritable domainDir "domain directory"
forM_ requestDomains $ canProvision optChallengeDir >=> (`unless` error "Error: cannot provision files to web server via challenge directory")
runACME directoryUrl keys $ do
forM_ optEmail $ register terms >=> statusReport
let producer :: Producer ChallengeRequest ACME ()
producer = for (each requestDomains) $ challengeRequest >=> statusReport >=> extractCR >=> yield
consumer :: Consumer ChallengeRequest ACME ()
consumer = forever $ await >>= consume1
consume1 (ChallengeRequest nextUri token thumbtoken) = do
lift $ liftIO $ BC.writeFile (optChallengeDir </> BC.unpack token) thumbtoken
notifyChallenge nextUri thumbtoken >>= statusReport >>= ncErrorReport
runEffect $ producer >-> consumer
retrieveCert csrData >>= statusReport >>= saveCert domainCertFile
(</>) :: String -> String -> String
a </> b = a ++ "/" ++ b
infixr 5 </>
canProvision :: FilePath -> String -> IO Bool
canProvision challengeDir domain = do
randomish <- fromString . show <$> getPOSIXTime
let absFile = challengeDir </> relFile
relFile = ".test." ++ show randomish
LC.writeFile absFile randomish
r <- W.get $ "http://" ++ domain </> ".well-known/acme-challenge" </> relFile
removeFile absFile
return $ r ^. responseBody == randomish
ensureWritable :: FilePath -> String -> IO ()
ensureWritable file name = (writable <$> getPermissions file) >>= flip unless (err name)
where err n = error $ "Error: " ++ n ++ " is not writable"
extractCR :: MonadReader Env m => Response LC.ByteString -> m ChallengeRequest
extractCR r = do
Keys _ pub <- asks getKeys
let httpChallenge :: (Value -> Const (Endo s) Value) -> Response LC.ByteString -> Const (Endo s) (Response LC.ByteString)
httpChallenge = responseBody .
JSON.key "challenges" .
to universe .
traverse .
(filtered . has $ ix "type" . only "http-01")
token = r ^?! httpChallenge . JSON.key "token" . _String . to encodeUtf8
crUri = r ^?! httpChallenge . JSON.key "uri" . _String . to T.unpack
thumb = thumbprint (JWK (rsaE pub) "RSA" (rsaN pub))
thumbtoken = toStrict (LB.fromChunks [token, ".", thumb])
return $ ChallengeRequest crUri token thumbtoken
ncErrorReport :: (Show body, AsValue body, MonadIO m) => Response body -> m ()
ncErrorReport r =
when (Just "pending" /= r ^? responseBody . JSON.key "status" . _String) $ liftIO $ do
putStrLn "Unexpected response to challenge-response request:"
print r
saveCert :: MonadIO m => FilePath -> Response LC.ByteString -> m ()
saveCert domainCertFile r =
if isSuccess $ r ^. responseStatus . statusCode
then liftIO $ LC.writeFile domainCertFile $ r ^. responseBody
else liftIO $ do
let (summary, details) = (k "type", k "detail")
k x = r ^?! responseBody . JSON.key x . _String . to T.unpack
liftIO $ putStrLn $ summary ++ " ---- " ++ details
where
isSuccess n = n >= 200 && n <= 300
retrieveCert :: (MonadReader Env m, MonadState Nonce m, MonadIO m) => ByteString -> m (Response LC.ByteString)
retrieveCert input = sendPayload _newCert (csr input)
notifyChallenge :: (MonadReader Env m, MonadState Nonce m, MonadIO m) => String -> ByteString -> m (Response LC.ByteString)
notifyChallenge crUri thumbtoken = sendPayload (const crUri) (challenge thumbtoken)
data Env = Env { getDir :: Directory, getKeys :: Keys, getSession :: WS.Session }
type ACME = RWST Env () Nonce IO
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
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 terms email = sendPayload _newReg (registration email terms)
challengeRequest :: (MonadIO m, MonadState Nonce m, MonadReader Env m) => String -> m (Response LC.ByteString)
challengeRequest domain = sendPayload _newAuthz (authz domain)
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) => String -> LC.ByteString -> 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
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