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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# 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 Network.ACME where
import Control.Arrow
import Control.Error
import Control.Lens hiding (each, (.=))
import Control.Monad
import Control.Monad.RWS.Strict
import Control.Monad.Trans.Resource hiding (register)
import Data.Aeson (Value)
import Data.Aeson.Lens hiding (key)
import qualified Data.Aeson.Lens as JSON
import Data.ByteString (ByteString)
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.List
import Data.String (fromString)
import qualified Data.Text as T
import Data.Text.Encoding (decodeUtf8, encodeUtf8)
import Data.Time.Clock.POSIX (getPOSIXTime)
import Network.ACME.Encoding
import Network.URI
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 hiding (sign)
import OpenSSL.PEM
import OpenSSL.RSA
import OpenSSL.X509 (X509, readDerX509)
import OpenSSL.X509.Request
import System.Directory
import Text.Domain.Validate hiding (validate)
import Text.Email.Validate
genReq :: Keys -> [DomainName] -> IO CSR
genReq _ [] = error "genReq called with zero domains"
genReq (Keys priv pub) domains@(domain:_) = withOpenSSL $ do
Just dig <- getDigestByName "SHA256"
req <- newX509Req
setSubjectName req [("CN", domainToString domain)]
setVersion req 0
setPublicKey req pub
void $ addExtensions req [(nidSubjectAltName, intercalate ", " (map (("DNS:" ++) . domainToString) domains))]
signX509Req req priv (Just dig)
CSR domains . toStrict <$> writeX509ReqDER req
where
nidSubjectAltName = 85
data Keys = Keys RSAKeyPair RSAPubKey
readKeys :: String -> IO (Maybe Keys)
readKeys privKeyData = do
keypair :: SomeKeyPair <- readPrivateKey privKeyData PwTTY
let (priv :: Maybe RSAKeyPair) = toKeyPair keypair
pub <- maybe (return Nothing) (fmap Just . rsaCopyPublic) priv
return $ Keys <$> priv <*> pub
signPayload :: Keys -> String -> ByteString -> IO LC.ByteString
signPayload (Keys priv pub) = signPayload' sign pub
where
sign x = do
Just dig <- getDigestByName "SHA256"
signBS dig priv x
type HttpProvisioner = URI -> ByteString -> ResIO ()
fileProvisioner :: WritableDir -> HttpProvisioner
fileProvisioner challengeDir uri thumbtoken = do
void $ allocate (return f) removeFile
liftIO $ BC.writeFile f thumbtoken
where
f = (coerce challengeDir </>) . takeWhileEnd (/= '/') . uriPath $ uri
takeWhileEnd s = reverse . takeWhile s . reverse
acmeChallengeURI :: DomainName -> BC.ByteString -> URI
acmeChallengeURI dom tok = URI
"http:"
(Just $ URIAuth "" (domainToString dom) "")
("/.well-known/acme-challenge" </> BC.unpack tok)
""
""
certify :: URI -> Keys -> Maybe (URI, EmailAddress) -> HttpProvisioner -> CSR -> IO (Either String X509)
certify directoryUrl keys reg provision certReq =
(mapM readDerX509 =<<) $ runACME directoryUrl keys $ do
forM_ reg $ uncurry register >=> statusReport
let performChallenge domain (ChallengeRequest nextUri token thumbtoken) = do
liftResourceT $ provision (acmeChallengeURI domain token) thumbtoken
notifyChallenge nextUri thumbtoken >>= statusReport >>= ncErrorReport
cr dom = challengeRequest dom >>= statusReport >>= extractCR >>= performChallenge dom
runResourceT $ do
challengeResultLinks <- forM (csrDomains certReq) cr
lift . runExceptT $ do
ExceptT $ pollResults challengeResultLinks <&> left ("certificate receipt was not attempted because a challenge failed: " ++)
ExceptT $ retrieveCert certReq >>= statusReport <&> checkCertResponse
pollResults :: [Response LC.ByteString] -> ACME (Either String ())
pollResults [] = return $ Right ()
pollResults (link:links) = do
-- TODO: use "Retry-After" header if present
let Just uri = link ^? responseBody . JSON.key "uri" . _String
r <- liftIO $ W.get (T.unpack uri) >>= statusReport
let status = r ^. responseBody . JSON.key "status" . _String
case status of
"pending" -> pollResults $ links ++ [r]
"valid" -> pollResults links
"invalid" -> return . Left $ r ^. responseBody . JSON.key "error" . to extractAcmeError
_ -> return . Left $ "unexpected response from ACME server: " ++ show r
data ChallengeRequest = ChallengeRequest { crUri :: String, crToken :: ByteString, crThumbToken :: ByteString }
data CSR = CSR { csrDomains :: [DomainName], csrData :: ByteString }
newtype WritableDir = WritableDir String
ensureWritableDir :: FilePath -> String -> IO WritableDir
ensureWritableDir file name = do
(writable <$> getPermissions file) >>= flip unless (e name)
return $ WritableDir file
where e n = error $ "Error: " ++ n ++ " is not writable"
(</>) :: String -> String -> String
a </> b = a ++ "/" ++ b
infixr 5 </>
domainToString :: DomainName -> String
domainToString = T.unpack . decodeUtf8 . Text.Domain.Validate.toByteString
canProvision :: WritableDir -> DomainName -> IO Bool
canProvision challengeDir domain = do
token <- (".test." ++) . show <$> getPOSIXTime
let uri = acmeChallengeURI domain (fromString token)
r <- runResourceT $ do
fileProvisioner challengeDir uri (fromString token)
liftIO $ W.get (show uri)
return $ r ^. responseBody == fromString token
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
nextU = 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 nextU token thumbtoken
ncErrorReport :: (Show body, AsValue body, MonadIO m) => Response body -> m (Response body)
ncErrorReport r = do
when (Just "pending" /= r ^? responseBody . JSON.key "status" . _String) $ liftIO $ do
putStrLn "Unexpected response to challenge-response request:"
print r
return r
extractAcmeError :: forall s. AsValue s => s -> String
extractAcmeError r = summary ++ " ---- " ++ details
where
(Just summary, Just details) = (k "type", k "detail")
k x = r ^? JSON.key x . _String . to T.unpack
checkCertResponse :: Response LC.ByteString -> Either String LC.ByteString
checkCertResponse r =
if isSuccess $ r ^. responseStatus . statusCode
then Right $ r ^. responseBody
else Left $ r ^. responseBody . to extractAcmeError
where
isSuccess n = n >= 200 && n <= 300
retrieveCert :: (MonadReader Env m, MonadState Nonce m, MonadIO m) => CSR -> m (Response LC.ByteString)
retrieveCert input = sendPayload _newCert (csr $ csrData input)
notifyChallenge :: (MonadReader Env m, MonadState Nonce m, MonadIO m) => String -> ByteString -> m (Response LC.ByteString)
notifyChallenge uri thumbtoken = sendPayload (const uri) (challenge thumbtoken)
data Env = Env { getDir :: Directory, getKeys :: Keys, getSession :: WS.Session }
type ACME = RWST Env () Nonce IO
runACME :: URI -> Keys -> ACME a -> IO a
runACME url keys f = WS.withSession $ \sess -> do
Just (dir, nonce) <- getDirectory sess (show 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 :: URI -> EmailAddress -> ACME (Response LC.ByteString)
register terms email = sendPayload _newReg (registration email (show terms))
challengeRequest :: (MonadIO m, MonadState Nonce m, MonadReader Env m) => DomainName -> m (Response LC.ByteString)
challengeRequest = sendPayload _newAuthz . authz . domainToString
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
|
