{- Yesod webapp - - Copyright 2012-2014 Joey Hess - - License: BSD-2-clause -} {-# LANGUAGE OverloadedStrings, CPP, RankNTypes #-} module Utility.WebApp where import Common import Utility.Tmp import Utility.FileMode import Utility.Hash import qualified Yesod import qualified Network.Wai as Wai import Network.Wai.Handler.Warp import Network.Wai.Handler.WarpTLS import Network.HTTP.Types import qualified Data.CaseInsensitive as CI import Network.Socket import "crypto-api" Crypto.Random import qualified Web.ClientSession as CS import qualified Data.ByteString.Lazy as L import qualified Data.ByteString as B import qualified Data.Text as T import qualified Data.Text.Encoding as TE import Blaze.ByteString.Builder.Char.Utf8 (fromText) import Blaze.ByteString.Builder (Builder) import Control.Arrow ((***)) import Control.Concurrent import Data.SecureMem import Data.Byteable #ifdef __ANDROID__ import Data.Endian #endif localhost :: HostName localhost = "localhost" {- Builds a command to use to start or open a web browser showing an url. -} browserProc :: String -> CreateProcess #ifdef darwin_HOST_OS browserProc url = proc "open" [url] #else #ifdef __ANDROID__ -- Warning: The `am` command does not work very reliably on Android. browserProc url = proc "am" ["start", "-a", "android.intent.action.VIEW", "-d", url] #else #ifdef mingw32_HOST_OS -- Warning: On Windows, no quoting or escaping of the url seems possible, -- so spaces in it will cause problems. One approach is to make the url -- be a relative filename, and adjust the returned CreateProcess to change -- to the directory it's in. browserProc url = proc "cmd" ["/c start " ++ url] #else browserProc url = proc "xdg-open" [url] #endif #endif #endif {- Binds to a socket on localhost, or possibly a different specified - hostname or address, and runs a webapp on it. - - An IO action can also be run, to do something with the address, - such as start a web browser to view the webapp. -} runWebApp :: Maybe TLSSettings -> Maybe HostName -> Wai.Application -> (SockAddr -> IO ()) -> IO () runWebApp tlssettings h app observer = withSocketsDo $ do sock <- getSocket h void $ forkIO $ go webAppSettings sock app sockaddr <- fixSockAddr <$> getSocketName sock observer sockaddr where go = (maybe runSettingsSocket (\ts -> runTLSSocket ts) tlssettings) fixSockAddr :: SockAddr -> SockAddr #ifdef __ANDROID__ {- On Android, the port is currently incorrectly returned in network - byte order, which is wrong on little endian systems. -} fixSockAddr (SockAddrInet (PortNum port) addr) = SockAddrInet (PortNum $ swapEndian port) addr #endif fixSockAddr addr = addr -- disable buggy sloworis attack prevention code webAppSettings :: Settings webAppSettings = setTimeout halfhour defaultSettings where halfhour = 30 * 60 {- Binds to a local socket, or if specified, to a socket on the specified - hostname or address. Selects any free port, unless the hostname ends with - ":port" - - Prefers to bind to the ipv4 address rather than the ipv6 address - of localhost, if it's available. -} getSocket :: Maybe HostName -> IO Socket getSocket h = do #if defined(__ANDROID__) || defined (mingw32_HOST_OS) -- getAddrInfo currently segfaults on Android. -- The HostName is ignored by this code. when (isJust h) $ error "getSocket with HostName not supported on this OS" addr <- inet_addr "127.0.0.1" sock <- socket AF_INET Stream defaultProtocol preparesocket sock bindSocket sock (SockAddrInet aNY_PORT addr) use sock where #else addrs <- getAddrInfo (Just hints) (Just hostname) Nothing case (partition (\a -> addrFamily a == AF_INET) addrs) of (v4addr:_, _) -> go v4addr (_, v6addr:_) -> go v6addr _ -> error "unable to bind to a local socket" where hostname = fromMaybe localhost h hints = defaultHints { addrSocketType = Stream } {- Repeated attempts because bind sometimes fails for an - unknown reason on OSX. -} go addr = go' 100 addr go' :: Int -> AddrInfo -> IO Socket go' 0 _ = error "unable to bind to local socket" go' n addr = do r <- tryIO $ bracketOnError (open addr) close (useaddr addr) either (const $ go' (pred n) addr) return r open addr = socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr) useaddr addr sock = do preparesocket sock bind sock (addrAddress addr) use sock #endif preparesocket sock = setSocketOption sock ReuseAddr 1 use sock = do listen sock maxListenQueue return sock lookupRequestField :: CI.CI B.ByteString -> Wai.Request -> B.ByteString lookupRequestField k req = fromMaybe "" . lookup k $ Wai.requestHeaders req {- Rather than storing a session key on disk, use a random key - that will only be valid for this run of the webapp. -} webAppSessionBackend :: Yesod.Yesod y => y -> IO (Maybe Yesod.SessionBackend) webAppSessionBackend _ = do g <- newGenIO :: IO SystemRandom case genBytes 96 g of Left e -> error $ "failed to generate random key: " ++ show e Right (s, _) -> case CS.initKey s of Left e -> error $ "failed to initialize key: " ++ show e Right key -> use key where timeout = 120 * 60 -- 120 minutes use key = Just . Yesod.clientSessionBackend key . fst <$> Yesod.clientSessionDateCacher timeout type AuthToken = SecureMem toAuthToken :: T.Text -> AuthToken toAuthToken = secureMemFromByteString . TE.encodeUtf8 fromAuthToken :: AuthToken -> T.Text fromAuthToken = TE.decodeLatin1 . toBytes {- Generates a random sha2_512 string, encapsulated in a SecureMem, - suitable to be used for an authentication secret. -} genAuthToken :: IO AuthToken genAuthToken = do g <- newGenIO :: IO SystemRandom return $ case genBytes 512 g of Left e -> error $ "failed to generate auth token: " ++ show e Right (s, _) -> toAuthToken $ T.pack $ show $ sha2_512 $ L.fromChunks [s] {- A Yesod isAuthorized method, which checks the auth cgi parameter - against a token extracted from the Yesod application. - - Note that the usual Yesod error page is bypassed on error, to avoid - possibly leaking the auth token in urls on that page! -} checkAuthToken :: (Monad m, Yesod.MonadHandler m) => (Yesod.HandlerSite m -> AuthToken) -> m Yesod.AuthResult checkAuthToken extractAuthToken = do webapp <- Yesod.getYesod req <- Yesod.getRequest let params = Yesod.reqGetParams req if (toAuthToken <$> lookup "auth" params) == Just (extractAuthToken webapp) then return Yesod.Authorized else Yesod.sendResponseStatus unauthorized401 () {- A Yesod joinPath method, which adds an auth cgi parameter to every - url matching a predicate, containing a token extracted from the - Yesod application. - - A typical predicate would exclude files under /static. -} insertAuthToken :: forall y. (y -> AuthToken) -> ([T.Text] -> Bool) -> y -> T.Text -> [T.Text] -> [(T.Text, T.Text)] -> Builder insertAuthToken extractAuthToken predicate webapp root pathbits params = fromText root `mappend` encodePath pathbits' encodedparams where pathbits' = if null pathbits then [T.empty] else pathbits encodedparams = map (TE.encodeUtf8 *** go) params' go "" = Nothing go x = Just $ TE.encodeUtf8 x authparam = (T.pack "auth", fromAuthToken (extractAuthToken webapp)) params' | predicate pathbits = authparam:params | otherwise = params {- Creates a html shim file that's used to redirect into the webapp, - to avoid exposing the secret token when launching the web browser. -} writeHtmlShim :: String -> String -> FilePath -> IO () writeHtmlShim title url file = viaTmp writeFileProtected file $ genHtmlShim title url {- TODO: generate this static file using Yesod. -} genHtmlShim :: String -> String -> String genHtmlShim title url = unlines [ "" , "" , ""++ title ++ "" , "" , "" , "

" , "" ++ title ++ "" , "

" , "" , "" ]