Ensure JWT expires

src/PostgREST/Auth.hs

@@ -25,6 +25,7 @@ import           Data.Map                as M (fromList, toList)
 import           Data.Monoid             ((<>))
 import           Data.String.Conversions (cs)
 import           Data.Text               (Text)
+import           Data.Time.Clock         (NominalDiffTime)
 import           PostgREST.PgQuery       (pgFmtLit, pgFmtIdent, unquoted)
 import qualified Web.JWT                 as JWT
 import qualified Data.HashMap.Lazy       as H
@@ -49,10 +50,19 @@ claimsToSQL = map setVar . toList
   returns a map of JWT claims
   In case there is any problem decoding the JWT it returns Nothing.
 -}
-jwtClaims :: Text -> Text -> Maybe JWT.ClaimsMap
-jwtClaims secret input = JWT.unregisteredClaims . JWT.claims <$> decoded
+jwtClaims :: Text -> Text -> NominalDiffTime -> Maybe JWT.ClaimsMap
+jwtClaims secret input time =
+  case claim JWT.exp of
+    Just (Just expires) ->
+      if JWT.secondsSinceEpoch expires > time
+        then customClaims
+        else Nothing
+    _ -> customClaims
   where
     decoded = JWT.decodeAndVerifySignature (JWT.secret secret) input
+    claim :: (JWT.JWTClaimsSet -> a) -> Maybe a
+    claim prop = prop . JWT.claims <$> decoded
+    customClaims = claim JWT.unregisteredClaims
 
 -- | Receives the name of a role and returns a SET ROLE statement
 setRole :: Text -> Text

src/PostgREST/Main.hs

@@ -24,6 +24,7 @@ import qualified Hasql.Postgres                       as P
 import           Network.Wai
 import           Network.Wai.Handler.Warp             hiding (Connection)
 import           Network.Wai.Middleware.RequestLogger (logStdout)
+import           Data.Time.Clock.POSIX                (getPOSIXTime)
 import           System.IO                            (BufferMode (..),
                                                        hSetBuffering, stderr,
                                                        stdin, stdout)
@@ -72,13 +73,6 @@ main = do
           <> show minimumPgVersion)
     ) supportedOrError
 
-  -- what was this code for?
-  -- roleOrError <- H.session pool $ do
-  --   Identity (role :: Text) <- H.tx Nothing $ H.singleEx
-  --     [H.stmt|SELECT SESSION_USER|]
-  --   return role
-  -- authenticator <- either hasqlError return roleOrError
-
   let txSettings = Just (H.ReadCommitted, Just True)
   metadata <- H.session pool $ H.tx txSettings $ do
     tabs <- allTables
@@ -105,7 +99,8 @@ main = do
   -- print $ findRelation (fakeRels ++ allRels) "test" "pg_source" "clients"
 
   runSettings appSettings $ middle $ \ req respond -> do
+    time <- getPOSIXTime
     body <- strictRequestBody req
     resOrError <- liftIO $ H.session pool $ H.tx txSettings $
-      runWithClaims conf (app dbstructure conf body) req
+      runWithClaims conf time (app dbstructure conf body) req
     either (respond . errResponse) respond resOrError

src/PostgREST/Middleware.hs

@@ -7,6 +7,7 @@ import           Data.Maybe                    (fromMaybe, isNothing)
 import           Data.Monoid
 import           Data.Text
 import           Data.String.Conversions       (cs)
+import           Data.Time.Clock               (NominalDiffTime)
 import qualified Hasql                         as H
 import qualified Hasql.Postgres                as P
 
@@ -32,27 +33,30 @@ import qualified Data.Vector             as V
 import qualified Hasql.Backend           as B
 import qualified Data.Map.Lazy           as M
 
-runWithClaims :: forall s. AppConfig ->
+runWithClaims :: forall s. AppConfig -> NominalDiffTime ->
                  (Request -> H.Tx P.Postgres s Response) ->
                  Request -> H.Tx P.Postgres s Response
-runWithClaims conf app req = do
-    mapM_ H.unitEx $ stmt <$> env
-    app req
- where
-   stmt = (flip $ flip B.Stmt V.empty) True
-   hdrs = requestHeaders req
-   jwtSecret = (cs $ configJwtSecret conf) :: Text
-   auth = fromMaybe "" $ lookup hAuthorization hdrs
-   anon = cs $ configAnonRole conf
-   claims =
-     fromMaybe (M.fromList []) $
-     case split (==' ') (cs auth) of
-       ("Bearer" : jwt : _) -> jwtClaims jwtSecret jwt
-       _ -> Nothing
-   env = if M.member "role" claims
-            then jwtEnv
-            else setRole anon : jwtEnv
-   jwtEnv = claimsToSQL claims
+runWithClaims conf time app req = do
+    _ <- H.unitEx $ stmt setAnon
+    case split (== ' ') (cs auth) of
+      ("Bearer" : tokenStr : _) ->
+        case jwtClaims jwtSecret tokenStr time of
+          Just claims ->
+            if M.member "role" claims
+            then do
+              mapM_ H.unitEx $ stmt <$> claimsToSQL claims
+              app req
+            else invalidJWT
+          _ -> invalidJWT
+      _ -> app req
+  where
+    stmt = (flip $ flip B.Stmt V.empty) True
+    hdrs = requestHeaders req
+    jwtSecret = (cs $ configJwtSecret conf) :: Text
+    auth = fromMaybe "" $ lookup hAuthorization hdrs
+    anon = cs $ configAnonRole conf
+    setAnon = setRole anon
+    invalidJWT = return $ responseLBS status400 [] "Invalid JWT"
 
 redirectInsecure :: Application -> Application
 redirectInsecure app req respond = do