feat: support string comparison for jwt-role-claim-key

PostgREST · Dec 12, 2024 · af6b79d · af6b79d
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -12,6 +12,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2858, Performance improvements when calling RPCs via GET using indexes in more cases - @wolfgangwalther
  - #3560, Log resolved host in "Listening on ..." messages - @develop7
  - #3727, Log maximum pool size - @steve-chavez
+ - #1536, Add string comparison feature for jwt-role-claim-key - @taimoorzaeem
 
 ### Fixed
 

diff --git a/docs/postgrest.dict b/docs/postgrest.dict
@@ -27,10 +27,12 @@ CSV
 durations
 DDL
 DOM
+DSL
 DevOps
 dockerize
 enum
 Enums
+Entra
 eq
 ETH
 Ethereum
@@ -68,9 +70,11 @@ isdistinct
 JS
 js
 JSON
+JSPath
 JWK
 JWT
 jwt
+Keycloak
 Kubernetes
 localhost
 login
@@ -94,10 +98,11 @@ npm
 nxl
 nxr
 OAuth
+ORM
 Observability
+Okta
 OpenAPI
 openapi
-ORM
 ov
 parametrized
 passphrase

diff --git a/docs/references/auth.rst b/docs/references/auth.rst
@@ -161,6 +161,43 @@ JWT Claims Validation
 
 PostgREST honors the :code:`exp` claim for token expiration, rejecting expired tokens.
 
+.. _jwt_role_claim_key_extract:
+
+JWT Role Claim Key Extraction
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A JSPath DSL that specifies the location of the :code:`role` key in the JWT claims. This can be used to consume a JWT provided by a third party service like Auth0, Okta, Microsoft Entra or Keycloak.
+
+The DSL follows the `JSONPath <https://goessner.net/articles/JsonPath/>`_ expression grammar with extended string comparison operators. Supported operators are:
+
+- ``==`` selects the first array element that exactly matches the right operand
+- ``!=`` selects the first array element that does not match the right operand
+- ``^==`` selects the first array element that starts with the right operand
+- ``==^`` selects the first array element that ends with the right operand
+- ``*==`` selects the first array element that contains the right operand
+
+Usage examples:
+
+  .. code:: bash
+
+    # {"postgrest":{"roles": ["other", "author"]}}
+    # the DSL accepts characters that are alphanumerical or one of "_$@" as keys
+    jwt-role-claim-key = ".postgrest.roles[1]"
+
+    # {"https://www.example.com/role": { "key": "author" }}
+    # non-alphanumerical characters can go inside quotes(escaped in the config value)
+    jwt-role-claim-key = ".\"https://www.example.com/role\".key"
+
+    # {"postgrest":{"roles": ["other", "author"]}}
+    # `@` represents the current element in the array
+    # all the these match the string "author"
+    jwt-role-claim-key = ".postgrest.roles[?(@ == \"author\")]"
+    jwt-role-claim-key = ".postgrest.roles[?(@ != \"other\")]"
+    jwt-role-claim-key = ".postgrest.roles[?(@ ^== \"aut\")]"
+    jwt-role-claim-key = ".postgrest.roles[?(@ ==^ \"hor\")]"
+    jwt-role-claim-key = ".postgrest.roles[?(@ *== \"utho\")]"
+
+
 JWT Security
 ~~~~~~~~~~~~
 

diff --git a/docs/references/configuration.rst b/docs/references/configuration.rst
@@ -620,17 +620,7 @@ jwt-role-claim-key
 
   *For backwards compatibility, this config parameter is also available without prefix as "role-claim-key".*
 
-  A JSPath DSL that specifies the location of the :code:`role` key in the JWT claims. This can be used to consume a JWT provided by a third party service like Auth0, Okta or Keycloak. Usage examples:
-
-  .. code:: bash
-
-    # {"postgrest":{"roles": ["other", "author"]}}
-    # the DSL accepts characters that are alphanumerical or one of "_$@" as keys
-    jwt-role-claim-key = ".postgrest.roles[1]"
-
-    # {"https://www.example.com/role": { "key": "author }}
-    # non-alphanumerical characters can go inside quotes(escaped in the config value)
-    jwt-role-claim-key = ".\"https://www.example.com/role\".key"
+  See :ref:`jwt_role_claim_key_extract` on how to specify key paths and usage examples.
 
 .. _jwt-secret:
 

diff --git a/src/PostgREST/Auth.hs b/src/PostgREST/Auth.hs
@@ -27,6 +27,7 @@ import qualified Data.ByteString                 as BS
 import qualified Data.ByteString.Lazy.Char8      as LBS
 import qualified Data.Cache                      as C
 import qualified Data.Scientific                 as Sci
+import qualified Data.Text                       as T
 import qualified Data.Vault.Lazy                 as Vault
 import qualified Data.Vector                     as V
 import qualified Jose.Jwk                        as JWT
@@ -46,7 +47,8 @@ import System.TimeIt           (timeItT)
 
 import PostgREST.AppState (AppState, AuthResult (..), getConfig,
                            getJwtCache, getTime)
-import PostgREST.Config   (AppConfig (..), JSPath, JSPathExp (..))
+import PostgREST.Config   (AppConfig (..), FilterExp (..), JSPath,
+                           JSPathExp (..))
 import PostgREST.Error    (Error (..))
 
 import Protolude
@@ -121,8 +123,20 @@ parseClaims AppConfig{..} jclaims@(JSON.Object mclaims) = do
     walkJSPath x                      []                = x
     walkJSPath (Just (JSON.Object o)) (JSPKey key:rest) = walkJSPath (KM.lookup (K.fromText key) o) rest
     walkJSPath (Just (JSON.Array ar)) (JSPIdx idx:rest) = walkJSPath (ar V.!? idx) rest
+    walkJSPath (Just (JSON.Array ar)) [JSPFilter (EqualsCond txt)] = findFirstMatch (==) txt ar
+    walkJSPath (Just (JSON.Array ar)) [JSPFilter (NotEqualsCond txt)] = findFirstMatch (/=) txt ar
+    walkJSPath (Just (JSON.Array ar)) [JSPFilter (StartsWithCond txt)] = findFirstMatch T.isPrefixOf txt ar
+    walkJSPath (Just (JSON.Array ar)) [JSPFilter (EndsWithCond txt)] = findFirstMatch T.isSuffixOf txt ar
+    walkJSPath (Just (JSON.Array ar)) [JSPFilter (ContainsCond txt)] = findFirstMatch T.isInfixOf txt ar
     walkJSPath _                      _                 = Nothing
 
+    findFirstMatch matchWith pattern = foldr checkMatch Nothing
+      where
+        checkMatch (JSON.String txt) acc
+            | pattern `matchWith` txt = Just $ JSON.String txt
+            | otherwise = acc
+        checkMatch _ acc = acc
+
     unquoted :: JSON.Value -> BS.ByteString
     unquoted (JSON.String t) = encodeUtf8 t
     unquoted v               = LBS.toStrict $ JSON.encode v

diff --git a/src/PostgREST/Config.hs b/src/PostgREST/Config.hs
@@ -15,6 +15,7 @@ module PostgREST.Config
   , Environment
   , JSPath
   , JSPathExp(..)
+  , FilterExp(..)
   , LogLevel(..)
   , OpenAPIMode(..)
   , Proxy(..)
@@ -54,8 +55,9 @@ import System.Posix.Types      (FileMode)
 
 import PostgREST.Config.Database         (RoleIsolationLvl,
                                           RoleSettings)
-import PostgREST.Config.JSPath           (JSPath, JSPathExp (..),
-                                          dumpJSPath, pRoleClaimKey)
+import PostgREST.Config.JSPath           (FilterExp (..), JSPath,
+                                          JSPathExp (..), dumpJSPath,
+                                          pRoleClaimKey)
 import PostgREST.Config.Proxy            (Proxy (..),
                                           isMalformedProxyUri, toURI)
 import PostgREST.SchemaCache.Identifiers (QualifiedIdentifier, dumpQi,

diff --git a/src/PostgREST/Config/JSPath.hs b/src/PostgREST/Config/JSPath.hs
@@ -1,6 +1,8 @@
+{-# OPTIONS_GHC -Wno-unused-do-bind #-}
 module PostgREST.Config.JSPath
   ( JSPath
   , JSPathExp(..)
+  , FilterExp(..)
   , dumpJSPath
   , pRoleClaimKey
   ) where
@@ -14,38 +16,85 @@ import Text.Read                     (read)
 import Protolude
 
 
--- | full jspath, e.g. .property[0].attr.detail
+-- | full jspath, e.g. .property[0].attr.detail[?(@ == "role1")]
 type JSPath = [JSPathExp]
 
--- | jspath expression, e.g. .property, .property[0] or ."property-dash"
+-- NOTE: We only accept one JSPFilter expr (at the end of input)
+-- | jspath expression
 data JSPathExp
-  = JSPKey Text
-  | JSPIdx Int
+  = JSPKey Text         -- .property or ."property-dash"
+  | JSPIdx Int          -- [0]
+  | JSPFilter FilterExp -- [?(@ == "match")]
+
+data FilterExp
+  = EqualsCond Text
+  | NotEqualsCond Text
+  | StartsWithCond Text
+  | EndsWithCond Text
+  | ContainsCond Text
 
 dumpJSPath :: JSPathExp -> Text
 -- TODO: this needs to be quoted properly for special chars
 dumpJSPath (JSPKey k) = "." <> show k
 dumpJSPath (JSPIdx i) = "[" <> show i <> "]"
+dumpJSPath (JSPFilter cond) = "[?(@" <> expr <> ")]"
+  where
+    expr =
+      case cond of
+        EqualsCond text     -> " == " <> show text
+        NotEqualsCond text  -> " != " <> show text
+        StartsWithCond text -> " ^== " <> show text
+        EndsWithCond text   -> " ==^ " <> show text
+        ContainsCond text   -> " *== " <> show text
+
 
 -- Used for the config value "role-claim-key"
 pRoleClaimKey :: Text -> Either Text JSPath
 pRoleClaimKey selStr =
   mapLeft show $ P.parse pJSPath ("failed to parse role-claim-key value (" <> toS selStr <> ")") (toS selStr)
 
 pJSPath :: P.Parser JSPath
-pJSPath = toJSPath <$> (period *> pPath `P.sepBy` period <* P.eof)
-  where
-    toJSPath :: [(Text, Maybe Int)] -> JSPath
-    toJSPath = concatMap (\(key, idx) -> JSPKey key : maybeToList (JSPIdx <$> idx))
-    period = P.char '.' <?> "period (.)"
-    pPath :: P.Parser (Text, Maybe Int)
-    pPath = (,) <$> pJSPKey <*> P.optionMaybe pJSPIdx
+pJSPath = P.many1 pJSPathExp <* P.eof
+
+pJSPathExp :: P.Parser JSPathExp
+pJSPathExp = pJSPKey <|> pJSPFilter <|> pJSPIdx
+
+pJSPKey :: P.Parser JSPathExp
+pJSPKey = do
+  P.char '.'
+  val <- toS <$> P.many1 (P.alphaNum <|> P.oneOf "_$@") <|> pQuotedValue
+  return (JSPKey val) <?> "pJSPKey: JSPath attribute key"
+
+pJSPIdx :: P.Parser JSPathExp
+pJSPIdx = do
+  P.char '['
+  num <- read <$> P.many1 P.digit
+  P.char ']'
+  return (JSPIdx num) <?> "pJSPIdx: JSPath array index"
 
-pJSPKey :: P.Parser Text
-pJSPKey = toS <$> P.many1 (P.alphaNum <|> P.oneOf "_$@") <|> pQuotedValue <?> "attribute name [a..z0..9_$@])"
+pJSPFilter :: P.Parser JSPathExp
+pJSPFilter = do
+  P.try $ P.string "[?("
+  condition <- pFilterConditionParser
+  P.char ')'
+  P.char ']'
+  P.eof -- this should be the last jspath expression
+  return (JSPFilter condition) <?> "pJSPFilter: JSPath filter exp"
 
-pJSPIdx :: P.Parser Int
-pJSPIdx = P.char '[' *> (read <$> P.many1 P.digit) <* P.char ']' <?> "array index [0..n]"
+pFilterConditionParser :: P.Parser FilterExp
+pFilterConditionParser = do
+  P.char '@'
+  P.spaces
+  filt <- matchOperator
+  P.spaces
+  filt <$> pQuotedValue
+    where
+      matchOperator =
+        P.try (P.string "==^" $> EndsWithCond)
+        <|> P.try (P.string "==" $> EqualsCond)
+        <|> P.try (P.string "!=" $> NotEqualsCond)
+        <|> P.try (P.string "^==" $> StartsWithCond)
+        <|> P.try (P.string "*==" $> ContainsCond)
 
 pQuotedValue :: P.Parser Text
 pQuotedValue = toS <$> (P.char '"' *> P.many (P.noneOf "\"") <* P.char '"')
diff --git a/test/io/configs/expected/jwt-role-claim-key1.config b/test/io/configs/expected/jwt-role-claim-key1.config
@@ -0,0 +1,39 @@
+db-aggregates-enabled = false
+db-anon-role = ""
+db-channel = "pgrst"
+db-channel-enabled = true
+db-extra-search-path = "public"
+db-hoisted-tx-settings = "statement_timeout,plan_filter.statement_cost_limit,default_transaction_isolation"
+db-max-rows = ""
+db-plan-enabled = false
+db-pool = 10
+db-pool-acquisition-timeout = 10
+db-pool-max-lifetime = 1800
+db-pool-max-idletime = 30
+db-pool-automatic-recovery = true
+db-pre-request = ""
+db-prepared-statements = true
+db-root-spec = ""
+db-schemas = "public"
+db-config = true
+db-pre-config = ""
+db-tx-end = "commit"
+db-uri = "postgresql://"
+jwt-aud = ""
+jwt-role-claim-key = ".\"roles\"[?(@ == \"role1\")]"
+jwt-secret = ""
+jwt-secret-is-base64 = false
+jwt-cache-max-lifetime = 0
+log-level = "error"
+openapi-mode = "follow-privileges"
+openapi-security-active = false
+openapi-server-proxy-uri = ""
+server-cors-allowed-origins = ""
+server-host = "!4"
+server-port = 3000
+server-trace-header = ""
+server-timing-enabled = false
+server-unix-socket = ""
+server-unix-socket-mode = "660"
+admin-server-host = "!4"
+admin-server-port = ""
diff --git a/test/io/configs/expected/jwt-role-claim-key2.config b/test/io/configs/expected/jwt-role-claim-key2.config
@@ -0,0 +1,39 @@
+db-aggregates-enabled = false
+db-anon-role = ""
+db-channel = "pgrst"
+db-channel-enabled = true
+db-extra-search-path = "public"
+db-hoisted-tx-settings = "statement_timeout,plan_filter.statement_cost_limit,default_transaction_isolation"
+db-max-rows = ""
+db-plan-enabled = false
+db-pool = 10
+db-pool-acquisition-timeout = 10
+db-pool-max-lifetime = 1800
+db-pool-max-idletime = 30
+db-pool-automatic-recovery = true
+db-pre-request = ""
+db-prepared-statements = true
+db-root-spec = ""
+db-schemas = "public"
+db-config = true
+db-pre-config = ""
+db-tx-end = "commit"
+db-uri = "postgresql://"
+jwt-aud = ""
+jwt-role-claim-key = ".\"roles\"[?(@ != \"role1\")]"
+jwt-secret = ""
+jwt-secret-is-base64 = false
+jwt-cache-max-lifetime = 0
+log-level = "error"
+openapi-mode = "follow-privileges"
+openapi-security-active = false
+openapi-server-proxy-uri = ""
+server-cors-allowed-origins = ""
+server-host = "!4"
+server-port = 3000
+server-trace-header = ""
+server-timing-enabled = false
+server-unix-socket = ""
+server-unix-socket-mode = "660"
+admin-server-host = "!4"
+admin-server-port = ""
diff --git a/test/io/configs/expected/jwt-role-claim-key3.config b/test/io/configs/expected/jwt-role-claim-key3.config
@@ -0,0 +1,39 @@
+db-aggregates-enabled = false
+db-anon-role = ""
+db-channel = "pgrst"
+db-channel-enabled = true
+db-extra-search-path = "public"
+db-hoisted-tx-settings = "statement_timeout,plan_filter.statement_cost_limit,default_transaction_isolation"
+db-max-rows = ""
+db-plan-enabled = false
+db-pool = 10
+db-pool-acquisition-timeout = 10
+db-pool-max-lifetime = 1800
+db-pool-max-idletime = 30
+db-pool-automatic-recovery = true
+db-pre-request = ""
+db-prepared-statements = true
+db-root-spec = ""
+db-schemas = "public"
+db-config = true
+db-pre-config = ""
+db-tx-end = "commit"
+db-uri = "postgresql://"
+jwt-aud = ""
+jwt-role-claim-key = ".\"roles\"[?(@ ^== \"role1\")]"
+jwt-secret = ""
+jwt-secret-is-base64 = false
+jwt-cache-max-lifetime = 0
+log-level = "error"
+openapi-mode = "follow-privileges"
+openapi-security-active = false
+openapi-server-proxy-uri = ""
+server-cors-allowed-origins = ""
+server-host = "!4"
+server-port = 3000
+server-trace-header = ""
+server-timing-enabled = false
+server-unix-socket = ""
+server-unix-socket-mode = "660"
+admin-server-host = "!4"
+admin-server-port = ""