CA-352073: Ensure all serialized calls can pass rbac checks

Explicitly define a list of tuples with names and values so the rbac
checks can never fail at runtime on differing lengths for these. Instead
now the check will fail at build time.

Calls with defaults allowed the values list to be shorter as they never
bothered to contain the default values. Now the default values are
collected to match all the names of the parameters.

Signed-off-by: Pau Ruiz Safont <pau.safont@citrix.com>

ocaml/idl/ocaml_backend/gen_server.ml

@@ -193,11 +193,12 @@ let operation (obj : obj) (x : message) =
     else
       List.exists (fun a -> is_session_arg a) args_without_default_values
   in
-  let unmarshall_default_params =
+  let name_default_params, unmarshall_default_params =
     List.mapi
       (fun param_count default_param ->
         let param_name = OU.ocaml_of_record_name default_param.DT.param_name in
         let param_type = OU.alias_of_ty default_param.DT.param_type in
+        let param_rpc = to_rpc_name param_name in
         let try_and_get_default =
           Printf.sprintf "List.nth default_args %d" param_count
         in
@@ -208,10 +209,14 @@ let operation (obj : obj) (x : message) =
           | Some default ->
               Datamodel_values.to_ocaml_string default
         in
-        Printf.sprintf "let %s = %s_of_rpc (try %s with _ -> %s) in" param_name
-          param_type try_and_get_default default_value
+        ( Printf.sprintf "let %s = try %s with _ -> %s in" param_rpc
+            try_and_get_default default_value
+        , Printf.sprintf "let %s = %s_of_rpc %s in" param_name param_type
+            param_rpc
+        )
       )
       msg_params_with_default_values
+    |> List.split
   in
   let rbac_check_begin =
     if has_session_arg then
@@ -221,19 +226,43 @@ let operation (obj : obj) (x : message) =
       let serialize_name_list lst =
         List.map (Printf.sprintf {|"%s"|}) lst |> serialize_list
       in
+      let serialize_args args =
+        List.map (fun (n, v) -> Printf.sprintf {|("%s", %s)|} n v) args
+        |> serialize_list
+      in
       let default_arg_name_params =
         if is_non_constructor_with_defaults then
           List.map (fun dp -> dp.DT.param_name) msg_params_with_default_values
         else
           []
       in
       let arg_names = orig_string_args @ default_arg_name_params in
+      let default_arg_values =
+        List.map
+          (fun dp -> to_rpc_name (OU.ocaml_of_record_name dp.DT.param_name))
+          msg_params_with_default_values
+      in
+      let arg_values = string_args @ default_arg_values in
+      let args =
+        try List.combine arg_names arg_values
+        with Invalid_argument _ ->
+          let msg =
+            Printf.sprintf
+              "Cannot serialize call %s.%s: number of arguments doesn't match \
+               with the number of names for it; in %s"
+              (OU.ocaml_of_obj_name obj.DT.name)
+              x.msg_name __LOC__
+          in
+          failwith msg
+      in
       let key_names = List.map fst x.msg_map_keys_roles in
       [
-        Printf.sprintf "let arg_names = %s in" (serialize_name_list arg_names)
+        Printf.sprintf "let arg_names_values = %s in" (serialize_args args)
+      ; (* This incurs a runtime cost *)
+        "let arg_names, arg_values = List.split arg_names_values in"
       ; Printf.sprintf "let key_names = %s in" (serialize_name_list key_names)
       ; "let rbac __context fn = Rbac.check session_id __call \
-         ~args:(arg_names,__params) ~keys:key_names ~__context ~fn in"
+         ~args:(arg_names, arg_values) ~keys:key_names ~__context ~fn in"
       ]
     else
       ["let rbac __context fn = fn () in"]
@@ -380,6 +409,7 @@ let operation (obj : obj) (x : message) =
     let all_list =
       if not (DU.has_been_removed x.DT.msg_lifecycle) then
         comments
+        @ name_default_params
         @ unmarshall_code
         @ session_check_exp
         @ rbac_check_begin
@@ -504,10 +534,15 @@ let gen_module api : O.Module.t =
                  ; "      Session_check.check ~intra_pool_only:false \
                     ~session_id;"
                  ; "      (* based on the Host.call_extension call *)"
-                 ; "      let arg_names = [\"session_id\"; __call] in"
+                 ; "      let call_rpc = Rpc.String __call in "
+                 ; "      let arg_names, arg_values ="
+                 ; "        [(\"session_id\", session_id_rpc); (__call, \
+                    call_rpc)]"
+                 ; "        |> List.split"
+                 ; "      in"
                  ; "      let key_names = [] in"
                  ; "      let rbac __context fn = Rbac.check session_id \
-                    \"Host.call_extension\" ~args:(arg_names, __params) \
+                    \"Host.call_extension\" ~args:(arg_names, arg_values) \
                     ~keys:key_names ~__context ~fn in"
                  ; "      Server_helpers.forward_extension ~__context rbac { \
                     call with Rpc.name = __call }"