source/interprocedural_analyses/taint/annotationParser.ml

(*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

open Core
open Result

type taint_kind =
  | Named
  | Parametric

type source_or_sink = {
  name: string;
  kind: taint_kind;
}

let parse_source ~allowed ?subkind name =
  match
    List.find allowed ~f:(fun { name = source_name; _ } -> String.equal source_name name), subkind
  with
  (* In order to support parsing parametric sources and sinks for rules, we allow matching
     parametric source kinds with no subkind. *)
  | Some _, None -> Ok (Sources.NamedSource name)
  | Some { kind = Parametric; _ }, Some subkind ->
      Ok (Sources.ParametricSource { source_name = name; subkind })
  | _ -> Error (Format.sprintf "Unsupported taint source `%s`" name)


let parse_sink ~allowed ?subkind name =
  match
    List.find allowed ~f:(fun { name = sink_name; _ } -> String.equal sink_name name), subkind
  with
  (* In order to support parsing parametric sources and sinks for rules, we allow matching
     parametric source kinds with no subkind. *)
  | Some _, None -> Ok (Sinks.NamedSink name)
  | Some { kind = Parametric; _ }, Some subkind ->
      Ok (Sinks.ParametricSink { sink_name = name; subkind })
  | _ -> Error (Format.sprintf "Unsupported taint sink `%s`" name)


let parse_transform ~allowed name =
  match List.find allowed ~f:(TaintTransform.equal (TaintTransform.Named name)) with
  | Some transform -> Ok transform
  | None -> Error (Format.sprintf "Unsupported transform `%s`" name)


let parse_tito ~allowed_transforms ?subkind name =
  match name, subkind with
  | "LocalReturn", _ -> Ok Sinks.LocalReturn
  | update, _ when String.is_prefix update ~prefix:"ParameterUpdate" ->
      let index = String.chop_prefix_exn update ~prefix:"ParameterUpdate" in
      Ok (ParameterUpdate (Int.of_string index))
  | "Transform", None -> Error "Tito transform requires name of the transform as parameter"
  | "Transform", Some transform ->
      parse_transform ~allowed:allowed_transforms transform
      >>= fun transform ->
      Ok
        (Sinks.Transform
           {
             local = TaintTransforms.of_named_transforms [transform];
             global = TaintTransforms.empty;
             base = Sinks.LocalReturn;
           })
  | name, _ -> Error (Format.sprintf "Unsupported taint in taint out specification `%s`" name)