propagate tainted sources

Reviewed By: mbouaziz

Differential Revision: D3723878

fbshipit-source-id: 6774e0b

infer/src/checkers/accessPath.ml

@@ -103,8 +103,8 @@ let of_exp exp typ ~(f_resolve_id : Ident.t -> raw option) =
         None in
   of_exp_ exp typ []
 
-let append (base, accesses) access =
-  base, accesses @ [access]
+let append (base, old_accesses) new_accesses =
+  base, old_accesses @ new_accesses
 
 let rec is_prefix_path path1 path2 =
   if path1 == path2
@@ -143,7 +143,8 @@ let pp_access fmt = function
 
 let pp_raw fmt (base, accesses) =
   let pp_access_list fmt accesses =
-    F.pp_print_list pp_access fmt accesses in
+    let pp_sep _ _ = () in
+    F.pp_print_list ~pp_sep pp_access fmt accesses in
   F.fprintf fmt "%a%a" pp_base base pp_access_list accesses
 
 let pp fmt = function

infer/src/checkers/accessPath.mli

@@ -50,8 +50,9 @@ val of_id : Ident.t -> Typ.t -> raw
 (** convert [exp] to a raw access path, resolving identifiers using [f_resolve_id] *)
 val of_exp : Exp.t -> Typ.t -> f_resolve_id:(Ident.t -> raw option) -> raw option
 
-(** append a new access to an existing access path; e.g., `append_access g x.f` produces `x.f.g` *)
-val append : raw -> access -> raw
+(** append new accesses to an existing access path; e.g., `append_access x.f [g, h]` produces
+    `x.f.g.h` *)
+val append : raw -> access list -> raw
 
 (** return true if [ap1] is a prefix of [ap2]. returns true for equal access paths *)
 val is_prefix : raw -> raw -> bool

infer/src/quandary/TaintAnalysis.ml

@@ -65,22 +65,106 @@ module Make (TraceDomain : Trace.S) = struct
     type formal_list = AccessPath.base list
     type extras = formal_list
 
+    let is_formal base proc_data =
+      IList.exists (AccessPath.base_equal base) proc_data.ProcData.extras
+
+    let is_rooted_in_formal ap proc_data =
+      let root, _ = AccessPath.extract ap in
+      is_formal root proc_data
+
+    let resolve_id id_map id =
+      try Some (IdMapDomain.find id id_map)
+      with Not_found -> None
+
+    (* get the node associated with [access_path] in [access_tree] *)
+    let access_path_get_node access_path access_tree proc_data loc =
+      match TaintDomain.get_node access_path access_tree with
+      | Some _ as node_opt ->
+          node_opt
+      | None when is_rooted_in_formal access_path proc_data ->
+          let call_site = CallSite.make (Cfg.Procdesc.get_proc_name proc_data.ProcData.pdesc) loc in
+          let trace =
+            TraceDomain.of_source (TraceDomain.Source.make_footprint access_path call_site) in
+          Some (TaintDomain.make_normal_leaf trace)
+      | None ->
+          None
+
+    (* get the node associated with [exp] in [access_tree] *)
+    let exp_get_node exp typ { Domain.access_tree; id_map; } proc_data loc =
+      let f_resolve_id = resolve_id id_map in
+      match AccessPath.of_exp exp typ ~f_resolve_id with
+      | Some access_path ->
+          access_path_get_node (AccessPath.Exact access_path) access_tree proc_data loc
+      | None ->
+          (* can't make an access path from [exp] *)
+          None
+
+    let analyze_assignment lhs_access_path rhs_exp rhs_typ astate proc_data loc =
+      let rhs_node =
+        match exp_get_node rhs_exp rhs_typ astate proc_data loc with
+        | Some node -> node
+        | None -> TaintDomain.empty_node in
+      let access_tree = TaintDomain.add_node lhs_access_path rhs_node astate.Domain.access_tree in
+      { astate with Domain.access_tree; }
+
     let add_source source ret_id ret_typ access_tree =
       let trace = TraceDomain.of_source source in
       let id_ap = AccessPath.Exact (AccessPath.of_id ret_id ret_typ) in
       TaintDomain.add_trace id_ap trace access_tree
 
-    let exec_instr ({ Domain.access_tree; } as astate) proc_data _ instr =
+    let exec_instr ({ Domain.access_tree; id_map; } as astate) proc_data _ instr =
+      let f_resolve_id = resolve_id id_map in
       match instr with
+      | Sil.Letderef (lhs_id, rhs_exp, rhs_typ, _loc) ->
+          begin
+            match AccessPath.of_exp rhs_exp rhs_typ ~f_resolve_id with
+            | Some rhs_access_path ->
+                let id_map' = IdMapDomain.add lhs_id rhs_access_path id_map in
+                { astate with Domain.id_map = id_map'; }
+            | None ->
+                astate
+          end
+      | Sil.Set (lhs_exp, lhs_typ, rhs_exp, loc) ->
+          let lhs_access_path =
+            match AccessPath.of_exp lhs_exp lhs_typ ~f_resolve_id with
+            | Some access_path ->
+                access_path
+            | None ->
+                failwithf
+                  "Assignment to unexpected lhs expression %a in proc %a at loc %a"
+                  (Sil.pp_exp pe_text) lhs_exp
+                  Procname.pp (Cfg.Procdesc.get_proc_name (proc_data.ProcData.pdesc))
+                  Location.pp loc in
+          let astate' =
+            analyze_assignment
+              (AccessPath.Exact lhs_access_path) rhs_exp lhs_typ astate proc_data loc in
+          begin
+            (* direct `exp = id` assignments are treated specially; we update the id map too. this
+               is so future reads of `exp` will get the subtree associated with `id` (needed to
+               handle the `id = foo(); exp = id case` and similar). *)
+            match rhs_exp with
+            | Exp.Var rhs_id ->
+                let existing_accesses =
+                  try snd (IdMapDomain.find rhs_id astate'.Domain.id_map)
+                  with Not_found -> [] in
+                let lhs_ap' = AccessPath.append lhs_access_path existing_accesses in
+                let id_map' = IdMapDomain.add rhs_id lhs_ap' astate'.Domain.id_map in
+                { astate' with Domain.id_map = id_map'; }
+            | _ ->
+                astate'
+          end
       | Sil.Call (ret_ids, Const (Cfun callee_pname), _, callee_loc, _) ->
           let call_site = CallSite.make callee_pname callee_loc in
           let ret_typ =
             match callee_pname with
             | Procname.Java java_pname ->
                 let ret_typ_str = Procname.java_get_return_type java_pname in
-                Option.default
-                  Typ.Tvoid
-                  (Tenv.lookup_java_typ_from_string (proc_data.ProcData.tenv) ret_typ_str)
+                begin
+                  match Tenv.lookup_java_typ_from_string (proc_data.ProcData.tenv) ret_typ_str with
+                  | Some (Typ.Tstruct _ as typ) -> Typ.Tptr (typ, Typ.Pk_pointer)
+                  | Some typ -> typ
+                  | None -> Typ.Tvoid
+                end
             | Procname.C _ ->
                 Typ.Tvoid (* for tests only, since tests use C-style procnames *)
             | _ ->
@@ -99,8 +183,6 @@ module Make (TraceDomain : Trace.S) = struct
           astate_with_source
       | Sil.Call _ ->
           failwith "Unimp: non-pname call expressions"
-      | Sil.Letderef _ | Set _ ->
-          failwith "Unimp: assignment, load, and store"
       | Sil.Prune _ | Remove_temps _ | Nullify _ | Abstract _ | Stackop _ | Declare_locals _ ->
           astate
   end

infer/src/unit/TaintTests.ml

@@ -112,6 +112,11 @@ let tests =
   let assign_to_non_source ret_str =
     let procname = Procname.from_string_c_fun "NON-SOURCE" in
     make_call ~procname [ident_of_str ret_str] [] in
+  let assign_id_to_field root_str fld_str rhs_id_str =
+    let rhs_exp = Exp.Var (ident_of_str rhs_id_str) in
+    make_store ~rhs_typ:Typ.Tvoid (Exp.Var (ident_of_str root_str)) fld_str ~rhs_exp in
+  let read_field_to_id lhs_id_str root_str fld_str =
+    make_load ~rhs_typ:Typ.Tvoid lhs_id_str fld_str (Exp.Var (ident_of_str root_str)) in
   let assert_empty = invariant "{  }" in
   let test_list = [
     "source recorded",
@@ -124,5 +129,84 @@ let tests =
       assign_to_non_source "ret_id";
       assert_empty;
     ];
+    "source flows to var",
+    [
+      assign_to_source "ret_id";
+      var_assign_id "var" "ret_id";
+      invariant "{ ret_id$0 => (SOURCE -> ?), &var => (SOURCE -> ?) }";
+    ];
+    "source flows to field",
+    [
+      assign_to_source "ret_id";
+      assign_id_to_field "base_id" "f" "ret_id";
+      invariant "{ base_id$0.f => (SOURCE -> ?), ret_id$0 => (SOURCE -> ?) }";
+    ];
+    "source flows to field then var",
+    [
+      assign_to_source "ret_id";
+      assign_id_to_field "base_id" "f" "ret_id";
+      read_field_to_id "read_id" "base_id" "f";
+      var_assign_id "var" "read_id";
+      invariant
+        "{ base_id$0.f => (SOURCE -> ?), ret_id$0 => (SOURCE -> ?), &var => (SOURCE -> ?) }";
+    ];
+    "source flows to var then cleared",
+    [
+      assign_to_source "ret_id";
+      var_assign_id "var" "ret_id";
+      invariant "{ ret_id$0 => (SOURCE -> ?), &var => (SOURCE -> ?) }";
+      assign_to_non_source "non_source_id";
+      var_assign_id "var" "non_source_id";
+      invariant "{ ret_id$0 => (SOURCE -> ?) }";
+    ];
+    "source flows to field then cleared",
+    [
+      assign_to_source "ret_id";
+      assign_id_to_field "base_id" "f" "ret_id";
+      invariant "{ base_id$0.f => (SOURCE -> ?), ret_id$0 => (SOURCE -> ?) }";
+      assign_to_non_source "non_source_id";
+      assign_id_to_field "base_id" "f" "non_source_id";
+      invariant "{ ret_id$0 => (SOURCE -> ?) }";
+    ];
+    "var id alias test",
+    [
+      assign_to_non_source "ret_id";
+      var_assign_id "var1" "ret_id";
+      assign_to_source "source_id";
+      assign_id_to_field "ret_id" "f" "source_id";
+      invariant "{ source_id$0 => (SOURCE -> ?), &var1.f => (SOURCE -> ?) }";
+      read_field_to_id "read_id" "ret_id" "f";
+      invariant "{ source_id$0 => (SOURCE -> ?), &var1.f => (SOURCE -> ?) }";
+      var_assign_id "var2" "read_id";
+      invariant
+        "{ source_id$0 => (SOURCE -> ?), &var1.f => (SOURCE -> ?), &var2 => (SOURCE -> ?) }";
+    ];
+    "field id alias test1",
+    [
+      assign_to_non_source "ret_id";
+      assign_to_source "source_id";
+      assign_id_to_field "ret_id" "g" "source_id";
+      assign_to_non_source "var_id";
+      var_assign_id "var" "var_id";
+      assign_id_to_field "var_id" "f" "ret_id";
+      invariant
+        "{ ret_id$0.g => (SOURCE -> ?), source_id$0 => (SOURCE -> ?), &var.f.g => (SOURCE -> ?) }";
+    ];
+    "field id alias test2",
+    [
+      assign_to_non_source "ret_id";
+      read_field_to_id "g_id" "ret_id" "g";
+      var_assign_id "var1" "g_id";
+      assign_to_source "source_id";
+      invariant "{ source_id$0 => (SOURCE -> ?) }";
+      assign_id_to_field "g_id" "f" "source_id";
+      invariant "{ source_id$0 => (SOURCE -> ?), &var1.g.f => (SOURCE -> ?) }";
+      id_assign_var "var_id" "var1";
+      read_field_to_id "var_g_id" "var_id" "g";
+      read_field_to_id "var_g_f_id" "var_g_id" "f";
+      var_assign_id "var2" "var_g_f_id";
+      invariant
+        "{ source_id$0 => (SOURCE -> ?), &var1.g.f => (SOURCE -> ?), &var2 => (SOURCE -> ?) }";
+    ];
   ] |> TestInterpreter.create_tests ~pp_opt:pp_sparse [] in
   "taint_test_suite">:::test_list

infer/src/unit/accessPathTests.ml

@@ -55,8 +55,8 @@ let tests =
     let assert_eq input expected =
       assert_equal ~cmp:AccessPath.raw_equal ~pp_diff input expected in
     let append_test_ _ =
-      assert_eq xF (AccessPath.append x f_access);
-      assert_eq xFG (AccessPath.append xF g_access) in
+      assert_eq xF (AccessPath.append x [f_access]);
+      assert_eq xFG (AccessPath.append xF [g_access]) in
     "append">::append_test_ in
 
   let prefix_test =

infer/src/unit/analyzerTester.ml

@@ -248,6 +248,8 @@ module Make
       let post_str =
         try
           let state = M.find node_id inv_map in
+          (*L.stderr "post is %a@." I.A.pp state.post;
+            L.stderr "and with sparse pringer: %a@." pp_state state.post;*)
           pp_to_string pp_state state.post
         with Not_found -> "_|_" in
       if inv_str <> post_str then