(* * Copyright (c) 2016 - present * * Programming Research Laboratory (ROPAS) * Seoul National University, Korea * All rights reserved. * * This source code is licensed under the BSD style license found in the * LICENSE file in the root directory of this source tree. An additional grant * of patent rights can be found in the PATENTS file in the same directory. *) open! IStd open AbsLoc open! AbstractDomain.Types module L = Logging module Dom = BufferOverrunDomain module PO = BufferOverrunProofObligations module Trace = BufferOverrunTrace module TraceSet = Trace.Set module Summary = Summary.Make (struct type payload = Dom.Summary.t let update_payload astate (summary: Specs.summary) = {summary with payload= {summary.payload with buffer_overrun= Some astate}} let read_payload (summary: Specs.summary) = summary.payload.buffer_overrun end) module TransferFunctions (CFG : ProcCfg.S) = struct module CFG = CFG module Domain = Dom.Mem module BoUtils = BufferOverrunUtils.Make (CFG) module Sem = BoUtils.Sem module Models = BufferOverrunModels.Make (BoUtils) type extras = Typ.Procname.t -> Procdesc.t option let declare_symbolic_val : Typ.Procname.t -> Tenv.t -> CFG.node -> Location.t -> Loc.t -> Typ.typ -> inst_num:int -> new_sym_num:(unit -> int) -> Domain.t -> Domain.t = fun pname tenv node location loc typ ~inst_num ~new_sym_num mem -> let max_depth = 2 in let new_alloc_num = BoUtils.counter_gen 1 in let rec decl_sym_val pname tenv node location ~depth ~may_last_field loc typ mem = if depth > max_depth then mem else let depth = depth + 1 in match typ.Typ.desc with | Typ.Tint ikind -> let unsigned = Typ.ikind_is_unsigned ikind in let v = Dom.Val.make_sym ~unsigned pname new_sym_num |> Dom.Val.add_trace_elem (Trace.SymAssign (loc, location)) in Dom.Mem.add_heap loc v mem | Typ.Tfloat _ -> let v = Dom.Val.make_sym pname new_sym_num |> Dom.Val.add_trace_elem (Trace.SymAssign (loc, location)) in Dom.Mem.add_heap loc v mem | Typ.Tptr (typ, _) -> BoUtils.Exec.decl_sym_arr ~decl_sym_val:(decl_sym_val ~may_last_field) pname tenv node location ~depth loc typ ~inst_num ~new_sym_num ~new_alloc_num mem | Typ.Tarray {elt; length} -> let size = match length with | Some length when may_last_field && (IntLit.iszero length || IntLit.isone length) -> Some (Itv.make_sym pname new_sym_num) | _ -> Option.map ~f:Itv.of_int_lit length in let offset = Itv.zero in BoUtils.Exec.decl_sym_arr ~decl_sym_val:(decl_sym_val ~may_last_field:false) pname tenv node location ~depth loc elt ~offset ?size ~inst_num ~new_sym_num ~new_alloc_num mem | Typ.Tstruct typename -> ( match Models.TypName.dispatch typename with | Some {Models.declare_symbolic} -> let model_env = Models.mk_model_env pname node location tenv in declare_symbolic ~decl_sym_val:(decl_sym_val ~may_last_field) model_env ~depth loc ~inst_num ~new_sym_num ~new_alloc_num mem | None -> let decl_fld ~may_last_field mem (fn, typ, _) = let loc_fld = Loc.append_field loc ~fn in decl_sym_val pname tenv node location ~depth loc_fld typ ~may_last_field mem in let decl_flds str = IList.fold_last ~f:(decl_fld ~may_last_field:false) ~f_last:(decl_fld ~may_last_field) ~init:mem str.Typ.Struct.fields in let opt_struct = Tenv.lookup tenv typename in Option.value_map opt_struct ~default:mem ~f:decl_flds ) | _ -> if Config.bo_debug >= 3 then L.(debug BufferOverrun Verbose) "/!\\ decl_fld of unhandled type: %a at %a@." (Typ.pp Pp.text) typ Location.pp (CFG.loc node) ; mem in decl_sym_val pname tenv node location ~depth:0 ~may_last_field:true loc typ mem let declare_symbolic_parameters : Typ.Procname.t -> Tenv.t -> CFG.node -> Location.t -> inst_num:int -> (Pvar.t * Typ.t) list -> Dom.Mem.astate -> Dom.Mem.astate = fun pname tenv node location ~inst_num formals mem -> let new_sym_num = BoUtils.counter_gen 0 in let add_formal (mem, inst_num) (pvar, typ) = let loc = Loc.of_pvar pvar in let mem = declare_symbolic_val pname tenv node location loc typ ~inst_num ~new_sym_num mem in (mem, inst_num + 1) in List.fold ~f:add_formal ~init:(mem, inst_num) formals |> fst let instantiate_ret ret callee_pname ~callee_entry_mem ~callee_exit_mem subst_map mem ret_alias location = let copy_reachable_new_locs_from locs mem = let copy loc acc = let v = Dom.Mem.find_heap loc callee_exit_mem |> (fun v -> Dom.Val.subst v subst_map location) |> Dom.Val.add_trace_elem (Trace.Return location) in Dom.Mem.add_heap loc v acc in let new_locs = Dom.Mem.get_new_heap_locs ~prev:callee_entry_mem ~next:callee_exit_mem in let reachable_locs = Dom.Mem.get_reachable_locs_from locs callee_exit_mem in PowLoc.fold copy (PowLoc.inter new_locs reachable_locs) mem in match ret with | Some (id, _) -> let ret_loc = Loc.of_pvar (Pvar.get_ret_pvar callee_pname) in let ret_val = Dom.Mem.find_heap ret_loc callee_exit_mem in let ret_var = Loc.of_var (Var.of_id id) in let add_ret_alias l = Dom.Mem.load_alias id l mem in let mem = Option.value_map ret_alias ~default:mem ~f:add_ret_alias in Dom.Val.subst ret_val subst_map location |> Dom.Val.add_trace_elem (Trace.Return location) |> Fn.flip (Dom.Mem.add_stack ret_var) mem |> copy_reachable_new_locs_from (Dom.Val.get_all_locs ret_val) | None -> mem let instantiate_param tenv pdesc params callee_entry_mem callee_exit_mem subst_map location mem = let formals = Sem.get_formals pdesc in let actuals = List.map ~f:(fun (a, _) -> Sem.eval a mem) params in let f mem formal actual = match (snd formal).Typ.desc with | Typ.Tptr (typ, _) -> ( match typ.Typ.desc with | Typ.Tstruct typename -> ( match Tenv.lookup tenv typename with | Some str -> let formal_locs = Dom.Mem.find_heap (Loc.of_pvar (fst formal)) callee_entry_mem |> Dom.Val.get_array_blk |> ArrayBlk.get_pow_loc in let instantiate_fld mem (fn, _, _) = let formal_fields = PowLoc.append_field formal_locs ~fn in let v = Dom.Mem.find_heap_set formal_fields callee_exit_mem in let actual_fields = PowLoc.append_field (Dom.Val.get_all_locs actual) ~fn in Dom.Val.subst v subst_map location |> Fn.flip (Dom.Mem.strong_update_heap actual_fields) mem in List.fold ~f:instantiate_fld ~init:mem str.Typ.Struct.fields | _ -> mem ) | _ -> let formal_locs = Dom.Mem.find_heap (Loc.of_pvar (fst formal)) callee_entry_mem |> Dom.Val.get_array_blk |> ArrayBlk.get_pow_loc in let v = Dom.Mem.find_heap_set formal_locs callee_exit_mem in let actual_locs = Dom.Val.get_all_locs actual in Dom.Val.subst v subst_map location |> Fn.flip (Dom.Mem.strong_update_heap actual_locs) mem ) | _ -> mem in try List.fold2_exn formals actuals ~init:mem ~f with Invalid_argument _ -> mem let instantiate_mem : Tenv.t -> (Ident.t * Typ.t) option -> Procdesc.t option -> Typ.Procname.t -> (Exp.t * Typ.t) list -> Dom.Mem.astate -> Dom.Summary.t -> Location.t -> Dom.Mem.astate = fun tenv ret callee_pdesc callee_pname params caller_mem summary location -> let callee_entry_mem = Dom.Summary.get_input summary in let callee_exit_mem = Dom.Summary.get_output summary in let callee_ret_alias = Dom.Mem.find_ret_alias callee_exit_mem in match callee_pdesc with | Some pdesc -> let subst_map, ret_alias = Sem.get_subst_map tenv pdesc params caller_mem callee_entry_mem ~callee_ret_alias in instantiate_ret ret callee_pname ~callee_entry_mem ~callee_exit_mem subst_map caller_mem ret_alias location |> instantiate_param tenv pdesc params callee_entry_mem callee_exit_mem subst_map location | None -> caller_mem let print_debug_info : Sil.instr -> Dom.Mem.astate -> Dom.Mem.astate -> unit = fun instr pre post -> L.(debug BufferOverrun Verbose) "@\n@\n================================@\n" ; L.(debug BufferOverrun Verbose) "@[Pre-state : @,%a" Dom.Mem.pp pre ; L.(debug BufferOverrun Verbose) "@]@\n@\n%a" (Sil.pp_instr Pp.text) instr ; L.(debug BufferOverrun Verbose) "@\n@\n" ; L.(debug BufferOverrun Verbose) "@[Post-state : @,%a" Dom.Mem.pp post ; L.(debug BufferOverrun Verbose) "@]@\n" ; L.(debug BufferOverrun Verbose) "================================@\n@." let exec_instr : Dom.Mem.astate -> extras ProcData.t -> CFG.node -> Sil.instr -> Dom.Mem.astate = fun mem {pdesc; tenv; extras} node instr -> let pname = Procdesc.get_proc_name pdesc in let output_mem = match instr with | Load (id, _, _, _) when Ident.is_none id -> mem | Load (id, exp, _, _) -> BoUtils.Exec.load_val id (Sem.eval exp mem) mem | Store (exp1, _, exp2, location) -> let locs = Sem.eval exp1 mem |> Dom.Val.get_all_locs in let v = Sem.eval exp2 mem |> Dom.Val.add_trace_elem (Trace.Assign location) in let mem = Dom.Mem.update_mem locs v mem in let mem = if PowLoc.is_singleton locs then let loc_v = PowLoc.min_elt locs in match Typ.Procname.get_method pname with | "__inferbo_empty" when Loc.is_return loc_v -> ( match Sem.get_formals pdesc with | [(formal, _)] -> let formal_v = Dom.Mem.find_heap (Loc.of_pvar formal) mem in Dom.Mem.store_empty_alias formal_v loc_v exp2 mem | _ -> assert false ) | _ -> Dom.Mem.store_simple_alias loc_v exp2 mem else mem in let mem = Dom.Mem.update_latest_prune exp1 exp2 mem in mem | Prune (exp, _, _, _) -> Sem.prune exp mem | Call (ret, Const Cfun callee_pname, params, location, _) -> ( let model_env = Models.mk_model_env callee_pname node location tenv ?ret in match Models.Call.dispatch callee_pname params with | Some {Models.exec} -> exec model_env mem | None -> match Summary.read_summary pdesc callee_pname with | Some summary -> let callee = extras callee_pname in instantiate_mem tenv ret callee callee_pname params mem summary location | None -> L.(debug BufferOverrun Verbose) "/!\\ Unknown call to %a at %a@\n" Typ.Procname.pp callee_pname Location.pp location ; let val_unknown = Dom.Val.unknown_from ~callee_pname ~location in Models.model_by_value val_unknown model_env mem |> Dom.Mem.add_heap Loc.unknown val_unknown ) | Declare_locals (locals, location) -> (* array allocation in stack e.g., int arr[10] *) let rec decl_local pname node location loc typ ~inst_num ~dimension mem = match typ.Typ.desc with | Typ.Tarray {elt= typ; length; stride} -> let stride = Option.map ~f:IntLit.to_int stride in BoUtils.Exec.decl_local_array ~decl_local pname node location loc typ ~length ?stride ~inst_num ~dimension mem | Typ.Tstruct typname -> ( match Models.TypName.dispatch typname with | Some {Models.declare_local} -> let model_env = Models.mk_model_env pname node location tenv in declare_local ~decl_local model_env loc ~inst_num ~dimension mem | None -> (mem, inst_num) ) | _ -> (mem, inst_num) in let try_decl_local (mem, inst_num) (pvar, typ) = let loc = Loc.of_pvar pvar in decl_local pname node location loc typ ~inst_num ~dimension:1 mem in let mem, inst_num = List.fold ~f:try_decl_local ~init:(mem, 1) locals in let formals = Sem.get_formals pdesc in declare_symbolic_parameters pname tenv node location ~inst_num formals mem | Call (_, fun_exp, _, location, _) -> let () = L.(debug BufferOverrun Verbose) "/!\\ Call to non-const function %a at %a" Exp.pp fun_exp Location.pp location in mem | Remove_temps (temps, _) -> Dom.Mem.remove_temps temps mem | Abstract _ | Nullify _ -> mem in print_debug_info instr mem output_mem ; output_mem end module Analyzer = AbstractInterpreter.Make (ProcCfg.Normal) (TransferFunctions) module CFG = Analyzer.TransferFunctions.CFG type invariant_map = Analyzer.invariant_map module Report = struct (* I'd like to avoid rebuilding this :( Everything depend on CFG only because of `get_allocsite` *) module BoUtils = BufferOverrunUtils.Make (CFG) module Sem = BoUtils.Sem module Models = BufferOverrunModels.Make (BoUtils) type extras = Typ.Procname.t -> Procdesc.t option let rec add_condition : Typ.Procname.t -> Exp.t -> Location.t -> Dom.Mem.astate -> PO.ConditionSet.t -> PO.ConditionSet.t = fun pname exp location mem cond_set -> match exp with | Exp.Var _ -> let v = Sem.eval exp mem in let arr = Dom.Val.get_array_blk v in let arr_traces = Dom.Val.get_traces v in BoUtils.Check.array_access ~arr ~arr_traces ~idx:Itv.zero ~idx_traces:TraceSet.empty ~is_plus:true pname location cond_set | Exp.Lindex (array_exp, index_exp) -> cond_set |> add_condition pname array_exp location mem |> add_condition pname index_exp location mem |> BoUtils.Check.lindex ~array_exp ~index_exp mem pname location | Exp.BinOp ((Binop.PlusA as bop), e1, e2) | Exp.BinOp ((Binop.MinusA as bop), e1, e2) -> let v_arr = Sem.eval e1 mem in let arr = Dom.Val.get_array_blk v_arr in let arr_traces = Dom.Val.get_traces v_arr in let v_idx = Sem.eval e2 mem in let idx = Dom.Val.get_itv v_idx in let idx_traces = Dom.Val.get_traces v_idx in let is_plus = Binop.equal bop Binop.PlusA in cond_set |> add_condition pname e1 location mem |> add_condition pname e2 location mem |> BoUtils.Check.array_access ~arr ~arr_traces ~idx ~idx_traces ~is_plus pname location | Exp.Lfield (e, _, _) | Exp.UnOp (_, e, _) | Exp.Exn e | Exp.Cast (_, e) -> add_condition pname e location mem cond_set | Exp.BinOp (_, e1, e2) -> cond_set |> add_condition pname e1 location mem |> add_condition pname e2 location mem | Exp.Closure {captured_vars} -> List.fold captured_vars ~init:cond_set ~f:(fun cond_set (e, _, _) -> add_condition pname e location mem cond_set ) | _ -> cond_set let instantiate_cond : Tenv.t -> Typ.Procname.t -> Procdesc.t option -> (Exp.t * Typ.t) list -> Dom.Mem.astate -> Summary.payload -> Location.t -> PO.ConditionSet.t = fun tenv caller_pname callee_pdesc params caller_mem summary location -> let callee_entry_mem = Dom.Summary.get_input summary in let callee_cond = Dom.Summary.get_cond_set summary in match callee_pdesc with | Some pdesc -> let subst_map, _ = Sem.get_subst_map tenv pdesc params caller_mem callee_entry_mem ~callee_ret_alias:None in let pname = Procdesc.get_proc_name pdesc in PO.ConditionSet.subst callee_cond subst_map caller_pname pname location | _ -> callee_cond let print_debug_info : Sil.instr -> Dom.Mem.astate -> PO.ConditionSet.t -> unit = fun instr pre cond_set -> L.(debug BufferOverrun Verbose) "@\n@\n================================@\n" ; L.(debug BufferOverrun Verbose) "@[Pre-state : @,%a" Dom.Mem.pp pre ; L.(debug BufferOverrun Verbose) "@]@\n@\n%a" (Sil.pp_instr Pp.text) instr ; L.(debug BufferOverrun Verbose) "@[@\n@\n%a" PO.ConditionSet.pp cond_set ; L.(debug BufferOverrun Verbose) "@]@\n" ; L.(debug BufferOverrun Verbose) "================================@\n@." module ExitStatement = struct let non_significant_instr = function | Sil.(Abstract _ | Nullify _ | Remove_temps _) -> true | _ -> false (* check that we are the last significant instruction * of a procedure (no more significant instruction) * or of a block (goes directly to a node with multiple predecessors) *) let rec is_end_of_block_or_procedure node rem_instrs = List.for_all rem_instrs ~f:non_significant_instr && match Procdesc.Node.get_succs node with | [] -> true | [succ] -> ( is_end_of_block_or_procedure succ (CFG.instrs succ) || match Procdesc.Node.get_preds succ with | _ :: _ :: _ -> true (* [succ] is a join, i.e. [node] is the end of a block *) | _ -> false ) | _ :: _ :: _ -> false end let rec collect_instrs : Specs.summary -> extras ProcData.t -> CFG.node -> Sil.instr list -> Dom.Mem.astate -> PO.ConditionSet.t -> PO.ConditionSet.t = fun summary ({pdesc; tenv; extras} as pdata) node instrs mem cond_set -> match instrs with | [] -> cond_set | instr :: rem_instrs -> let pname = Procdesc.get_proc_name pdesc in let cond_set = match instr with | Sil.Load (_, exp, _, location) | Sil.Store (exp, _, _, location) -> add_condition pname exp location mem cond_set | Sil.Call (_, Const Cfun callee_pname, params, location, _) -> ( match Models.Call.dispatch callee_pname params with | Some {Models.check} -> check (Models.mk_model_env pname node location tenv) mem cond_set | None -> match Summary.read_summary pdesc callee_pname with | Some callee_summary -> let callee = extras callee_pname in instantiate_cond tenv pname callee params mem callee_summary location |> PO.ConditionSet.join cond_set | _ -> cond_set ) | _ -> cond_set in let mem' = Analyzer.TransferFunctions.exec_instr mem pdata node instr in let () = match (mem, mem') with | NonBottom _, Bottom -> ( match instr with | Sil.Prune (_, _, _, (Ik_land_lor | Ik_bexp)) -> () | Sil.Prune (cond, location, true_branch, _) -> let i = match cond with Exp.Const Const.Cint i -> i | _ -> IntLit.zero in let desc = Errdesc.explain_condition_always_true_false tenv i cond node location in let exn = Exceptions.Condition_always_true_false (desc, not true_branch, __POS__) in Reporting.log_warning summary ~loc:location exn (* special case for `exit` when we're at the end of a block / procedure *) | Sil.Call (_, Const Cfun pname, _, _, _) when String.equal (Typ.Procname.get_method pname) "exit" && ExitStatement.is_end_of_block_or_procedure node rem_instrs -> () | _ -> let location = Sil.instr_get_loc instr in let desc = Errdesc.explain_unreachable_code_after location in let exn = Exceptions.Unreachable_code_after (desc, __POS__) in Reporting.log_error summary ~loc:location exn ) | _ -> () in print_debug_info instr mem' cond_set ; collect_instrs summary pdata node rem_instrs mem' cond_set let collect_node : Specs.summary -> extras ProcData.t -> Analyzer.invariant_map -> PO.ConditionSet.t -> CFG.node -> PO.ConditionSet.t = fun summary pdata inv_map cond_set node -> match Analyzer.extract_pre (CFG.id node) inv_map with | Some mem -> let instrs = CFG.instrs node in collect_instrs summary pdata node instrs mem cond_set | _ -> cond_set let collect : Specs.summary -> extras ProcData.t -> Analyzer.invariant_map -> PO.ConditionSet.t = fun summary ({pdesc} as pdata) inv_map -> let add_node1 acc node = collect_node summary pdata inv_map acc node in Procdesc.fold_nodes pdesc ~f:add_node1 ~init:PO.ConditionSet.empty let make_err_trace : Trace.t -> string -> Errlog.loc_trace = fun trace issue_desc -> let f elem (trace, depth) = match elem with | Trace.ArrAccess location -> let desc = "ArrayAccess: " ^ issue_desc in (Errlog.make_trace_element depth location desc [] :: trace, depth) | Trace.ArrDecl location -> (Errlog.make_trace_element depth location "ArrayDeclaration" [] :: trace, depth) | Trace.Assign location -> (Errlog.make_trace_element depth location "Assignment" [] :: trace, depth) | Trace.Call location -> (Errlog.make_trace_element depth location "Call" [] :: trace, depth + 1) | Trace.Return location -> (Errlog.make_trace_element (depth - 1) location "Return" [] :: trace, depth - 1) | Trace.SymAssign (loc, location) -> if Loc.contains_allocsite loc then (* ugly, don't show *) (trace, depth) else let desc = Format.asprintf "Parameter: %a" Loc.pp loc in (Errlog.make_trace_element depth location desc [] :: trace, depth) | Trace.UnknownFrom (pname, location) -> let desc = Format.asprintf "Unknown value from: %a" Typ.Procname.pp pname in (Errlog.make_trace_element depth location desc [] :: trace, depth) in List.fold_right ~f ~init:([], 0) trace.trace |> fst |> List.rev let report_errors : Specs.summary -> Procdesc.t -> PO.ConditionSet.t -> unit = fun summary pdesc cond_set -> let pname = Procdesc.get_proc_name pdesc in let report cond trace issue_type = let caller_pname, location = match PO.ConditionTrace.get_cond_trace trace with | PO.ConditionTrace.Inter (caller_pname, _, location) -> (caller_pname, location) | PO.ConditionTrace.Intra pname -> (pname, PO.ConditionTrace.get_location trace) in if Typ.Procname.equal pname caller_pname then let description = PO.description cond trace in let error_desc = Localise.desc_buffer_overrun description in let exn = Exceptions.Checkers (issue_type, error_desc) in let trace = match TraceSet.choose_shortest trace.PO.ConditionTrace.val_traces with | trace -> make_err_trace trace description | exception _ -> [Errlog.make_trace_element 0 location description []] in Reporting.log_error summary ~loc:location ~ltr:trace exn in PO.ConditionSet.check_all ~report cond_set end let compute_invariant_map : Callbacks.proc_callback_args -> Analyzer.invariant_map = fun {proc_desc; tenv; get_proc_desc} -> Preanal.do_preanalysis proc_desc tenv ; let pdata = ProcData.make proc_desc tenv get_proc_desc in Analyzer.exec_pdesc ~initial:Dom.Mem.init pdata let extract_post inv_map node = let id = CFG.id node in Analyzer.extract_post id inv_map let compute_post : Specs.summary -> Analyzer.TransferFunctions.extras ProcData.t -> Summary.payload option = fun summary ({pdesc} as pdata) -> let cfg = CFG.from_pdesc pdesc in let inv_map = Analyzer.exec_pdesc ~initial:Dom.Mem.init pdata in let entry_mem = extract_post inv_map (CFG.start_node cfg) in let exit_mem = extract_post inv_map (CFG.exit_node cfg) in let cond_set = Report.collect summary pdata inv_map in Report.report_errors summary pdesc cond_set ; match (entry_mem, exit_mem) with | Some entry_mem, Some exit_mem -> Some (entry_mem, exit_mem, cond_set) | _ -> None let print_summary : Typ.Procname.t -> Dom.Summary.t -> unit = fun proc_name s -> L.(debug BufferOverrun Medium) "@\n@[Summary of %a :@,%a@]@." Typ.Procname.pp proc_name Dom.Summary.pp_summary s let checker : Callbacks.proc_callback_args -> Specs.summary = fun {proc_desc; tenv; summary; get_proc_desc} -> Preanal.do_preanalysis proc_desc tenv ; let proc_data = ProcData.make proc_desc tenv get_proc_desc in match compute_post summary proc_data with | Some post -> ( if Config.bo_debug >= 1 then let proc_name = Specs.get_proc_name summary in print_summary proc_name post ) ; Summary.update_summary post summary | None -> summary