(* * Copyright (c) 2017-present, Facebook, Inc. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. *) open! IStd open! AbstractDomain.Types module F = Format module L = Logging module ItvPure = Itv.ItvPure module Relation = BufferOverrunDomainRelation module MF = MarkupFormatter module ValTraceSet = BufferOverrunTrace.Set module Bound = Bounds.Bound type checked_condition = {report_issue_type: IssueType.t option; propagate: bool} module AllocSizeCondition = struct type t = ItvPure.astate let get_symbols = ItvPure.get_symbols let pp fmt length = F.fprintf fmt "alloc(%a)" ItvPure.pp length let pp_description fmt length = F.fprintf fmt "Length: %a" ItvPure.pp length let make ~length = if ItvPure.is_invalid length then None else Some length let have_similar_bounds = ItvPure.have_similar_bounds let xcompare ~lhs ~rhs = match ItvPure.xcompare ~lhs ~rhs with | `Equal -> `Equal | `NotComparable -> `NotComparable | `LeftSubsumesRight -> `LeftSubsumesRight | `RightSubsumesLeft -> `RightSubsumesLeft | (`LeftSmallerThanRight | `RightSmallerThanLeft) as cmp -> let lpos = ItvPure.le_sem ItvPure.zero lhs in let rpos = ItvPure.le_sem ItvPure.zero rhs in if not (Itv.Boolean.equal lpos rpos) then `NotComparable else if Itv.Boolean.is_true lpos then match cmp with | `LeftSmallerThanRight -> `RightSubsumesLeft | `RightSmallerThanLeft -> `LeftSubsumesRight else if Itv.Boolean.is_false lpos then match cmp with | `LeftSmallerThanRight -> `LeftSubsumesRight | `RightSmallerThanLeft -> `RightSubsumesLeft else `NotComparable let itv_big = ItvPure.of_int 1_000_000 let check length = match ItvPure.xcompare ~lhs:length ~rhs:ItvPure.zero with | `Equal | `RightSubsumesLeft -> {report_issue_type= Some IssueType.inferbo_alloc_is_zero; propagate= false} | `LeftSmallerThanRight -> {report_issue_type= Some IssueType.inferbo_alloc_is_negative; propagate= false} | _ -> let is_symbolic = ItvPure.is_symbolic length in match ItvPure.xcompare ~lhs:length ~rhs:ItvPure.mone with | `Equal | `LeftSmallerThanRight | `RightSubsumesLeft -> {report_issue_type= Some IssueType.inferbo_alloc_is_negative; propagate= false} | `LeftSubsumesRight when Bound.is_not_infty (ItvPure.lb length) -> { report_issue_type= Some IssueType.inferbo_alloc_may_be_negative ; propagate= is_symbolic } | cmp_mone -> match ItvPure.xcompare ~lhs:length ~rhs:itv_big with | `Equal | `RightSmallerThanLeft | `RightSubsumesLeft -> {report_issue_type= Some IssueType.inferbo_alloc_is_big; propagate= false} | `LeftSubsumesRight when Bound.is_not_infty (ItvPure.ub length) -> {report_issue_type= Some IssueType.inferbo_alloc_may_be_big; propagate= is_symbolic} | cmp_big -> let propagate = match (cmp_mone, cmp_big) with | (`NotComparable | `LeftSubsumesRight), _ | _, (`NotComparable | `LeftSubsumesRight) -> is_symbolic | _ -> false in {report_issue_type= None; propagate} let subst bound_map length = match ItvPure.subst length bound_map with NonBottom length -> Some length | Bottom -> None end module ArrayAccessCondition = struct type t = { idx: ItvPure.astate ; size: ItvPure.astate ; idx_sym_exp: Relation.SymExp.t option ; size_sym_exp: Relation.SymExp.t option ; relation: Relation.astate } [@@deriving compare] let get_symbols c = ItvPure.get_symbols c.idx @ ItvPure.get_symbols c.size let set_size_pos : t -> t = fun c -> let size' = ItvPure.make_positive c.size in if phys_equal size' c.size then c else {c with size= size'} let pp : F.formatter -> t -> unit = fun fmt c -> let c = set_size_pos c in F.fprintf fmt "%a < %a" ItvPure.pp c.idx ItvPure.pp c.size ; if Option.is_some Config.bo_relational_domain then F.fprintf fmt "@,%a < %a when %a" Relation.SymExp.pp_opt c.idx_sym_exp Relation.SymExp.pp_opt c.size_sym_exp Relation.pp c.relation let pp_description : F.formatter -> t -> unit = fun fmt c -> let c = set_size_pos c in F.fprintf fmt "Offset: %a Size: %a" ItvPure.pp c.idx ItvPure.pp c.size let make : idx:ItvPure.t -> size:ItvPure.t -> idx_sym_exp:Relation.SymExp.t option -> size_sym_exp:Relation.SymExp.t option -> relation:Relation.astate -> t option = fun ~idx ~size ~idx_sym_exp ~size_sym_exp ~relation -> if ItvPure.is_invalid idx || ItvPure.is_invalid size then None else Some {idx; size; idx_sym_exp; size_sym_exp; relation} let have_similar_bounds {idx= lidx; size= lsiz} {idx= ridx; size= rsiz} = ItvPure.have_similar_bounds lidx ridx && ItvPure.have_similar_bounds lsiz rsiz let has_infty {idx; size} = ItvPure.has_infty idx || ItvPure.has_infty size let xcompare ~lhs:{idx= lidx; size= lsiz} ~rhs:{idx= ridx; size= rsiz} = let idxcmp = ItvPure.xcompare ~lhs:lidx ~rhs:ridx in let sizcmp = ItvPure.xcompare ~lhs:lsiz ~rhs:rsiz in match (idxcmp, sizcmp) with | `Equal, `Equal -> `Equal | `NotComparable, _ -> `NotComparable | `Equal, (`LeftSmallerThanRight | `LeftSubsumesRight) -> `LeftSubsumesRight | `Equal, (`RightSmallerThanLeft | `RightSubsumesLeft) -> `RightSubsumesLeft | `LeftSubsumesRight, (`Equal | `LeftSubsumesRight) -> `LeftSubsumesRight | `RightSubsumesLeft, (`Equal | `RightSubsumesLeft) -> `RightSubsumesLeft | (`LeftSmallerThanRight | `RightSmallerThanLeft), _ -> let lidxpos = ItvPure.le_sem ItvPure.zero lidx in let ridxpos = ItvPure.le_sem ItvPure.zero ridx in if not (Itv.Boolean.equal lidxpos ridxpos) then `NotComparable else if Itv.Boolean.is_true lidxpos then (* both idx >= 0 *) match (idxcmp, sizcmp) with | `LeftSmallerThanRight, (`Equal | `RightSmallerThanLeft | `RightSubsumesLeft) -> `RightSubsumesLeft | `RightSmallerThanLeft, (`Equal | `LeftSmallerThanRight | `LeftSubsumesRight) -> `LeftSubsumesRight | _ -> `NotComparable else if Itv.Boolean.is_false lidxpos then (* both idx < 0, size doesn't matter *) match idxcmp with | `LeftSmallerThanRight -> `LeftSubsumesRight | `RightSmallerThanLeft -> `RightSubsumesLeft | `Equal -> `Equal | _ -> `NotComparable else `NotComparable | _ -> `NotComparable let filter1 : t -> bool = fun c -> ItvPure.is_top c.idx || ItvPure.is_top c.size || ItvPure.is_lb_infty c.idx || ItvPure.is_lb_infty c.size || (ItvPure.is_nat c.idx && ItvPure.is_nat c.size) let filter2 : t -> bool = fun c -> (* basically, alarms involving infinity are filtered *) (not (ItvPure.is_finite c.idx) || not (ItvPure.is_finite c.size)) && (* except the following cases *) not ( Bound.is_not_infty (ItvPure.lb c.idx) && (* idx non-infty lb < 0 *) Bound.lt (ItvPure.lb c.idx) Bound.zero || Bound.is_not_infty (ItvPure.lb c.idx) && (* idx non-infty lb > size lb *) Bound.gt (ItvPure.lb c.idx) (ItvPure.lb c.size) || Bound.is_not_infty (ItvPure.lb c.idx) && (* idx non-infty lb > size ub *) Bound.gt (ItvPure.lb c.idx) (ItvPure.ub c.size) || Bound.is_not_infty (ItvPure.ub c.idx) && (* idx non-infty ub > size lb *) Bound.gt (ItvPure.ub c.idx) (ItvPure.lb c.size) || Bound.is_not_infty (ItvPure.ub c.idx) && (* idx non-infty ub > size ub *) Bound.gt (ItvPure.ub c.idx) (ItvPure.ub c.size) ) (* check buffer overrun and return its confidence *) let check : is_collection_add:bool -> t -> checked_condition = fun ~is_collection_add c -> (* idx = [il, iu], size = [sl, su], For arrays : we want to check that 0 <= idx < size For adding into arraylists: we want to check that 0 <= idx <= size *) let c' = set_size_pos c in (* if sl < 0, use sl' = 0 *) let not_overrun = if is_collection_add then ItvPure.le_sem c'.idx c'.size else if Relation.lt_sat_opt c'.idx_sym_exp c'.size_sym_exp c'.relation then Itv.Boolean.true_ else ItvPure.lt_sem c'.idx c'.size in let not_underrun = if Relation.le_sat_opt (Some Relation.SymExp.zero) c'.idx_sym_exp c'.relation then Itv.Boolean.true_ else ItvPure.le_sem ItvPure.zero c'.idx in (* il >= 0 and iu < sl, definitely not an error *) if Itv.Boolean.is_true not_overrun && Itv.Boolean.is_true not_underrun then {report_issue_type= None; propagate= false} (* iu < 0 or il >= su, definitely an error *) else if Itv.Boolean.is_false not_overrun || Itv.Boolean.is_false not_underrun then {report_issue_type= Some IssueType.buffer_overrun_l1; propagate= false} (* su <= iu < +oo, most probably an error *) else if Bound.is_not_infty (ItvPure.ub c.idx) && Bound.le (ItvPure.ub c.size) (ItvPure.ub c.idx) then {report_issue_type= Some IssueType.buffer_overrun_l2; propagate= false} (* symbolic il >= sl, probably an error *) else if Bound.is_symbolic (ItvPure.lb c.idx) && Bound.le (ItvPure.lb c'.size) (ItvPure.lb c.idx) then {report_issue_type= Some IssueType.buffer_overrun_s2; propagate= true} else (* other symbolic bounds are probably too noisy *) let is_symbolic = ItvPure.is_symbolic c.idx || ItvPure.is_symbolic c.size in let report_issue_type = if Config.bo_debug <= 3 && is_symbolic then None else if filter1 c then Some IssueType.buffer_overrun_l5 else if filter2 c then Some IssueType.buffer_overrun_l4 else Some IssueType.buffer_overrun_l3 in {report_issue_type; propagate= is_symbolic} let subst : Itv.Bound.t bottom_lifted Itv.SymbolMap.t -> Relation.SubstMap.t -> Relation.astate -> t -> t option = fun bound_map rel_map caller_relation c -> match (ItvPure.subst c.idx bound_map, ItvPure.subst c.size bound_map) with | NonBottom idx, NonBottom size -> let idx_sym_exp = Relation.SubstMap.symexp_subst_opt rel_map c.idx_sym_exp in let size_sym_exp = Relation.SubstMap.symexp_subst_opt rel_map c.size_sym_exp in let relation = Relation.instantiate rel_map ~caller:caller_relation ~callee:c.relation in Some {idx; size; idx_sym_exp; size_sym_exp; relation} | _ -> None let forget_locs : AbsLoc.PowLoc.t -> t -> t = fun locs c -> {c with relation= Relation.forget_locs locs c.relation} end module Condition = struct type t = | AllocSize of AllocSizeCondition.t | ArrayAccess of {is_collection_add: bool; c: ArrayAccessCondition.t} let make_alloc_size = Option.map ~f:(fun c -> AllocSize c) let make_array_access ~is_collection_add = Option.map ~f:(fun c -> ArrayAccess {is_collection_add; c}) let get_symbols = function | AllocSize c -> AllocSizeCondition.get_symbols c | ArrayAccess {c} -> ArrayAccessCondition.get_symbols c let subst bound_map rel_map caller_relation = function | AllocSize c -> AllocSizeCondition.subst bound_map c |> make_alloc_size | ArrayAccess {is_collection_add; c} -> ArrayAccessCondition.subst bound_map rel_map caller_relation c |> make_array_access ~is_collection_add let have_similar_bounds c1 c2 = match (c1, c2) with | AllocSize c1, AllocSize c2 -> AllocSizeCondition.have_similar_bounds c1 c2 | ArrayAccess {c= c1}, ArrayAccess {c= c2} -> ArrayAccessCondition.have_similar_bounds c1 c2 | _ -> false let has_infty = function ArrayAccess {c} -> ArrayAccessCondition.has_infty c | _ -> false let xcompare ~lhs ~rhs = match (lhs, rhs) with | AllocSize lhs, AllocSize rhs -> AllocSizeCondition.xcompare ~lhs ~rhs | ArrayAccess {is_collection_add= b1; c= lhs}, ArrayAccess {is_collection_add= b2; c= rhs} when Bool.equal b1 b2 -> ArrayAccessCondition.xcompare ~lhs ~rhs | _ -> `NotComparable let pp fmt = function | AllocSize c -> AllocSizeCondition.pp fmt c | ArrayAccess {c} -> ArrayAccessCondition.pp fmt c let pp_description fmt = function | AllocSize c -> AllocSizeCondition.pp_description fmt c | ArrayAccess {c} -> ArrayAccessCondition.pp_description fmt c let check = function | AllocSize c -> AllocSizeCondition.check c | ArrayAccess {is_collection_add; c} -> ArrayAccessCondition.check ~is_collection_add c let forget_locs locs x = match x with | ArrayAccess {is_collection_add; c} -> ArrayAccess {is_collection_add; c= ArrayAccessCondition.forget_locs locs c} | AllocSize _ -> x end module ConditionTrace = struct type cond_trace = Intra | Inter of {call_site: Location.t; callee_pname: Typ.Procname.t} [@@deriving compare] type t = {cond_trace: cond_trace; issue_location: Location.t; val_traces: ValTraceSet.t} [@@deriving compare] let pp_location : F.formatter -> t -> unit = fun fmt ct -> Location.pp_file_pos fmt ct.issue_location let pp : F.formatter -> t -> unit = fun fmt ct -> if Config.bo_debug <= 1 then F.fprintf fmt "at %a" pp_location ct else match ct.cond_trace with | Inter {callee_pname; call_site} -> let pname = Typ.Procname.to_string callee_pname in F.fprintf fmt "at %a by call to %s at %a (%a)" pp_location ct pname Location.pp_file_pos call_site ValTraceSet.pp ct.val_traces | Intra -> F.fprintf fmt "%a (%a)" pp_location ct ValTraceSet.pp ct.val_traces let pp_description : F.formatter -> t -> unit = fun fmt ct -> match ct.cond_trace with | Inter {callee_pname} when Config.bo_debug >= 1 || not (SourceFile.is_cpp_model ct.issue_location.Location.file) -> F.fprintf fmt " by call to %a " MF.pp_monospaced (Typ.Procname.to_string callee_pname) | _ -> () let get_val_traces {val_traces} = val_traces let get_report_location : t -> Location.t = fun ct -> match ct.cond_trace with Intra -> ct.issue_location | Inter {call_site} -> call_site let make : Location.t -> ValTraceSet.t -> t = fun issue_location val_traces -> {issue_location; cond_trace= Intra; val_traces} let make_call_and_subst ~traces_caller ~callee_pname call_site ct = let val_traces = ValTraceSet.instantiate ~traces_caller ~traces_callee:ct.val_traces call_site in {ct with cond_trace= Inter {callee_pname; call_site}; val_traces} let has_unknown ct = ValTraceSet.has_unknown ct.val_traces let check : t -> IssueType.t option = fun ct -> if has_unknown ct then Some IssueType.buffer_overrun_u5 else None end module Reported = struct type t = IssueType.t [@@deriving compare] let make issue_type = issue_type let equal = [%compare.equal : t] end module ConditionWithTrace = struct type t = {cond: Condition.t; trace: ConditionTrace.t; reported: Reported.t option} let make cond trace = {cond; trace; reported= None} let pp fmt {cond; trace} = F.fprintf fmt "%a %a" Condition.pp cond ConditionTrace.pp trace let have_similar_bounds {cond= cond1} {cond= cond2} = Condition.have_similar_bounds cond1 cond2 let xcompare ~lhs ~rhs = match Condition.xcompare ~lhs:lhs.cond ~rhs:rhs.cond with | `Equal -> if ConditionTrace.compare lhs.trace rhs.trace <= 0 then `LeftSubsumesRight else `RightSubsumesLeft | (`LeftSubsumesRight | `RightSubsumesLeft | `NotComparable) as cmp -> cmp let subst (bound_map, trace_map) rel_map caller_relation callee_pname call_site cwt = let symbols = Condition.get_symbols cwt.cond in if List.is_empty symbols then L.(die InternalError) "Trying to substitute a non-symbolic condition %a from %a at %a. Why was it propagated in \ the first place?" pp cwt Typ.Procname.pp callee_pname Location.pp call_site ; match Condition.subst bound_map rel_map caller_relation cwt.cond with | None -> None | Some cond -> let traces_caller = List.fold symbols ~init:ValTraceSet.empty ~f:(fun val_traces symbol -> match Itv.SymbolMap.find symbol trace_map with | symbol_trace -> ValTraceSet.join symbol_trace val_traces | exception Caml.Not_found -> val_traces ) in let trace = ConditionTrace.make_call_and_subst ~traces_caller ~callee_pname call_site cwt.trace in Some {cond; trace; reported= cwt.reported} let set_buffer_overrun_u5 {cond; trace} issue_type = if ( IssueType.equal issue_type IssueType.buffer_overrun_l3 || IssueType.equal issue_type IssueType.buffer_overrun_l4 || IssueType.equal issue_type IssueType.buffer_overrun_l5 ) && Condition.has_infty cond then Option.value (ConditionTrace.check trace) ~default:issue_type else issue_type let check_aux cwt = let {report_issue_type; propagate} as checked = Condition.check cwt.cond in match report_issue_type with | None -> checked | Some issue_type -> let issue_type = set_buffer_overrun_u5 cwt issue_type in (* Only report if the precision has improved. This is approximated by: only report if the issue_type has changed. *) let report_issue_type = match cwt.reported with | Some reported when Reported.equal reported issue_type -> (* already reported and the precision hasn't improved *) None | _ -> (* either never reported or already reported but the precision has improved *) Some issue_type in {report_issue_type; propagate} let check ~report cwt = let {report_issue_type; propagate} = check_aux cwt in match report_issue_type with | Some issue_type -> report cwt.cond cwt.trace issue_type ; if propagate then Some {cwt with reported= Some (Reported.make issue_type)} else None | None -> Option.some_if propagate cwt let forget_locs locs cwt = {cwt with cond= Condition.forget_locs locs cwt.cond} end module ConditionSet = struct type t = ConditionWithTrace.t list (* invariant: join_one of one of the elements should return the original list *) let empty = [] let try_merge ~existing ~new_ = (* we don't want to remove issues that would end up in a higher bucket, e.g. [a, b] < [c, d] is subsumed by [a, +oo] < [c, d] but the latter is less precise *) if ConditionWithTrace.have_similar_bounds existing new_ then match ConditionWithTrace.xcompare ~lhs:existing ~rhs:new_ with | `LeftSubsumesRight -> `DoNotAddAndStop | `RightSubsumesLeft -> `RemoveExistingAndContinue | `NotComparable -> `KeepExistingAndContinue else `KeepExistingAndContinue let join_one condset new_ = let rec aux ~new_ acc ~same = function | [] -> if Config.bo_debug >= 3 then L.(debug BufferOverrun Verbose) "[InferboPO] Adding new condition %a@." ConditionWithTrace.pp new_ ; if same then new_ :: condset else new_ :: acc | existing :: rest as existings -> match try_merge ~existing ~new_ with | `DoNotAddAndStop -> if Config.bo_debug >= 3 then L.(debug BufferOverrun Verbose) "[InferboPO] Not adding condition %a (because of existing %a)@." ConditionWithTrace.pp new_ ConditionWithTrace.pp existing ; if same then condset else List.rev_append acc existings | `RemoveExistingAndContinue -> if Config.bo_debug >= 3 then L.(debug BufferOverrun Verbose) "[InferboPO] Removing condition %a (because of new %a)@." ConditionWithTrace.pp existing ConditionWithTrace.pp new_ ; aux ~new_ acc ~same:false rest | `KeepExistingAndContinue -> aux ~new_ (existing :: acc) ~same rest in aux ~new_ [] ~same:true condset let join condset1 condset2 = List.fold_left ~f:join_one condset1 ~init:condset2 let add_opt location val_traces condset = function | None -> condset | Some cond -> let trace = ConditionTrace.make location val_traces in let cwt = ConditionWithTrace.make cond trace in join [cwt] condset let add_array_access location ~idx ~size ~is_collection_add ~idx_sym_exp ~size_sym_exp ~relation val_traces condset = ArrayAccessCondition.make ~idx ~size ~idx_sym_exp ~size_sym_exp ~relation |> Condition.make_array_access ~is_collection_add |> add_opt location val_traces condset let add_alloc_size location ~length val_traces condset = AllocSizeCondition.make ~length |> Condition.make_alloc_size |> add_opt location val_traces condset let subst condset bound_map_trace_map rel_subst_map caller_relation callee_pname call_site = let subst_add_cwt condset cwt = match ConditionWithTrace.subst bound_map_trace_map rel_subst_map caller_relation callee_pname call_site cwt with | None -> condset | Some cwt -> join_one condset cwt in List.fold condset ~f:subst_add_cwt ~init:[] let check_all ~report condset = List.filter_map condset ~f:(ConditionWithTrace.check ~report) let pp_summary : F.formatter -> t -> unit = fun fmt condset -> let pp_sep fmt () = F.fprintf fmt ", @," in F.fprintf fmt "@[Safety conditions:@," ; F.fprintf fmt "@[{ " ; F.pp_print_list ~pp_sep ConditionWithTrace.pp fmt condset ; F.fprintf fmt " }@]" ; F.fprintf fmt "@]" let pp : Format.formatter -> t -> unit = fun fmt condset -> let pp_sep fmt () = F.fprintf fmt ",@," in F.fprintf fmt "Safety conditions:@;@[{ %a }@]" (F.pp_print_list ~pp_sep ConditionWithTrace.pp) condset let forget_locs : AbsLoc.PowLoc.t -> t -> t = fun locs x -> List.map x ~f:(ConditionWithTrace.forget_locs locs) end let description cond trace = F.asprintf "%a%a" Condition.pp_description cond ConditionTrace.pp_description trace