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(*
* Copyright (c) 2013-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
module L = Logging
type printf_signature = {unique_id: string; format_pos: int; vararg_pos: int option}
let printf_like_functions =
ref
[ { unique_id=
"java.io.PrintStream.printf(java.lang.String,java.lang.Object[]):java.io.PrintStream"
; format_pos= 1
; vararg_pos= Some 2 }
; { unique_id=
"java.io.PrintStream.printf(java.lang.Locale,java.lang.String,java.lang.Object[]):java.io.PrintStream"
; format_pos= 2
; vararg_pos= Some 3 }
; { unique_id= "java.lang.String(java.lang.String,java.lang.Object[]):java.lang.String"
; format_pos= 1
; vararg_pos= Some 2 }
; { unique_id=
"java.lang.String(java.lang.Locale,java.lang.String,java.lang.Object[]):java.lang.String"
; format_pos= 2
; vararg_pos= Some 3 } ]
let printf_like_function (proc_name : Typ.Procname.t) : printf_signature option =
List.find
~f:(fun printf -> String.equal printf.unique_id (Typ.Procname.to_unique_id proc_name))
!printf_like_functions
let default_format_type_name (format_type : string) : string =
match format_type with
| "d" | "i" | "u" | "x" | "X" | "o" ->
"java.lang.Integer"
| "a" | "A" | "f" | "F" | "g" | "G" | "e" | "E" ->
"java.lang.Double"
| "c" ->
"java.lang.Character"
| "b" ->
"java.lang.Boolean"
| "s" ->
"java.lang.String"
| "h" | "H" ->
"java.lang.Object"
| _ ->
"unknown"
let format_type_matches_given_type (format_type : string) (given_type : string) : bool =
match format_type with
| "d" | "i" | "u" | "x" | "X" | "o" ->
List.mem ~equal:String.equal
["java.lang.Integer"; "java.lang.Long"; "java.lang.Short"; "java.lang.Byte"]
given_type
| "a" | "A" | "f" | "F" | "g" | "G" | "e" | "E" ->
List.mem ~equal:String.equal ["java.lang.Double"; "java.lang.Float"] given_type
| "c" ->
String.equal given_type "java.lang.Character"
| "b" | "h" | "H" | "s" ->
true (* accepts pretty much anything, even null *)
| _ ->
false
(* The format string and the nvar of the varargs array *)
let format_arguments (printf : printf_signature) (args : (Exp.t * Typ.t) list) :
string option * Exp.t option =
let format_string =
match List.nth_exn args printf.format_pos with
| Exp.Const (Const.Cstr fmt), _ ->
Some fmt
| _ ->
None
in
let varargs_nvar =
match printf.vararg_pos with Some pos -> Some (fst (List.nth_exn args pos)) | None -> None
in
(format_string, varargs_nvar)
(* Extract type names from format string *)
let rec format_string_type_names (fmt_string : string) (start : int) : string list =
try
let fmt_re = Str.regexp "%[0-9]*\\.?[0-9]*[A-mo-z]" in
(* matches '%2.1d' etc. *)
ignore (Str.search_forward fmt_re fmt_string start) ;
let fmt_match = Str.matched_string fmt_string in
let fmt_type = String.sub fmt_match ~pos:(String.length fmt_match - 1) ~len:1 in
fmt_type :: format_string_type_names fmt_string (Str.match_end ())
with Caml.Not_found -> []
let check_printf_args_ok tenv (node : Procdesc.Node.t) (instr : Sil.instr)
(proc_name : Typ.Procname.t) (proc_desc : Procdesc.t) summary : unit =
(* Check if format string lines up with arguments *)
let rec check_type_names instr_loc n_arg instr_proc_name fmt_type_names arg_type_names =
let instr_name = Typ.Procname.to_simplified_string instr_proc_name in
let instr_line = Location.to_string instr_loc in
match (fmt_type_names, arg_type_names) with
| ft :: fs, gt :: gs ->
if not (format_type_matches_given_type ft gt) then
let description =
Printf.sprintf
"%s at line %s: parameter %d is expected to be of type %s but %s was given."
instr_name instr_line n_arg (default_format_type_name ft) gt
in
Reporting.log_error summary ~loc:instr_loc IssueType.checkers_printf_args description
else check_type_names instr_loc (n_arg + 1) instr_proc_name fs gs
| [], [] ->
()
| _ ->
let description =
Printf.sprintf "format string arguments don't mach provided arguments in %s at line %s"
instr_name instr_line
in
Reporting.log_error summary ~loc:instr_loc IssueType.checkers_printf_args description
in
(* Get the array ivar for a given nvar *)
let array_ivar instrs nvar =
match nvar with
| Exp.Var nid ->
Instrs.find_map instrs ~f:(function
| Sil.Load (id, Exp.Lvar iv, _, _) when Ident.equal id nid ->
Some iv
| _ ->
None )
|> IOption.find_value_exn
| _ ->
raise Caml.Not_found
in
match instr with
| Sil.Call (_, Exp.Const (Const.Cfun pn), args, cl, _) -> (
match printf_like_function pn with
| Some printf -> (
try
let fmt, array_nvar = format_arguments printf args in
let instrs = Procdesc.Node.get_instrs node in
let vararg_ivar_type_names =
match array_nvar with
| Some nvar ->
let ivar = array_ivar instrs nvar in
PatternMatch.get_vararg_type_names tenv node ivar
| None ->
[]
in
match fmt with
| Some fmt ->
check_type_names cl (printf.format_pos + 1) pn (format_string_type_names fmt 0)
vararg_ivar_type_names
| None ->
if not (Reporting.is_suppressed tenv proc_desc IssueType.checkers_printf_args) then
Reporting.log_warning summary ~loc:cl IssueType.checkers_printf_args
"Format string must be string literal"
with e ->
L.internal_error "%s Exception when analyzing %s: %s@."
IssueType.checkers_printf_args.unique_id
(Typ.Procname.to_string proc_name)
(Exn.to_string e) )
| None ->
() )
| _ ->
()
let callback_printf_args {Callbacks.tenv; proc_desc; summary} : Summary.t =
let proc_name = Procdesc.get_proc_name proc_desc in
Procdesc.iter_instrs
(fun n i -> check_printf_args_ok tenv n i proc_name proc_desc summary)
proc_desc ;
summary