0004229: Casser le typage avec Dynlink

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Project

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Date Submitted

Last Update

0004229

OCaml

OCaml documentation

public

2007-03-14 14:32

2012-09-14 23:52

Reporter

frisch

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

acknowledged

Resolution

open

Platform

OS Version

Product Version

Target Version

4.00.2+dev

Fixed in Version

Summary

0004229: Casser le typage avec Dynlink

Description

Dynlink autorise à charger un module déjà présent dans le programme principal ou déjà dynlinké avant (si sa signature est la même). En particulier, cela permet de redéfinir l'implémentation d'un type abstrait et donc de casser le typage. Certes, il faut vraiment le chercher (cf plus bas).

Une solution un peu moche consisterait à empecher de cacher un symbole global.

Dans symtable.ml:

let slot_for_setglobal id =
  if Tbl.mem id !global_table.num_tbl then 0xffff
  else enter_numtable global_table id

Dans interp.c:

    Instruct(SETGLOBAL):
      if (*pc != 0xffff) caml_modify(&Field(caml_global_data, *pc), accu);
      accu = Val_unit;
      pc++;
      Next;

Steps To Reproduce

abstract.mli:
type t
val print: t -> unit
val x: t

abstract.ml:
type t = int
let print i = Printf.printf "Abstract %i\n" i
let x = 10

static.ml:
let f = Abstract.print

client.ml:
let () = Static.f Abstract.x

sub/abstract.mli = abstract.ml

sub/abstract.ml:
type t = string
let print i = Printf.printf "Abstract %s\n" i
let x = "foo"

main.ml:let () =
  Dynlink.init ();
  Dynlink.loadfile "client.cmo"; (* utilise abstract.cmo *)
  Dynlink.loadfile "sub/abstract.cmo";
  Dynlink.loadfile "client.cmo" (* utilise sub/abstract.cmo *)

On compile tout ça...

$ ocamlc -o main dynlink.cma abstract.cmo static.cmo main.cmo
$ ./main
Abstract 10
Abstract 67345600

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Attached Files

Relationships

related to	0004231	resolved	lefessan	Link multiple casse le système de types
related to	0004839	acknowledged		natdynlink reproducible segfault

Notes
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Issue History
Date Modified	Username	Field	Change
2007-03-14 14:32	frisch	New Issue
2007-11-10 13:52	xleroy	Status	new => acknowledged
2009-07-22 09:19	frisch	Relationship added	child of 0004839
2009-07-22 09:19	frisch	Relationship added	related to 0004231
2009-07-22 09:19	frisch	Relationship deleted	child of 0004839
2009-07-22 09:19	frisch	Relationship added	related to 0004839
2012-07-11 16:11	doligez	Target Version	=> 4.01.0+dev
2012-07-31 13:37	doligez	Target Version	4.01.0+dev => 4.00.1+dev
2012-09-14 23:52	doligez	Target Version	4.00.1+dev => 4.00.2+dev