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Fix prototype chain traversing (#4458)

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After the introduction of the Proxy builtin object there was
a possibility to traverse the prototype chain with an invalid object.
The prototype was freed before it's data/properties were queried resulting
in accessing invalid information.

By forcing the allocator to always do a gc (`--mem-stres-test=on` build option)
it was possible to trigger the issue without complicated tests.

New internal method:
* `ecma_op_object_get_prototype_of` which always returns the prototype
  of an object and the return value must be freed (if it is valid).

Updated prototype chain traversing in:
* `jerry_object_get_property_names`
* `ecma_builtin_object_prototype_lookup_getter_setter`
* `ecma_op_function_has_instance`
* `ecma_op_function_get_super_constructor`
* `ecma_op_object_is_prototype_of`
* `ecma_op_object_enumerate`

Removed method `ecma_proxy_object_prototype_to_cp`

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.usz@partner.samsung.com
This commit is contained in:
Péter Gál
2021-01-15 20:54:09 +01:00
committed by GitHub
parent abedab5ac2
commit 5e483633f3
8 changed files with 198 additions and 178 deletions
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jerry-core/ecma/builtin-objects/ecma-builtin-object-prototype.c
+14 -23
View File
@@ -324,11 +324,10 @@ ecma_builtin_object_prototype_lookup_getter_setter (ecma_value_t this_arg, /**<
return ECMA_VALUE_ERROR;
}
jmem_cpointer_t obj_cp;
ECMA_SET_NON_NULL_POINTER (obj_cp, obj_p);
ecma_value_t ret_value = ECMA_VALUE_UNDEFINED;
ecma_ref_object (obj_p);
/* 3. */
while (true)
{
@@ -339,6 +338,7 @@ ecma_builtin_object_prototype_lookup_getter_setter (ecma_value_t this_arg, /**<
if (ECMA_IS_VALUE_ERROR (get_desc))
{
ret_value = get_desc;
ecma_deref_object (obj_p);
break;
}
@@ -360,35 +360,26 @@ ecma_builtin_object_prototype_lookup_getter_setter (ecma_value_t this_arg, /**<
}
ecma_free_property_descriptor (&desc);
ecma_deref_object (obj_p);
break;
}
/* 3.c */
#if ENABLED (JERRY_BUILTIN_PROXY)
if (ECMA_OBJECT_IS_PROXY (obj_p))
{
ecma_value_t parent = ecma_proxy_object_get_prototype_of (obj_p);
ecma_object_t *proto_p = ecma_op_object_get_prototype_of (obj_p);
ecma_deref_object (obj_p);
if (ECMA_IS_VALUE_ERROR (parent))
{
ret_value = parent;
break;
}
obj_cp = ecma_proxy_object_prototype_to_cp (parent);
}
else
#endif /* ENABLED (JERRY_BUILTIN_PROXY) */
{
obj_cp = ecma_op_ordinary_object_get_prototype_of (obj_p);
}
if (obj_cp == JMEM_CP_NULL)
if (proto_p == NULL)
{
break;
}
else if (JERRY_UNLIKELY (proto_p == ECMA_OBJECT_POINTER_ERROR))
{
ret_value = ECMA_VALUE_ERROR;
break;
}
obj_p = ECMA_GET_NON_NULL_POINTER (ecma_object_t, obj_cp);
/* Advance up on prototype chain. */
obj_p = proto_p;
}
ecma_free_value (to_obj);