stack overflow in debug_write_type

Another fuzzer attack.  This one was a "set" with elements using an
indirect type pointing back at the set.  The existing recursion check
only prevented simple recursion.

	* debug.c (struct debug_type_s): Add mark.
	(debug_write_type): Set mark and check before recursing into
	indirect types.
This commit is contained in:
Alan Modra 2023-05-09 17:11:46 +09:30
parent 06ba6be629
commit 55a75aae9d

View file

@ -105,6 +105,8 @@ struct debug_type_s
enum debug_type_kind kind;
/* Size of type (0 if not known). */
unsigned int size;
/* Used by debug_write to stop DEBUG_KIND_INDIRECT infinite recursion. */
unsigned int mark;
/* Type which is a pointer to this type. */
debug_type pointer;
/* Tagged union with additional information about the type. */
@ -2422,6 +2424,9 @@ debug_write_type (struct debug_handle *info,
if (type == DEBUG_TYPE_NULL)
return (*fns->empty_type) (fhandle);
/* Mark the type so that we don't define a type in terms of itself. */
type->mark = info->mark;
/* If we have a name for this type, just output it. We only output
typedef names after they have been defined. We output type tags
whenever we are not actually defining them. */
@ -2485,7 +2490,7 @@ debug_write_type (struct debug_handle *info,
return false;
case DEBUG_KIND_INDIRECT:
/* Prevent infinite recursion. */
if (*type->u.kindirect->slot == type)
if ((*type->u.kindirect->slot)->mark == info->mark)
return (*fns->empty_type) (fhandle);
return debug_write_type (info, fns, fhandle, *type->u.kindirect->slot,
name);