* stack overflow in debug_write_type
@ 2023-05-09 7:48 Alan Modra
0 siblings, 0 replies; 2+ messages in thread
From: Alan Modra @ 2023-05-09 7:48 UTC (permalink / raw)
To: binutils
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.
diff --git a/binutils/debug.c b/binutils/debug.c
index 53b45879e00..5cc77f74906 100644
--- a/binutils/debug.c
+++ b/binutils/debug.c
@@ -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);
--
Alan Modra
Australia Development Lab, IBM
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: stack overflow in debug_write_type
@ 2023-05-10 13:41 Alan Modra
0 siblings, 0 replies; 2+ messages in thread
From: Alan Modra @ 2023-05-10 13:41 UTC (permalink / raw)
To: binutils
Apparently u.kindirect->slot can point at a NULL.
* debug.c (debug_write_type): Don't segfault on NULL indirect.
diff --git a/binutils/debug.c b/binutils/debug.c
index 5cc77f74906..bb26d9143d0 100644
--- a/binutils/debug.c
+++ b/binutils/debug.c
@@ -2490,7 +2490,8 @@ debug_write_type (struct debug_handle *info,
return false;
case DEBUG_KIND_INDIRECT:
/* Prevent infinite recursion. */
- if ((*type->u.kindirect->slot)->mark == info->mark)
+ if (*type->u.kindirect->slot != DEBUG_TYPE_NULL
+ && (*type->u.kindirect->slot)->mark == info->mark)
return (*fns->empty_type) (fhandle);
return debug_write_type (info, fns, fhandle, *type->u.kindirect->slot,
name);
--
Alan Modra
Australia Development Lab, IBM
^ permalink raw reply [flat|nested] 2+ messages in thread
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