epan: Make AT_NUMERIC behave more safely

Implement a better handling of byte sizes as well as preventing
possible memory bleeds

Fixes: 18147

1 files changed, 7 insertions, 1 deletions

diff --git a/epan/address.h b/epan/address.h
index 9016ba72a0..21f5768b59 100644
--- a/epan/address.h
+++ b/epan/address.h
@@ -28,6 +28,12 @@ extern "C" {
  * If an address type is added here, it must be "registered" within address_types.c
  * For dissector address types, just use the address_type_dissector_register function
  * from address_types.h
+ *
+ * AT_NUMERIC - a numeric address type can consist of a guint8, guint16, guint32 or guint64
+ * little-endian value. If no correct length is provided, to avoid data bleed, a guint8 is
+ * assumed. If the value represented is originating from a big-endian system, it is the
+ * responsibility of the dissector to do the proper conversion. Only representation (aka
+ * conversion of value to string) is implemented for this type.
  */
 typedef enum {
     AT_NONE,               /* no link-layer address */
@@ -42,7 +48,7 @@ typedef enum {
     AT_IB,                 /* Infiniband GID/LID */
     AT_AX25,               /* AX.25 */
     AT_VINES,              /* Banyan Vines address */
-    AT_NUMERIC,            /* Numeric address type */
+    AT_NUMERIC,            /* Numeric address type. */
 
     AT_END_OF_LIST         /* Must be last in list */
 } address_type;