added safeguard to ensure that PgfRevision is an actual object

2021-09-08 09:17:12 +02:00
parent f741bd9332
commit 2e846cdf59
4 changed files with 35 additions and 17 deletions
--- a/src/runtime/c/pgf/db.cxx
+++ b/src/runtime/c/pgf/db.cxx
@@ -958,6 +958,13 @@ void PgfDB::free_internal(object o)
    }
 }

+bool PgfDB::is_valid_object(object o, size_t bytes)
+{
+    if (o <= sizeof(*ms) || o >= ms->top)
+        return false;
+    mchunk *chunk = mem2chunk(ptr(ms,o));
+    return (chunksize(chunk) == request2size(bytes));
+}

 DB_scope::DB_scope(PgfDB *db, DB_scope_mode tp)
 {