Avoid UB with flexible array member

Accessing past the end of an array is technically UB. Use C99 flexible
array member instead to avoid the UB and simplify allocation size
calculation.

See also: DCL38-C in the SEI CERT C Coding Standard

1 files changed, 2 insertions, 2 deletions

diff --git a/vm_callinfo.h b/vm_callinfo.h
index 013811d15e..b3de14dcab 100644
--- a/vm_callinfo.h
+++ b/vm_callinfo.h
@@ -33,14 +33,14 @@ enum vm_call_flag_bits {
 
 struct rb_callinfo_kwarg {
     int keyword_len;
-    VALUE keywords[1];
+    VALUE keywords[];
 };
 
 static inline size_t
 rb_callinfo_kwarg_bytes(int keyword_len)
 {
     return rb_size_mul_add_or_raise(
-        keyword_len - 1,
+        keyword_len,
         sizeof(VALUE),
         sizeof(struct rb_callinfo_kwarg),
         rb_eRuntimeError);