obj_dat: don't shift a->length into the sign bit

For an OID of excessive length >= 2^12, a->length << 20L is undefined,
so add a cast to the target type of (unsigned long).

From Kenjiro Nakayama

1 files changed, 2 insertions, 2 deletions

diff --git a/src/lib/libcrypto/objects/obj_dat.c b/src/lib/libcrypto/objects/obj_dat.c
index ed8140b54a..a2de78b545 100644
--- a/src/lib/libcrypto/objects/obj_dat.c
+++ b/src/lib/libcrypto/objects/obj_dat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: obj_dat.c,v 1.92 2025/02/26 09:49:54 tb Exp $ */
+/* $OpenBSD: obj_dat.c,v 1.93 2025/02/26 09:52:55 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -100,7 +100,7 @@ added_obj_hash(const ADDED_OBJ *ca)
         a = ca->obj;
         switch (ca->type) {
         case ADDED_DATA:
-                ret = a->length << 20L;
+                ret = (unsigned long)a->length << 20L;
                 p = (unsigned char *)a->data;
                 for (i = 0; i < a->length; i++)
                         ret ^= p[i] << ((i * 3) % 24);