cls/cas/cls_cas_internal: Initialize 'hash' value before decoding into it

In the decode function for chunk_refs_by_hash_t, initialize the variable
'hash' of type ceph_le32 to zero before its first use.
This prevents the variable from containing dirty (uninitialized) values,
which could lead to unexpected behavior later in the code.

Fixes: https://tracker.ceph.com/issues/64854
Signed-off-by: Nitzan Mordechai <[email protected]>

Author: NitzanMordhai

src/cls/cas/cls_cas_internal.h

@@ -244,7 +244,7 @@ struct chunk_refs_by_hash_t : public chunk_refs_t::refs_t {
     int hash_bytes = (hash_bits + 7) / 8;
     while (n--) {
       int64_t poolid;
-      ceph_le32 hash;
+      ceph_le32 hash{0};
       uint64_t count;
       denc_signed_varint(poolid, p);
       memcpy(&hash, p.get_pos_add(hash_bytes), hash_bytes);