smb: server: handle readdir_info_level_struct_sz() error

early exit in smb2_populate_readdir_entry() if the requested info_level
is unknown.

Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Marios Makassikis

fs/smb/server/smb2pdu.c

@@ -3946,7 +3946,13 @@ static int smb2_populate_readdir_entry(struct ksmbd_conn *conn, int info_level,
 		goto free_conv_name;
 	}
 
-	struct_sz = readdir_info_level_struct_sz(info_level) + conv_len;
+	struct_sz = readdir_info_level_struct_sz(info_level);
+	if (struct_sz == -EOPNOTSUPP) {
+		rc = -EINVAL;
+		goto free_conv_name;
+	}
+
+	struct_sz += conv_len;
 	next_entry_offset = ALIGN(struct_sz, KSMBD_DIR_INFO_ALIGNMENT);
 	d_info->last_entry_off_align = next_entry_offset - struct_sz;