Re: [patch iproute2-next v3 3/6] devlink: extend pr_out_nested_handle() to print object

[David Ahern <dsahern@gmail.com>]

On 10/24/23 4:04 AM, Jiri Pirko wrote:
> @@ -2861,6 +2842,38 @@ static void pr_out_selftests_handle_end(struct dl *dl)
>  		__pr_out_newline();
>  }
>  
> +static void __pr_out_nested_handle(struct dl *dl, struct nlattr *nla_nested_dl,
> +				   bool is_object)
> +{
> +	struct nlattr *tb[DEVLINK_ATTR_MAX + 1] = {};
> +	int err;
> +
> +	err = mnl_attr_parse_nested(nla_nested_dl, attr_cb, tb);
> +	if (err != MNL_CB_OK)
> +		return;
> +
> +	if (!tb[DEVLINK_ATTR_BUS_NAME] ||
> +	    !tb[DEVLINK_ATTR_DEV_NAME])
> +		return;
> +
> +	if (!is_object) {
> +		char buf[64];
> +
> +		sprintf(buf, "%s/%s", mnl_attr_get_str(tb[DEVLINK_ATTR_BUS_NAME]),
> +			mnl_attr_get_str(tb[DEVLINK_ATTR_DEV_NAME]));

buf[64] - 1 for null terminator - 16 for IFNAMSIZ leaves 47. I do not
see limits on bus name length, so how can you guarantee it is always <
47 characters?

Make this snprintf, check the return and make sure buf is null terminated.

> +		print_string(PRINT_ANY, "nested_devlink", " nested_devlink %s", buf);
> +		return;
> +	}
> +
> +	__pr_out_handle_start(dl, tb, false, false);
> +	pr_out_handle_end(dl);
> +}
> +
> +static void pr_out_nested_handle(struct nlattr *nla_nested_dl)
> +{
> +	__pr_out_nested_handle(NULL, nla_nested_dl, false);
> +}
> +
>  static bool cmp_arr_last_port_handle(struct dl *dl, const char *bus_name,
>  				     const char *dev_name, uint32_t port_index)
>  {