Re: [PATCH net-next 19/20] net: Update netconf dump handlers for strict data checking

[David Ahern <dsahern@gmail.com>]

On 10/7/18 4:53 AM, Christian Brauner wrote:
>> @@ -2076,6 +2077,21 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb,
>>  	struct in_device *in_dev;
>>  	struct hlist_head *head;
>>  
>> +	if (cb->strict_check) {
>> +		struct netlink_ext_ack *extack = cb->extack;
>> +		struct netconfmsg *ncm;
>> +
>> +		if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ncm))) {
>> +			NL_SET_ERR_MSG(extack, "Invalid header");
>> +			return -EINVAL;
>> +		}
>> +
>> +		if (nlh->nlmsg_len != nlmsg_msg_size(sizeof(*ncm))) {
>> +			NL_SET_ERR_MSG(extack, "Invalid data after header");
>> +			return -EINVAL;
>> +		}
> 
> Hm, I think this could just be one branch with !=
> But if you've done this to report back a more meaningful error message
> to userspace, fine. :)

Consistency with other dump handlers and better userspace error
messages. If netconf ever gets a filter the length check is removed in
favor of nlmsg_parse_strict