Re: [PATCH net] genetlink: fix genlmsg_nlhdr()

[Michal Kubecek]

On Wed, Nov 15, 2017 at 01:20:10PM +0100, Johannes Berg wrote:
> On Wed, 2017-11-15 at 13:09 +0100, Michal Kubecek wrote:
> > According to the description, first argument of genlmsg_nlhdr() points to
> > what genlmsg_put() returns, i.e. beginning of user header. Therefore we
> > should only subtract size of genetlink header and netlink message header,
> > not user header.
> > 
> > This also means we don't need to pass the pointer to genetlink family and
> > the same is true for genl_dump_check_consistent() which is the only caller
> > of genlmsg_nlhdr(). (Note that at the moment, these functions are only
> > used for families which do not have user header so that they are not
> > affected.)
> > 
> > Fixes: 670dc2833d14 ("netlink: advertise incomplete dumps")
> > Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
> 
> Looks sensible, though I don't think it's really needed in net since it
> really has no effect - as you note, family->hdrsize is 0 for all the
> families calling this right now.
> 
> Reviewed-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>

Well, I'm currently working on one with hdrsize > 0 which is how I found
this. :-) But it will still need some time before it can get even into
net-next.

Michal Kubecek