On Thu, Sep 13, 2018 at 01:25:15PM +0200, Johannes Berg wrote:
> On Thu, 2018-09-13 at 12:49 +0200, Michal Kubecek wrote:
>
> > > if (type > 0 && type <= maxtype) {
> > > if (policy) {
> > > - err = validate_nla(nla, maxtype, policy);
> > > + err = validate_nla(nla, maxtype, policy,
> > > + extack);
> > > if (err < 0) {
> > > - NL_SET_ERR_MSG_ATTR(extack, nla,
> > > - "Attribute failed policy validation");
> > > + NL_SET_BAD_ATTR(extack, nla);
> > > + if (extack && !extack->_msg)
> > > + NL_SET_ERR_MSG(extack,
> > > + "Attribute failed policy validation");
> > > goto errout;
> > > }
> > > }
> > > --
> >
> > Technically, this would change the outcome when nla_parse() is called
> > with extack->_msg already set nad validate_nla() fails on something else
> > than NLA_REJECT; it will preserve the previous message in such case.
> > But I don't think this is a serious problem.
>
> Yes, that's true. I looked at quite a few of the setters just now (there
> are ~500 already, wow!), and they all set & return, so this shouldn't be
> an issue.
In ethtool (work in progress) I sometimes use extack message for
non-fatal warnings but AFAICS never before parsing the userspace
request (actually always shortly before returning). So I don't have
a problem with it.
Michal Kubecek
