On Thu, Sep 13, 2018 at 04:20:14PM -0300, Marcelo Ricardo Leitner wrote:
> On Thu, Sep 13, 2018 at 02:05:54PM +0200, Michal Kubecek wrote:
> > 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.
>
> Considering we can only report 1 message, it should be okay to drop
> the previous message in favor of the new one, which is either a
> critical one or just another non-fatal one.
What I wanted to point out is that the code above does not behave like
this. It does not distinguish between extack->_msg set by NLA_REJECT
branch and extack->_msg which had been set before nla_parse() was
called.
Michal Kubecek
