Re: [PATCH] kobject: fix suppressing modalias in uevents delivered over netlink

[Tariq Toukan]

On 19/12/2017 11:12 AM, Eric Dumazet wrote:
> On Tue, Dec 19, 2017 at 12:48 AM, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Wed, Dec 13, 2017 at 03:21:22PM -0800, Dmitry Torokhov wrote:
> > > The commit 4a336a23d619 ("kobject: copy env blob in one go") optimized
> > > constructing uevent data for delivery over netlink by using the raw
> > > environment buffer, instead of reconstructing it from individual
> > > environment pointers. Unfortunately in doing so it broke suppressing
> > > MODALIAS attribute for KOBJ_UNBIND events, as the code that suppressed this
> > > attribute only adjusted the environment pointers, but left the buffer
> > > itself alone. Let's fix it by making sure the offending attribute is
> > > obliterated form the buffer as well.
> > >
> > > Reported-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
> > > Reported-by: Casey Leedom <leedom@xxxxxxxxxxx>
> > > Fixes: 4a336a23d619 ("kobject: copy env blob in one go")
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> > > ---
> > >   lib/kobject_uevent.c | 16 ++++++++++++----
> > >   1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > Ok, I'm lost here, is this patch still needed for 4.15-final?

Yes this is needed, it solves the issue I reported.
Thanks.

> > And am I supposed to be taking it through my tree as the offending patch
> > didn't come from me?  :)
>
> Sorry for that, I sent a patch series (
> 8ca712c373a462cfa1b62272870b6c2c74aa83f9 )
> that was mostly network related stuff (dealing with skbs and all rtnl batching),
> and sent it to David before Dmitry patch was visible in David tree.
>
> Yes, we believe fix in zap_modalias_env() is needed.
>
> Thanks.