Re: [PATCH] net: mac802154: Fix a condition in the receive path

From: Greg KH <gregkh@linuxfoundation.org>
To: Alexander Aring <aahringo@redhat.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
	Alexander Aring <alex.aring@gmail.com>,
	Stefan Schmidt <stefan@datenfreihafen.org>,
	linux-wpan - ML <linux-wpan@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Eric Dumazet <edumazet@google.com>,
	Network Development <netdev@vger.kernel.org>,
	David Girault <david.girault@qorvo.com>,
	Romuald Despres <romuald.despres@qorvo.com>,
	Frederic Blain <frederic.blain@qorvo.com>,
	Nicolas Schodet <nico@ni.fr.eu.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH] net: mac802154: Fix a condition in the receive path
Date: Mon, 29 Aug 2022 07:28:19 +0200	[thread overview]
Message-ID: <YwxOc+X7VpMhKv+4@kroah.com> (raw)
In-Reply-To: <CAK-6q+imPjpBxSZG7e5nxYYgtkrM5pfncxza9=vA+sq+eFQsUw@mail.gmail.com>

On Sun, Aug 28, 2022 at 08:16:20PM -0400, Alexander Aring wrote:
> Hi,
> 
> On Fri, Aug 26, 2022 at 10:31 AM Miquel Raynal
> <miquel.raynal@bootlin.com> wrote:
> >
> > Upon reception, a packet must be categorized, either it's destination is
> > the host, or it is another host. A packet with no destination addressing
> > fields may be valid in two situations:
> > - the packet has no source field: only ACKs are built like that, we
> >   consider the host as the destination.
> > - the packet has a valid source field: it is directed to the PAN
> >   coordinator, as for know we don't have this information we consider we
> >   are not the PAN coordinator.
> >
> > There was likely a copy/paste error made during a previous cleanup
> > because the if clause is now containing exactly the same condition as in
> > the switch case, which can never be true. In the past the destination
> > address was used in the switch and the source address was used in the
> > if, which matches what the spec says.
> >
> > Cc: stable@vger.kernel.org
> > Fixes: ae531b9475f6 ("ieee802154: use ieee802154_addr instead of *_sa variants")
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  net/mac802154/rx.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
> > index b8ce84618a55..c439125ef2b9 100644
> > --- a/net/mac802154/rx.c
> > +++ b/net/mac802154/rx.c
> > @@ -44,7 +44,7 @@ ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
> >
> >         switch (mac_cb(skb)->dest.mode) {
> >         case IEEE802154_ADDR_NONE:
> > -               if (mac_cb(skb)->dest.mode != IEEE802154_ADDR_NONE)
> > +               if (hdr->source.mode != IEEE802154_ADDR_NONE)
> >                         /* FIXME: check if we are PAN coordinator */
> >                         skb->pkt_type = PACKET_OTHERHOST;
> >                 else
> 
> 
> This patch looks okay but it should not be addressed to stable. Leave
> of course the fixes tag.

Why do that?  Do you not want this in the stable tree?

> Wpan sends pull requests to net and they have their own way to get
> into the stable tree when they are in net.

No, the normal method has been used for quite a while now.

Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.