netdev - Re: [PATCH net v2] lan966x: Fix crash when adding interface under a lag

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Mon, 12 Feb 2024 09:10:38 +0100
From: Horatiu Vultur <horatiu.vultur@...rochip.com>
To: Jakub Kicinski <kuba@...nel.org>
CC: <davem@...emloft.net>, <edumazet@...gle.com>, <pabeni@...hat.com>,
	<UNGLinuxDriver@...rochip.com>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Michal Swiatkowski
	<michal.swiatkowski@...ux.intel.com>
Subject: Re: [PATCH net v2] lan966x: Fix crash when adding interface under a
 lag

The 02/09/2024 13:52, Jakub Kicinski wrote:

Hi Jakub,

> 
> On Tue, 6 Feb 2024 13:30:54 +0100 Horatiu Vultur wrote:
> >       for (lag = 0; lag < lan966x->num_phys_ports; ++lag) {
> > -             struct net_device *bond = lan966x->ports[lag]->bond;
> > +             struct lan966x_port *port = lan966x->ports[lag];
> >               int num_active_ports = 0;
> > +             struct net_device *bond;
> >               unsigned long bond_mask;
> >               u8 aggr_idx[16];
> >
> > -             if (!bond || (visited & BIT(lag)))
> > +             if (!port || !port->bond || (visited & BIT(lag)))
> >                       continue;
> >
> > +             bond = port->bond;
> >               bond_mask = lan966x_lag_get_mask(lan966x, bond);
> >
> >               for_each_set_bit(p, &bond_mask, lan966x->num_phys_ports) {
> >                       struct lan966x_port *port = lan966x->ports[p];
> >
> > +                     if (!port)
> > +                             continue;
> 
> Why would lan966x_lag_get_mask() set a bit for a port that doesn't
> exist? Earlier check makes sense. This one seems too defensive.

You are right, the lan966x_lag_get_mask() will not set a bit for a port
that doesn't exist[1]. Therefore this check is not needed.

[1] https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/microchip/lan966x/lan966x_lag.c#L354

> --
> pw-bot: cr

-- 
/Horatiu