netdev - Re: net: vrf: Handle ipv6 multicast and link-local addresses

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 for Android: free password hash cracker in your pocket

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

Message-ID: <CAMuHMdWd1mYcPFU6Xntr96AkHoiZ_gOC61Oe_pnHcq1mWfoRdA@mail.gmail.com>
Date:	Thu, 4 Aug 2016 11:43:25 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	David Ahern <dsa@...ulusnetworks.com>
Cc:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: net: vrf: Handle ipv6 multicast and link-local addresses

Hi David,

On Thu, Aug 4, 2016 at 7:01 AM, David Ahern <dsa@...ulusnetworks.com> wrote:
> Does making the code the same between those 2 functions matter?

Yes, it does make the warning go away.

> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 1ce7420322ee..3951a2c98431 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -862,15 +862,17 @@ static void vrf_ip6_input_dst(struct sk_buff *skb, struct net_device *vrf_dev,
>                               int ifindex)
>  {
>         const struct ipv6hdr *iph = ipv6_hdr(skb);
> +       struct net *net = dev_net(vrf_dev);
>         struct flowi6 fl6 = {
> +               .flowi6_oif     = 0,
> +               .flowi6_iif     = ifindex,
>                 .daddr          = iph->daddr,
>                 .saddr          = iph->saddr,
>                 .flowlabel      = ip6_flowinfo(iph),
>                 .flowi6_mark    = skb->mark,
>                 .flowi6_proto   = iph->nexthdr,
> -               .flowi6_iif     = ifindex,
> +               .flowi6_flags   = 0,
>         };
> -       struct net *net = dev_net(vrf_dev);
>         struct rt6_info *rt6;

The critical change seems to be moving the initialization of
.flowi6_iif: if that
is done before the initialization of .flowlabel, there's no compiler warning.

The generated asm output is identical, though, so I think this is some sort of
false positive or compiler bug. Hence let's ignore it.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds