netdev - Re: [PATCH] Set DF bit for IPv4 GRE tunnels with fixed TTL

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:	Sat, 5 Dec 2015 13:48:42 -0800
From:	Pravin Shelar <pshelar@...ira.com>
To:	Konstantin Shemyak <konstantin@...myak.com>
Cc:	David Miller <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>
Subject: Re: [PATCH] Set DF bit for IPv4 GRE tunnels with fixed TTL

On Sat, Dec 5, 2015 at 12:55 PM, Konstantin Shemyak
<konstantin@...myak.com> wrote:
> The DF bit on IPv4 GRE tunnels with fixed TTL is enforced in order
> to prevent networking loops. This was the original behavior of GRE
> tunnels, lost in the refactoring.
>
> Signed-off-by: Konstantin Shemyak <konstantin@...myak.com>
> ---
>  net/ipv4/ip_gre.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> index 6145214..485bf27 100644
> --- a/net/ipv4/ip_gre.c
> +++ b/net/ipv4/ip_gre.c
> @@ -679,6 +679,10 @@ static int ipgre_tunnel_ioctl(struct net_device *dev,
>                     ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
>                         return -EINVAL;
>         }
> +
> +        if (p.iph.ttl)
> +                p.iph.frag_off |= htons(IP_DF);
> +

Same code already exist in ip_tunnel_ioctl() which is common function
for IP based tunnel modules. Why does that not work?


>         p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
>         p.o_flags = gre_flags_to_tnl_flags(p.o_flags);
>
> --
> 1.9.1
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html