netdev - Re: fib_frontend: Add network specific broadcasts, when it takes a sense

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 Dec 2016 09:44:54 -0500
From:   Brandon Philips <brandon.philips@...eos.com>
To:     Jiri Benc <jbenc@...hat.com>
Cc:     netdev@...r.kernel.org, Tom Denham <tom@...era.io>,
        Aaron Levy <aaron.levy@...eos.com>,
        Brad Ison <bison@...eos.com>
Subject: Re: fib_frontend: Add network specific broadcasts, when it takes a sense

On Mon, Dec 12, 2016 at 9:30 AM, Jiri Benc <jbenc@...hat.com> wrote:
> On Fri, 9 Dec 2016 15:41:52 -0800, Brandon Philips wrote:
>> The issue we have: when creating the VXLAN interface and assigning it
>> an address we see a broadcast route being added by the Kernel. For
>> example if we have 10.4.0.0/16 a broadcast route to 10.4.0.0 is
>> created. This route is unwanted because we assign 10.4.0.0 to one of
>> our VXLAN interfaces.
>
> Are you saying you're trying to assign the IP address 10.4.0.0/16 as a
> unicast address to an interface? Then you'll run into way more problems
> than the one you're describing. You can't have host part of the IP
> address consisting of all zeros (or all ones). Just don't do it. Choose
> a valid IP address instead.

Yes, this is what we are doing; it is because of an upstream, to us,
address assignment so I will figure it out upstream.

Regardless, it is hard to find an RFC that says "simply don't do this
because _____". The closest I could find was RFC 922 after sending
this which says:

"There is probably no reason for such addresses to appear anywhere but
as the source address of an ICMP Information".

I will submit a patch that at least documents this RFC and quote.

Thanks!

Brandon