netdev - ipv6 syn cookie questions

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>] [day] [month] [year] [list]

Date:	Thu, 17 Jan 2008 18:06:18 -0800
From:	"Glenn Griffin" <ggriffin.kernel@...il.com>
To:	netdev@...r.kernel.org
Subject: ipv6 syn cookie questions

In researching the linux implementation of syn cookies I stumbled on a few
points that aren't initially clear to me.  I was hoping somehow could elaborate
and shed some light onto what I'm missing.

at net/ipv6/tcp_ipv6.c:1249 within tcp_v6_conn_request()

There is the following comment:

        /*
         *      There are no SYN attacks on IPv6, yet...
         */

Also above that in the same file within tcp_v6_hnd_req() it looks like pieces
of an ipv6 syn cookie implementation were left but have been commented out.

I was not aware of ipv6 making any changes to how tcp behaved (ignoring obvious
details such as pseudo-header changes in checksum calculations, etc.), so the
comment above puzzles me.  How does ipv6 change the viability of syn attacks
against tcp?

Also if anyone can provide any background that may exist on an ipv6
implementation of syn cookies that would be appreciated.  I'm considering
working on an implementation, but would like to know if anyone is already
working on one or it's been submitted but deemed unnecessary for some reasons.

--Glenn
--
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