netdev - Re: TCP MD5 and socket accept

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]

Message-ID: <396556a20806261337n794c22nf538a0953c942879@mail.gmail.com>
Date:	Thu, 26 Jun 2008 13:37:08 -0700
From:	"Adam Langley" <agl@...erialviolet.org>
To:	"Stephen Hemminger" <shemminger@...tta.com>
Cc:	"David Miller" <davem@...emloft.net>,
	"吉藤英明" <yoshfuji@...ux-ipv6.org>,
	netdev@...r.kernel.org
Subject: Re: TCP MD5 and socket accept

On Thu, Jun 26, 2008 at 7:46 AM, Adam Langley <agl@...erialviolet.org> wrote:
> I'll have a look at this later today

Setup: Linux net-2.6 (almost) <-> Linux net-2.6 (almost)). Userspace
is only setting TCP_MD5SIG just before connect on the client side and
just before bind on the server side. Packet dumps show that all
packets are signed correctly.

>From the code, it appears that we might, in fact, be coping the key
information twice:

tcp_minisocks.c:tcp_check_req is calling
inet_csk(sk)->icsk_af_ops->syn_recv_sock, which becomes
tcp_ipv4.c:tcp_v4_syn_recv_sock which appears to copy the MD5 keys
over. Additionally, right after that call in tcp_check_req, it appears
that the keys are copied again.

Can you provide packet dumps of Linux screwing up in the face of a
connection to a Cisco?

Cheers,

-- 
Adam Langley agl@...erialviolet.org http://www.imperialviolet.org
--
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