netdev - Re: rp_filter and ip rule break ipsec policy

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

Message-Id: <E1JDSSS-0008Ph-00@gondolin.me.apana.org.au>
Date:	Sat, 12 Jan 2008 09:34:36 +1100
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	pupilla@...mail.com (Marco Berizzi)
Cc:	netdev@...r.kernel.org
Subject: Re: rp_filter and ip rule break ipsec policy

Marco Berizzi <pupilla@...mail.com> wrote:
>
> When I insert the rule number #601 packets to
> x.y.z.214 aren't ate by xfrm anymore. This
> happens when rp_filter is set to 1 on eth0.
> Disabling rp_filter on eth0 resolve the problem:
> xfrm eat the packets.
> Is this the expected behaviour? Why should

Absolutely.  While on local output, IPsec lookup does override
routing lookup (however there we do the route lookup first and
use that as the key for the IPsec lookup).  On forwarding this
is not the case.  We decapsulate and check policy first (if
encrypted), and then do a route lookup, at which point rp_filter
can eat your packet, and only after that do we perform the output
IPsec lookup.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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