Date: Sat, 30 Oct 2004 23:42:12 +0200 From: Joost Bekkers <joost@jodocus.org> To: Ari Suutari <ari@suutari.iki.fi> Cc: freebsd-net@freebsd.org Subject: Re: ipfw and ipsec processing order for outgoing packets wrong Message-ID: <20041030214212.GA1737@bps.jodocus.org> In-Reply-To: <200410300927.51286.ari@suutari.iki.fi> References: <200410300927.51286.ari@suutari.iki.fi>
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On Sat, Oct 30, 2004 at 09:27:50AM +0300, Ari Suutari wrote: > Hi, > > I noticed that processing order of ipsec and ipfw (pfil_hook) is not > correct for outgoing packets. Currently, ipsec processing is done first, > which makes packets to go through without firewall inspection. > This might be a security problem for someone, but at least it > breaks stateful rule handling. > > My test setup is (all freebsd 5.3-rc1 machines): > > freebsd laptop <-> ipsec tunnel <->freebsd server > > When server sends packet to laptop, it now goes like this: > > ip_output -> ipsec -> ip_output -> ipfw -> network > > It should go like this: > > ip_output -> ipfw -> ipsec -> ip_output -> ipfw -> network > > I think that this could be fixed by just moving pfil_hook > processing in ip_output before ipsec processing. > I've been pondering the same issue and am currently running 5.3-R modified in the way you've described. (diff at http://jodocus.org/ipsec-pfil.diff I'm not an experienced kernel-hacker, so use at own risk) For IPSEC this also means that the resulting ESP and AH packets don't traverse the firewall when leaving the system. (at least if I read the code correctly; not tested) With FAST_IPSEC both the original and the resulting ESP/AH packets traverse the firewall. In my case I also stumbled on a nice FAST_IPSEC feature where the decoded packets seemed to arrive through the corresponding gif* interface. (with tunnel-mode ipsec) -- greetz Joost joost@jodocus.org
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