On Tue, Oct 09, 2018 at 09:18:22PM +0300, Ivan Mitev wrote:
> 
> 
> On 10/9/18 7:44 PM, mfreemon wrote:
> > On 10/8/18 10:56 AM, mfreemon wrote:
> > > On 10/2/18 2:25 AM, Ivan Mitev wrote:
> > > > On 10/2/18 1:32 AM, Chris Laprise wrote:
> > > > > On 10/01/2018 05:48 PM, mfreemon wrote:
> > > > > > On 1/11/18 3:01 PM, Chris Laprise wrote:
> > > > > >   > On 01/10/2018 03:47 PM, Connor Page wrote:
> > > > > >   >> The official templates use nftables so shouldn’t be mixed with
> > > > > > iptables. I didn’t have time to learn about nftables, so just 
> > > > > > removed
> > > > > > nftables package from debian 9 template. YMMV.
> > > > > >   >
> > > > > >   > Hmmm, I was just thinking how Qubes' own guest scripts still use
> > > > > >   > iptables even in fedora-26.
> > > > > >   >
> > > > > >   > IIUC, iptables and nft are two different interfaces
> > > > > > to netfilter. I
> > > > > >   > don't know if it really matters, at least for the R4.0 window. 
> > > > > > I'd
> > > > > >   > prefer to put the syntax change (for docs) off until
> > > > > > a later release.
> > > > > > 
> > > > > > I was recently thrown by the mix of both nftables and iptables in 
> > > > > > R4.
> > > > > > 
> > > > > > The qubes docs don't clarify much.  The qubes firewall scripts use
> > > > > > nft. Most of the discussion on the qubes website documentation is
> > > > > > about iptables, but there are also a few mentions of nft.  The 
> > > > > > upgrade
> > > > > > instructions (going from R3.2 to R4) did not mention converting 
> > > > > > rules
> > > > > > from iptables to nftables.  It looks like other related projects 
> > > > > > (one
> > > > > > example is qubes-tunnel) is using iptables.
> > > > > > 
> > > > > > Just reading a few things and trying to come up to speed, I get the
> > > > > > impression that nftables and iptables should not both by used at the
> > > > > > same time.  Even if technically possible (i.e. both sets of rules
> > > > > > applied correctly), it strikes me as not a great idea to maintain
> > > > > > packet filtering rules in two different ways.
> > > > > > 
> > > > > > What is the best practice recommendation on this (for R4, Fedora 28
> > > > > > template)?  Are we to be using, exclusively, nftables in R4?
> > > > > 
> > > > > The last I read about this (for 4.0) is that nftables is used in 
> > > > > Fedora
> > > > > Qubes code, but Debian Qubes is still using iptables. That
> > > > > still appears
> > > > > to be the case since nftables is not installed in my
> > > > > debian-9 templates.
> > > > > 
> > > > > I've submitted qubes-tunnel to Qubes with iptables commands only, with
> > > > > the intention to transition to nftables (or that other new interface 
> > > > > in
> > > > > Linux, name escapes me just now) for Qubes 4.1. Someone who is just
> > > > > starting a project might be better off going with nftables.
> > > > 
> > > > ... until yet another packet filtering mechanism replaces nftables (in
> > > > that case, bpfilter [1]).
> > > > 
> > > > I understand the rationale behind using nftables [2] but given how it is
> > > > widespread (hint: close to 0 even amongst seasoned sysadmins) IMHO it
> > > > wasn't worth it. The OP's post confirms there's quite some confusion
> > > > about how it interacts with iptables, and the official documentation is
> > > > far from helpful.
> > > > I'm quite proficient with iptables and networking in general but it took
> > > > me half an hour to understand how to tweak Qubes' nftables rules last
> > > > time I wanted to change something in the firewall, while I would have
> > > > done that task in less than one minute with iptables. I could have spent
> > > > a few hours learning nftables to improve the official doc but at my age
> > > > I prefer to spend time learning tech that significantly improves things
> > > > (eg. Qubes OS over standard linux distribution) over loosing time
> > > > learning stuff that is only marginally better.
> > > > Anyway - I digress :)
> > > > 
> > > > [1] https://old.lwn.net/Articles/747551/
> > > > [2]
> > > > https://github.com/QubesOS/qubes-issues/issues/1815#issuecomment-245109500
> > > > 
> > > 
> > > I'm concerned about the confusion and unnecessary complexity here.
> > > 
> > > Network packet filtering is certainly (one of) those features that
> > > software such Qubes needs to be solid on (in both design approach
> > > and implementation detail).
> > > 
> > > Is the Qubes team confident in the current situation, such that
> > > users of Qubes should not be concerned?
> > > 
> > > nb.  This is not meant to be a criticism at all.  I very much
> > > appreciate the hard (and complicated) work going into Qubes.  I'm
> > > just looking to understand the current situation better so as to
> > > judge whether my concern is warranted or not.
> > 
> > 
> > As an example:  I'm wanting to enable some specific network traffic
> > between two qubes.  The docs say to use iptables 
> > (https://www.qubes-os.org/doc/firewall/#enabling-networking-between-two-qubes).
> >  qubes-firewall-user-script also specifies iptables rules.  But
> > qvm-firewall implements the rules it manages using nftables.  So the
> > firewall VMs have both iptables rules and nftables rules in effect.  And
> > these are different sets of rules.  It's not that the iptables command
> > and the nft command are just two user interfaces showing the same packet
> > filtering rules.  They are different packet filtering rules.  This seems
> > like a receipt for disaster.
> > 
> > Is this the wrong forum for this discussion?  Should this be on
> > qubes-devel, or an issue in qubes-issues at
> > https://github.com/QubesOS/qubes-issues/issues?
> 
> You'll definitely get more visibility on qubes-devel.
> 
> FWIW I'm not concerned about the complexity itself: I trust the Qubes devs
> not to mess up.
> IMHO the problem is that people proficient with iptables are not willing to
> spend time learning yet another packet filter tool when iptables works for
> 99.99% of the cases (+, as others pointed out, nftables is still not feature
> complete wrt. iptables). For those users - an overwhelming majority - Qubes'
> nftables firewall is a black box that is difficult to
> understand/tweak/debug.
> 

I think this is the problem. I remember stalwarts hanging on to ipchains
for similar reasons. (I speak as someone who has clung on to iptables for
far too long.)
It seems to me that the few features lacking in nftables are only of
interest to people who are fully capable of learning a new tool. The
extras that nft brings completely outweigh the deficiencies.
nft provides tools to translate your iptables rules in to the new
syntax, so there's really no excuse for not diving in. Even if you have
minimal time, you can write your iptables rules and then translate them
to nft.

Qubes tries to provide a straightforward experience for relatively
inexperienced users, and the nft/iptables mix per distribution is a
compromise to that end.

The docs need to be updated to provide nft rules throughout.

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