111 lines
5.4 KiB
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111 lines
5.4 KiB
HTML
Executable File
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<title>Re: GSoC Port Forwarding</title>
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<table border=0 cellspacing=0 cellpadding=0 width="100%" class="header-part1"><tr><td><div class="headerdisplayname" style="display:inline;">Oggetto: </div>Re: GSoC Port Forwarding</td></tr><tr><td><div class="headerdisplayname" style="display:inline;">Mittente: </div>Giulio <giulio@gmx.com></td></tr><tr><td><div class="headerdisplayname" style="display:inline;">Data: </div>15/08/2021, 17:35</td></tr></table><table border=0 cellspacing=0 cellpadding=0 width="100%" class="header-part2"><tr><td><div class="headerdisplayname" style="display:inline;">A: </div>Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com></td></tr><tr><td><div class="headerdisplayname" style="display:inline;">CC: </div>Frédéric Pierret <frederic.pierret@qubes-os.org></td></tr></table><br>
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<div class="moz-text-flowed" style="font-family: -moz-fixed; font-size: 14px;" lang="x-unicode">Hello,
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<br>Thank you for you fast reply.
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<br>
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<br>Il 14/08/2021 23:43, Marek Marczykowski-Górecki ha scritto:
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<br><blockquote type=cite style="color: #007cff;">
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<br>As for the nft syntax, I think iptables-translate tool can help you
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<br>(part of the iptables-nft package).
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<br>See <a class="moz-txt-link-freetext" href="https://wiki.nftables.org/wiki-nftables/index.php/Moving_from_iptables_to_nftables">https://wiki.nftables.org/wiki-nftables/index.php/Moving_from_iptables_to_nftables</a>
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<br>
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<br><blockquote type=cite style="color: #007cff;">You can see in [4] how I organized the forwarding mechanism. All the
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<br>necessary information, as well as ipv4/ipv6 support should already be in
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<br>the 'prepare_forward_rules' function meaning that only the actual
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<br>building syntax is left.
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<br></blockquote>
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<br></blockquote>
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<br>I have tried to write the external nft rules as well the extarnal ones,
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with the exception of the destination domain.
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<br>
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<br>Assume the following setup:
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<br>sys-net - 10.137.0.5 (ens6 phy with 192.168.10.20)
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<br>sys-firewall - 10.137.0.6
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<br>personal - 10.137.0.7
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<br>
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<br>All of them are running fedora-32.
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<br>
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<br>And assume the following rule added via qvm-firewall:
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<br># qvm-firewall personal add action=forward forwardtype=external
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scrports=22-22 proto=tcp dstports=2222-2222 srchost=192.168.10.0/24
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<br>.
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<br>First, a table for the forwarding rules is created:
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<br>
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<br>flush chain {family} qubes-firewall-forward prerouting
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<br>flush chain {family} qubes-firewall-forward postrouting
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<br>table {family} qubes-firewall-forward {
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<br> chain postrouting {
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<br> type nat hook postrouting priority srcnat; policy accept;
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<br> masquerade
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<br> }
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<br> chain prerouting {
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<br> type nat hook prerouting priority dstnat; policy accept;
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<br> }
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<br>}
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<br>
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<br>Then, if the qube is marked as 'last', meaning that it is the external
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qube with the physical interface the following rules are added:
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<br>
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<br>table {family} qubes-firewall-forward {
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<br> chain prerouting {
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<br> meta iifname "ens6" {family} saddr 192.168.10.0/24 tcp dport {{ 22 }}
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dnat to 10.137.0.6:2222
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<br> }
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<br>}
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<br>
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<br>table {family} qubes-firewall {
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<br> chain forward {
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<br> meta iifname "eth0" {family} daddr 10.137.0.6 tcp dport 2222 ct state
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new counter accept
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<br> }
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<br>}
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<br>
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<br>And that is all for sys-net.
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<br>
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<br>In sys-firewall, since it is an 'internal' qube, the following rules are
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added instead:
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<br>
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<br>table {family} qubes-firewall-forward {
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<br> chain prerouting {
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<br> meta iifname "eth0" {family} saddr 120.137.0.5 tcp dport {{ 2222 }}
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dnat to 10.137.0.7:2222
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<br> }
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<br>}
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<br>
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<br>table {family} qubes-firewall {
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<br> chain forward {
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<br> meta iifname "eth0" {family} daddr 10.137.0.7 tcp dport 2222 ct state
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new counter accept
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<br> }
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<br>}
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<br>
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<br>Lastly, the appropriate rules allowing incoming traffic on the selected
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port from the previous hop should be added directly yo the 'personal'
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domain. However I see that there the nft ruleset is empty, while
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iptables seems indeed to be in use. I guess that those rules are the
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ones specified in qubes-core-agent-linux/network/iptables, however I am
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wondering how we should proceed on this one?
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<br>
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<br>Also are you able to spot errors or something missing in the
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aforedescribed rule flow? When testing I can see the incoming connection
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on port 22 of the physical interface of sys-net, but then I am losing
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track of the connection after that...
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<br>
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<br>
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<br><blockquote type=cite style="color: #007cff;">In both cases, the code will need some tests of course.
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<br>
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<br></blockquote>
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<br>As soon as everything seems to work with my manual test, I will start
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progressively writing the automated tests.
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<br>
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<br>Cheers
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<br>Giulio
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<br></div></body>
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</html>
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</table></div> |