[pve-devel] [PATCH] firewall: resources: accept invalid ct state by default

[Hannes Laimer]

We only add a `block-conntrack-invalid` jump to the in chain, if
the `nf_conntrack_allow_invalid` option is not set in the config. But we
already drop connections with an invalid ct state by default. So we have
to either allow connections with an invalid ct state by default, or explicitly
allow them when checking for the option and keeping them blocked by default.
I chose to change the 'default' as it has the same result but is
simpler a change.

Signed-off-by: Hannes Laimer <h.laimer at proxmox.com>
---
relevant code[1]
```
        if self.config.host().block_invalid_conntrack() {
            log::debug!("set block_invalid_conntrack");

            commands.push(Add::rule(AddRule::from_statement(
                chain_in,
                Statement::jump("block-conntrack-invalid"),
            )));
        }
```
I am not sure whether adding a jump to `block-conntrack-invalid` would
also make sense for the out chain.

[1] https://git.proxmox.com/?p=proxmox-firewall.git;a=blob;f=proxmox-firewall/src/firewall.rs;h=941aa2008b4e3a22d9b37a0f8bc39c3643eb97c8;hb=bea3e651b47f2a9113b93e45db2904ddfd2fe174#l394

 proxmox-firewall/resources/proxmox-firewall.nft | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/proxmox-firewall/resources/proxmox-firewall.nft b/proxmox-firewall/resources/proxmox-firewall.nft
index f42255c..be9a930 100644
--- a/proxmox-firewall/resources/proxmox-firewall.nft
+++ b/proxmox-firewall/resources/proxmox-firewall.nft
@@ -316,7 +316,7 @@ table bridge proxmox-firewall-guests {
     }
 
     chain pre-vm-out {
-        meta protocol != arp ct state vmap { established : accept, related : accept, invalid : drop }
+        meta protocol != arp ct state vmap { established : accept, related : accept, invalid : accept }
     }
 
     chain vm-out {
@@ -326,7 +326,7 @@ table bridge proxmox-firewall-guests {
     }
 
     chain pre-vm-in {
-        meta protocol != arp ct state vmap { established : accept, related : accept, invalid : drop }
+        meta protocol != arp ct state vmap { established : accept, related : accept, invalid : accept }
         meta protocol arp accept
     }
 
-- 
2.39.5