Bouncer does not block when ban gets readded

I run an instance of Uptime-Kuma and added the IP of the Container to my crowdsec banlist. Like this I can check the functionality of the firewall bouncer with hitting the secured host with a tcp request and get a timeout because the IP is blocked. If the blocking does not work anymore, I get an notification. The secured host uses nftables as firewall.

I created a cron job, adding the descision every night with 25h duration. Like this I am sure, the ban does never end.

But now the strange things happen.

the firewallbouncer blocks everything like expected
after 24h I get notified the block is no longer working
when the decision is readded at the second night, the ban starts working again

In crowdsec itself i can list the decision and my manually added one is there all the time.

It looks to me like the firewallbouncer adds a rule with the bantime at time x. When the decision gets added again at time y the bouncer just checks that the ip is already banned but does not extend or rewrite the bantime of the nftables rule to "y + bantime". Therefore the rule expires after "x + bantime". (just my impression)

Attempt to replicate doesn't seem to be an issue with the actual LAPI. It may be an issue adding the IP to the ruleset if the IP already exists so most likely need to implement a check if it does then update it??

╭─loz repo: crowdsec on  master [!] via  v1.20.2 as 🧙 took 11ms
╰─λ sudo cscli decisions add --ip 1.2.3.4
INFO[16-03-2023 13:54:32] Decision successfully added

╭─loz repo: crowdsec on  master [!] via  v1.20.2 as 🧙 took 85ms
╰─λ curl -H "X-Api-Key: $C_API_KEY" "http://127.0.0.1:8080/v1/decisions/stream?startup=true"
{"deleted":null,"new":[{"duration":"3h59m58.43935709s","id":452794,"origin":"cscli","scenario":"manual 'ban' from '6df9e06234fa428d9ba8e78f9b557c4aGkQkN2JSuj3A6d7I'","scope":"Ip","type":"ban","uuid":"21040800-6d54-4d87-b4f4-db560636cea0","value":"1.2.3.4"}]}⏎                                                        

╭─loz repo: crowdsec on  master [!] via  v1.20.2 as 🧙 took 11ms
╰─λ curl -H "X-Api-Key: $C_API_KEY" "http://127.0.0.1:8080/v1/decisions/stream?startup=false"
{"deleted":null,"new":null}⏎           

╭─loz repo: crowdsec on  master [!] via  v1.20.2 as 🧙 took 11ms
╰─λ sudo cscli decisions add --ip 1.2.3.4
INFO[16-03-2023 13:54:47] Decision successfully added

╭─loz repo: crowdsec on  master [!] via  v1.20.2 as 🧙 took 89ms
╰─λ curl -H "X-Api-Key: $C_API_KEY" "http://127.0.0.1:8080/v1/decisions/stream?startup=false"
{"deleted":null,"new":[{"duration":"3h59m57.396779288s","id":452795,"origin":"cscli","scenario":"manual 'ban' from '6df9e06234fa428d9ba8e78f9b557c4aGkQkN2JSuj3A6d7I'","scope":"Ip","type":"ban","uuid":"81ac7236-a96a-4b14-9f6c-aec27ab42fb5","value":"1.2.3.4"}]}⏎

EDIT: checking with the team it most likely an issue just with NFTables as it doesn't like overlapping IP's or ranges so we implemented a check but I guess the check didn't go as fast as checking if the decisions is new as you can run the bouncer in ipset mode only meaning nothing is lost between reboots.

crowdsecurity / cs-firewall-bouncer

Bouncer does not block when ban gets readded #243