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housecarl/docs/permissions.md
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abrown38andClaude Opus 5.5 34292eeebb Build Housecarl 0.1.0: the nftables firewall manager
Zones, address sets (IPv4 and IPv6 mixed, dynamic sets with timeouts) and
services, ordered rules in the early, input, forward and output chains,
port forwards with hairpin NAT and IPv6 pinholes, source NAT, redirects,
and switchable built-ins (loopback, conntrack, ICMPv6, antispoofing, MSS
clamping, DHCPv6 client, flowtable). Every change is validated, checked
with nft -c and applied in one transaction to Housecarl's own table,
inet housecarl; changes made over the network roll back unless
confirmed, and the confirmed ruleset is loaded at boot by
housecarl-ruleset.service. An empty configuration applies nothing.

Also: hit counters and the drop log (nflog), 'hc import' of an existing
nftables ruleset and 'hc takeover', the hc CLI, the REST API and the web
UI, users, scoped tokens (sets:write:NAME), the audit log, the web UI's
certificate through Jarl, Debian packages, docs, unit tests with real
nft 1.1.3, and an e2e test with real traffic (71 checks).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-19 07:57:14 +01:00

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Users, permissions and tokens

Users

Administrators may do everything, including managing users. Everyone else gets grants, resource:access:

Resource read write
config settings, zones, sets, services, rules, NAT, the ruleset, history, interfaces, probation (the web UI shows the forms locked) change them, undo, import, confirm and roll back
sets dynamic sets' entries add and remove entries
log hit counters and the log –
audit the audit log –
* all of the above

A sets grant can name the sets it covers: sets:write:guests may change the entries of the set guests and no other; sets:read:guests,blocked may read two. That is the grant for another program, such as Steward's captive portal, which should be able to let a client in and nothing more. A dynamic set's entries need a sets grant even for those with config:write.

Only administrators may delete other tables (hc takeover), and manage users and the certificate (hc cert, Server → Certificate).

Roles are ready-made sets of grants:

Role Grants
viewer config:read sets:read log:read
operator config:write sets:write log:read audit:read
log log:read, e.g. for a monitoring script
hc user add sam --role operator
hc user add portal --no-password --grant sets:write:guests     # tokens only
hc user update sam --grant config:read --grant log:read

The last administrator can't be removed, demoted or disabled.

API tokens

A token has its user's permissions, or fewer. A token made with --role or --grant can do only that, even if its user can do more:

hc token create portal --user portal --grant sets:write:guests --expires 365d

The secret is shown once; only its hash is stored. A restricted token can only create tokens with a subset of its own grants. The web UI only offers roles within what your account may do; a token with more would get no more than its user anyway.

Rotating gives a token a new secret, keeping its ID, name and permissions, so only the programs that use it need updating:

hc token rotate 7 --grace 1h           # the old secret works for another hour
hc token rotate --current --save       # this CLI's own token

A token that expires gets its lifetime again, from now (--expires 90d or never to change it). Without --grace the old secret stops at once: use that when it may have leaked. Using an old secret during its grace period is logged, naming the token and the address, so you can find the programs still to update. A restricted token may rotate itself and tokens no wider than itself. hc token list shows when each token was last used, and from where. hc token revoke ID stops one at once.

The local socket

On the firewall, /run/housecarl/housecarl.sock lets root and the housecarl user act as administrator without a token, and their changes aren't on probation. The audit log shows them by their system user name. Both can already change the machine's firewall, so this adds convenience, not power. Anyone else on the socket needs a token, and their changes are on probation like any other.

The audit log

Logins (and failed ones), users, tokens, every configuration change (with its history entry), confirmations and rollbacks, imports, takeovers and dynamic set entries are recorded with who, from where and how: session, token or socket.