glovebox-hosts

The one answer to "which host is this" that every part of glovebox uses: the egress proxy's verdict service, the launcher, the WebFetch hook, the session driver and the evals.

A host is compared in one spelling: ASCII only, surrounding whitespace removed, lowercased, and an IP literal in its standard form. A name that is not ASCII, or that starts or ends with a dot, is refused with HostError rather than folded, so two readers can never disagree about it.

>>> from glovebox_hosts import canonical_host, split_authority, granting_entries
>>> split_authority("[2001:DB8::1]:443")
('2001:db8::1', 443)
>>> granting_entries("API.example.com", ["example.com"])
['example.com']
>>> granting_entries("a.b.example.com", ["example.com"])
[]

A grant on a name reaches that host alone, and a *.S grant every name below S. A bar (constraining_entries) reaches any depth. A grant may not name a *. wildcard over a public suffix, or over a name with one below it (suffix_below): grant_name_refusal says why, reading the Public Suffix List that tldextract bundles. A grant on a public suffix itself is allowed, since it reaches that one host. That is the package's one dependency, and it is imported only when a grant name is judged.

pod_grants reads a Kata pod's glovebox.dev/egress-grants annotation as every node reads it, so an admission webhook can refuse a pod at submission for the same reason the node would refuse it later. It returns the granted hosts at their tiers, the address grants and the port grants, and raises GrantRefused with the node's own message for the first entry the node refuses. How wide an address grant may be is each node's own setting, so it is not checked here.

A host with a port, such as {"host": "git.example.com:22", "rw": true}, is a port grant. The node relays a raw stream to that port on the name's public addresses, so it needs "rw": true. A host without a port keeps its plain host meaning.

>>> from glovebox_hosts import GrantRefused, pod_grants
>>> granted = pod_grants('["httpbin.org", {"host": "git.example.com:22", "rw": true}]')
>>> granted.hosts
{'httpbin.org': 'ro'}
>>> granted.ports
[PortGrant(host='git.example.com', port=22)]
>>> pod_grants('["*.amazonaws.com"]')
Traceback (most recent call last):
...
glovebox_hosts.GrantRefused: glovebox.dev/egress-grants: '*.amazonaws.com' is a wildcard over a name with the public suffix ...

glovebox_hosts.flock holds an exclusive file lock: held for a block, or acquire and release when the hold spans two calls. It lives here because the host tools and the monitor package can both import it.