3 Commits

Author SHA1 Message Date
Kristoffer Dalby
d5b2837231 policy/v2: match default proto set for tests with no proto
The policy `tests` block lets entries omit `proto`. Tailscale's client
maps that to the default protocol set {TCP, UDP, ICMP, ICMPv6} — the
captured packet_filter_matches show all four IANA numbers explicitly
when no proto is set — and a rule restricted to any one of them
satisfies an empty-proto reachability test.

srcReachesDst was passing the empty Protocol through unchanged, which
landed an empty []int in ruleMatchesProto. The matcher then short-
circuited to "no match" for every rule with a non-empty IPProto
restriction, including TCP-only grants compiled from `ip: ["tcp:80"]`.
The bug surfaced in the captured allpass-acls-and-grants-mixed
scenario: the grant `tag:client → webserver:80` was reachable in the
compiled filter but the empty-proto test could not see it.

Expand the empty Protocol to the default set at the call site so
ruleMatchesProto's intersection check sees the right requested
protocols. Drop the now-dead empty-requestedProtos branch from the
matcher. The last divergence drops out of knownPolicyTesterDivergences
as a result.

Updates #1803
2026-05-12 11:54:54 +01:00
Kristoffer Dalby
f172dba0e3 policy/v2: validate tests block at parse boundary
A `tests` entry describes one connection attempt to one specific
host on one specific port over a connection-oriented protocol, and
asserts whether it is allowed or denied. Five shape rules follow —
single-port dst, proto in {tcp, udp, sctp, ""}, no
autogroup:internet dst, no CIDR-typed dst (raw `/N` or hosts:-alias
to a multi-host prefix), at least one of accept/deny — and every
one was previously silently accepted by headscale even though
Tailscale SaaS rejects them as "test(s) failed".

Enforce them in one pass over `pol.Tests` from `Policy.validate()`,
reusing the existing parse-time multierr aggregation. The same
shapes remain valid inside ACL or Grant destinations where the rule
does not apply; the validator only walks the tests array.

The compat runner now treats parse-time errors equivalently to
SetPolicy errors so the captured Tailscale body still matches via
substring regardless of which step surfaces the rejection. Nine
divergences resolved by this validation pass drop out of
knownPolicyTesterDivergences.

Updates #1803
2026-05-12 11:54:54 +01:00
Kristoffer Dalby
b29ae25356 policy/v2: evaluate the tests block on user-initiated writes
v2 silently dropped policy.tests, so a policy that contradicted its
own assertions still applied. Resolve src/dst via the existing Alias
machinery, walk the compiled global filter rules (acls and grants
both contribute), and run on every user-write boundary: SetPolicy,
the file watcher, and `headscale policy check`. A failing test
rejects the write before it mutates live state.

Boot-time reload skips evaluation; an already-stored policy that
references a deleted user shouldn't lock the server out.

`headscale policy check` is a thin frontend for the new CheckPolicy
gRPC method. The server-side handler builds a fresh PolicyManager
from the request bytes and the state's live users/nodes, runs
SetPolicy on the sandbox so the tests block executes, and returns
the result through gRPC status. No persistence, no policy_mode
coupling. --bypass-grpc-and-access-database-directly opens the DB
directly when the server is not running.

cmd/headscale/cli/root.go no longer special-cases `policy check` in
init() (the early return from PR #2580 broke --config registration
and viper priming for --bypass).

integration/cli_policy_test.go covers policy_mode={file,database} x
fixture={acl-only, acl+passing-tests, acl+failing-tests} x
bypass={false,true} = 12 rows.

Updates #1803

Co-authored-by: Janis Jansons <janhouse@gmail.com>
2026-05-12 11:54:54 +01:00