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docs(specs): refuse names a box's allow list does not match before forwarding upstream - #2009
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…rwarding upstream
Spec 18 had no requirement for the non-matching case of a box's
egress.allow_dns_hosts. NET-066 covers only matched names. Design
section 5.3 states the rule as normative ("Non-matching names are
refused"), and the spec's own annotation on NET-003 assumes it.
Add NET-141, the complement of NET-066.
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| Check name | Status | Explanation |
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| Title check |  |
The title clearly and concisely describes the main change: refusing unmatched DNS names before upstream forwarding. It uses a valid Conventional Commit style. |
| Description check | |
The description provides a detailed summary, rationale, requirement scope, limitations, and validation information. It uses a "Validation" section instead of the template's "Testing" section and omits… |
| Docstring Coverage | |
Docstring coverage is 90.91% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 11 functions across 6 files. (1 skipped: 1 … |
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Check skipped because no linked issues were found for this pull request. |
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Explanation
The description provides a detailed summary, rationale, requirement scope, limitations, and validation information. It uses a "Validation" section instead of the template's "Testing" section and omits the checklist, but it remains mostly complete.
Full details: Docstring Coverage
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Explanation
Docstring coverage is 90.91% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 11 functions across 6 files. (1 skipped: 1 unsupported.)
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A rabbit checks the resolver's door
Unmatched names are forwarded no more
NET-141 takes its place
NET-143 marks the gate
Clear references hop across the floor
Comment @coderabbitai help to get the list of available commands.
Spec lint
Advisory. None of this blocks the merge; the review decides. Advisory, and never a merge gate. Linter: |
Define the onward hop as any resolver beyond the one Minimal owns for the box, answer REFUSED rather than NXDOMAIN or a timeout, decide refusal with NET-066's matcher, scope the requirement to queries that reach Minimal's resolver (native host-address boxes are the conceded residual), raise it to T1 with a property, and add the egress invariant it covers.
…owns Move the scope into the requirement's trigger and the invariant, name the native host-address bypass as the invariant's residual, and say which resolver Minimal owns for each box type: the relay's DNS gate for an own-address box, the node's DNS layer for a host-address box inside a VM-backed host once its routing lands.
Match the invariant's enforcement to NET-066's two legs, require the VM-host proof at the host-side leg, record that minvmd cannot yet refuse a query, and state both limits visibly in Design reasoning.
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Reviewed: 3 findings, none blocking at Address the comments on the diff. Clobber: None found. No other NET-143 exists, and the remaining NET-141 references in code and |
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/revise |
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Round 1 of 1 is on this pull request. branch Updated 2026-10-07T00:19:35.401Z. |
The invariant's enforced by claimed the VM-backed refusal is decided host-side in minvmd's DNS gate, while the design-reasoning paragraph the same branch added states minvmd cannot refuse a query yet, so the refusal holds only inside the VM. A reader of the invariant alone believed the host-side gate enforces the guarantee today. The enforced by now says where the refusal is answered, names the host-side leg as the residual until minvmd can refuse a query itself, and points at the design reasoning, which states both limits.
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Round 1 of 1 on a /revise note, pushed as No Review threads the coder judged:
On this branch, the NET-141 security invariant's 'enforced by' now names its own residual: a reader of the invariant alone sees that on a VM-backed host the refusal is made at the in-VM gate, for as long as minvmd's host-side DNS gate cannot refuse a query itself, and is pointed at the design-reasoning paragraph that states that residual and the native host-address box's bypass — so the invariant no longer claims a host-side enforcement the same PR concedes is not yet present. Notes from the agent: One thread, judged valid and fixed. The PR is docs-only (spec 18's NET-141 requirement, its design-reasoning paragraph, and its security invariant); no product code and no cargo tests exist for it on this branch, and the survey left no 'test:' line, so the repository's declared gate for markdown — 'just lint-prose' — is the verification that was run. 'vale' is not installed on this box, so the recipe's _need check fails as shipped; I fetched the pinned-style-compatible release binary into /tmp (styles sync wrote only gitignored paths under styles/, verified 'git status' clean before commit) and ran the recipe's own command path against the spec. The gate is red on this file both before and after the change: the branch inherits the file's long-standing alert load (long EARS sentences, semicolons, ste/ai-tells hits that every requirement block carries), which the AGENTS.md prose rule tells a revise round to leave alone ('in a revise or conflict round the directive bounds the change, so report its hits in notes rather than fix them'). What the change had to not do is add alerts, and it did not: the edited block dropped its ste.Semicolon error and one SentenceLength warning and added nothing. Working-tree hygiene: only the one spec file was committed; /tmp held the binary and scratch lint candidates. The directive carried no conflicts.txt and no note beyond the thread. |
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Inline comments:
Review comments at @docs/specs/18-spec-box-networking/18-spec-box-networking.md:
- Line 456: Update the session e2e coverage claim in the networking
specification to state that the current test does not verify whether
non-matching names trigger onward queries. Keep the separate refusal requirement
intact; do not claim the session e2e proves no forwarding.
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…nmatched-names # Conflicts: # docs/specs/18-spec-box-networking/18-spec-box-networking.md
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Inline comments:
Review comments at @docs/specs/18-spec-box-networking/18-spec-box-networking.md:
- Line 455: Update the resolver forwarding property to allow forwarding when the
name matches an allow pattern or is in the box zone. Preserve the rule that
unmatched names outside the zone are never forwarded.
- Line 456: Update the session e2e coverage description to state that it does
not observe whether an onward DNS query occurs; do not claim it observes no
onward query. Keep the surrounding description of what the test checks
unchanged.
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… its property The session e2e's disallowed-name leg asserts only that the connection does not complete; the T1 property is the proof of no onward query. The property allows a zone name to be forwarded, as the relay does for an in-zone A query. The relay refuses only for a deny-all box today, so the partial allow list is a known gap.
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The deny-all box's leg already asserts a fast resolution failure. Only the leg of the box with a partial allow list does not.
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Approving. NET-141 closes a real gap: unmatched names get REFUSED with no onward query, which design §5.3 already requires. The property now allows forwarding only for matched or in-zone names.
One nit, not blocking (minimal-review's low-severity note is right): NET-141's annotation says the session e2e's disallowed-name leg must assert a fast resolution failure once the refusal ships. It already does on main: scripts/session-e2e.sh:2100-2105 requires the deny-all box's getent ahostsv4 example.com to fail in under 5 s, and :2166-2175 requires curl https://example.com to fail with "could not resolve". Worth rewording it to say the e2e already asserts the fast refusal.
Pull request was converted to draft
…nmatched-names # Conflicts: # docs/specs/18-spec-box-networking/18-spec-box-networking.md
NET-141 names the resolver's refusal of names a box's allow list does not match, the meaning the DNS gate code and the session e2e already cite. The user-namespace gate took the same number on main; it moves to NET-143 in the spec and in the comments that cite it.
| - **NET-141** WHEN the resolver Minimal owns for a box receives a query for a name that its `egress.allow_dns_hosts` does not match, as NET-066 matches names, and that is not in the box zone (NET-072, including `host.min.internal`), THE SYSTEM SHALL answer REFUSED and forward the query to no resolver beyond it. | ||
| tier: T1 | ||
| verify: cargo nextest run -p minimald unmatched_name_refused_without_upstream_forward | ||
| property: for every name, every allow-pattern set, and every zone, the resolver forwards the query beyond the one Minimal owns for the box only if the name matches a pattern or is in the zone, and it never forwards a name that matches none and is not in the zone |
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LOW · correctness · confidence 0.60 · in NET-141
NET-141 states a general rule and a property over every allow-pattern set. Its verify: test unmatched_name_refused_without_upstream_forward in crates/minimald/src/net/dns_gate.rs drives only a deny-all relay (deny_all_egress()). The annotation admits that a partial allow list is still forwarded. So the requirement is false for partial lists and the verify line passes without proving it. Add a partial-list case to the test, or scope the requirement to deny-all until the gate refuses for every list.
What the reviewer checked
dns_gate.rs:2687 test uses spawn_test_relay(&deny_all_egress()); annotation: 'NET-141 holds only for deny-all boxes'
Hand this to an agent
Act on a code-review finding.
File: docs/specs/18-spec-box-networking/18-spec-box-networking.md
Lines: 487-490
Category: correctness
Severity: low (reviewer confidence 0.60)
Finding:
NET-141 states a general rule and a property over every allow-pattern set. Its `verify:` test `unmatched_name_refused_without_upstream_forward` in `crates/minimald/src/net/dns_gate.rs` drives only a deny-all relay (`deny_all_egress()`). The annotation admits that a partial allow list is still forwarded. So the requirement is false for partial lists and the verify line passes without proving it. Add a partial-list case to the test, or scope the requirement to deny-all until the gate refuses for every list.
First verify this against the code yourself. It is model output and
may be wrong. If it is wrong, or the tradeoff was deliberate, say so
and change nothing.
👍 useful · 👎 noise — react to tell the reviewer. Replying works too, and says more.
| for a box (NET-141) has two stated limits. A native host-address box shares the | ||
| host's network namespace. If its egress rules allow the host's own resolver, | ||
| it can query that resolver directly, and no Minimal resolver sees the query. | ||
| The design concedes this reduced tier for host-address boxes. On a VM-backed | ||
| host, the host-side DNS table cannot yet refuse a query. Until it can, the | ||
| refusal holds only inside the VM, below the escape boundary. |
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LOW · correctness · confidence 0.50 · in NET-141
The text says the host-side DNS table cannot yet refuse a query. But crates/minvmd/src/net/dns_pins.rs (deny_all_refusal) already decides deny-all box queries host-side. It drops them before the switch. The residual is true for partial allow lists only. State that difference, or the paragraph and the invariant misdescribe the deny-all case.
What the reviewer checked
d 10BC8 ns_pins.rs:1299 'The host-side deny-all DNS gate ... decided outside the VM for own-address rows'
Hand this to an agent
Act on a code-review finding.
File: docs/specs/18-spec-box-networking/18-spec-box-networking.md
Lines: 1296-1301
Category: correctness
Severity: low (reviewer confidence 0.50)
Finding:
The text says the host-side DNS table cannot yet refuse a query. But `crates/minvmd/src/net/dns_pins.rs` (`deny_all_refusal`) already decides deny-all box queries host-side. It drops them before the switch. The residual is true for partial allow lists only. State that difference, or the paragraph and the invariant misdescribe the deny-all case.
First verify this against the code yourself. It is model output and
may be wrong. If it is wrong, or the tradeoff was deliberate, say so
and change nothing.
👍 useful · 👎 noise — react to tell the reviewer. Replying works too, and says more.
| - **Invariant:** THE SYSTEM SHALL carry no name that a box's allow list does | ||
| not match, outside the box zone, beyond the resolver Minimal owns for the | ||
| box, for every query that reaches that resolver. | ||
| enforced by: the refusal at the resolver Minimal owns for the box. On a | ||
| VM-backed host the in-VM gate makes it, until minvmd's host-side DNS gate | ||
| can refuse a query itself. That residual and the native host-address box's | ||
| bypass are the two limits stated in the design reasoning. | ||
| covered by: NET-141 |
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LOW · security · confidence 0.55 · in NET-141
The new invariant says no unmatched name leaves the box's resolver, with no qualifier. NET-141's own comment says the relay's DNS gate refuses only for deny-all boxes. A box with a partial allow list still forwards unmatched names upstream, and the verify test covers only deny-all. The invariant is therefore false today for the common case, and a reader will assume the exfiltration channel is closed. Add the partial-allow-list gap to the invariant's enforced by text, next to the two stated limits.
What the reviewer checked
NET-141 comment: 'Known gap: the relay's DNS gate refuses only for a deny-all box ... Until the gate refuses for every allow list and the test covers a partial list, NET-141 holds only for deny-all boxes.'
Hand this to an agent
Act on a code-review finding.
File: docs/specs/18-spec-box-networking/18-spec-box-networking.md
Lines: 1340-1347
Category: security
Severity: low (reviewer confidence 0.55)
Finding:
The new invariant says no unmatched name leaves the box's resolver, with no qualifier. NET-141's own comment says the relay's DNS gate refuses only for deny-all boxes. A box with a partial allow list still forwards unmatched names upstream, and the verify test covers only deny-all. The invariant is therefore false today for the common case, and a reader will assume the exfiltration channel is closed. Add the partial-allow-list gap to the invariant's `enforced by` text, next to the two stated limits.
First verify this against the code yourself. It is model output and
may be wrong. If it is wrong, or the tradeoff was deliberate, say so
and change nothing.
👍 useful · 👎 noise — react to tell the reviewer. Replying works too, and says more.
# Conflicts: # crates/minimald/src/rpc.rs
Summary
Adds NET-141 to spec 18. It is the complement of NET-066:
Why
NET-066 covers only matched names, where it admits the answer's addresses. Nothing in the spec covers a name the allow list does not match. Today such a query is forwarded upstream, the box gets an answer, and only the connection that follows is dropped (NET-062). A forwarded query already carries data out in the queried name, so dropping the connection afterwards is too late.
This is a gap in the spec, not a design choice:
What the requirement says
host.min.internal. Names steered to the Box Egress Proxy need no exemption, because the credentialed set stays inside the allow list.Not in this PR
The deny-all case is on main: the relay's DNS gate refuses a deny-all box's names outside the zone, and
unmatched_name_refused_without_upstream_forwardtests it. Two parts are separate work:Until that work lands, the egress allow-list slice of the box-networking epic carries this as a known gap.
Validation
just lint-proseon the spec: the new requirement adds only the alerts that every requirement block in the file already has (theverify:line and long EARS sentences).Summary by CodeRabbit