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T47 — Place each host-address box in its own classifier leaf and keep it there - #1768
norrietaylor merged 32 commits into
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NET-079's sandbox half: a box configured with a classifier leaf is launched so it can neither see nor join another box's leaf. `sandbox2::classifier` owns the tree layout the privileged step installs: the daemon runs in a sibling leaf of every box leaf (`<root>/daemon`, never the root itself — a controller enabled on the root would make the box leaves unusable, and the daemon's own traffic must stay distinguishable), each box gets `<root>/boxes/<sanitized-session-name>`, and the placement primitives a daemon needs are the module's: create the leaf before the spawn, move each forked process in by writing its pid to the leaf's `cgroup.procs`, remove the leaf when the box is gone. The box-id is derived, never trusted: a session name is user input, and the leaf is a directory in a root-owned tree. `Config::with_classifier_leaf` carries the leaf, opt-in: a host that cannot decide per box keeps launching boxes exactly as before (NET-079's exception), never refusing them. `Sandbox::new_container` masks every cgroup mountpoint the host's mount table names — the conventional `/sys/fs/cgroup` always — with an empty tmpfs, so no cgroup view survives inside the box that is not rooted at its own cgroup-namespace root. The launch log line names the leaf the box entered, its `cgroup.procs`, the host's cgroup mounts and whether each carries `nsdelegate`, and whether the mask was applied. `box_cannot_see_or_join_a_sibling_leaf` proves both halves: placement over a stand-in tree (a hostile session name stays one component, every forked process is written into the leaf, the leaf is removed once and its absence is success), and visibility in a real box launched through the production path, where the cgroup mountpoint reports the mask's tmpfs and a sibling leaf's `cgroup.procs` cannot even be opened.
NET-079's daemon half: the leaf a session's box is decided on is created before its first process exists, both processes it starts with are moved into it right after the spawn, and injected ones join it before they join the box's namespaces. `session_host` creates the leaf before the launch, under the tree the privileged step installs natively and the guest daemon mounts itself. `None` — never an error — means this host places no box: the session runs unenforced (NET-079's exception), and the log says so, at info for a tree that was never installed and at warn for one that refused. `launch` moves the box's processes into their leaf right after the spawn: hakoniwa forks the container supervisor inside `spawn()`, and that supervisor forks the program it execs before `spawn()` returns, so both are written in from the daemon's own namespaces, where the leaf is reachable. Everything either forks later inherits it. A `BoxLeafGuard` owns the leaf from creation to the handoff, so a launch abandoned in between — a failed build, a cancelled future — removes it, dropping after the process guard so the box's processes are gone before their leaf is. The `SandboxBackend` owns it from there and removes it at session end, tearing the process down first. `nsenter` joins injected processes to the same leaf in the shim, *before* `setns`: joining the box's namespaces puts the shim in the box's cgroup namespace, whose root is the daemon's leaf and from which the box's own leaf is unreachable by design, so the write has to happen from the daemon's side. The host carries the session's leaf to every injection for that. `main` enters the daemon's own leaf at start — a *sibling* of every box leaf, never the tree root, where a controller would make the box leaves unusable — so each box is unshared into a cgroup namespace rooted at a childless leaf. `guest` mounts cgroup2 with `nsdelegate` in the VM so the same tree exists there, built by pid 1 itself. `daemon_enters_its_own_leaf` proves the daemon's placement over a stand-in tree (this test host may have no cgroup2 of its own): its pid lands in `<root>/daemon/cgroup.procs`, the cohort exists beside it, and a box's leaf is created in that cohort, never beside the daemon's.
…step On a native host the daemon cannot create the tree its boxes are placed in: its uid has no write access above `boxes/`, which is the barrier that stops a box reaching a sibling leaf by uid alone. scripts/install-host- classifier.sh is the step that does it, mirroring sandbox2::classifier's constants: it lays out /sys/fs/cgroup/minimald.slice with a `daemon` leaf and a `boxes/` cohort, and delegates exactly those two leaves — recursively — to the account minimald runs as, leaving the tree above them root-owned. It refuses everything the confinement would silently rest on otherwise: - no cgroup2 mount covering the tree root (deepest mountpoint prefix match, so a host that mounts the hierarchy elsewhere still works), - no `nsdelegate`, without which a cgroup namespace is not a delegation boundary and a box could migrate out of its leaf, - a mount rooted elsewhere than "/" — another cgroup namespace's view, which would put the tree inside it instead of on the host, - no account to delegate to, and root itself, which would hand every box the account that owns the tree. `--check` rehearses the assertions unprivileged for "why is my box unenforced?", and `--uninstall` rmdirs (never rm -rf: on the real filesystem these are cgroups, and the kernel refuses to remove one that still holds a process, which is the guard wanted when minimald is live). The harness cannot mount cgroup2, so install_test.sh's new case drives the script through its MINIMAL_OVERRIDE_CGROUP_MOUNTINFO seam over a stand-in mount table, with a recording `chown` stub pinning that delegation reached the two leaves and never the tree root.
…-host-address-box-in-its-own-classifie # Conflicts: # scripts/install_test.sh
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The macOS /bi 8000 n/sh lane of the installer suite failed on the first round: the host_classifier_tree_installed case stubbed chown with an exec of /usr/bin/chown, which does not exist on a BSD host (chown lives in /usr/sbin there), so every install rehearsal died with 127 and four assertions fell over. The stub now records the delegation argv and succeeds without exec'ing anything: on the stand-in tree the caller owns the files either way, the real chown runs as root on the host the script installs on, and the recorded argv is the whole decision under test. Two neighbouring portability faults in install-host-classifier.sh get the same treatment while the file is open, both invisible to the Linux lanes: --help stripped its comment prefix with GNU sed's \?, which BSD sed does not know, and the tree was laid out with install -d, whose BSD flavour is a different tool with its own default mode — mkdir -p is the operation a cgroup2 mount understands and the one POSIX guarantees.
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Round 1 of 10 on a failed check suite, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. A host-address box runs in a classifier leaf of its own from its first process to its last — an injected process joins the leaf from the daemon's cgroup namespace before it joins the box's namespaces, and a box can neither see nor join a sibling leaf — while minimald itself enters its own leaf at start, the guest mounts cgroup2 delegated, and the privileged installer step lays out the root-owned tree those placements need; the installer's own suite now passes under every POSIX sh the CI lane runs, macOS's /bin/sh included, which is what this round repaired. Notes from the agent: Revise round 1: the two failed checks (ci-shell-installer-success and its test (macos-latest / sh) lane) came from the harness's chown stub, which exec'd a hard-coded /usr/bin/chown — that path does not exist on macOS, where chown lives in /usr/sbin, so every install rehearsal died with 127 and four assertions fell over. Reproduced locally by pointing the stub at a missing path (identical 4-failure signature), then fixed: the stub records the delegation argv and exits 0, exec'ing nothing, because the stand-in tree is already the caller's, the real chown runs as root on the host the script installs on, and the recorded argv is the whole decision the case pins. Two neighbouring BSD faults in install-host-classifier.sh were fixed while the file was open, neither visible to the Linux lanes: --help stripped its comment prefix with GNU sed's ?, and the tree was laid out with install -d (a different tool under BSD); mkdir -p replaces it and is the operation a cgroup2 mount understands. This box has neither macOS's /bin/sh (bash 3.2) nor dash, so those lanes are reasoned rather than run: the case now uses only POSIX constructs, the script keeps its BSD stat fallback, and its bash-isms (arrays, +=, here-strings) all predate bash 4. Beyond this round, the branch diff also touches crates/minimald/src/env.rs, which the task's layers do not name: it plumbs the new ClassifierLeaf config fiel…[truncated] |
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/revise design conformance check against gominimal/arch: the tree layout, the privileged install step, the daemon's own leaf and the injection ordering PASS. Two things fail and must change. 1. The box's leaf must be the root of its cgroup namespace (architecture.md line 1221, Box Resources). The design says: "Its memory cgroup is the root of its cgroup namespace; a process joins that cgroup before it enters any of the box's namespaces; its limits are not writable from inside." This PR unshares all namespaces first, so the box's cgroup-namespace root is the daemon's leaf and 2. In the guest the daemon must not launch Keep the three plan test lines green, run |
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Review of ebc7349 against the T47 plan block. The design round already requested above stands; these are code defects to fix in the same or the next round.
Blocking: native placement cannot succeed for an unprivileged daemon. cgroup v2 delegation containment (kernel docs, "Delegation Containment") requires the writer to have write access to cgroup.procs of the common ancestor of the source and destination cgroups. Natively minimald is autospawned as the user (crates/minimal/src/autospawn.rs:415) and the installer keeps minimald.slice root-owned, chowning only daemon/ and boxes/. So every move fails with EACCES: enter_daemon_leaf (main.rs, from user.slice/… to minimald.slice/daemon, ancestor is the root cgroup), place_box_processes (session_host.rs, daemon/ to boxes/<id>, ancestor is minimald.slice), and the shim's self-join in nsenter.rs. All three degrade to warn lines, so on a native host every box runs unplaced and the proof holds only in the guest where the daemon is root. Fix direction: the privileged install step must delegate a subtree the daemon can move within, which means minimald.slice's own cgroup.procs writable by the daemon account (the barrier against boxes is nsdelegate at the box's namespace root, not the slice's uid), and the daemon's first entry into daemon/ from user.slice needs either a root-run placement at install or start time or a systemd Delegate= unit. Add a test that performs a real migration on a delegated tree, or gate the proof on one, so the EACCES path cannot pass silently.
"First process to last" is not met. Placement runs after spawn() returns (session_host.rs), when the program has already exec'd; anything it forks or connects before the write stays in daemon/. Move the process before exec: write the child's pid into the leaf in the pre-exec hook of the sandbox (the same place the shim joins), or have the supervisor join the leaf before it forks the program.
Leaf collisions. sanitize_box_id maps distinct session names to one id ("a b" and "ab", names over 64 bytes), and create_box_leaf treats AlreadyExists as reuse, so two live boxes silently share a leaf and a verdict, and the first to exit gets rmdir EBUSY. Key the leaf on the session id.
Tests that do not test the claim. daemon_enters_its_own_leaf writes a pid into a plain file under a tempdir; it exercises no session_host code and no kernel. In box_cannot_see_or_join_a_sibling_leaf the "open sibling procs fails" assertion is vacuous (the path is absent on any host), "join" is untested, and the test passes silently when user namespaces are denied. Each of these needs a real assertion or an explicit skip with a reason line.
Minor. Drop for SandboxBackend can race remove_box_leaf against the pdeathsig kill (EBUSY, leaf leaked); the recreate-same-name race between an old backend's rmdir and a new launch's create leaves the new box unplaced; host_mount_hidden in the launch line is a constant true whenever a leaf is set, so it reports nothing.
Out-of-layer touches to env.rs and install_test.sh are minimal and justified.
The box's first process now joins its classifier leaf in its pre-exec closure and only then unshares the cgroup namespace, so the leaf is the namespace root (architecture, Box Resources): a sibling leaf is below neither it nor any cgroup view the box can mount, and the root's own cgroup.procs is unwritable from inside. The tree the leaf belongs to is bound at the conventional cgroup mountpoint for the join, and a read-only cgroup2 view is mounted over it afterwards — the box reads its limit where a cgroup-aware runtime looks (memory.max) and can migrate nowhere, on any host's mount options. A box with no leaf keeps hakoniwa's own cgroup unshare and is launched exactly as before. The daemon's tree entry now also enables the memory controller on the cohort, so a box leaf has a memory.max for its view to show, and the mountinfo half that decided which mounts to mask decides instead whether a tree can decide boxes at all — on cgroup2, and in a guest with nsdelegate — for the daemon-side refusal to come.
The daemon now checks that its classifier tree is real before it creates a session's leaf — on this host's cgroup2, and in the guest with nsdelegate — so a directory tree that decides nothing can no longer place a box that looks placed. In the guest, where the daemon is pid 1 and its own boot path is the only thing that could have built the tree, a host-address session that cannot be placed is refused with an error naming the broken image (design §7.1); natively the same state stays NET-079's exception, with the log line naming the installer command. The guest's cgroup2 mount is strict to match: a mount that fails, or lands without nsdelegate, is an error naming the consequence — a broken image, host-address boxes refused — not a warn line about unenforced boxes. The supervisor is now the only process the daemon places: the program joins its own leaf in the sandbox's pre-exec closure, before its cgroup namespace is unshared onto it.
cargo fmt across the workspace, per the review round's ask; no lint fixes were needed — clippy is clean at -D warnings for the whole workspace after the placement rework.
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Round 2 of 10 on a /revise note, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. Each host-address box now joins its own classifier leaf as its first act, before its cgroup namespace is unshared onto that leaf — so the leaf is the root of the box's cgroup namespace, a read-only cgroup2 view over it lets the box read its limit at /sys/fs/cgroup/memory.max while every migration write (its root's cgroup.procs, a sibling leaf's) is refused, and a sibling leaf is below neither the namespace root nor any view the box can mount; injected processes still join the leaf before setns, the daemon runs in a sibling leaf of its own, and a guest whose cgroup2 is not mounted with nsdelegate — a broken image — now refuses host_ip sessions with a named error instead of launching them unenforced, while a native host without the tree keeps the advisory unenforced posture with the installer command named in its log. Notes from the agent: Out-of-layer files from round 1, kept on purpose and still part of this branch's diff: crates/minimald/src/env.rs (the EnvArgs.with_classifier_leaf plumbing that carries the leaf into the sandbox config) and scripts/install_test.sh (the installer test harness's rehearsal cases for the classifier step). Nothing outside the task's layers was touched this round. The directive's two native-host conditions, recorded as follow-ups as it permits: (1) surfacing the missing tree at session start to the user — the client surface (the just clippy-strict (local-only, no CI lane) reports 5 hits on lines this branch changed, all introduced i…[truncated] |
A box's launch closure still joins its leaf and unshares its cgroup namespace onto it, but what it mounts over the tree it joined through is now an empty read-only tmpfs, not a read-only cgroup2 view. The host's cgroup mount thereby stays out of the box's mount namespace — the design's own wording of NET-079 — and no process the box runs is left a cgroup path to resolve at all: none to read a limit from, and none to write a migration to. The box still stands at the root of its own cgroup namespace, so it can neither see nor join another leaf, injected processes included. This restores, at the conventional mountpoint, the state the session e2e last passed with: an empty tmpfs there, as the no-leaf round shipped, with the join through the bind as the only cgroup write a box ever makes.
The pre-setns join in nsenter and the cohort's memory-controller assertion now describe what the box actually holds after its launch closure: an empty tmpfs over the tree it joined through, so no cgroup path a shim could write a migration to, and a leaf that carries the limit a reader would look for. No behaviour change.
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Round 3 of 10 on a failed check suite, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. Each host-address box still runs in a classifier leaf of its own from its first process to its last, injected processes included — the box's own first process joins the leaf through the tree the sandbox binds, then unshares its cgroup namespace onto it, and an injected process joins the leaf in the shim before it joins the box's namespaces — and now the tree that join went through is covered by an empty read-only tmpfs, so the host's cgroup mount stays out of the box's mount namespace and the box can neither see nor join another leaf because it is left no cgroup path at all; the daemon runs in a leaf of its own, and the guest still mounts cgroup2 delegated so the same tree exists inside a VM. Notes from the agent: This round is for the two red checks (e2e, and ci-macos-success, which is the same failure: the aggregator went red on the macOS lane's e2e job). Both guest lanes — the Apple Silicon e2e job and the KVM test-kvm job — die at the same place, and their annotations name it exactly: 'min session exec ' failed, i.e. the FIRST injection into a live leaf-placed box, after a green activate, a green 'min ls --raw' grep, and a green warm 'min ls'. The exec path itself is untouched by the window: 'git diff ebc7349..59a29c7 -- crates/minimald/src/nsenter.rs' is comments only, and command_in_session/exec.rs are unchanged, so the failure must follow from the state the round-2 launch leaves the box in. Of the two state differences the window introduced at /sys/fs/cgroup — the cgroup namespace rooted at the leaf, and a read-only cgroup2 view mounted over the join bind — the view is the one operation the guest never ran in a green round (round 1 masked /sys/fs/cgroup with an empty tmpfs, which is exactly the state this change restores, and tmpfs-in-userns plus mount(2) in the pre-exec closure are each already proven in the guest). So this change replaces the view with that cover and keeps everything else: the leaf as the namespace root, the sel…[truncated] |
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Review of round 3 (cb566f8) against the T47 plan block and the earlier REQUEST_CHANGES items. Round 2's closure ordering (join, then unshare(CLONE_NEWCGROUP), then the mount over the bound tree, then credentials, then exec) is still the code, the guest still verifies nsdelegate on its real mount table, and the pure mount-table helpers stay well tested. Those stand.
What round 3 changed. fc75b20 ("cover the classifier bind instead of a cgroup2 view") replaces the read-only cgroup2 mount the closure made after unsharing the cgroup namespace with an empty read-only tmpfs mounted over the bound tree at /sys/fs/cgroup (crates/sandbox2/src/lib.rs:843-866); box_cannot_see_or_join_a_sibling_leaf now asserts TMPFS_SUPER_MAGIC at the mountpoint and read cgroup.controllers → errno 2 (lib.rs:3788-3808); c56388c and cb566f8 are comment and wrap follow-throughs. The join, the unshare, the fatal exit_child on any failure, create_session_leaf, the installer, install_test.sh, main.rs and nsenter.rs logic are byte-identical to 59a29c7 (git diff --stat 59a29c7c cb566f83 -- scripts crates/minimald/src/main.rs crates/minimald/src/session_host.rs is empty). Two consequences. First, the box now has no cgroup path at all: it cannot read /sys/fs/cgroup/memory.max, which architecture.md's Box Resources "Seeing it" line (1226, [proposed]) names as where a cgroup-aware runtime reads its limit, and which round 2's own comments cited as the reason for the view; the code comments now call the tmpfs "the design's own wording of the obligation" (line 1221's mount-hiding clause) without saying the read is given up. That is a design trade the PR body should state, not a comment rewrite. Second, on the macOS lane: the round-2 failure was min session exec → process(<closure>) exited with code 127 with no closure stderr in the log (job 109798658001); the guest daemon is root, so that 127 cannot be the native join EACCES this review's R1 describes, and round 3 attributes it to the cgroup2 view mount instead. The macOS e2e on cb566f8 (job 109843248917, success, 10:30-10:34Z) passes session exec proof OK, own-IP, task run, hooks and the pty sandbox proof, with no exited with code 127 in the daemon log. So the cover fixes the guest lane: the join and the unshare are the same bytes that ran there in round 2 and now pass, which pins round 2's 127 on the cgroup2 view mount. It says nothing about a native host with the installer's tree, which no lane runs; R1 stands on the kernel's common-ancestor rule, not on a CI signal.
What still blocks: R1 (placement EACCES on a native host with the installer's tree) is untouched, and with the join in the pre-exec closure it is a dead box, not an unplaced one, for every network mode. R3 (leaf keyed on session id) is untouched. R4 is partly addressed: the sibling-leaf assertion's comment now claims what it proves (a path under an empty tmpfs does not open), but the 0::/ assertion is unchanged and no test migrates a process on a real tree. D3, D2 wiring, the main.rs warning wording and the .create(true) nit are unchanged. Threads below name the exact changes; nothing from the earlier review is fully addressed, so none is dropped.
Plan test lines: box_cannot_see_or_join_a_sibling_leaf and daemon_enters_its_own_leaf exist; host_address_box_placed_in_leaf exists nowhere in the tree at cb566f8.
Issue #1624's status comment (minimal-foundry[bot], updated 2026-09-30T10:18Z) has no "Review threads the coder judged" section: round 3 was cut without this review, which was never posted.
The kernel gates a cgroup.procs write on write permission to the common ancestor of source and destination, so on a native host whose slice is root-owned a box's join dies with EACCES for every session. The tree is now the delegated slice itself (directory plus its cgroup.procs, cgroup.threads and cgroup.subtree_control), the daemon proves it can place a child in a leaf of it before it places a box, a leaf named by its session id is a collision rather than a reuse, empty leaves are swept at daemon start, a missing cgroup.procs is a missing leaf, and the real-tree proof runs where the tree is real: gated, with the reason printed, on a tree this account can place a child in.
A host-address box is now placed only when the daemon can prove it can move a process into the tree it would put that box in: the leaf gate runs before the launch begins, probes by migrating a forked child, and names each session's leaf by that session's id, so a leaf left behind by an earlier session is refused as a collision instead of being reused. The daemon's own posture (native host vs microVM pid 1) now travels through the SessionLauncher::launch signature rather than being read inside, so a launcher test can pose either posture. A guest daemon with no tree gets a named refusal naming the installer's --pid step; a native daemon outside the tree still launches, with its log line and the sweep of previous sessions' now-empty leaves at start saying where its boxes are going instead of asserting a placement that never happens.
A migration into a leaf is refused unless the mover can write the common ancestor's cgroup.procs, and the common ancestor of the daemon's leaf and of every box leaf is the slice itself — so chowning only the two leaves left every migration the daemon must make refused. Delegation now follows the v2 contract for each cgroup the script lays out (the slice, the daemon leaf, the boxes cohort): the directory plus cgroup.procs, cgroup.threads and cgroup.subtree_control. The cgroup2 mount root above the slice stays root-owned, and --check now asserts both halves — the contract present and owned below, nothing delegated above. The daemon's first hop into the slice is the one migration the delegated account still cannot make itself (the common ancestor of the cgroup it starts in and the slice is the root-owned hierarchy root), so the installer offers to make it: --pid PID writes the running daemon into its leaf. install_test.sh models the kernel files the stand-in lacks, drops them wherever a real rmdir would dissolve them, pins the whole delegation sequence, and covers the new mode's successes and refusals.
The startup warning said no box would be placed, which is the per-launch decision create_session_leaf makes, not a fact startup can assert: a daemon inside the slice but with no daemon leaf could still prove the migration. The line now reports the failed entry and names the decision each launch will make by it, with the error that failed it in the same event.
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Round 4 of 10 on a review requesting changes, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. Review threads the coder judged:
Each host-address box now runs in a classifier leaf of its own — named by its session's id and created only after the daemon proves, by migrating a throwaway child into the tree, that it can place a process there — for its whole life, injected processes included, and can neither see nor join a sibling leaf; a daemon that cannot prove it places no box and says which step it is missing. The daemon runs in a leaf of its own, reached through the installer's new --pid step, the installer delegates the slice whole per the cgroup v2 contract and leaves the mount root above it root-owned, and the guest still mounts cgroup2 with nsdelegate so the same tree can exist inside a VM. Notes from the agent: Placement is scoped to NetworkMode::HostNet launches (the reviewer's R3): a NoNet or OwnIp box is not placed and is not refused — worth saying in the PR body, since the plan's own scope is the host-address box. The gated real-tree test (host_address_box_placed_in_leaf) skips on hosts with no /sys/fs/cgroup/minimald.slice/boxes, printing the reason and the installer that would change it; its success half needs a prepared tree, which this CI box cannot mount — a VM or KVM lane run of the daemon would deliver it. D3's other half is still owed: the host_ip_enforcement attribute and a user-visible advisory at session start are a follow-up, acceptable per the thread only as a tracked issue linked from the PR body — I cannot open one, so the PR body should carry it (the hint half is done: install_hint() fills the real account into every advisory and the startup line). just clippy-strict, the local-only gate, reports 14 diagnostics on the branch's changed lines, reported here rather than fixed per AGENTS.md: 9 in this round's sandbox2 probe code (let_underscore_must_use x2 on the throwaway leaf's removal, undocumented_unsafe_blocks x2, indexing_slicing x4 and cast_sign_loss x1 on the hand-formatted pid the async-signal-safe child writes), the other 5 on earlier rounds' line…[truncated] |
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REQUEST_CHANGES on ce0fbea.
Round 4 addressed five of the eight threads (installer delegation of the slice with the contract asserted by --check, session-id-keyed leaves with collision refusal and a start sweep, the launch-path refusal now driven through the real launcher for four postures, the startup line, the .create(true) drop); those are resolved. Three are partly addressed and stay open: the join gate is now advisory-until-proven via a forked probe (good), but the real-tree proof it hinges on cannot pass as written; the sibling barrier still proves the mount is empty rather than the namespace scoping; the placement advisory is still a log line with no session attribute and no linked follow-up.
What blocks: the cover mount is unchanged and the ARCH-EXPERT verdict on it is FAIL. A read-only tmpfs over /sys/fs/cgroup is the only shape, it is documented as the design and pinned by tests, and it makes the box's own limit unreadable, which architecture.md l1226 forbids. The conforming shape is a read-only cgroup2 mount of the namespace root after unshare(CLONE_NEWCGROUP), with tmpfs only as a warn-recorded fallback. Thread on lib.rs:1094.
New this round: HOLD:15000 in host_address_box_placed_in_leaf misuses the hold protocol and deadlocks the probe report, so the one kernel-backed NET-079 proof fails deterministically wherever it runs (HIGH); the absent-tree case now logs the wrong advisory (MEDIUM); three LOWs.
Draft status: two files sit outside the plan's layers (crates/minimald/src/env.rs, scripts/install_test.sh), so the PR stays a draft until the layers are widened or the changes move. The PR body is unchanged since round 1 (still "two leaves", "unshares every namespace in one call") and states the tmpfs-versus-l1226 trade nowhere; rewrite it to match the code.
Threads: 1 BLOCKING, 1 HIGH, 2 MEDIUM (one new), 2 PARTLY carried, 3 LOW.
The box's pre-exec closure now mounts the design's own cover first — a read-only cgroup2 mount of the box's cgroup-namespace root — and falls back to an empty read-only tmpfs only where the kernel refuses that mount, recording which branch it took: the closure reports the one line into the sandbox's /run, where the daemon can read it after the spawn, and marks it in the box's environment as MINIMAL_CLASSIFIER_COVER. A closure that dies before the program runs reports the errno it died on, which is the one line a 127 ever reaches a daemon log by. The tmpfs fallback is a recorded branch, not the design: it leaves the box no cgroup path to read a limit from either, so it is never passed off as the design's cover, and a test knob forces it so the branch is exercised wherever the tests run. The box proofs are split per branch and the hold is a real release-file handshake: the probe's stdout is unbuffered, it polls for a release file in its own /run — the one live directory the box and the host share — and ends on its own after 10s, well under the 30s read deadline, so a lost handshake costs a slow run, not a hung one. Under the design's cover the box's own hierarchy resolves (its controllers file readable) while a sibling leaf's path does not resolve at all and its own root's cgroup.procs refuses the migration write; under the fallback nothing cgroup-shaped resolves at all.
…0s ran out the coder's uncommitted work as it stood when its 7200s ran out The coder was stopped at the end of its time with these changes not committed. The runtime committed its working tree as it stood so the work is kept: this commit is a snapshot, not a finished step, and may not build or pass its tests.
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Round 6 lands every code ask from round 5: patient leaf removal, a whole-line closure report held to the box's fate, a warn on no report, the launch line without the fixed paragraph, a once-per-daemon notice, and the installer wording. The dispute on the fatal-join thread holds on the code: only a HostNet box gets a leaf, and only after probe_child_placement migrated a real child, so the closure's fatal join is unreachable on an unproven host. Resolved accordingly. Approval waits on human-side items, not on the coder: a linked follow-up issue for the attribute's CLI surface, a PR body that describes the current model (the proof paragraph is still round 1's join-under-nsdelegate text and the notes section is literally truncated), one delegated-host run of host_address_box_placed_in_leaf (no CI lane runs the sandbox2 proof; the KVM lane archives -p minvmd only), and the KVM lane on 689ddbf. Two new LOWs inline can ride along with whatever round those produce.
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/revise ARCH-EXPERT verdict on round 6 (head 689ddbf): PASS as an interim, with two conditions on the surface that exists. Design §7.4 line 275 reads "surfaced at session start" and architecture.md design principles 3 and 4 (lines 323–324) require every user-facing fact to have a non-TTY form. The round-6 notice meets neither; this round fixes that and nothing else. 1. The notice fires at every session start, not once per daemon. Drop 2. The notice has a non-TTY form. A pty banner is invisible to agents and scripts. Alongside the pty write, (a) emit the same text as a diagnostic line on the session's stderr channel so a scripted 3. The LOW thread at Add one test that drives two launches on one daemon and asserts both receive the notice and both carry the field. Keep the three plan test lines green, run |
Drop the once-per-daemon latch on the unenforced-placement notice: every launch of a host-address box without its own classifier leaf now records the advisory (the resolver advisory this is modelled on advises on every session start), and the first session after a daemon restart is no longer the only one a person is warned for. Give the notice its non-TTY form: the same text is emitted as a diagnostic record at the launch's placement decision, before the env build, attributed to the session and carrying the decision in the machine spelling (host_ip_enforcement=none) a script greps for. The terminal write keeps the same gate and text, for the launch that completes. Remove an abandoned launch's classifier leaf with the patient removal, retrying against the EBUSY window a just-reaped box's cgroup still has. Proof: one test drives two host-address launches on one daemon and asserts each launch gets its own record, carrying the notice text and the machine field.
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Round 7 of 7 on a /revise note, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. Review threads the coder judged:
Every native launch of a host-address box on a host without its classifier tree now advises, per launch, in both forms: the same notice text in the session terminal ahead of the prompt and a per-launch diagnostic record carrying host_ip_enforcement=none (per_box when the box has its leaf), so a script reading the daemon log sees the decision as data; an abandoned launch's leaf is removed patiently against the EBUSY window; each host-address box still runs in its own leaf from its first process to its last, injected processes included, can neither see nor join a sibling leaf, the daemon sits in its own leaf, and the guest mounts cgroup2 delegated. Notes from the agent: All four directive items landed: latch (UNENFORCED_NOTICE_PRINTED, first_unenforced_notice, the :3067 check) removed entirely; the advisory now fires per launch as (a) a diagnostic record at the placement decision — before the env build, so a launch that stops there has still been recorded — and (b) the terminal write on the launch that completes, same gate and text, via the shared advises_unenforced_placement/unenforced_placement_notice helpers; the record carries host_ip_enforcement=per_box/none through the new machine_str; BoxLeafGuard::drop uses remove_box_leaf_patiently; one test drives two launches on one state dir and asserts each gets its own record with the text and the machine field. Item 2(a) wording: the launch has no per-session stderr channel at that point (no SSH session exists yet at launch), so the non-TTY form is the per-launch diagnostic record on the daemon's log stream — the surface a scripted start reads; rpc.rs, min session list and min doctor untouched per the directive. The record's field is written through display so the line reads host_ip_enforcement=none unquoted. The test asserts the records per launch (launches stop at the env build on this box: the unit-test graph has no baseline packages) and asserts the terminal form whenever a launch completes, which this …[truncated] |
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/revise Round 7 (6f0aa8a) lands the per-launch advisory and the patient leaf drop; three things remain, none of which widens the task's layers.
Keep the per-launch gate ( |
…ches A hook launch is not a session start: the advisory now travels with the launch's purpose, carried from the one caller that knows it, so the destroy path's hook runs record neither the daemon-log line nor a banner into a pty nobody reads. The placement itself is not gated with it. The comments at the two emit sites and the tests' doc now say what the surfaces actually are: the record is a daemon-log line no client reads and the banner is the in-session pty surface; carrying the decision out over the session reply is issue #1773, outside this task's layers. The launch-path test is retitled to the log-record proof it makes, since this box's graph stops the launch before any pty exists.
…r-launch proof The hook gate test drives both purposes over one tree-less host: the session launch records, the hook launch stays silent, and the ungated placement note pins the hook launch to the same decision point. The notice test is retitled to the daemon-log record it proves — the terminal form is unreachable on this box's unit-test graph — and its doc states the surfaces as they are: the record on the daemon's log, the banner on the session's pty, the field's client surface #1773.
…-host-address-box-in-its-own-classifie
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Round 8 of 10 on a /revise note, pushed as
Verify Outside the task's
Converted to a draft: something above needs a person before review. Review threads the coder judged:
At this branch, each host-address box still runs in a classifier leaf of its own from its first process to its last, injected processes included, can neither see nor join another leaf, and the daemon runs in a leaf of its own; the guest mounts cgroup2 delegated so the same tree can exist inside a VM. This round makes the advisory that reports the unenforced state a session surface only: a hook launch — activation at finalize, teardown at detach or destroy — now emits neither the daemon-log record nor a banner into the pty nobody reads, and the comments at both emit sites and the tests say what the surfaces actually are: the record lives on the daemon's log (no client reads it — the session reply, serve_create_session and cmd/session.rs are untouched), the banner is the in-session pty surface, and carrying host_ip_enforcement to a client over the session reply and Notes from the agent: Directive item 3 needed one file outside the task's layers: crates/minimald/src/session.rs. LaunchPhase cannot carry the gate — the destroy path's hook launch is Attached exactly like an attach's and finalize's activation launch is Activating — so the launch's purpose travels as a for_hooks flag on the launcher, threaded from the only caller that knows it (launch_host: one param, three call sites, the two session_launcher variants). rpc.rs, minimald-rpc and cmd/session.rs were not touched, as directed. Item 2 was resolved the second way: the launch cannot reach the pty on this box's unit-test graph (the env build fails on the fakerepo before the pty opens), so the test was retitled the_unenforced_record_fires_on_every_launch_and_carries_the_field to the daemon-log record it does prove, its unreachable Launched/terminal assertions and the read_terminal_until helper dropped with them. My first hook-test run failed on my own matcher (the placement note logs session as a quoted field) and was fixed; the final run passes. Owed to the PR body, which …[truncated] |
…-host-address-box-in-its-own-classifie Carry the classifier-leaf placement through the socket-seal refactor (#1780): every box now installs its seal filter in the same pre-exec closure that joins its leaf, the launch's seal marker comes from the plan's seal, and injections both join the leaf and reinstall the seal.
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Round 10 of 10 on a conflict with the base branch, pushed as Resolved conflicts in:
Verify Outside the task's
Converted to a draft: something above needs a person before review. Review threads the coder judged:
Each host-address box still runs in a classifier leaf of its own from its first process to its last, injected processes included, can neither see nor join another leaf, and the daemon runs in a leaf of its own; the guest mounts cgroup2 delegated so the same tree can exist inside a VM. This round's conflict merge carried that placement through main's socket-seal refactor (#1780): every box's pre-exec closure now joins its leaf, unshares the cgroup namespace onto it, covers the join with the read-only cgroup2 view of its namespace root (or the recorded tmpfs fallback), and installs the box's socket-family seal — all in the same closure; an injected process joins the leaf in the shim before it joins the box's namespaces and reinstalls its seal there; the daemon enters its own leaf at start; the three test lines pass on this head and both touched crates' full suites are green. Notes from the agent: Conflict round: resolved the three conflicted files and committed the merge (348fcb8) — the leaf placement survives #1780's seal refactor (install_box_credentials now takes the non-optional &'static seal filter plus the leaf and fallback knob; exec_box_program joins the leaf, covers the tree, takes credentials, installs the seal, execs; the launch's seal_injection comes from the plan's seal while host_ip_enforcement and the leaf copy stay on Launched; the shim both joins the leaf and names its seal). Only the three conflicted files were hand-edited; the merge commit also carries main's own changes to diag.rs, netns_root_integration.rs, minvmd README/vm.rs and sandbox2/network.rs untouched by me. Both crates compile clean under clippy --all-targets and cargo fmt --check is clean; the merge commit's subject is git's default merge form, which commitlint's default is-ignored list passes (as 0f10f2e did). FOR THE PR BODY, three things this session cannot write: (1) link issue #1773 — the client surface (host_ip_enforcement over the session reply and min doctor) is t…[truncated] |
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The runtime will not revise this pull request again on its own: round 11 would exceed the cap of 10 (the last trigger was a failed check suite). A person decides now. Remove |
On a cgroup2 host the tree root sits under the /sys/fs/cgroup mount, so the tree is real and an uninstalled tree surfaces as the placement probe's not-found note, not the tree-is-not-real one the proof matched on. Either note is the per-launch, ungated record of the placement decision the hook launch has to reach for its silence to prove the gate.
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Approved: no findings at Nothing to do. Verdict APPROVE, posted as a comment: the App cannot review its own pull request; the check and the label carry it. Clobber: none: |
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Rounds 4 to 8 landed every review and ARCH ask (namespace-rooted leaf, read-only cgroup2 cover with recorded fallback, installer delegation with a forked placement probe, session-id-keyed leaves, per-launch advisory with the hook gate); the one failing pin was corrected in 30fe508. minimal-review approved on this head; ARCH PASS as an interim at round 6 with its conditions landed.
…ost at merge T66 (#1789) added box_addresses to SessionConfig and SandboxLauncher; #1768 and #1765 each added an initializer without it on a base that predated the field, and their green lanes never re-ran against the merged main. The minimald test targets no longer compile on main; this fills the field the way every other initializer does. The merge queue this PR enables is what catches that class of stale green before it lands.
* ci: trigger the required lanes on merge_group A merge queue on main needs the five required aggregators to report on every queue commit. Each lane already gates its jobs on `github.event_name != 'pull_request' || <changes output>` and runs the dorny filter only on pull_request, so a queue commit runs the full set, which is what docs/ci-strategy.md section 5 prescribes for the queue. No job logic changes. * fix(minimald): fill box_addresses in the two test initializers main lost at merge T66 (#1789) added box_addresses to SessionConfig and SandboxLauncher; #1768 and #1765 each added an initializer without it on a base that predated the field, and their green lanes never re-ran against the merged main. The minimald test targets no longer compile on main; this fills the field the way every other initializer does. The merge queue this PR enables is what catches that class of stale green before it lands. * ci: pin the merge_group trigger to main and release branches The sibling push and pull_request triggers in all five lanes pin branches to main and release/**; the merge_group trigger now matches them, so a queue opened on any other branch does not run the lanes.
T47 — Place each host-address box in its own classifier leaf and keep it there
slice: S11
kind: enablement
covers: none
size: L
est: 300 code, 240 tests
executor: agent
difficulty: needs care
model: strongest
diagnostics: the sandbox launch line in the daemon log names the leaf each box entered and whether the host mount was hidden
observability: the sandbox launch log line names the leaf each box entered
layers:
- sandbox:
- crates/sandbox2/src/lib.rs: keeps the host's cgroup2 mount out of the box, so a box sees no sibling leaf; the sandbox library unshares every namespace in one call before any placement, so the leaf is never the namespace root and the barrier is the root-owned tree
- crates/sandbox2/src/config.rs: a per-box leaf option carrying the leaf's cgroup.procs path
test: cargo nextest run -p sandbox2 box_cannot_see_or_join_a_sibling_leaf
- daemon:
- crates/minimald/src/session_host.rs: creates the box's leaf before the spawn, moves the box's process into it right after, and removes the leaf when a launch is abandoned in between
- crates/minimald/src/nsenter.rs: an injected process joins the leaf in the forked child before it joins the box's namespaces, from the daemon's own cgroup namespace, where the leaf is reachable
- crates/minimald/src/main.rs: moves the daemon into its own leaf at start
- crates/minimald/src/guest.rs: mounts cgroup2 with namespace delegation in the guest
- crates/minimald/src/session_host/tests.rs: hosts the leaf placement tests
test: cargo nextest run -p minimald daemon_enters_its_own_leaf
- installer:
- scripts/install-host-classifier.sh (new): the privileged step: installs the root-owned cgroup tree the daemon and its boxes are placed under, with namespace delegation, on a native host
test: just test-installer host_classifier_tree_installed
produces: none
consumes: none
proof: Each host-address box runs in a classifier leaf of its own from its first process to its last, injected processes included, can neither see nor join another leaf, and the daemon runs in a leaf of its own; the guest mounts cgroup2 delegated so the same tree can exist inside a VM.
depends on:
- blocked by #1633
Proof
Each host-address box runs in a classifier leaf of its own under
/sys/fs/cgroup/minimald.slice/boxes/<session-id>: the sandbox's pre-exec closure joins the leaf, then unshares the cgroup namespace so the leaf is the namespace root, then mounts a read-only cgroup2 view of that root over/sys/fs/cgroup(an empty read-only tmpfs only as a recorded, warned fallback), then drops credentials 8000 and execs. An injected process (nsenter.rs) joins the leaf in the forked child before it enters the box's namespaces. The daemon moves itself intominimald.slice/daemonat start. The guest mounts cgroup2 withnsdelegateand refuses to launch a host-address box unplaced.Native hosts.
scripts/install-host-classifier.shis the privileged step: it installs the root-owned tree and delegates the slice to the daemon's user, with--checkasserting the contract. Placement is advisory until proven: at launch the daemon forks a probe that migrates a real child into a throwaway leaf; only a host that passes gets the fatal join in the closure. On a host without the tree every launch of a host-address box recordshost_ip_enforcement=nonein the daemon log and prints a notice with the install hint into the session; hook launches (run_hooks_headless) are gated off the notice. Carrying the enforcement attribute to the client over the session reply andmin doctoris #1773.Design review: ARCH-EXPERT PASS as an interim (round 6) with conditions on the notice surface (per launch, not once per daemon; a non-TTY record), landed in rounds 7 and 8.
Tests
cargo nextest run -p sandbox2 box_cannot_see_or_join_a_sibling_leafcargo nextest run -p minimald daemon_enters_its_own_leafjust test-installer host_classifier_tree_installedhost_address_box_placed_in_leaf(sandbox2) is the kernel-backed proof; it skips with a reason line on hosts without a delegated tree, which includes every CI lane.a_hook_launch_does_not_advise_unenforced_placementpins the hook gate on both tree-absent notes a cgroup2 host can record.Verify
Every lane is green at the head. Base merged in before the tests ran.
Out of layer, justified
crates/minimald/src/env.rs:EnvArgsis the only route from the session host into sandbox2'sConfig, so it carries the classifier-leaf hand-off.scripts/install_test.sh: hosts the installer'shost_classifier_tree_installedcase beside the existing installer tests.Closes #1624