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fix(minimal): hold the answerer channel socket owner-only - #2297
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The box-zone answerer's channel socket was world-connectable: the launchd plist bound it SockPathMode 0666 and the systemd socket unit SocketMode=0666, leaving the peer-uid gate the only check on who may connect. Both units now bind it owner-only -- SockPathOwner the operator, SockPathMode 0600 on launchd; SocketUser the operator, SocketMode=0600 on systemd -- with the uid gate kept as defence in depth. An install whose socket node carries group or other bits -- one that predates the mode, or a hand that relaxed it -- now fails custody through a channel_mode fact, so the advisory re-surfaces and a step re-run re-binds the socket. The accept loop's foreign-refusal warn is rate-limited to a few lines a second, so a connect storm cannot flood the log; the refusals themselves are never limited.
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A rabbit checks the socket door,
With operator keys and mode secure.
Four brief warnings mark the stream,
While foreign peers are turned away.
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[inbox-patch:clobber] This PR would revert recently merged workSimulating this merge shows it undoing commits that landed on the base branch within the last 3 day(s):
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Inline comments:
Review comments at @crates/minimal/src/resolver.rs:
- Line 1760: Update the `file_custody` handling to retain the full custody fact
instead of mapping it to `custody.mode`, then require the socket owner UID to
match the operator UID as well as satisfy the existing mode check before
reporting `Installed`.
Review comments at @crates/minvmd/src/net/answerer.rs:
- Around line 4940-4943: Make the warning-count test deterministic by testing
the limiter’s window boundary with an injected time value instead of relying on
the accept loop’s scheduling; keep the socket test focused on verifying that
every peer is refused, without asserting an exact warning count.
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crates/minimal/src/cmd/finalize_install.rscrates/minimal/src/resolver.rscrates/minvmd/src/net/answerer.rs
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…nnel connect A daemon whose connect the owner-only channel socket refuses now says the host's DNS service belongs to another account, not a bare Permission denied. The answerer step needs the operator's account to resolve, with no stand-in uid, and custody fails a channel socket the operator does not own.
A channel socket owned by another existing, non-root account is that operator's service: the answerer step is now unavailable with the same sentence the daemons say on a refused connect, instead of a custody failure whose step would reinstall the unit and take the service over. A root-owned socket, or one whose uid names no account, still fails custody so the step re-binds it. The minvmd tests that take the process-global foreign-refusal slots now run one at a time and start and end with every slot free, and the warn-rate test bounds the burst at two windows' worth of lines, so a slow runner that spreads the burst does not fail it.
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Inline comments:
Review comments at @crates/minimal/src/resolver.rs:
- Around line 1353-1371: Update refuse_foreign_operator to return
AnswererStep::Absent unchanged, alongside existing SourceUnavailable steps,
before checking channel ownership; only wrap steps that indicate an installed
service.
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crates/minimal/src/resolver.rscrates/minimald/src/net/answerer.rscrates/minvmd/src/net/answerer.rs
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A channel socket another account owns refuses the answerer step only when a service is installed; with none, the step's install removes the leftover socket before it loads the unit, so it is offered.
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…(0.7.0 backport) (#2742) * fix(minimal): hold the answerer channel socket owner-only (#2297) * fix(minimal,minvmd): hold the answerer channel socket owner-only The box-zone answerer's channel socket was world-connectable: the launchd plist bound it SockPathMode 0666 and the systemd socket unit SocketMode=0666, leaving the peer-uid gate the only check on who may connect. Both units now bind it owner-only -- SockPathOwner the operator, SockPathMode 0600 on launchd; SocketUser the operator, SocketMode=0600 on systemd -- with the uid gate kept as defence in depth. An install whose socket node carries group or other bits -- one that predates the mode, or a hand that relaxed it -- now fails custody through a channel_mode fact, so the advisory re-surfaces and a step re-run re-binds the socket. The accept loop's foreign-refusal warn is rate-limited to a few lines a second, so a connect storm cannot flood the log; the refusals themselves are never limited. * fix(minimal,minimald,minvmd): name the other account on a refused channel connect A daemon whose connect the owner-only channel socket refuses now says the host's DNS service belongs to another account, not a bare Permission denied. The answerer step needs the operator's account to resolve, with no stand-in uid, and custody fails a channel socket the operator does not own. * fix(minimal,minvmd): leave another operator's DNS service alone A channel socket owned by another existing, non-root account is that operator's service: the answerer step is now unavailable with the same sentence the daemons say on a refused connect, instead of a custody failure whose step would reinstall the unit and take the service over. A root-owned socket, or one whose uid names no account, still fails custody so the step re-binds it. The minvmd tests that take the process-global foreign-refusal slots now run one at a time and start and end with every slot free, and the warn-rate test bounds the burst at two windows' worth of lines, so a slow runner that spreads the burst does not fail it. * fix(minimal): offer the step over a socket another account left behind A channel socket another account owns refuses the answerer step only when a service is installed; with none, the step's install removes the leftover socket before it loads the unit, so it is offered. --------- Co-authored-by: gominimal-aw-bot[bot] <281738952+gominimal-aw-bot[bot]@users.noreply.github.com> (cherry picked from commit 746770d) * fix(net): refuse out-of-zone names at a guest deny-subtree DNS listener (#2300) * fix(net): refuse out-of-zone names at a guest deny-subtree DNS listener A deny-all host-address box on a VM-backed guest resolved out-of-zone names at the switch gateway: the interim NET-079 carve-out admitted the gateway's port 53 whole, UDP and TCP, so a box that admits no destination could still ask a resolver beyond the machine — and DNS over TCP could retry past the verdict. The guest's deny subtree now steers its UDP-53 lookups onto a loopback listener on the answerer's port (NET-141 slice 2): deny_out admits the listener beside the reply direction, the dstnat match carries no destination address (the box asks the gateway like every other host-address box; the steer is the carve-out), and the listener itself answers REFUSED for every name outside the box zone — apex and a non-lowercase zone suffix among them — NODATA for an in-zone non-A question, and forwards the zone's A questions to the switch gateway alone. DNS over TCP is neither steered nor admitted. The guest daemon starts the listener after its classifier table loads; the daemon's own lookups are untouched (cgroup-keyed match, deny path only). The interim --gateway-resolver installer flag and every test, digest and pin that spelled the interim carve-out follow the new shape. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * fix(net): bound and pin the guest DNS listener's forwards Connect each forward socket to the gateway so a datagram from any other sender is dropped, cap forwards in flight so a flood cannot exhaust the daemon's descriptors, and drop the needless to_string calls clippy rejects in the guest classifier integration test. * fix(net): refuse questionless and non-QUERY messages at the guest DNS listener decide() forwarded a message with no question, and an UPDATE or NOTIFY whose zone section named an in-zone A, because every per-question check passed vacuously. Answer the first REFUSED and the rest NOTIMP, so the forward path carries only standard lookups. Bind the listener directly so its log does not read as the box-zone answerer, pin the integration test's boot-log check to the exact example.com REFUSED line, and cite NET-079 (the deny-all case) rather than NET-141 at the lines this change added. --------- Co-authored-by: gominimal-aw-bot[bot] <281738952+gominimal-aw-bot[bot]@users.noreply.github.com> Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> (cherry picked from commit 2c2f8cc) * fix(net): spawn the guest DNS tasks with tokio::spawn on release/0.7.0 crate::traced landed on main after the release branch was cut, so the cherry-pick of #2300 did not compile here. * build: declare 0.7.3 for the release/0.7.0 backports v0.7.2 is tagged at the branch head, so the version check requires the next patch release. * chore(deps): update pulldown-cmark to 0.13.5 for RUSTSEC-2026-0414 * fix(minimald): close the host classifier's mark, IPv6 and probe gaps (T105) (#2712) * fix(minimald): close the classifier's mark, IPv6 and probe gaps The install's conflict scan now treats a ct-mark write with no mask as a user of every bit, names each rule with its table and chain, and --ct-mark-mask refuses the ranges Tailscale and kube-proxy class with. The table refuses non-loopback IPv6 from the boxes subtree and counts that refusal in the same named counter as the deny chain. The per-launch probe reads with a UDP datagram, so a launch no longer waits the SYN retransmit a refused TCP connect pays. The reading at daemon start keeps its TCP leg. Each probe logs its leg and duration. * test(minimald): prove the classifier's mark, IPv6 and probe gaps live Three root-lane proofs load the real table: the install refuses a whole-mark ct writer and a mask in a well-known range, and an allow box's IPv6 connection to a peer is refused and counted. The live probe proof also checks the per-launch reading waits no retransmit. * fix(minimald): pass shellcheck and pin the new mask refusals The rerun hint's empty assignment tripped SC1007 in the shell lint gate. The installer test pinned the old remedy text and escaped with 0x0000c000, the kube-proxy range the install now refuses: it now pins the new remedy, escapes with 0x03000000, and pins the well-known range refusal. The IPv6 refusal comment names the condition that replaces it. * fix(minimald): re-apply the recorded ct-mark mask and name min finalize-install With no --ct-mark-mask, the install step adopts the mask a previous install recorded under the tree. Mask refusals now name min finalize-install --ct-mark-mask <mask>. The conflict scan joins the nft and iptables-save hits with a newline. * feat(minimal): add min finalize-install --ct-mark-mask and keep it at boot The mask record lives in cgroupfs, so a reboot empties it. The classifier step's block now passes the chosen or recorded mask to the one-time run and to the boot unit's ExecStart, so the operator's bits survive a reboot. A requested mask that differs from the loaded table's re-runs the step. * fix(minimald): refuse a CONNMARK --restore-mark that copies the whole mark The install's ct-mark scan now treats --restore-mark with no --mask, --ctmask or --nfmask, or an all-ones one, as a whole-mark writer, as it does --save-mark. A restore with a narrow mask is still no conflict. * fix(minimald): allow --restore-mark, bind probe datagrams first A CONNMARK --restore-mark copies the connection mark into the packet mark and never writes the connection mark, which is all the classifier reads. This reverts 16d9160 and pins a restore with no mask as no conflict. hold_probe_listeners now binds its datagram endpoints before it spawns any TCP drain thread, so a failed datagram bind returns before a listener serves. --------- Co-authored-by: minimal-foundry[bot] <327719912+minimal-foundry[bot]@users.noreply.github.com> (cherry picked from commit 354548e) * fix(minimald): adapt the host classifier gaps backport to release/0.7.0 The cherry-pick before this one keeps main's text for every line #2712 changes. Main's neighbouring code comes from the QUIC block work (#2513, #2553, #2601, #2644), the box-name placement (#2722) and the crate renames, none of which release/0.7.0 has. The conflicts were resolved onto release's code without importing that work: - classifier.rs: the four new unit tests are appended after release's last test, without the QUIC cohort tests main has above them. Their sandbox::classifier paths are sandbox2::classifier here. - install-host-classifier.sh: the table gains the refused counter. The QUIC leaf set that main declares beside it is not on release, so it stays out. The --help range (2,87p) matches release's header too. - finalize_install.rs: release has one classifier item, built by classifier_item_on_this_host, not main's classifier_items_on_this_host with the QUIC block helper item. That function takes --ct-mark-mask and fills recorded_mask and requested_mask itself. plan_for_this_host keeps release's names item placement and only passes the mask on. - #2712's edits to finalize_install_names_the_quic_block_helper are dropped: release has no QUIC block helper item or test. - install_test.sh: run_hc puts HC_PATH_PREFIX ahead of PATH, the line #2601 added on main. Without it the new --restore-mark case never reaches its stand-in iptables-save, and shellcheck flags the variable as unused. The user-facing text is main's, unchanged. --------- Co-authored-by: gominimal-aw-bot[bot] <281738952+gominimal-aw-bot[bot]@users.noreply.github.com> Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Co-authored-by: minimal-foundry[bot] <327719912+minimal-foundry[bot]@users.noreply.github.com>
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The box-zone answerer's channel unix socket was world-connectable: the launchd plist bound it SockPathMode 0666 and the systemd socket unit SocketMode=0666, leaving the in-process peer-uid gate the only check on who may connect. Both service definitions now bind it owner-only — SockPathOwner the operator + SockPathMode 0600 (384) on launchd, SocketUser the operator + SocketMode=0600 on systemd — with the uid gate kept as defence in depth. Existing installs migrate through a new channel_mode custody fact: an installed socket node carrying group or other bits fails custody, re-surfacing the advisory so a step re-run re-binds it. The accept loop's per-refusal warn is now rate-limited to a few lines per second, so a connect storm cannot flood the log; the refusals themselves are never limited.
A second operator's daemon now meets the owner-only socket at the connect itself, so both publishers (
minimaldandminvmdconnect_and_publish) turn aPermissionDeniedfrom that connect into the gate's sentence: the host's DNS service belongs to another account, and hosts with more than one operator are not supported. The socket owner's uid comes from the operator's account with no stand-in: when the operator's name resolves to no account, the answerer step is unavailable and the advisory nam 10000 es the account. Custody also checks the channel socket's owner (channel_owner, read besidechannel_mode) against the operator's uid, with its own check sentence; an absent socket node still changes no verdict.The owner check tells two cases apart. A socket owned by root, or by a uid that names no account, is a stale or relaxed install and fails custody, so the step re-binds it. A socket owned by another existing account is that operator's service: the answerer step is unavailable with the same sentence the daemons say (the host's DNS service belongs to another account; hosts with more than one operator are not supported), and the advisory carries no install step that would take the service over. A socket another account left behind with no service installed does not block the step, because the step's install replaces it.
Verification
cargo fmt --all --check --manifest-path Cargo.toml— cleancargo clippy --workspace --all-targets --locked --manifest-path Cargo.toml -- -D warnings— cleancargo test --locked --manifest-path Cargo.toml -p minimal— 523 passed; the one failure (tests::legacy_network_spellings_parse_with_hint) reproduces on pristine main and is unrelated to this changecargo test --locked --manifest-path Cargo.toml -p minvmd— 571 passed including the two new tests; the three failures (a_warned_daemon_announces_its_first_registration,answerer_service_forgets_rows_of_a_gone_node,sock::tests::resolve_uds_path_lives_in_provider_dir, plus an intermittentbep_attachone) reproduce identically on pristine main — pre-existing parallel-run flakes, each passes in isolationforeign_refusal_warns_are_rate_limitedproves 16 concurrent foreign connects yield at most two windows' worth of warn lines while every peer is refused and no row is ever held; the extendedadvisory_installs_manager_held_answererproves the rendered units assert SockPathOwner/0600 and SocketUser/0600 with no 0666 anywhere, and that achannel_modeof 0o666 fails custody naming the socket while an absent socket node leaves the verdict unchangeda_connect_the_socket_mode_refuses_names_the_other_account(minimald and minvmd) binds a channel socket, sets mode 000, and asserts the connect error reads the gate's sentence (skipped as root); the custody test gains a socket owned by uid 0 failing with "is owned by uid 0, not the operator's";advisory_names_an_unavailable_answerer_stepcovers an operator name that resolves to no account. Ranjust clippyandjust test -p minimal(Linux guest), andjust test-one answerer -p minvmd(macOS): all new tests pass. Threefinalize_install_undo_*tests failed in the Linux guest because its/etc/systemd/system/minimald-place.*files are root-owned there; they depend on the host environment, not on this changeanswerer_channel_refuses_foreign_uid,foreign_refusals_past_the_cap_close_bare,foreign_refusal_warns_are_rate_limited) now hold one test-only lock and start and end with every slot free. The warn-rate test allows up to two windows' worth of lines, so a slow runner does not fail it. Ranjust test -p minvmd(macOS): 1235 passed. Ranjust clippyandjust test -p minimalin the Linux guest: all pass except the same threefinalize_install_undo_*tests, which fail because of the guest's environment.github/workflows/ci-macos.yml) runs against this PR's head and will exercise the plist changes against a live launchd; it is not runnable in this sandboxSummary by CodeRabbit