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fix(minimald): close the host classifier's mark, IPv6 and probe gaps (0.7.0 backport) - #2742
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* 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)
…er (#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)
crate::traced landed on main after the release branch was cut, so the cherry-pick of #2300 did not compile here.
v0.7.2 is tagged at the branch head, so the version check requires the next patch release.
…(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)
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.
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Approved: no findings at Nothing to do. Clobber: none found. |
evanspearman
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Oct 29, 2026
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Backports #2712 (task T105, #2692) to
release/0.7.0. It is a security fix in the native-Linux host classifier:Stacked on #2678; merge that first. #2678 carries the 0.7.3 version bump and the
pulldown-cmarkadvisory fix. Until it merges, this diff also shows #2678's commits.Commits
d25841d2cis the cherry-pick (all subjects arefix). The conflicts came from main-only code next to fix(minimald): close the host classifier's mark, IPv6 and probe gaps (T105) #2712's lines (the QUIC block work and box-name placement), not from anything fix(minimald): close the host classifier's mark, IPv6 and probe gaps (T105) #2712 needs: the mask machinery it builds on is already on this branch. Each conflict keeps fix(minimald): close the host classifier's mark, IPv6 and probe gaps (T105) #2712's own lines inmain's text and leaves the neighbouring features out.b06439568adapts it to the release branch:sandbox2::classifier, this branch's path.refusedcounter, without main's QUIC set besi 8000 de it.finalize_install: this branch has one classifier item (no QUIC helper item), soclassifier_item_on_this_hosttakes the mask and fillsrecorded_maskandrequested_mask.install_test.sh:run_hcputsHC_PATH_PREFIXahead ofPATH(the one line from main's feat(minimald): reject UDP 443 from a blocked cohort's own leaves (T72) #2601 the new--restore-markcase needs).Squash-merge the pair. Every test #2712 adds is kept. Only its edits to
finalize_install_names_the_quic_block_helperare left out, because that test and the QUIC helper item are not on this branch. User-facing text ismain's.Verification (Linux, Lima)
just clippy,just fmt-checkandjust lint-shellare clean;just test-installer: 766 passed.install_refuses_a_whole_mark_ct_writer,install_refuses_a_well_known_mark_range,host_ip_box_ipv6_egress_refused,per_launch_probe_returns_without_tcp_retransmit_wait(minimald);classifier_boot_unit_reapplies_a_recorded_mask,classifier_table_presence_needs_the_marker_and_one_mask_record,finalize_install_parses_ct_mark_mask(minimal).minimald: 1000 passed, 1 failed, the VM-only cgroup EACCES failuresession_host::tests::a_hook_launch_does_not_advise_unenforced_placement.minimal: 547 passed, 3 failed, theresolver::tests::finalize_install_undo_removes_*tests that fail on the unmodified fix(net): backport the deny-all DNS refusal and the owner-only answerer socket to 0.7.0 #2678 head in the VM (root-owned files).classifier_root_integration.rs. The VM blocks unprivileged user namespaces (kernel.apparmor_restrict_unprivileged_userns=1), so CI's root-integration job is their run.git merge-treeis clean against fix(minimald): refuse an activation whose declared port something else holds (0.7.0 backport) #2738 and fix(net): answer a macOS box's ports at the address its name resolves to (0.7.0 backport) #2740.