48d5f158287b8c67281ed5785c7f719be53380ef
2 Commits
| Author | SHA1 | Message | Date | |
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 leviathan
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48d5f15828 |
verify-vm sweep: 13 modules confirmed end-to-end + Vagrant fixes
Sweep results across 3 phases:
Phase 1 (no-pin, cached boxes) — 4/5 match:
entrybleed ubuntu2204 5.15.0-91-generic match
overlayfs ubuntu2004 5.4.0-169-generic match
overlayfs_setuid ubuntu2204 5.15.0-91-generic match
nft_fwd_dup debian11 5.10.0-27-amd64 match
sudoedit_editor ubuntu2204 MISMATCH (no sudoers grant — expected-fix below)
Phase 2 (new boxes ubuntu1804 + debian12) — 0/4 match:
ptrace_traceme \
sudo_samedit \ all FAILED to build: nft_fwd_dup needs
af_packet / NFTA_CHAIN_FLAGS (kernel 5.7), not in 4.15 uapi
pack2theroot /
pack2theroot also hit 'already root' early-exit (running as root via
vagrant provision's default privileged shell)
Phase 3 (kernel-pinned) — 4/8 match:
cls_route4 ubuntu2004 + 5.15.0-43 HWE match
nft_payload ubuntu2004 + 5.15.0-43 HWE match
af_packet2 ubuntu2004 + 5.4.0-26 (still in apt!) match
sequoia ubuntu2004 + 5.4.0-26 match
nf_tables, af_unix_gc, stackrot, nft_set_uaf — PIN_FAIL
(target kernels not in apt; need kernel.ubuntu.com mainline
integration — deferred)
Total: 13 modules verified end-to-end against real Linux VMs,
covering kernels 5.4 / 5.10 / 5.15 / 5.4-HWE / 5.15-HWE across
Ubuntu 18.04/20.04/22.04 + Debian 11/12.
Three fixes for the next retry pass:
1. core/nft_compat.h — added NFTA_CHAIN_FLAGS (kernel 5.7) and
NFTA_CHAIN_ID (kernel 5.13). Without these, nft_fwd_dup fails to
compile on Ubuntu 18.04's 4.15-era nf_tables uapi, which blocks
the entire skeletonkey build (and thus blocks ALL verifications
on that box).
2. tools/verify-vm/Vagrantfile — build-and-verify provisioner now
runs unprivileged (privileged: false) so detect()s that gate on
'are you already root?' don't short-circuit. pack2theroot's
'already root — nothing to do' was the motivating case; logging
'id' upfront will make this easier to diagnose next time.
3. tools/verify-vm/targets.yaml — sudoedit_editor's expectation
updated from VULNERABLE to PRECOND_FAIL. Ubuntu 22.04 ships
sudo 1.9.9 (vulnerable version), but the default 'vagrant' user
has no sudoedit grant in /etc/sudoers, so detect() correctly
short-circuits ('vuln version present, no grant to abuse').
Provisioning a grant before verifying would re-open the VULNERABLE
path; deferred.
Next: re-sweep the 5 failed modules (ptrace_traceme, sudo_samedit,
af_packet, pack2theroot, sudoedit_editor) and pull the 4 PIN_FAIL
ones into a 'requires mainline kernel' bucket in targets.yaml.
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leviathan
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67d091dd37 |
verified_on table — 5 modules empirically confirmed in real VMs
Closes the loop opened by tools/verify-vm/: every JSON verification
record now persists into docs/VERIFICATIONS.jsonl, gets folded into
the embedded core/verifications.c lookup table, and surfaces in
--list / --module-info / --explain / --scan --json.
New: docs/VERIFICATIONS.jsonl
Append-only store. One JSON record per verify.sh run. Records carry
module, ISO timestamp, host_kernel, host_distro, vm_box, expected
vs actual verdict, and match status. 6 lines today (5 unique after
dedup; the extra is dirty_pipe's pre-correction MISMATCH that
surfaced the silent-backport finding — kept in the JSONL for
history, deduped out of the C table).
New: tools/refresh-verifications.py
Parses VERIFICATIONS.jsonl, dedupes to latest per
(module, vm_box, host_kernel), generates core/verifications.c with a
static array + lookup functions:
verifications_for_module(name, &count_out)
verifications_module_has_match(name)
--check mode for CI drift detection.
New: core/verifications.{h,c}
Embedded record table. Lookup is O(corpus); we have <50 records.
skeletonkey.c surfacing:
- --list: new 'VFY' column shows ✓ for modules with >=1 'match'
record. Five modules show ✓ today (pwnkit, cgroup_release_agent,
netfilter_xtcompat, fuse_legacy, dirty_pipe).
- --module-info: new '--- verified on ---' section enumerates every
record with date / distro / kernel / vm_box / status. Modules with
zero records get a 'run tools/verify-vm/verify.sh <name>' hint.
- --explain: new 'VERIFIED ON' section in the operator briefing.
- --scan --json / --module-info --json: 'verified_on' array of
record objects per module.
Verification records baked in:
pwnkit Ubuntu 20.04.6 LTS 5.4.0-169 match (polkit 0.105)
cgroup_release_agent Debian 11 (bullseye) 5.10.0-27 match
netfilter_xtcompat Debian 11 (bullseye) 5.10.0-27 match
fuse_legacy Debian 11 (bullseye) 5.10.0-27 match
dirty_pipe Ubuntu 22.04.3 LTS 5.15.0-91 match (OK; silent backport)
The dirty_pipe record is particularly informative: stock Ubuntu 22.04
ships 5.15.0-91-generic. Our version-only kernel_range check would say
VULNERABLE (5.15.0 < 5.15.25 backport in our table). The --active
probe writes a sentinel via the dirty_pipe primitive then re-reads;
on this host the primitive is blocked → sentinel doesn't land →
verdict OK. Ubuntu silently backports CVE fixes into the patch level
(-91 here) without bumping uname's X.Y.Z. The targets.yaml entry was
updated from 'expect: VULNERABLE' to 'expect: OK' to reflect what
the active probe definitively determined; the original VULNERABLE
expectation is preserved in the JSONL history as a demonstration of
why we ship an active-probe path at all (this is the verified-vs-
claimed bar in action).
Plumbing fixes that landed in the same loop:
- core/nft_compat.h — conditional defines for newer-kernel nft uapi
constants (NFT_CHAIN_HW_OFFLOAD, NFTA_VERDICT_CHAIN_ID, etc.)
that aren't in Ubuntu 20.04's pre-5.5 linux-libc-dev. Without
this, nft_* modules failed to compile inside the verifier guest.
Included from each nft module after <linux/netfilter/nf_tables.h>.
- tools/verify-vm/Vagrantfile — wrap config in c.vm.define so each
module gets its own tracked machine; disable Parallels Tools
auto-install (fails on older guest kernels); translate
underscores in guest hostname to hyphens (RFC 952).
- tools/verify-vm/verify.sh — explicit 'vagrant rsync' before
'vagrant provision build-and-verify' (vagrant only auto-rsyncs on
fresh up, not on already-running VMs); fix verdict-grep regex to
tolerate Vagrant's 'skk-<module>:' line prefix + '|| true' so a
grep miss doesn't trigger set-e+pipefail; append JSON record to
docs/VERIFICATIONS.jsonl on every run.
- tools/verify-vm/targets.yaml — dirty_pipe retargeted from
ubuntu2004 + pinned 5.13.0-19 (no longer in 20.04's apt) to
ubuntu2204 stock 5.15.0-91 (apt-installable + exercises the
active-probe-overrides-version-check path).
What's next for the verifier:
- Mainline kernel.ubuntu.com integration so we can actually pin
arbitrary historical kernels (currently the pin path only works
with apt-installable packages).
- Sweep the remaining ~18 verifiable modules and accumulate records.
- Per-module verified_on counts in --explain header.
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