The 4 dirty_frag siblings + the GCM variant all gate on unprivileged
user-namespace creation (the XFRM-ESP / AF_RXRPC paths are
unreachable without it). The inner DIRTYFAIL detect functions
already check this, but the check happened deep inside the legacy
code — invisible to the test harness, and the bridge wrappers would
delegate first and only short-circuit afterwards.
Move the check up to the bridge: a single cff_check_userns() helper
inspects ctx->host->unprivileged_userns_allowed and returns
PRECOND_FAIL (with a host-fingerprint-annotated message) BEFORE
calling the inner detect. The inner check stays in place as belt-
and-suspenders.
copy_fail itself uses AF_ALG (no userns needed) and bypasses the
gate — its inner detect still confirms the primitive empirically
via the active probe.
modules/copy_fail_family/skeletonkey_modules.c:
- #include "../../core/host.h" alongside the existing includes.
- new static cff_check_userns(modname, ctx) helper.
- copy_fail_gcm_detect_wrap, dirty_frag_esp_detect_wrap,
dirty_frag_esp6_detect_wrap, dirty_frag_rxrpc_detect_wrap all
call cff_check_userns before delegating.
- copy_fail_detect_wrap is intentionally untouched.
tests/test_detect.c: 4 new EXPECT_DETECT cases assert that all 4
gated bridge wrappers return PRECOND_FAIL when
unprivileged_userns_allowed=false, using the existing
h_kernel_5_14_no_userns fingerprint.
29 → 33 tests, all pass on Linux.
The vendored DIRTYFAIL exploits call typed_confirm("DIRTYFAIL"), which
reads stdin interactively. SKELETONKEY already gates --exploit/--auto
behind --i-know, so the prompt is redundant and deadlocks non-interactive
runs like `skeletonkey --auto --i-know`.
Add a dirtyfail_assume_yes flag, forwarded from skeletonkey_ctx.authorized
by the bridge layer's apply_ctx(). When set, typed_confirm() auto-satisfies
its gate and logs that it did so.
The YES_BREAK_SSH self-lockout guard is exempt — it protects the
operator's own access rather than gating authorization, so it still
requires an interactive answer.
Standalone DIRTYFAIL builds are unchanged: the flag defaults false.
- copy_fail_family/iamroot_modules.c: two new bridge functions
- copy_fail_family_mitigate: calls existing mitigate_apply() which
blacklists algif_aead + esp4 + esp6 + rxrpc, sets
kernel.apparmor_restrict_unprivileged_userns=1, drops caches.
- copy_fail_family_cleanup: heuristic-routed cleanup. If the
mitigation conf file (/etc/modprobe.d/dirtyfail-mitigations.conf)
exists → mitigate_revert(). Otherwise → try_revert_passwd_page_cache()
to evict /etc/passwd from page cache.
- All 5 copy_fail_family modules' .mitigate and .cleanup fields now
point at these shared family-wide handlers (the mitigation is
family-wide, not per-CVE).
- dirty_pipe and entrybleed: no --mitigate offered (no canonical
patches / only-fix-is-upgrade). Documented in ROADMAP.
Verified end-to-end on kctf-mgr as non-root user:
iamroot --mitigate copy_fail → 'mitigate requires root' (correct)
iamroot --cleanup copy_fail → 'no mitigation conf; evicting page cache'
CVES.md gains a per-module ops table; ROADMAP.md marks Phase 6 partial.
leviathan