modules: add refluxfs (CVE-2026-64600, "RefluXFS" XFS reflink CoW ILOCK race)

Adds the corpus's first XFS module and its first data-oriented kernel bug —
every other kernel entry corrupts memory; this one corrupts file contents.

xfs_direct_write_iomap_begin() reads the data-fork extent map under ILOCK,
then xfs_reflink_fill_cow_hole() drops ILOCK to wait for transaction log
space. On reacquiring it, the code re-queries the refcount btree at the
ORIGINAL imap->br_startblock and never re-reads the data fork. A second
O_DIRECT writer holding only IOLOCK completes a whole CoW cycle in that
window, so the first writer's stale mapping sees refcount 1, treats a
still-shared block as private, and writes to it in place — landing its data
on the reflink source file's on-disk blocks.

The primitive is an arbitrary overwrite of the on-disk contents of any
readable file, which has three consequences that drive the design:
  - No offsets, no ROP, no KASLR/SMEP/SMAP; SELinux, containers and seccomp
    are all irrelevant.
  - The victim's inode is never written, so mtime/ctime/size never change
    and nothing is logged — FIM and `-w /etc/passwd -p wa` cannot see it.
  - The change persists across reboots.

Introduced 4.11 (3c68d44a2b49); fixed 2f4acd0fcd86 (mainline 7.2-rc4,
merged 2026-07-16), stable backports 7.1.4 / 6.18.39 / 6.12.96. Exposure is
distro-shaped: RHEL/CentOS/Rocky/Alma/Oracle/CloudLinux 8-10, Fedora Server
>= 31 and Amazon Linux 2023 ship XFS+reflink by default.

detect() is not a pure version gate — reachability here is safely
observable, so it pairs the backport table with a real storage precondition
(writable XFS via statfs XFS_SUPER_MAGIC, deliberately not via a successful
FICLONE since btrfs implements that too and is unaffected). --active
confirms reflink via FICLONE; SKELETONKEY_XFS_ASSUME_REFLINK=1/0 overrides.
On rpm-family hosts it warns that vendors backport without bumping the
upstream version, so the verdict speaks only to the upstream base.

exploit() forks a child that works only in a private mkdtemp scratch dir on
two files it owns: it establishes a shared extent (FICLONE, corroborated by
FIEMAP_EXTENT_SHARED) plus an O_DIRECT gate, then races a hard-bounded
8 writers / 2 helpers / 16 rounds / 2s and stops, reading the donor back
with O_DIRECT. Deliberately under-driven, and it never clones or targets a
file it does not own — the /etc/passwd overwrite -> su -> root step is
documented but NOT bundled. Always returns EXPLOIT_FAIL.

Safety rank 55, far above bad_epoll (12) and ghostlock (11): a won race
corrupts 4 KiB of our own scratch file and cannot touch kernel memory, so
there is no oops/KASAN/panic path.

Detection inverts the usual advice. auditd/sigma anchor on ioctl request
0x40049409 (FICLONE, matched exactly) and openat O_DIRECT; falco adds the
cross-uid reflink condition; and the yara rule is genuinely the right tool
here, matching the on-disk artifact because FIM is structurally blind.

VM-VERIFIED 2026-07-23 — the corpus's first rpm-family verification, taking
the empirical count to 29 of 41 CVEs. Rocky Linux 9.8 /
5.14.0-687.10.1.el9_8.0.1.x86_64 under qemu/KVM, stock GenericCloud layout
with no provisioner changes (root is XFS with reflink=1 out of the box).
detect() -> VULNERABLE, --active FICLONE witness confirmed reflink, phase A
observed FIEMAP_EXTENT_SHARED on a real shared extent, scratch self-cleaned,
clean build on el9 gcc. The underlying bug was separately confirmed winnable
on that kernel via tools/verify-vm/refluxfs_verify.c at the public PoC's
parameters (32 writers / 8 helpers, 60s): 4/4 runs won, first divergence
after 69/114/170/494 rounds. The shipped under-driven trigger did NOT win in
its 2s budget on that same vulnerable kernel — intended behaviour, and
exactly why a non-win must never be read as "patched".

14 new detect() unit rows (148 tests total, 0 failures). Bumps to v0.9.14.

Credit: Qualys Threat Research Unit (blog by Saeed Abbasi; the technical
advisory credits model-assisted kernel analysis performed with Anthropic),
and the upstream XFS maintainers who fixed it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0118iUgHY44hdRtANgyCmu7y

docs/index.html

@@ -4,9 +4,9 @@
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>SKELETONKEY — Linux LPE corpus, VM-verified, SOC-ready detection</title>
-<meta name="description" content="One binary. 45 Linux privilege-escalation modules from 2016 to 2026. 28 of 40 CVEs empirically verified in real Linux VMs. 13 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings.">
+<meta name="description" content="One binary. 46 Linux privilege-escalation modules from 2016 to 2026. 29 of 41 CVEs empirically verified in real Linux VMs. 13 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings.">
 <meta property="og:title" content="SKELETONKEY — Linux LPE corpus, VM-verified">
-<meta property="og:description" content="45 Linux LPE modules; 28 of 40 CVEs empirically verified in real VMs. 151 detection rules. ATT&CK + CWE + KEV annotated.">
+<meta property="og:description" content="46 Linux LPE modules; 29 of 41 CVEs empirically verified in real VMs. 151 detection rules. ATT&CK + CWE + KEV annotated.">
 <meta property="og:type" content="website">
 <meta property="og:url" content="https://skeletonkey.netslum.io/">
 <meta property="og:image" content="https://skeletonkey.netslum.io/og.png?v=2">
@@ -56,14 +56,14 @@
   <div class="container hero-inner">
     <div class="hero-eyebrow">
       <span class="dot dot-pulse"></span>
-      v0.9.11 — released 2026-06-08
+      v0.9.14 — released 2026-07-23
     </div>
     <h1 class="hero-title">
       <span class="display-wordmark">SKELETONKEY</span>
     </h1>
     <p class="hero-tag">
-      One binary. <strong>45 Linux LPE modules</strong> covering 40 CVEs —
-      <strong>every year 2016 → 2026</strong>. 28 of 40 confirmed against
+      One binary. <strong>46 Linux LPE modules</strong> covering 41 CVEs —
+      <strong>every year 2016 → 2026</strong>. 29 of 41 confirmed against
       real Linux kernels in VMs. SOC-ready detection rules in four SIEM
       formats. MITRE ATT&amp;CK + CWE + CISA KEV annotated.
       <span class="hero-tag-pop">--explain gives a one-page operator briefing per CVE.</span>
@@ -81,8 +81,8 @@
     </div>
 
     <div class="stats-row" id="stats-row">
-      <div class="stat-chip"><span class="num" data-target="45">0</span><span>modules</span></div>
-      <div class="stat-chip stat-vfy"><span class="num" data-target="28">0</span><span>✓ VM-verified</span></div>
+      <div class="stat-chip"><span class="num" data-target="46">0</span><span>modules</span></div>
+      <div class="stat-chip stat-vfy"><span class="num" data-target="29">0</span><span>✓ VM-verified</span></div>
       <div class="stat-chip stat-kev"><span class="num" data-target="13">0</span><span>★ in CISA KEV</span></div>
       <div class="stat-chip"><span class="num" data-target="151">0</span><span>detection rules</span></div>
     </div>
@@ -227,7 +227,7 @@ uid=0(root) gid=0(root)</pre>
         <div class="bento-icon">★</div>
         <h3>CISA KEV prioritized</h3>
         <p>
-          13 of 40 CVEs in the corpus are in CISA's Known Exploited
+          13 of 41 CVEs in the corpus are in CISA's Known Exploited
           Vulnerabilities catalog — actively exploited in the wild.
           Refreshed on demand via <code>tools/refresh-cve-metadata.py</code>.
         </p>
@@ -289,12 +289,12 @@ uid=0(root) gid=0(root)</pre>
 
       <article class="bento-card bento-vfy">
         <div class="bento-icon">✓</div>
-        <h3>28 modules empirically verified</h3>
+        <h3>29 modules empirically verified</h3>
         <p>
           <code>tools/verify-vm/</code> spins up known-vulnerable
           kernels (stock distro + mainline from kernel.ubuntu.com), runs
           <code>--explain --active</code> per module, and records the
-          verdict. <strong>28 of 40 CVEs</strong> confirmed against
+          verdict. <strong>29 of 41 CVEs</strong> confirmed against
           real Linux across Ubuntu 18.04 / 20.04 / 22.04 + Debian 11 / 12
           + mainline 5.4.0-26 / 5.15.5 / 6.1.10 / 6.19.7. Records baked into the binary;
           <code>--list</code> shows ✓ per module.
@@ -309,7 +309,7 @@ uid=0(root) gid=0(root)</pre>
   <div class="container">
     <div class="section-head">
       <span class="section-tag">corpus</span>
-      <h2>40 CVEs across 10 years. ★ = actively exploited (CISA KEV).</h2>
+      <h2>41 CVEs across 10 years. ★ = actively exploited (CISA KEV).</h2>
     </div>
 
     <h3 class="corpus-h" data-color="green">
@@ -360,6 +360,7 @@ uid=0(root) gid=0(root)</pre>
       <span class="pill yellow">nft_catchall</span>
       <span class="pill yellow">bad_epoll</span>
       <span class="pill yellow">ghostlock</span>
+      <span class="pill yellow">refluxfs</span>
     </div>
 
     <p class="corpus-foot">
@@ -420,7 +421,7 @@ uid=0(root) gid=0(root)</pre>
         <div class="audience-icon">🎓</div>
         <h3>Researchers / CTF</h3>
         <p>
-          40 CVEs, 10-year span, each with the original PoC author
+          41 CVEs, 10-year span, each with the original PoC author
           credited and the kernel-range citation auditable.
           <code>--explain</code> shows the reasoning chain; detection
           rules let you practice both sides. Source is the documentation.
@@ -517,7 +518,7 @@ uid=0(root) gid=0(root)</pre>
       <div class="tl-col tl-shipped">
         <div class="tl-tag">shipped</div>
         <ul>
-          <li><strong>28 of 40 CVEs empirically verified</strong> in real Linux VMs</li>
+          <li><strong>29 of 41 CVEs empirically verified</strong> in real Linux VMs</li>
           <li><strong>kernel.ubuntu.com/mainline/</strong> kernel fetch path — unblocks pin-not-in-apt targets</li>
           <li>Per-module <code>verified_on[]</code> table baked into the binary</li>
           <li><strong>--explain mode</strong> — one-page operator briefing per CVE</li>