Files
SKELETONKEY/core/module.h
T
leviathan 4f30d00a1c core/host: shared host fingerprint refactor
Adds core/host.{h,c} — a single struct skeletonkey_host populated once
at startup and handed to every module callback via ctx->host. Replaces
the per-detect uname / /etc/os-release / sysctl / userns-fork-probe
calls scattered across the corpus with O(1) cached lookups, and gives
the dispatcher one consistent view of the host.

What's in the fingerprint:

- Identity: kernel_version (parsed from uname.release), arch (machine),
  nodename, distro_id / distro_version_id / distro_pretty (parsed once
  from /etc/os-release).
- Process state: euid, real_uid (defeats userns illusion via
  /proc/self/uid_map), egid, username, is_root, is_ssh_session.
- Platform family: is_linux, is_debian_family, is_rpm_family,
  is_arch_family, is_suse_family (file-existence checks once).
- Capability gates (Linux): unprivileged_userns_allowed (live
  fork+unshare probe), apparmor_restrict_userns,
  unprivileged_bpf_disabled, kpti_enabled, kernel_lockdown_active,
  selinux_enforcing, yama_ptrace_restricted.
- System services: has_systemd, has_dbus_system.

Wiring:

- core/module.h forward-declares struct skeletonkey_host and adds the
  pointer to skeletonkey_ctx. Modules opt-in by including
  ../../core/host.h.
- core/host.c is fully POD (no heap pointers) — uses a single file-
  static instance, returns a stable pointer on every call. Lazily
  populated on first skeletonkey_host_get().
- skeletonkey.c calls skeletonkey_host_get() at main() entry, stores
  in ctx.host before any register_*() runs.
- cmd_auto's bespoke distro-fingerprint code (was an inline
  read_os_release helper) is replaced with skeletonkey_host_print_banner(),
  which emits a two-line banner of identity + capability gates.

Migrations:

- dirtydecrypt: kernel_version_current() -> ctx->host->kernel.
- fragnesia: removed local fg_userns_allowed() fork-probe in favour of
  ctx->host->unprivileged_userns_allowed (no per-scan fork). Also
  pulls kernel from ctx->host. The PRECOND_FAIL message now notes
  whether AppArmor restriction is on.
- pack2theroot: access('/etc/debian_version') -> ctx->host->is_debian_family;
  also short-circuits when ctx->host->has_dbus_system is false (saves
  the GLib g_bus_get_sync attempt on systems without system D-Bus).
- overlayfs: replaced the inline is_ubuntu() /etc/os-release parser
  with ctx->host->distro_id comparison. Local helper preserved for
  symmetry / standalone builds.

Documentation: docs/ARCHITECTURE.md gains a 'Host fingerprint'
section describing the struct, the opt-in include pattern, and
example detect() usage. ROADMAP --auto accuracy log notes the
landing and flags remaining modules as an incremental follow-up.

Build verification:

- macOS (local): make clean && make -> Mach-O x86_64, 31 modules,
  banner prints with distro=?/? (no /etc/os-release).
- Linux (docker gcc:latest + libglib2.0-dev): make clean && make ->
  ELF 64-bit, 31 modules. Banner prints with kernel + distro=debian/13
  + 7 capability gates. dirtydecrypt correctly says 'predates the
  rxgk code added in 7.0'; fragnesia PRECOND_FAILs with
  '(host fingerprint)' annotation; pack2theroot PRECOND_FAILs on
  no-DBus; overlayfs reports 'not Ubuntu (distro=debian)'.
2026-05-22 23:18:00 -04:00

110 lines
4.5 KiB
C

/*
* SKELETONKEY — core module interface
*
* Every CVE module exports one or more `struct skeletonkey_module` entries
* via a registry function. The top-level dispatcher (skeletonkey.c) walks
* the global registry to implement --scan, --exploit, --mitigate, etc.
*
* This is intentionally a small interface. Modules carry the
* complexity; the dispatcher just routes.
*/
#ifndef SKELETONKEY_MODULE_H
#define SKELETONKEY_MODULE_H
#include <stddef.h>
#include <stdbool.h>
/* Standard result codes returned by detect()/exploit()/mitigate().
*
* These map to top-level exit codes when skeletonkey is invoked with a
* single-module operation:
*
* SKELETONKEY_OK exit 0 detect: not vulnerable / clean
* SKELETONKEY_VULNERABLE exit 2 detect: confirmed vulnerable
* SKELETONKEY_PRECOND_FAIL exit 4 detect: preconditions missing
* SKELETONKEY_TEST_ERROR exit 1 detect/exploit: error
* SKELETONKEY_EXPLOIT_OK exit 5 exploit: succeeded (root achieved)
* SKELETONKEY_EXPLOIT_FAIL exit 3 exploit: attempted but did not land
*
* Implementation note: copy_fail_family's df_result_t shares these
* numeric values intentionally so the family code can return its
* existing constants without translation.
*/
typedef enum {
SKELETONKEY_OK = 0,
SKELETONKEY_TEST_ERROR = 1,
SKELETONKEY_VULNERABLE = 2,
SKELETONKEY_EXPLOIT_FAIL = 3,
SKELETONKEY_PRECOND_FAIL = 4,
SKELETONKEY_EXPLOIT_OK = 5,
} skeletonkey_result_t;
/* Per-invocation context passed to module callbacks. The host
* fingerprint (kernel / distro / capability gates / service presence)
* is populated once at startup by core/host.c and handed to every
* module callback here — see core/host.h. */
struct skeletonkey_host; /* forward decl; full def in core/host.h */
struct skeletonkey_ctx {
bool no_color; /* --no-color */
bool json; /* --json (machine-readable output) */
bool active_probe; /* --active (do invasive probes in detect) */
bool no_shell; /* --no-shell (exploit prep but don't pop) */
bool authorized; /* user typed --i-know on exploit */
bool full_chain; /* --full-chain (attempt root-pop after primitive) */
bool dry_run; /* --dry-run (preview only; never call exploit/mitigate/cleanup) */
/* Host fingerprint — see core/host.h. Stable pointer, populated
* once by main() before any module callback runs. Modules that
* want to consult it #include "../../core/host.h". May be NULL
* only in degenerate test contexts; main() always sets it. */
const struct skeletonkey_host *host;
};
struct skeletonkey_module {
/* Short id used on the command line: `skeletonkey --exploit copy_fail`. */
const char *name;
/* CVE identifier (or "VARIANT" if no CVE assigned). */
const char *cve;
/* One-line human description. */
const char *summary;
/* Family this module belongs to (e.g. "copy_fail_family"). Modules
* with shared infrastructure live in the same family. */
const char *family;
/* Affected kernel range, prose. Machine-readable range goes in
* the module's kernel-range.json (consumed by CI). */
const char *kernel_range;
/* Probe the host. Should be side-effect-free unless ctx->active_probe
* is true. Return SKELETONKEY_VULNERABLE if confirmed,
* SKELETONKEY_PRECOND_FAIL if not applicable here, SKELETONKEY_OK if patched
* or otherwise immune, SKELETONKEY_TEST_ERROR on probe error. */
skeletonkey_result_t (*detect)(const struct skeletonkey_ctx *ctx);
/* Run the exploit. Caller has already passed the --i-know gate. */
skeletonkey_result_t (*exploit)(const struct skeletonkey_ctx *ctx);
/* Apply a temporary mitigation. NULL if none offered. */
skeletonkey_result_t (*mitigate)(const struct skeletonkey_ctx *ctx);
/* Undo --exploit (e.g. evict from page cache) or --mitigate side
* effects. NULL if no cleanup applies. */
skeletonkey_result_t (*cleanup)(const struct skeletonkey_ctx *ctx);
/* Detection rule corpus — embedded so the binary is self-
* contained. Each may be NULL if this module ships no rules for
* that format. Strings are NUL-terminated; concatenated in the
* order modules register. */
const char *detect_auditd; /* auditd .rules content */
const char *detect_sigma; /* sigma YAML content */
const char *detect_yara; /* yara rules content */
const char *detect_falco; /* falco rules content */
};
#endif /* SKELETONKEY_MODULE_H */