Files
SKELETONKEY/iamroot.c
T
leviathan 3eeee01f06 Phase 7: overlayfs CVE-2021-3493 module (Ubuntu userns LPE) — detect-only
10th module. Ubuntu-specific userns + overlayfs LPE that injects file
capabilities cross-namespace.

- modules/overlayfs_cve_2021_3493/iamroot_modules.{c,h}:
  - is_ubuntu() — parses /etc/os-release for ID=ubuntu or
    ID_LIKE=ubuntu. Non-Ubuntu hosts get IAMROOT_OK immediately (the
    bug is specific to Ubuntu's modified overlayfs).
  - unprivileged_userns_clone gate — sysctl=0 → PRECOND_FAIL
  - Active probe (--active): forks a child that enters userns +
    mountns and attempts the overlayfs mount inside /tmp. Mount
    success on Ubuntu = VULNERABLE. Mount denied = patched / AppArmor
    block. Child-isolated so parent's namespace state is untouched.
  - Version fallback: kernel < 5.13 = vulnerable-by-inference for
    Ubuntu kernels; recommend --active for confirmation.
  - Exploit: detect-only stub. Reference vsh's exploit-cve-2021-3493
    for full version (mount overlayfs in userns, drop binary with
    cap_setuid+ep into upper layer, re-exec outside ns).
  - Embedded auditd rules: mount(overlay) syscall + security.capability
    xattr writes (the exploit's two-step footprint).

Verified end-to-end on kctf-mgr (Debian):
  iamroot --scan → 'not Ubuntu — bug is Ubuntu-specific' → IAMROOT_OK

Module count: 10. Active-probe pattern now applies to dirty_pipe,
entrybleed, and overlayfs (and copy_fail_family via existing
dirtyfail_active_probes global). Detect quality across the corpus
materially improved this session.
2026-05-16 20:22:32 -04:00

317 lines
12 KiB
C

/*
* IAMROOT — top-level dispatcher
*
* Usage:
* iamroot --scan # run every module's detect()
* iamroot --scan --json # machine-readable output
* iamroot --scan --active # invasive probes (still no /etc/passwd writes)
* iamroot --list # list registered modules
* iamroot --exploit <name> --i-know # run a named module's exploit
* iamroot --mitigate <name> # apply a temporary mitigation
* iamroot --cleanup <name> # undo --exploit or --mitigate side effects
*
* Phase 1 scope: thin dispatcher over the copy_fail_family bridge.
* Future phases add: --detect-rules export, multi-family registry,
* fingerprint pre-pass, etc.
*/
#include "core/module.h"
#include "core/registry.h"
#include <getopt.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define IAMROOT_VERSION "0.1.0-phase1"
static const char BANNER[] =
"\n"
" ██╗ █████╗ ███╗ ███╗██████╗ ██████╗ ██████╗ ████████╗\n"
" ██║██╔══██╗████╗ ████║██╔══██╗██╔═══██╗██╔═══██╗╚══██╔══╝\n"
" ██║███████║██╔████╔██║██████╔╝██║ ██║██║ ██║ ██║ \n"
" ██║██╔══██║██║╚██╔╝██║██╔══██╗██║ ██║██║ ██║ ██║ \n"
" ██║██║ ██║██║ ╚═╝ ██║██║ ██║╚██████╔╝╚██████╔╝ ██║ \n"
" ╚═╝╚═╝ ╚═╝╚═╝ ╚═╝╚═╝ ╚═╝ ╚═════╝ ╚═════╝ ╚═╝ \n"
" Curated Linux kernel LPE corpus — v" IAMROOT_VERSION "\n"
" AUTHORIZED TESTING ONLY — see docs/ETHICS.md\n";
static void usage(const char *prog)
{
fprintf(stderr,
"Usage: %s [MODE] [OPTIONS]\n"
"\n"
"Modes (default: --scan):\n"
" --scan run every module's detect() across the host\n"
" --list list registered modules and exit\n"
" --exploit <name> run named module's exploit (REQUIRES --i-know)\n"
" --mitigate <name> apply named module's mitigation\n"
" --cleanup <name> undo named module's exploit/mitigate side effects\n"
" --detect-rules dump detection rules for every module\n"
" (combine with --format=auditd|sigma|yara|falco)\n"
" --version print version\n"
" --help this message\n"
"\n"
"Options:\n"
" --i-know authorization gate for --exploit modes\n"
" --active in --scan, do invasive sentinel probes (no /etc/passwd writes)\n"
" --no-shell in --exploit modes, prepare but don't drop to shell\n"
" --json machine-readable output (for SIEM/CI)\n"
" --no-color disable ANSI color codes\n"
" --format <f> with --detect-rules: auditd (default), sigma, yara, falco\n"
"\n"
"Exit codes:\n"
" 0 not vulnerable / OK 2 vulnerable 5 exploit succeeded\n"
" 1 test error 3 exploit failed 4 preconditions missing\n",
prog);
}
enum mode {
MODE_SCAN,
MODE_LIST,
MODE_EXPLOIT,
MODE_MITIGATE,
MODE_CLEANUP,
MODE_DETECT_RULES,
MODE_HELP,
MODE_VERSION,
};
enum detect_format {
FMT_AUDITD,
FMT_SIGMA,
FMT_YARA,
FMT_FALCO,
};
static const char *result_str(iamroot_result_t r)
{
switch (r) {
case IAMROOT_OK: return "OK";
case IAMROOT_TEST_ERROR: return "ERROR";
case IAMROOT_VULNERABLE: return "VULNERABLE";
case IAMROOT_EXPLOIT_FAIL: return "EXPLOIT_FAIL";
case IAMROOT_PRECOND_FAIL: return "PRECOND_FAIL";
case IAMROOT_EXPLOIT_OK: return "EXPLOIT_OK";
}
return "?";
}
static int cmd_list(void)
{
size_t n = iamroot_module_count();
fprintf(stdout, "%-20s %-18s %-25s %s\n",
"NAME", "CVE", "FAMILY", "SUMMARY");
fprintf(stdout, "%-20s %-18s %-25s %s\n",
"----", "---", "------", "-------");
for (size_t i = 0; i < n; i++) {
const struct iamroot_module *m = iamroot_module_at(i);
fprintf(stdout, "%-20s %-18s %-25s %s\n",
m->name, m->cve, m->family, m->summary);
}
return 0;
}
static int cmd_scan(const struct iamroot_ctx *ctx)
{
int worst = 0;
size_t n = iamroot_module_count();
if (!ctx->json) {
fprintf(stderr, "[*] iamroot scan: %zu module(s) registered\n", n);
} else {
fprintf(stdout, "{\"version\":\"%s\",\"modules\":[", IAMROOT_VERSION);
}
for (size_t i = 0; i < n; i++) {
const struct iamroot_module *m = iamroot_module_at(i);
if (m->detect == NULL) continue;
iamroot_result_t r = m->detect(ctx);
if (ctx->json) {
fprintf(stdout, "%s{\"name\":\"%s\",\"cve\":\"%s\",\"result\":\"%s\"}",
(i == 0 ? "" : ","), m->name, m->cve, result_str(r));
} else {
fprintf(stdout, "[%s] %-20s %-18s %s\n",
result_str(r), m->name, m->cve, m->summary);
}
/* track worst (highest) result code as overall exit */
if ((int)r > worst) worst = (int)r;
}
if (ctx->json) {
fprintf(stdout, "]}\n");
}
return worst;
}
/* Dump detection rules for every registered module in the requested
* format. Modules that don't ship a rule for that format are simply
* skipped (no error). Output goes to stdout so it can be redirected
* straight into /etc/audit/rules.d/, the SIEM, etc. */
static int cmd_detect_rules(enum detect_format fmt)
{
static const char *fmt_names[] = {
[FMT_AUDITD] = "auditd",
[FMT_SIGMA] = "sigma",
[FMT_YARA] = "yara",
[FMT_FALCO] = "falco",
};
size_t n = iamroot_module_count();
fprintf(stdout, "# IAMROOT detection rules — format: %s\n", fmt_names[fmt]);
fprintf(stdout, "# Generated from %zu registered modules\n", n);
fprintf(stdout, "# AUTHORIZED-TESTING tool; see docs/ETHICS.md\n\n");
/* Dedup by pointer: family-shared rule strings (e.g. all 5
* copy_fail_family modules share one auditd rule string) would
* otherwise emit identical blocks once per module. */
const char *seen[64] = {0};
size_t n_seen = 0;
int emitted = 0;
for (size_t i = 0; i < n; i++) {
const struct iamroot_module *m = iamroot_module_at(i);
const char *rules = NULL;
switch (fmt) {
case FMT_AUDITD: rules = m->detect_auditd; break;
case FMT_SIGMA: rules = m->detect_sigma; break;
case FMT_YARA: rules = m->detect_yara; break;
case FMT_FALCO: rules = m->detect_falco; break;
}
if (rules == NULL) continue;
/* Already emitted? */
bool dup = false;
for (size_t k = 0; k < n_seen; k++) {
if (seen[k] == rules) { dup = true; break; }
}
if (dup) {
fprintf(stdout, "# === %s (%s) — see family rules above ===\n\n",
m->name, m->cve);
continue;
}
if (n_seen < sizeof(seen)/sizeof(seen[0])) seen[n_seen++] = rules;
fprintf(stdout, "# === %s (%s) ===\n", m->name, m->cve);
fputs(rules, stdout);
fputc('\n', stdout);
emitted++;
}
fprintf(stderr, "[*] emitted detection rules for %d / %zu module(s) (format: %s)\n",
emitted, n, fmt_names[fmt]);
return 0;
}
static int cmd_one(const struct iamroot_module *m, const char *op,
const struct iamroot_ctx *ctx)
{
iamroot_result_t (*fn)(const struct iamroot_ctx *) = NULL;
if (strcmp(op, "exploit") == 0) fn = m->exploit;
else if (strcmp(op, "mitigate") == 0) fn = m->mitigate;
else if (strcmp(op, "cleanup") == 0) fn = m->cleanup;
if (fn == NULL) {
fprintf(stderr, "[-] module '%s' has no %s operation\n", m->name, op);
return 1;
}
iamroot_result_t r = fn(ctx);
fprintf(stderr, "[*] %s --%s result: %s\n", m->name, op, result_str(r));
return (int)r;
}
int main(int argc, char **argv)
{
/* Bring up the module registry. As new families land, add their
* register_* call here. */
iamroot_register_copy_fail_family();
iamroot_register_dirty_pipe();
iamroot_register_entrybleed();
iamroot_register_pwnkit();
iamroot_register_nf_tables();
iamroot_register_overlayfs();
enum mode mode = MODE_SCAN;
struct iamroot_ctx ctx = {0};
const char *target = NULL;
int i_know = 0;
enum detect_format dr_fmt = FMT_AUDITD;
static struct option longopts[] = {
{"scan", no_argument, 0, 'S'},
{"list", no_argument, 0, 'L'},
{"exploit", required_argument, 0, 'E'},
{"mitigate", required_argument, 0, 'M'},
{"cleanup", required_argument, 0, 'C'},
{"detect-rules", no_argument, 0, 'D'},
{"format", required_argument, 0, 6 },
{"i-know", no_argument, 0, 1 },
{"active", no_argument, 0, 2 },
{"no-shell", no_argument, 0, 3 },
{"json", no_argument, 0, 4 },
{"no-color", no_argument, 0, 5 },
{"version", no_argument, 0, 'V'},
{"help", no_argument, 0, 'h'},
{0, 0, 0, 0}
};
int c, opt_idx;
while ((c = getopt_long(argc, argv, "SLDE:M:C:Vh", longopts, &opt_idx)) != -1) {
switch (c) {
case 'S': mode = MODE_SCAN; break;
case 'L': mode = MODE_LIST; break;
case 'D': mode = MODE_DETECT_RULES; break;
case 'E': mode = MODE_EXPLOIT; target = optarg; break;
case 'M': mode = MODE_MITIGATE; target = optarg; break;
case 'C': mode = MODE_CLEANUP; target = optarg; break;
case 1 : i_know = 1; ctx.authorized = true; break;
case 2 : ctx.active_probe = true; break;
case 3 : ctx.no_shell = true; break;
case 4 : ctx.json = true; break;
case 5 : ctx.no_color = true; break;
case 6 :
if (strcmp(optarg, "auditd") == 0) dr_fmt = FMT_AUDITD;
else if (strcmp(optarg, "sigma") == 0) dr_fmt = FMT_SIGMA;
else if (strcmp(optarg, "yara") == 0) dr_fmt = FMT_YARA;
else if (strcmp(optarg, "falco") == 0) dr_fmt = FMT_FALCO;
else { fprintf(stderr, "[-] unknown --format: %s\n", optarg); return 1; }
break;
case 'V': printf("iamroot %s\n", IAMROOT_VERSION); return 0;
case 'h': mode = MODE_HELP; break;
default: usage(argv[0]); return 1;
}
}
if (mode == MODE_HELP) {
fputs(BANNER, stderr);
usage(argv[0]);
return 0;
}
if (!ctx.json) fputs(BANNER, stderr);
if (mode == MODE_SCAN) return cmd_scan(&ctx);
if (mode == MODE_LIST) return cmd_list();
if (mode == MODE_DETECT_RULES) return cmd_detect_rules(dr_fmt);
/* --exploit / --mitigate / --cleanup all take a target */
if (target == NULL) {
fprintf(stderr, "[-] mode requires a module name\n");
return 1;
}
const struct iamroot_module *m = iamroot_module_find(target);
if (m == NULL) {
fprintf(stderr, "[-] no module '%s'. Try --list.\n", target);
return 1;
}
if (mode == MODE_EXPLOIT) {
if (!i_know) {
fprintf(stderr,
"[-] --exploit requires --i-know. This will attempt to gain\n"
" root and corrupt /etc/passwd in the page cache.\n"
" Authorized testing only. See docs/ETHICS.md.\n");
return 1;
}
return cmd_one(m, "exploit", &ctx);
}
if (mode == MODE_MITIGATE) return cmd_one(m, "mitigate", &ctx);
if (mode == MODE_CLEANUP) return cmd_one(m, "cleanup", &ctx);
usage(argv[0]);
return 1;
}