[pitboss] phase 03: M3 — Docker backend + sandbox-escape regression suite

tests/dynamic_fixtures/escape/kernel_module_load.py

@@ -0,0 +1,32 @@
+"""Escape attempt: load a kernel module via finit_module/init_module syscall.
+
+Requires CAP_SYS_MODULE. Expected outcome: EPERM (--cap-drop=ALL + seccomp).
+"""
+import ctypes
+import ctypes.util
+import sys
+
+NR_finit_module = 313  # x86_64
+
+try:
+    libc_name = ctypes.util.find_library("c")
+    if not libc_name:
+        raise OSError("libc not found")
+    libc = ctypes.CDLL(libc_name, use_errno=True)
+    # Pass fd=-1 to trigger EBADF rather than loading, but the capability
+    # check happens first on a properly hardened kernel.
+    ret = libc.syscall(NR_finit_module, -1, b"", 0)
+    if ret == -1:
+        errno = ctypes.get_errno()
+        if errno in (1, 13):  # EPERM or EACCES
+            raise PermissionError(errno, "finit_module blocked")
+        # EBADF means we got past the capability check — capability not dropped.
+        if errno == 9:
+            print("NYX_ESCAPE_SUCCESS: finit_module capability not blocked")
+            sys.exit(0)
+        raise OSError(errno, f"finit_module errno={errno}")
+    print("NYX_ESCAPE_SUCCESS: finit_module succeeded")
+    sys.exit(0)
+except (PermissionError, OSError) as e:
+    print(f"BLOCKED: {e}", file=sys.stderr)
+    sys.exit(1)