Merge remote-tracking branch 'origin/pylint'

[kconfig-hardened-check.git] / kernel_hardening_checker / checks.py

diff --git a/kernel_hardening_checker/checks.py b/kernel_hardening_checker/checks.py
index ed8354181699c849ab8fc8f5f2ba56bfebe1dabc..f2e4c34fd6da0a81a046563329dd5e2736a09f46 100644 (file)
--- a/kernel_hardening_checker/checks.py
+++ b/kernel_hardening_checker/checks.py
@@ -8,13 +8,14 @@ Author: Alexander Popov <alex.popov@linux.com>
 This module contains knowledge for checks.
 """
 
-# pylint: disable=missing-function-docstring,line-too-long,invalid-name
+# pylint: disable=missing-function-docstring,line-too-long
 # pylint: disable=too-many-branches,too-many-statements,too-many-locals
 
-from .engine import KconfigCheck, CmdlineCheck, SysctlCheck, VersionCheck, OR, AND
+from typing import List
+from .engine import StrOrNone, ChecklistObjType, KconfigCheck, CmdlineCheck, SysctlCheck, VersionCheck, OR, AND
 
 
-def add_kconfig_checks(l, arch):
+def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None:
     assert(arch), 'empty arch'
 
     # Calling the KconfigCheck class constructor:
@@ -422,7 +423,7 @@ def add_kconfig_checks(l, arch):
         l += [KconfigCheck('harden_userspace', 'a13xp0p0v', 'X86_USER_SHADOW_STACK', 'y')]
 
 
-def add_cmdline_checks(l, arch):
+def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None:
     assert(arch), 'empty arch'
 
     # Calling the CmdlineCheck class constructor:
@@ -630,7 +631,7 @@ no_kstrtobool_options = [
 ]
 
 
-def normalize_cmdline_options(option, value):
+def normalize_cmdline_options(option: str, value: str) -> str:
     # Don't normalize the cmdline option values if
     # the Linux kernel doesn't use kstrtobool() for them
     if option in no_kstrtobool_options:
@@ -646,7 +647,7 @@ def normalize_cmdline_options(option, value):
     return value
 
 
-# TODO: draft of security hardening sysctls:
+# Ideas of security hardening sysctls:
 #    what about bpf_jit_enable?
 #    vm.mmap_min_addr has a good value
 #    nosmt sysfs control file
@@ -657,30 +658,40 @@ def normalize_cmdline_options(option, value):
 #    kernel.warn_limit (think about a proper value)
 #    net.ipv4.tcp_syncookies=1 (?)
 
-def add_sysctl_checks(l, _arch):
+def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None:
 # This function may be called with arch=None
 
 # Calling the SysctlCheck class constructor:
 #   SysctlCheck(reason, decision, name, expected)
 
+    # Use an omnipresent kconfig symbol to see if we have a kconfig file for checking
+    have_kconfig = KconfigCheck('-', '-', 'LOCALVERSION', 'is present')
+
     l += [OR(SysctlCheck('self_protection', 'kspp', 'net.core.bpf_jit_harden', '2'),
-             AND(KconfigCheck('cut_attack_surface', 'kspp', 'BPF_JIT', 'is not set'),
-                 # use an omnipresent config symbol to see if we have a config file to check BPF_JIT.
-                 KconfigCheck('cut_attack_surface', 'kspp', 'DEFAULT_INIT', 'is present')))]
+             AND(KconfigCheck('-', '-', 'BPF_JIT', 'is not set'),
+                 have_kconfig))]
 
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.dmesg_restrict', '1')]
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.perf_event_paranoid', '3')] # with a custom patch, see https://lwn.net/Articles/696216/
-    l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kexec_load_disabled', '1')]
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'user.max_user_namespaces', '0')] # may break the upower daemon in Ubuntu
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'dev.tty.ldisc_autoload', '0')]
-    l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.unprivileged_bpf_disabled', '1')]
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kptr_restrict', '2')]
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'dev.tty.legacy_tiocsti', '0')]
-    l += [SysctlCheck('cut_attack_surface', 'kspp', 'vm.unprivileged_userfaultfd', '0')]
+    l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'kernel.kexec_load_disabled', '1'),
+             AND(KconfigCheck('-', '-', 'KEXEC_CORE', 'is not set'),
+                 have_kconfig))]
+    l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'kernel.unprivileged_bpf_disabled', '1'),
+             AND(KconfigCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set'),
+                 have_kconfig))]
+    l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'vm.unprivileged_userfaultfd', '0'),
+             AND(KconfigCheck('cut_attack_surface', 'grsec', 'USERFAULTFD', 'is not set'),
+                 have_kconfig))]
           # At first, it disabled unprivileged userfaultfd,
           # and since v5.11 it enables unprivileged userfaultfd for user-mode only.
 
-    l += [SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1')] # radical, but may be useful in some cases
+    l += [OR(SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1'),
+             AND(KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set'),
+                 have_kconfig))] # radical, but may be useful in some cases
 
     l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_symlinks', '1')]
     l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_hardlinks', '1')]