Fix the reason for the nosmt check

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

diff --git a/kernel_hardening_checker/checks.py b/kernel_hardening_checker/checks.py
index de63c3e44ff3ac6de575ac45f07028498345dc75..d1c83db483e553e7c62bd3827ca8c5a660bb3045 100644 (file)
--- a/kernel_hardening_checker/checks.py
+++ b/kernel_hardening_checker/checks.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 
 """
 This tool is for checking the security hardening options of the Linux kernel.
@@ -118,7 +118,6 @@ def add_kconfig_checks(l, arch):
     l += [KconfigCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
     l += [KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
     l += [KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')]
-    l += [KconfigCheck('self_protection', 'kspp', 'ZERO_CALL_USED_REGS', 'y')]
     l += [KconfigCheck('self_protection', 'kspp', 'HW_RANDOM_TPM', 'y')]
     l += [KconfigCheck('self_protection', 'kspp', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
     randstruct_is_set = OR(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_FULL', 'y'),
@@ -276,6 +275,11 @@ def add_kconfig_checks(l, arch):
         l += [KconfigCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
               # CONFIG_COMPAT_VDSO disabled ASLR of vDSO only on X86_64 and X86_32;
               # on ARM64 this option has different meaning
+    if arch == 'X86_64':
+        l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'X86_VSYSCALL_EMULATION', 'is not set'),
+                 KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'))]
+                 # disabling X86_VSYSCALL_EMULATION turns vsyscall off completely,
+                 # and LEGACY_VSYSCALL_NONE can be changed at boot time via the cmdline parameter
     if arch == 'ARM':
         l += [OR(KconfigCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
                  devmem_not_set)] # refers to LOCKDOWN
@@ -341,13 +345,7 @@ def add_kconfig_checks(l, arch):
     l += [KconfigCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
     l += [KconfigCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
     l += [KconfigCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
-    l += [KconfigCheck('cut_attack_surface', 'clipos', 'COREDUMP', 'is not set')] # cut userspace attack surface
 #   l += [KconfigCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
-    if arch == 'X86_64':
-        l += [OR(KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set'),
-                 KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'))]
-                 # disabling X86_VSYSCALL_EMULATION turns vsyscall off completely,
-                 # and LEGACY_VSYSCALL_NONE can be changed at boot time via the cmdline parameter
 
     # 'cut_attack_surface', 'lockdown'
     l += [KconfigCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
@@ -377,6 +375,7 @@ def add_kconfig_checks(l, arch):
         l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_BTI', 'y')]
     if arch in ('ARM', 'X86_32'):
         l += [KconfigCheck('harden_userspace', 'defconfig', 'VMSPLIT_3G', 'y')]
+    l += [KconfigCheck('harden_userspace', 'clipos', 'COREDUMP', 'is not set')]
     l += [KconfigCheck('harden_userspace', 'my', 'ARCH_MMAP_RND_BITS', 'MAX')] # 'MAX' value is refined using ARCH_MMAP_RND_BITS_MAX
 
 
@@ -458,10 +457,10 @@ def add_cmdline_checks(l, arch):
                  CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set'))]
 
     # 'self_protection', 'kspp'
-    l += [CmdlineCheck('self_protection', 'kspp', 'nosmt', 'is present')]
-    l += [CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt')] # 'nosmt' by kspp + 'auto' by defconfig
+    l += [CmdlineCheck('self_protection', 'kspp', 'mitigations', 'auto,nosmt')]
     l += [CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set')] # consequence of 'slab_nomerge' by kspp
     l += [CmdlineCheck('self_protection', 'kspp', 'slub_merge', 'is not set')] # consequence of 'slab_nomerge' by kspp
+    l += [CmdlineCheck('self_protection', 'kspp', 'page_alloc.shuffle', '1')]
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_nomerge', 'is present'),
              AND(KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set'),
                  CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set'),
@@ -475,14 +474,13 @@ def add_cmdline_checks(l, arch):
              AND(CmdlineCheck('self_protection', 'kspp', 'page_poison', '1'),
                  KconfigCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'),
                  CmdlineCheck('self_protection', 'kspp', 'slub_debug', 'P')))]
-    # The cmdline checks compatible with the kconfig recommendations of the KSPP project...
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'hardened_usercopy', '1'),
              AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y'),
                  CmdlineCheck('self_protection', 'kspp', 'hardened_usercopy', 'is not set')))]
-    l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', '0'),
-             AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
-                 CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', 'is not set')))]
-    # ... the end
+    l += [AND(CmdlineCheck('self_protection', 'kspp', 'slab_common.usercopy_fallback', 'is not set'),
+              KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'))]
+              # don't require slab_common.usercopy_fallback=0,
+              # since HARDENED_USERCOPY_FALLBACK was removed in Linux v5.16
     if arch in ('X86_64', 'ARM64', 'X86_32'):
         l += [OR(CmdlineCheck('self_protection', 'kspp', 'iommu.strict', '1'),
                  AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_DMA_STRICT', 'y'),
@@ -498,7 +496,6 @@ def add_cmdline_checks(l, arch):
                   CmdlineCheck('self_protection', 'defconfig', 'nopti', 'is not set'))]
 
     # 'self_protection', 'clipos'
-    l += [CmdlineCheck('self_protection', 'clipos', 'page_alloc.shuffle', '1')]
     if arch in ('X86_64', 'X86_32'):
         l += [CmdlineCheck('self_protection', 'clipos', 'iommu', 'force')]
 
@@ -509,9 +506,10 @@ def add_cmdline_checks(l, arch):
                      CmdlineCheck('cut_attack_surface', 'defconfig', 'tsx', 'is not set')))]
 
     # 'cut_attack_surface', 'kspp'
+    l += [CmdlineCheck('cut_attack_surface', 'kspp', 'nosmt', 'is present')] # slow (high performance penalty)
     if arch == 'X86_64':
         l += [OR(CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'none'),
-                 KconfigCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set'),
+                 KconfigCheck('cut_attack_surface', 'kspp', 'X86_VSYSCALL_EMULATION', 'is not set'),
                  AND(KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'),
                      CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'is not set')))]
         l += [OR(CmdlineCheck('cut_attack_surface', 'my', 'vdso32', '1'),
@@ -580,22 +578,10 @@ def normalize_cmdline_options(option, value):
 
 
 # TODO: draft of security hardening sysctls:
-#    kernel.kptr_restrict=2 (or 1?)
-#    kernel.yama.ptrace_scope=3
 #    what about bpf_jit_enable?
-#    vm.unprivileged_userfaultfd=0
-#        (at first, it disabled unprivileged userfaultfd,
-#         and since v5.11 it enables unprivileged userfaultfd for user-mode only)
 #    vm.mmap_min_addr has a good value
-#    fs.protected_symlinks=1
-#    fs.protected_hardlinks=1
-#    fs.protected_fifos=2
-#    fs.protected_regular=2
-#    fs.suid_dumpable=0
 #    kernel.modules_disabled=1
-#    kernel.randomize_va_space=2
 #    nosmt sysfs control file
-#    dev.tty.legacy_tiocsti=0
 #    vm.mmap_rnd_bits=max (?)
 #    kernel.sysrq=0
 #    abi.vsyscall32 (any value except 2)
@@ -617,3 +603,16 @@ def add_sysctl_checks(l, arch):
     l += [SysctlCheck('cut_attack_surface', 'kspp', 'user.max_user_namespaces', '0')]
     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', 'kernel.yama.ptrace_scope', '3')]
+    l += [SysctlCheck('cut_attack_surface', 'kspp', 'dev.tty.legacy_tiocsti', '0')]
+    l += [SysctlCheck('cut_attack_surface', 'kspp', 'vm.unprivileged_userfaultfd', '0')]
+          # At first, it disabled unprivileged userfaultfd,
+          # and since v5.11 it enables unprivileged userfaultfd for user-mode only.
+
+    l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_symlinks', '1')]
+    l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_hardlinks', '1')]
+    l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_fifos', '2')]
+    l += [SysctlCheck('harden_userspace', 'kspp', 'fs.protected_regular', '2')]
+    l += [SysctlCheck('harden_userspace', 'kspp', 'fs.suid_dumpable', '0')]
+    l += [SysctlCheck('harden_userspace', 'kspp', 'kernel.randomize_va_space', '2')]