Check disabling XFS_SUPPORT_V4 for cutting attack surface

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

diff --git a/kconfig_hardened_check/checks.py b/kconfig_hardened_check/checks.py
index ba29e2db76751649477c11124621e900ce7c6f8a..d857ad132c5658f04641564208920c0feea2a95e 100644 (file)
--- a/kconfig_hardened_check/checks.py
+++ b/kconfig_hardened_check/checks.py
@@ -1,54 +1,13 @@
 #!/usr/bin/python3
 
 """
-This tool helps me to check Linux kernel options against
-my security hardening preferences for X86_64, ARM64, X86_32, and ARM.
-Let the computers do their job!
+This tool is for checking the security hardening options of the Linux kernel.
 
 Author: Alexander Popov <alex.popov@linux.com>
 
 This module contains knowledge for checks.
 """
 
-# N.B. Hardening sysctls:
-#    kernel.kptr_restrict=2 (or 1?)
-#    kernel.dmesg_restrict=1 (also see the kconfig option)
-#    kernel.perf_event_paranoid=2 (or 3 with a custom patch, see https://lwn.net/Articles/696216/)
-#    kernel.kexec_load_disabled=1
-#    kernel.yama.ptrace_scope=3
-#    user.max_user_namespaces=0 (for Debian, also see kernel.unprivileged_userns_clone)
-#    what about bpf_jit_enable?
-#    kernel.unprivileged_bpf_disabled=1
-#    net.core.bpf_jit_harden=2
-#    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
-#    dev.tty.ldisc_autoload=0
-#    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)
-#    kernel.oops_limit (think about a proper value)
-#    kernel.warn_limit (think about a proper value)
-#
-# Think of these boot params:
-#    module.sig_enforce=1
-#    lockdown=confidentiality
-#    mce=0
-#    nosmt=force
-#    intel_iommu=on
-#    amd_iommu=on
-#    efi=disable_early_pci_dma
-
 # pylint: disable=missing-function-docstring,line-too-long,invalid-name
 # pylint: disable=too-many-branches,too-many-statements
 
@@ -406,6 +365,7 @@ def add_kconfig_checks(l, arch):
     l += [KconfigCheck('cut_attack_surface', 'my', 'KGDB', 'is not set')]
     l += [KconfigCheck('cut_attack_surface', 'my', 'AIO', 'is not set')]
     l += [KconfigCheck('cut_attack_surface', 'my', 'CORESIGHT', 'is not set')]
+    l += [KconfigCheck('cut_attack_surface', 'my', 'XFS_SUPPORT_V4', 'is not set')]
     l += [OR(KconfigCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y'),
              modules_not_set)]
 
@@ -489,7 +449,7 @@ def add_cmdline_checks(l, arch):
                  AND(KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y'),
                      CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set')))]
     else:
-        l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', '1'),
+        l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', 'on'),
                  CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set'))]
 
     # 'self_protection', 'kspp'
@@ -587,6 +547,13 @@ no_kstrtobool_options = [
     'srbds', # See srbds_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
     'mmio_stale_data', # See mmio_stale_data_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
     'retbleed', # See retbleed_parse_cmdline() in arch/x86/kernel/cpu/bugs.c
+    'rodata', # See set_debug_rodata() in init/main.c
+    'ssbd', # See parse_spectre_v4_param() in arch/arm64/kernel/proton-pack.c
+    'slub_debug', # See setup_slub_debug() in mm/slub.c
+    'iommu', # See iommu_setup() in arch/x86/kernel/pci-dma.c
+    'vsyscall', # See vsyscall_setup() in arch/x86/entry/vsyscall/vsyscall_64.c
+    'vdso32', # See vdso32_setup() in arch/x86/entry/vdso/vdso32-setup.c
+    'vdso', # See vdso32_setup() in arch/x86/entry/vdso/vdso32-setup.c
     'tsx' # See tsx_init() in arch/x86/kernel/cpu/tsx.c
 ]
 
@@ -598,10 +565,43 @@ def normalize_cmdline_options(option, value):
         return value
 
     # Implement a limited part of the kstrtobool() logic
-    if value in ('1', 'on', 'On', 'ON', 'y', 'Y', 'yes', 'Yes', 'YES'):
+    if value.lower() in ('1', 'on', 'y', 'yes', 't', 'true'):
         return '1'
-    if value in ('0', 'off', 'Off', 'OFF', 'n', 'N', 'no', 'No', 'NO'):
+    if value.lower() in ('0', 'off', 'n', 'no', 'f', 'false'):
         return '0'
 
     # Preserve unique values
     return value
+
+
+# def add_sysctl_checks(l, arch):
+# TODO: draft of security hardening sysctls:
+#    kernel.kptr_restrict=2 (or 1?)
+#    kernel.dmesg_restrict=1 (also see the kconfig option)
+#    kernel.perf_event_paranoid=2 (or 3 with a custom patch, see https://lwn.net/Articles/696216/)
+#    kernel.kexec_load_disabled=1
+#    kernel.yama.ptrace_scope=3
+#    user.max_user_namespaces=0 (for Debian, also see kernel.unprivileged_userns_clone)
+#    what about bpf_jit_enable?
+#    kernel.unprivileged_bpf_disabled=1
+#    net.core.bpf_jit_harden=2
+#    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
+#    dev.tty.ldisc_autoload=0
+#    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)
+#    kernel.oops_limit (think about a proper value)
+#    kernel.warn_limit (think about a proper value)
+#    net.ipv4.tcp_syncookies=1 (?)