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

diff --git a/kconfig_hardened_check/__init__.py b/kconfig_hardened_check/__init__.py
index 6487be1395887f0ede949e392d5b34a8248a04ca..d8df56fa5df02256fb691a924f75c32ae4175a0f 100644 (file)
--- a/kconfig_hardened_check/__init__.py
+++ b/kconfig_hardened_check/__init__.py
@@ -11,7 +11,6 @@
 #
 #
 # N.B Hardening command line parameters:
-#    page_alloc.shuffle=1
 #    iommu=force (does it help against DMA attacks?)
 #    slub_debug=FZ (slow)
 #    loadpin.enforce=1
@@ -311,6 +310,9 @@ def detect_version(fname):
 def add_kconfig_checks(l, arch):
     # Calling the KconfigCheck class constructor:
     #     KconfigCheck(reason, decision, name, expected)
+    #
+    # [!] Don't add CmdlineChecks in add_kconfig_checks() to avoid wrong results
+    #     when the tool doesn't check the cmdline.
 
     modules_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
     devmem_not_set = KconfigCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
@@ -647,9 +649,24 @@ def add_kconfig_checks(l, arch):
 def add_cmdline_checks(l, arch):
     # Calling the CmdlineCheck class constructor:
     #     CmdlineCheck(reason, decision, name, expected)
-    # Don't add CmdlineChecks in add_kconfig_checks() to avoid wrong results
-    # when the tool doesn't check the cmdline.
+    #
+    # [!] Don't add CmdlineChecks in add_kconfig_checks() to avoid wrong results
+    #     when the tool doesn't check the cmdline.
+    #
+    # [!] Make sure that values of the options in CmdlineChecks need normalization.
+    #     For more info see normalize_cmdline_options().
+    #
+    # A common pattern for checking the 'param_x' cmdline parameter
+    # that __overrides__ the 'PARAM_X_DEFAULT' kconfig option:
+    #   l += [OR(CmdlineCheck(reason, decision, 'param_x', '1'),
+    #            AND(KconfigCheck(reason, decision, 'PARAM_X_DEFAULT_ON', 'y'),
+    #                CmdlineCheck(reason, decision, 'param_x, 'is not set')))]
+    #
+    # Here we don't check the kconfig options or minimal kernel version
+    # required for the cmdline parameters. That would make the checks
+    # very complex and not give a 100% guarantee anyway.
 
+    # 'self_protection', 'defconfig'
     if arch == 'ARM64':
         l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', 'full'),
                  AND(KconfigCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y'),
@@ -658,6 +675,7 @@ def add_cmdline_checks(l, arch):
         l += [OR(CmdlineCheck('self_protection', 'defconfig', 'rodata', '1'),
                  CmdlineCheck('self_protection', 'defconfig', 'rodata', 'is not set'))]
 
+    # 'self_protection', 'kspp'
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'init_on_alloc', '1'),
              AND(KconfigCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y'),
                  CmdlineCheck('self_protection', 'kspp', 'init_on_alloc', 'is not set')))]
@@ -676,12 +694,16 @@ def add_cmdline_checks(l, arch):
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'iommu.passthrough', '0'),
              AND(KconfigCheck('self_protection', 'kspp', 'IOMMU_DEFAULT_PASSTHROUGH', 'is not set'),
                  CmdlineCheck('self_protection', 'kspp', 'iommu.passthrough', 'is not set')))]
+    # 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')))]
+    l += [OR(CmdlineCheck('self_protection', 'kspp', 'page_alloc.shuffle', '1'),
+             AND(KconfigCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y'),
+                 CmdlineCheck('self_protection', 'kspp', 'page_alloc.shuffle', 'is not set')))] # ... the end
     if arch in ('X86_64', 'ARM64', 'X86_32'):
         l += [OR(CmdlineCheck('self_protection', 'kspp', 'randomize_kstack_offset', '1'),
                  AND(KconfigCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y'),
@@ -689,12 +711,12 @@ def add_cmdline_checks(l, arch):
     if arch in ('X86_64', 'X86_32'):
         l += [CmdlineCheck('self_protection', 'kspp', 'pti', 'on')]
 
+    # 'cut_attack_surface', 'kspp'
     if arch == 'X86_64':
         l += [OR(CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'none'),
                  AND(KconfigCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y'),
                      CmdlineCheck('cut_attack_surface', 'kspp', 'vsyscall', 'is not set')))]
 
-    # TODO: add other
 
 
 def print_unknown_options(checklist, parsed_options):
@@ -837,6 +859,24 @@ def parse_kconfig_file(parsed_options, fname):
                 parsed_options[option] = value
 
 
+def normalize_cmdline_options(option, value):
+    # Handle special cases
+    if option == 'pti':
+        # Don't normalize the pti value since
+        # the Linux kernel doesn't use kstrtobool() for pti.
+        # See pti_check_boottime_disable() in linux/arch/x86/mm/pti.c
+        return value
+
+    # Implement a limited part of the kstrtobool() logic
+    if value in ('1', 'on', 'On', 'ON', 'y', 'Y', 'yes', 'Yes', 'YES'):
+        return '1'
+    if value in ('0', 'off', 'Off', 'OFF', 'n', 'N', 'no', 'No', 'NO'):
+        return '0'
+
+    # Preserve unique values
+    return value
+
+
 def parse_cmdline_file(parsed_options, fname):
     with open(fname, 'r') as f:
         line = f.readline()
@@ -852,6 +892,7 @@ def parse_cmdline_file(parsed_options, fname):
             else:
                 name = opt
                 value = '' # '' is not None
+            value = normalize_cmdline_options(name, value)
             parsed_options[name] = value