X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=kernel_hardening_checker%2Fchecks.py;h=f9b86d91c1d5d096bfc1e370b051f42c91ebc381;hb=HEAD;hp=42d9407b749e7141d8c1c3dd50091b0020e6ee5f;hpb=d995dd6eab4d14d8400abe16bbf14c3364f99fb6;p=kconfig-hardened-check.git

diff --git a/kernel_hardening_checker/checks.py b/kernel_hardening_checker/checks.py
index 42d9407..be2689e 100755
--- a/kernel_hardening_checker/checks.py
+++ b/kernel_hardening_checker/checks.py
@@ -166,14 +166,14 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None:
              vmap_stack_is_set)]
     kfence_is_set = KconfigCheck('self_protection', 'kspp', 'KFENCE', 'y')
     l += [kfence_is_set]
-    l += [AND(KconfigCheck('self_protection', 'kspp', 'KFENCE_SAMPLE_INTERVAL', 'is not off'),
+    l += [AND(KconfigCheck('self_protection', 'kspp', 'KFENCE_SAMPLE_INTERVAL', '100'),
               kfence_is_set)]
     randstruct_is_set = OR(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_FULL', 'y'),
                            KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y'))
     l += [randstruct_is_set]
-    l += [AND(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_PERFORMANCE', 'is not set'),
-              KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
-              randstruct_is_set)]
+#   l += [AND(KconfigCheck('self_protection', 'kspp', 'RANDSTRUCT_PERFORMANCE', 'is not set'),
+#             KconfigCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
+#             randstruct_is_set)] # Comment this out for now: KSPP has revoked this recommendation
     hardened_usercopy_is_set = KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
     l += [hardened_usercopy_is_set]
     l += [AND(KconfigCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
@@ -424,7 +424,6 @@ def add_kconfig_checks(l: List[ChecklistObjType], arch: str) -> None:
     l += [OR(KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MAGIC_SYSRQ_SERIAL', 'is not set'),
              KconfigCheck('cut_attack_surface', 'a13xp0p0v', 'MAGIC_SYSRQ_DEFAULT_ENABLE', '0x0'))]
 
-
     # 'harden_userspace'
     if arch == 'ARM64':
         l += [KconfigCheck('harden_userspace', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
@@ -534,8 +533,9 @@ def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None:
     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 += [CmdlineCheck('self_protection', 'kspp', 'cfi', 'kcfi')]
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'slab_nomerge', 'is present'),
-             AND(KconfigCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set'),
+             AND(KconfigCheck('self_protection', 'kspp', 'SLAB_MERGE_DEFAULT', 'is not set'),
                  CmdlineCheck('self_protection', 'kspp', 'slab_merge', 'is not set'),
                  CmdlineCheck('self_protection', 'kspp', 'slub_merge', 'is not set')))]
     l += [OR(CmdlineCheck('self_protection', 'kspp', 'init_on_alloc', '1'),
@@ -575,7 +575,7 @@ def add_cmdline_checks(l: List[ChecklistObjType], arch: str) -> None:
 
     # 'self_protection', 'a13xp0p0v'
     l += [OR(CmdlineCheck('self_protection', 'a13xp0p0v', 'kfence.sample_interval', 'is not off'),
-             AND(KconfigCheck('self_protection', 'a13xp0p0v', 'KFENCE_SAMPLE_INTERVAL', 'is not off'),
+             AND(KconfigCheck('self_protection', 'kspp', 'KFENCE_SAMPLE_INTERVAL', '100'),
                  CmdlineCheck('self_protection', 'a13xp0p0v', 'kfence.sample_interval', 'is not set')))]
 
     # 'cut_attack_surface', 'defconfig'
@@ -677,8 +677,6 @@ def normalize_cmdline_options(option: str, value: str) -> str:
 #    nosmt sysfs control file
 #    vm.mmap_rnd_bits=max (?)
 #    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 (?)
 
 def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None:
@@ -693,6 +691,12 @@ def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None:
     l += [OR(SysctlCheck('self_protection', 'kspp', 'net.core.bpf_jit_harden', '2'),
              AND(KconfigCheck('-', '-', 'BPF_JIT', 'is not set'),
                  have_kconfig))]
+    # Choosing a right value for 'kernel.oops_limit' and 'kernel.warn_limit' is not easy.
+    # A small value (e.g. 1, which is recommended by KSPP) allows easy DoS.
+    # A large value (e.g. 10000, which is default 'kernel.oops_limit') may miss the exploit attempt.
+    # Let's choose 100 as a reasonable compromise.
+    l += [SysctlCheck('self_protection', 'a13xp0p0v', 'kernel.oops_limit', '100')]
+    l += [SysctlCheck('self_protection', 'a13xp0p0v', 'kernel.warn_limit', '100')]
 
     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/
@@ -712,7 +716,7 @@ def add_sysctl_checks(l: List[ChecklistObjType], _arch: StrOrNone) -> None:
           # At first, it disabled unprivileged userfaultfd,
           # and since v5.11 it enables unprivileged userfaultfd for user-mode only.
 
-    l += [OR(SysctlCheck('cut_attack_surface', 'clipos', 'kernel.modules_disabled', '1'),
+    l += [OR(SysctlCheck('cut_attack_surface', 'kspp', 'kernel.modules_disabled', '1'),
              AND(KconfigCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set'),
                  have_kconfig))] # radical, but may be useful in some cases