forked from mirrors/nixpkgs
bd2bb9e381
"Kernel Electric-Fence (KFENCE) is a low-overhead sampling-based memory safety error detector. KFENCE detects heap out-of-bounds access, use-after-free, and invalid-free errors."
97 lines
3.6 KiB
Nix
97 lines
3.6 KiB
Nix
# Based on recommendations from:
|
|
# http://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project#Recommended_settings
|
|
# https://wiki.gentoo.org/wiki/Hardened/Hardened_Kernel_Project
|
|
#
|
|
# Dangerous features that can be permanently (for the boot session) disabled at
|
|
# boot via sysctl or kernel cmdline are left enabled here, for improved
|
|
# flexibility.
|
|
#
|
|
# See also <nixos/modules/profiles/hardened.nix>
|
|
|
|
{ lib, version }:
|
|
|
|
with lib;
|
|
with lib.kernel;
|
|
with (lib.kernel.whenHelpers version);
|
|
|
|
assert (versionAtLeast version "4.9");
|
|
|
|
{
|
|
# Report BUG() conditions and kill the offending process.
|
|
BUG = yes;
|
|
|
|
# Safer page access permissions (wrt. code injection). Default on >=4.11.
|
|
DEBUG_RODATA = whenOlder "4.11" yes;
|
|
DEBUG_SET_MODULE_RONX = whenOlder "4.11" yes;
|
|
|
|
# Mark LSM hooks read-only after init. SECURITY_WRITABLE_HOOKS n
|
|
# conflicts with SECURITY_SELINUX_DISABLE y; disabling the latter
|
|
# implicitly marks LSM hooks read-only after init.
|
|
#
|
|
# SELinux can only be disabled at boot via selinux=0
|
|
#
|
|
# We set SECURITY_WRITABLE_HOOKS n primarily for documentation purposes; the
|
|
# config builder fails to detect that it has indeed been unset.
|
|
SECURITY_SELINUX_DISABLE = whenAtLeast "4.12" no;
|
|
SECURITY_WRITABLE_HOOKS = whenAtLeast "4.12" (option no);
|
|
|
|
STRICT_KERNEL_RWX = whenAtLeast "4.11" yes;
|
|
|
|
# Perform additional validation of commonly targeted structures.
|
|
DEBUG_CREDENTIALS = yes;
|
|
DEBUG_NOTIFIERS = yes;
|
|
DEBUG_PI_LIST = whenOlder "5.2" yes; # doesn't BUG()
|
|
DEBUG_PLIST = whenAtLeast "5.2" yes;
|
|
DEBUG_SG = yes;
|
|
SCHED_STACK_END_CHECK = yes;
|
|
|
|
REFCOUNT_FULL = whenBetween "4.13" "5.5" yes;
|
|
|
|
# Randomize page allocator when page_alloc.shuffle=1
|
|
SHUFFLE_PAGE_ALLOCATOR = whenAtLeast "5.2" yes;
|
|
|
|
# Allow enabling slub/slab free poisoning with slub_debug=P
|
|
SLUB_DEBUG = yes;
|
|
|
|
# Wipe higher-level memory allocations on free() with page_poison=1
|
|
PAGE_POISONING = yes;
|
|
PAGE_POISONING_NO_SANITY = whenOlder "5.11" yes;
|
|
PAGE_POISONING_ZERO = whenOlder "5.11" yes;
|
|
|
|
# Enable the SafeSetId LSM
|
|
SECURITY_SAFESETID = whenAtLeast "5.1" yes;
|
|
|
|
# Reboot devices immediately if kernel experiences an Oops.
|
|
PANIC_TIMEOUT = freeform "-1";
|
|
|
|
GCC_PLUGINS = yes; # Enable gcc plugin options
|
|
# Gather additional entropy at boot time for systems that may not have appropriate entropy sources.
|
|
GCC_PLUGIN_LATENT_ENTROPY = yes;
|
|
|
|
GCC_PLUGIN_STRUCTLEAK = whenAtLeast "4.11" yes; # A port of the PaX structleak plugin
|
|
GCC_PLUGIN_STRUCTLEAK_BYREF_ALL = whenAtLeast "4.14" yes; # Also cover structs passed by address
|
|
GCC_PLUGIN_STACKLEAK = whenAtLeast "4.20" yes; # A port of the PaX stackleak plugin
|
|
GCC_PLUGIN_RANDSTRUCT = whenAtLeast "4.13" yes; # A port of the PaX randstruct plugin
|
|
GCC_PLUGIN_RANDSTRUCT_PERFORMANCE = whenAtLeast "4.13" yes;
|
|
|
|
# Disable various dangerous settings
|
|
ACPI_CUSTOM_METHOD = no; # Allows writing directly to physical memory
|
|
PROC_KCORE = no; # Exposes kernel text image layout
|
|
INET_DIAG = no; # Has been used for heap based attacks in the past
|
|
|
|
# INET_DIAG=n causes the following options to not exist anymore, but since they are defined in common-config.nix,
|
|
# make them optional
|
|
INET_DIAG_DESTROY = option no;
|
|
INET_RAW_DIAG = option no;
|
|
INET_TCP_DIAG = option no;
|
|
INET_UDP_DIAG = option no;
|
|
INET_MPTCP_DIAG = option no;
|
|
|
|
# Use -fstack-protector-strong (gcc 4.9+) for best stack canary coverage.
|
|
CC_STACKPROTECTOR_REGULAR = whenOlder "4.18" no;
|
|
CC_STACKPROTECTOR_STRONG = whenOlder "4.18" yes;
|
|
|
|
# Detect out-of-bound reads/writes and use-after-free
|
|
KFENCE = whenAtLeast "5.12" yes;
|
|
}
|