refactor: is_kernel_option_enabled

Current "is_kernel_option_enabled" function is doing many things, like checking for a kernel option AND checking a kernel module state AND checking if it is disabled
We split it in different functions:
        - is_kernel_monolithic
        - is_kernel_option_enabled -> check for a kernel configuration in the running kernel
        - is_kernel_module_loaded -> check if a module is currently loaded
        - is_kernel_module_available -> check if a module is configured in all available kernel configs
        - is_kernel_module_disabled   -> check if a kernel module is disabled in the modprobe configuration

Also:

- update its behaviour to debian 12 CIS recommendation, to check if a module is "available in ANY installed kernel"
- fix "disable_usb_storage" to look for correct module name once loaded : issue #249
- the associated checks now check separately if the module is loaded, and if it is configured
- for checks about kernel module presence, the "apply" function now manages to disable the module in the modprobe configuration (if kernel not monolithic) (but still wont unload it)
This commit is contained in:
Damien Cavagnini
2025-07-07 15:30:22 +02:00
parent ab0dba9f95
commit 3753a72723
13 changed files with 452 additions and 183 deletions

View File

@ -26,11 +26,25 @@ audit() {
# In an unprivileged container, the kernel modules are host dependent, so you should consider enforcing it
ok "Container detected, consider host enforcing or disable this check!"
else
is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_NAME"
if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
crit "$MODULE_NAME is enabled!"
is_kernel_module_loaded "$KERNEL_OPTION" "$MODULE_NAME"
if [ "$FNRET" -eq 0 ]; then # 0 means true in bash, so it IS activated
crit "$MODULE_NAME is loaded!"
else
ok "$MODULE_NAME is disabled"
ok "$MODULE_NAME is not loaded"
fi
if [ "$IS_MONOLITHIC_KERNEL" -eq 1 ]; then
is_kernel_module_disabled "$MODULE_NAME"
if [ "$FNRET" -eq 0 ]; then
ok "$MODULE_NAME is disabled in the modprobe configuration"
else
is_kernel_module_available "$KERNEL_OPTION"
if [ "$FNRET" -eq 0 ]; then
crit "$MODULE_NAME is available in some kernel config, but not disabled"
else
ok "$MODULE_NAME is not available in any kernel config"
fi
fi
fi
fi
}
@ -41,11 +55,18 @@ apply() {
# In an unprivileged container, the kernel modules are host dependent, so you should consider enforcing it
ok "Container detected, consider host enforcing!"
else
is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_NAME"
if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
warn "I cannot fix $MODULE_NAME, recompile your kernel or blacklist module $MODULE_NAME (/etc/modprobe.d/blacklist.conf : +install $MODULE_NAME /bin/true)"
else
ok "$MODULE_NAME is disabled"
is_kernel_module_loaded "$KERNEL_OPTION" "$LOADED_MODULE_NAME"
if [ "$FNRET" -eq 0 ]; then # 0 means true in bash, so it IS activated
crit "$LOADED_MODULE_NAME is loaded!"
warn "I wont unload the module, unload it manually or recompile the kernel if needed"
fi
if [ "$IS_MONOLITHIC_KERNEL" -eq 1 ]; then
is_kernel_module_disabled "$MODULE_NAME"
if [ "$FNRET" -eq 1 ]; then
echo "install $MODULE_NAME /bin/true" >>/etc/modprobe.d/"$MODULE_NAME".conf
info "$MODULE_NAME has been disabled in the modprobe configuration"
fi
fi
fi
}