#
# Security configuration
#
menu "Security options"
source security/keys/Kconfig
config SECURITY_DMESG_RESTRICT
bool "Restrict unprivileged access to the kernel syslog"
default n
help
This enforces restrictions on unprivileged users reading the kernel
syslog via dmesg(8).
If this option is not selected, no restrictions will be enforced
unless the dmesg_restrict sysctl is explicitly set to (1).
If you are unsure how to answer this question, answer N.
config SECURITY_PERF_EVENTS_RESTRICT
bool "Restrict unprivileged use of performance events"
depends on PERF_EVENTS
help
If you say Y here, the kernel.perf_event_paranoid sysctl
will be set to 3 by default, and no unprivileged use of the
perf_event_open syscall will be permitted unless it is
changed.
config SECURITY
bool "Enable different security models"
depends on SYSFS
depends on MULTIUSER
help
This allows you to choose different security modules to be
configured into your kernel.
If this option is not selected, the default Linux security
model will be used.
If you are unsure how to answer this question, answer N.
config SECURITY_WRITABLE_HOOKS
depends on SECURITY
bool
default n
config SECURITY_STACKING
bool "Security module stacking"
depends on SECURITY
help
Allows multiple major security modules to be stacked.
Modules are invoked in the order registered with a
"bail on fail" policy, in which the infrastructure
will stop processing once a denial is detected. Not
all modules can be stacked. SELinux and Smack are
known to be incompatible. User space components may
have trouble identifying the security module providing
data in some cases.
If you select this option you will have to select which
of the stackable modules you wish to be active. The
"Default security module" will be ignored. The boot line
"security=" option can be used to specify that one of
the modules identifed for stacking should be used instead
of the entire stack.
If you are unsure how to answer this question, answer N.
config SECURITY_LSM_DEBUG
bool "Enable debugging of the LSM infrastructure"
depends on SECURITY
help
This allows you to choose debug messages related to
security modules configured into your kernel. These
messages may be helpful in determining how a security
module is using security blobs.
If you are unsure how to answer this question, answer N.
config SECURITYFS
bool "Enable the securityfs filesystem"
help
This will build the securityfs filesystem. It is currently used by
the TPM bios character driver and IMA, an integrity provider. It is
not used by SELinux or SMACK.
If you are unsure how to answer this question, answer N.
config SECURITY_NETWORK
bool "Socket and Networking Security Hooks"
depends on SECURITY
help
This enables the socket and networking security hooks.
If enabled, a security module can use these hooks to
implement socket and networking access controls.
If you are unsure how to answer this question, answer N.
config PAGE_TABLE_ISOLATION
bool "Remove the kernel mapping in user mode"
default y
depends on X86_64 && !UML
help
This feature reduces the number of hardware side channels by
ensuring that the majority of kernel addresses are not mapped
into userspace.
See Documentation/x86/pti.txt for more details.
config SECURITY_INFINIBAND
bool "Infiniband Security Hooks"
depends on SECURITY && INFINIBAND
help
This enables the Infiniband security hooks.
If enabled, a security module can use these hooks to
implement Infiniband access controls.
If you are unsure how to answer this question, answer N.
config SECURITY_NETWORK_XFRM
bool "XFRM (IPSec) Networking Security Hooks"
depends on XFRM && SECURITY_NETWORK
help
This enables the XFRM (IPSec) networking security hooks.
If enabled, a security module can use these hooks to
implement per-packet access controls based on labels
derived from IPSec policy. Non-IPSec communications are
designated as unlabelled, and only sockets authorized
to communicate unlabelled data can send without using
IPSec.
If you are unsure how to answer this question, answer N.
config SECURITY_PATH
bool "Security hooks for pathname based access control"
depends on SECURITY
help
This enables the security hooks for pathname based access control.
If enabled, a security module can use these hooks to
implement pathname based access controls.
If you are unsure how to answer this question, answer N.
config INTEL_TXT
bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
depends on HAVE_INTEL_TXT
help
This option enables support for booting the kernel with the
Trusted Boot (tboot) module. This will utilize
Intel(R) Trusted Execution Technology to perform a measured launch
of the kernel. If the system does not support Intel(R) TXT, this
will have no effect.
Intel TXT will provide higher assurance of system configuration and
initial state as well as data reset protection. This is used to
create a robust initial kernel measurement and verification, which
helps to ensure that kernel security mechanisms are functioning
correctly. This level of protection requires a root of trust outside
of the kernel itself.
Intel TXT also helps solve real end user concerns about having
confidence that their hardware is running the VMM or kernel that
it was configured with, especially since they may be responsible for
providing such assurances to VMs and services running on it.
See for more information
about Intel(R) TXT.
See for more information about tboot.
See Documentation/intel_txt.txt for a description of how to enable
Intel TXT support in a kernel boot.
If you are unsure as to whether this is required, answer N.
config LSM_MMAP_MIN_ADDR
int "Low address space for LSM to protect from user allocation"
depends on SECURITY && SECURITY_SELINUX
default 32768 if ARM || (ARM64 && COMPAT)
default 65536
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
can help reduce the impact of kernel NULL pointer bugs.
For most ia64, ppc64 and x86 users with lots of address space
a value of 65536 is reasonable and should cause no problems.
On arm and other archs it should not be higher than 32768.
Programs which use vm86 functionality or have some need to map
this low address space will need the permission specific to the
systems running LSM.
config HAVE_HARDENED_USERCOPY_ALLOCATOR
bool
help
The heap allocator implements __check_heap_object() for
validating memory ranges against heap object sizes in
support of CONFIG_HARDENED_USERCOPY.
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
select BUG
help
This option checks for obviously wrong memory regions when
copying memory to/from the kernel (via copy_to_user() and
copy_from_user() functions) by rejecting memory ranges that
are larger than the specified heap object, span multiple
separately allocated pages, are not on the process stack,
or are part of the kernel text. This kills entire classes
of heap overflow exploits and similar kernel memory exposures.
config HARDENED_USERCOPY_PAGESPAN
bool "Refuse to copy allocations that span multiple pages"
depends on HARDENED_USERCOPY
depends on EXPERT
help
When a multi-page allocation is done without __GFP_COMP,
hardened usercopy will reject attempts to copy it. There are,
however, several cases of this in the kernel that have not all
been removed. This config is intended to be used only while
trying to find such users.
config FORTIFY_SOURCE
bool "Harden common str/mem functions against buffer overflows"
depends on ARCH_HAS_FORTIFY_SOURCE
help
Detect overflows of buffers in common string and memory functions
where the compiler can determine and validate the buffer sizes.
config STATIC_USERMODEHELPER
bool "Force all usermode helper calls through a single binary"
help
By default, the kernel can call many different userspace
binary programs through the "usermode helper" kernel
interface. Some of these binaries are statically defined
either in the kernel code itself, or as a kernel configuration
option. However, some of these are dynamically created at
runtime, or can be modified after the kernel has started up.
To provide an additional layer of security, route all of these
calls through a single executable that can not have its name
changed.
Note, it is up to this single binary to then call the relevant
"real" usermode helper binary, based on the first argument
passed to it. If desired, this program can filter and pick
and choose what real programs are called.
If you wish for all usermode helper programs are to be
disabled, choose this option and then set
STATIC_USERMODEHELPER_PATH to an empty string.
config STATIC_USERMODEHELPER_PATH
string "Path to the static usermode helper binary"
depends on STATIC_USERMODEHELPER
default "/sbin/usermode-helper"
help
The binary called by the kernel when any usermode helper
program is wish to be run. The "real" application's name will
be in the first argument passed to this program on the command
line.
If you wish for all usermode helper programs to be disabled,
specify an empty string here (i.e. "").
config LOCK_DOWN_KERNEL
bool "Allow the kernel to be 'locked down'"
help
Allow the kernel to be locked down under certain circumstances, for
instance if UEFI secure boot is enabled. Locking down the kernel
turns off various features that might otherwise allow access to the
kernel image (eg. setting MSR registers).
config ALLOW_LOCKDOWN_LIFT
bool
help
Allow the lockdown on a kernel to be lifted, thereby restoring the
ability of userspace to access the kernel image (eg. by SysRq+x under
x86).
source security/selinux/Kconfig
source security/smack/Kconfig
source security/tomoyo/Kconfig
source security/apparmor/Kconfig
source security/loadpin/Kconfig
source security/yama/Kconfig
source security/integrity/Kconfig
menu "Security Module Selection"
visible if !SECURITY_STACKING
choice
prompt "Default security module"
default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
default DEFAULT_SECURITY_DAC
help
Select the security module that will be used by default if the
kernel parameter security= is not specified.
config DEFAULT_SECURITY_SELINUX
bool "SELinux" if SECURITY_SELINUX=y
config DEFAULT_SECURITY_SMACK
bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
config DEFAULT_SECURITY_TOMOYO
bool "TOMOYO" if SECURITY_TOMOYO=y
config DEFAULT_SECURITY_APPARMOR
bool "AppArmor" if SECURITY_APPARMOR=y
config DEFAULT_SECURITY_DAC
bool "Unix Discretionary Access Controls"
endchoice
config DEFAULT_SECURITY
string
default "selinux" if DEFAULT_SECURITY_SELINUX
default "smack" if DEFAULT_SECURITY_SMACK
default "tomoyo" if DEFAULT_SECURITY_TOMOYO
default "apparmor" if DEFAULT_SECURITY_APPARMOR
default "" if DEFAULT_SECURITY_DAC
endmenu
menu "Security Module Stack"
visible if SECURITY_STACKING
choice
prompt "mutually exclusive LSMs"
default SECURITY_NO_EXCLUSIVE_LSM
config SECURITY_NO_EXCLUSIVE_LSM
bool "none"
help
Do no add an LSM to is mutually exclusive to the stack."
config SECURITY_SELINUX_STACKED
bool "SELinux" if SECURITY_SELINUX=y
help
Add the SELinux security module to the stack.
Please be sure your user space code is accomodating of
this security module.
Ensure that your network configuration is compatible
with your combination of security modules.
Incompatible with Smack being stacked.
If you are unsure how to answer this question, answer N.
config SECURITY_SMACK_STACKED
bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
help
Add the Smack security module to the stack.
Please be sure your user space code is accomodating of
this security module.
Ensure that your network configuration is compatible
with your combination of security modules.
Incompatible with SeLinux being stacked.
If you are unsure how to answer this question, answer N.
endchoice
config SECURITY_TOMOYO_STACKED
bool "TOMOYO support is enabled by default"
depends on SECURITY_TOMOYO && SECURITY_STACKING
default n
help
This option instructs the system to use the TOMOYO checks.
If not selected the module will not be invoked.
Stacked security modules may interact in unexpected ways.
Please be sure your user space code is accomodating of
multiple security modules.
If you are unsure how to answer this question, answer N.
config SECURITY_APPARMOR_STACKED
bool "AppArmor support is enabled by default"
depends on SECURITY_APPARMOR && SECURITY_STACKING
default n
help
This option instructs the system to use the AppArmor checks.
If not selected the module will not be invoked.
Stacked security modules may interact in unexpected ways.
Please be sure your user space code is accomodating of
multiple security modules.
If you are unsure how to answer this question, answer N.
choice
prompt "Default LSM for legacy interfaces"
default SECURITY_DEFAULT_DISPLAY_SELINUX if SECURITY_SELINUX_STACKED
default SECURITY_DEFAULT_DISPLAY_SMACK if SECURITY_SMACK_STACKED
default SECURITY_DEFAULT_DISPLAY_TOMOYO if SECURITY_TOMOYO_STACKED
default SECURITY_DEFAULT_DISPALY_APPARMOR if SECURITY_APPARMOR_STACKED
default SECURITY_DEFAULT_DISPLAY_FIRST
help
Select the security module context that will be displayed by
default on legacy interfaces if the kernel parameter
security.display= is not specified.
config SECURITY_DEFAULT_DISPLAY_SELINUX
bool "SELinux" if SECURITY_SELINUX=y
config SECURITY_DEFAULT_DISPLAY_SMACK
bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
config SECURITY_DEFAULT_DISPLAY_TOMOYO
bool "TOMOYO" if SECURITY_TOMOYO=y
config SECURITY_DEFAULT_DISPLAY_APPARMOR
bool "AppArmor" if SECURITY_APPARMOR=y
config SECURITY_DEFAULT_DISPLAY_FIRST
bool "First security module to register"
endchoice
config SECURITY_DEFAULT_DISPLAY_NAME
string
default "selinux" if SECURITY_DEFAULT_DISPLAY_SELINUX
default "smack" if SECURITY_DEFAULT_DISPLAY_SMACK
default "tomoyo" if SECURITY_DEFAULT_DISPLAY_TOMOYO
default "apparmor" if SECURITY_DEFAULT_DISPLAY_APPARMOR
default "" if SECURITY_DEFAULT_DISPLAY_FIRST
endmenu
endmenu