kernel_selinux(8) SELinux Policy kernel kernel_selinux(8)NAMEkernel_selinux - Security Enhanced Linux Policy for the kernel pro‐
cesses
DESCRIPTION
Security-Enhanced Linux secures the kernel processes via flexible
mandatory access control.
The kernel processes execute with the kernel_t SELinux type. You can
check if you have these processes running by executing the ps command
with the -Z qualifier.
For example:
ps -eZ | grep kernel_t
ENTRYPOINTS
The kernel_t SELinux type can be entered via the filesystem_type, unla‐
beled_t, proc_type, file_type, sysctl_type, mtrr_device_t file types.
The default entrypoint paths for the kernel_t domain are the following:
all files on the system, /dev/cpu/mtrr
PROCESS TYPES
SELinux defines process types (domains) for each process running on the
system
You can see the context of a process using the -Z option to ps
Policy governs the access confined processes have to files. SELinux
kernel policy is very flexible allowing users to setup their kernel
processes in as secure a method as possible.
The following process types are defined for kernel:
kernel_t
Note: semanage permissive -a kernel_t can be used to make the process
type kernel_t permissive. SELinux does not deny access to permissive
process types, but the AVC (SELinux denials) messages are still gener‐
ated.
BOOLEANS
SELinux policy is customizable based on least access required. kernel
policy is extremely flexible and has several booleans that allow you to
manipulate the policy and run kernel with the tightest access possible.
If you want to deny user domains applications to map a memory region as
both executable and writable, this is dangerous and the executable
should be reported in bugzilla, you must turn on the deny_execmem bool‐
ean. Enabled by default.
setsebool -P deny_execmem 1
If you want to deny any process from ptracing or debugging any other
processes, you must turn on the deny_ptrace boolean. Enabled by
default.
setsebool -P deny_ptrace 1
If you want to allow all domains to use other domains file descriptors,
you must turn on the domain_fd_use boolean. Enabled by default.
setsebool -P domain_fd_use 1
If you want to allow all domains to have the kernel load modules, you
must turn on the domain_kernel_load_modules boolean. Disabled by
default.
setsebool -P domain_kernel_load_modules 1
If you want to allow all domains to execute in fips_mode, you must turn
on the fips_mode boolean. Enabled by default.
setsebool -P fips_mode 1
If you want to enable reading of urandom for all domains, you must turn
on the global_ssp boolean. Disabled by default.
setsebool -P global_ssp 1
If you want to control the ability to mmap a low area of the address
space, as configured by /proc/sys/kernel/mmap_min_addr, you must turn
on the mmap_low_allowed boolean. Disabled by default.
setsebool -P mmap_low_allowed 1
If you want to allow any files/directories to be exported read/only via
NFS, you must turn on the nfs_export_all_ro boolean. Enabled by
default.
setsebool -P nfs_export_all_ro 1
If you want to allow any files/directories to be exported read/write
via NFS, you must turn on the nfs_export_all_rw boolean. Enabled by
default.
setsebool -P nfs_export_all_rw 1
If you want to allow system to run with NIS, you must turn on the
nis_enabled boolean. Disabled by default.
setsebool -P nis_enabled 1
If you want to disable kernel module loading, you must turn on the
secure_mode_insmod boolean. Enabled by default.
setsebool -P secure_mode_insmod 1
If you want to boolean to determine whether the system permits loading
policy, setting enforcing mode, and changing boolean values. Set this
to true and you have to reboot to set it back, you must turn on the
secure_mode_policyload boolean. Enabled by default.
setsebool -P secure_mode_policyload 1
If you want to allow unconfined executables to make their heap memory
executable. Doing this is a really bad idea. Probably indicates a
badly coded executable, but could indicate an attack. This executable
should be reported in bugzilla, you must turn on the selin‐
uxuser_execheap boolean. Disabled by default.
setsebool -P selinuxuser_execheap 1
If you want to allow all unconfined executables to use libraries
requiring text relocation that are not labeled textrel_shlib_t, you
must turn on the selinuxuser_execmod boolean. Enabled by default.
setsebool -P selinuxuser_execmod 1
If you want to allow unconfined executables to make their stack exe‐
cutable. This should never, ever be necessary. Probably indicates a
badly coded executable, but could indicate an attack. This executable
should be reported in bugzilla, you must turn on the selinuxuser_exec‐
stack boolean. Enabled by default.
setsebool -P selinuxuser_execstack 1
If you want to support X userspace object manager, you must turn on the
xserver_object_manager boolean. Enabled by default.
setsebool -P xserver_object_manager 1
If you want to allow ZoneMinder to run su/sudo, you must turn on the
zoneminder_run_sudo boolean. Disabled by default.
setsebool -P zoneminder_run_sudo 1
MANAGED FILES
The SELinux process type kernel_t can manage files labeled with the
following file types. The paths listed are the default paths for these
file types. Note the processes UID still need to have DAC permissions.
file_type
all files on the system
COMMANDS
semanage fcontext can also be used to manipulate default file context
mappings.
semanage permissive can also be used to manipulate whether or not a
process type is permissive.
semanage module can also be used to enable/disable/install/remove pol‐
icy modules.
semanage boolean can also be used to manipulate the booleans
system-config-selinux is a GUI tool available to customize SELinux pol‐
icy settings.
AUTHOR
This manual page was auto-generated using sepolicy manpage .
SEE ALSOselinux(8), kernel(8), semanage(8), restorecon(8), chcon(1), sepol‐
icy(8) , setsebool(8)kernel 13-11-20 kernel_selinux(8)
