bootloader_selinux(8) SELinux Policy bootloader bootloader_selinux(8)NAMEbootloader_selinux - Security Enhanced Linux Policy for the bootloader
processes
DESCRIPTION
Security-Enhanced Linux secures the bootloader processes via flexible
mandatory access control.
The bootloader processes execute with the bootloader_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 bootloader_t
ENTRYPOINTS
The bootloader_t SELinux type can be entered via the filesystem_type,
unlabeled_t, proc_type, file_type, bootloader_exec_t, sysctl_type,
mtrr_device_t file types.
The default entrypoint paths for the bootloader_t domain are the fol‐
lowing:
all files on the system, /sbin/grub.*, /sbin/lilo.*, /sbin/ybin.*,
/usr/sbin/grub.*, /usr/sbin/lilo.*, /usr/sbin/ybin.*, /sbin/zipl,
/usr/sbin/zipl, /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
bootloader policy is very flexible allowing users to setup their boot‐
loader processes in as secure a method as possible.
The following process types are defined for bootloader:
bootloader_t
Note: semanage permissive -a bootloader_t can be used to make the
process type bootloader_t permissive. SELinux does not deny access to
permissive process types, but the AVC (SELinux denials) messages are
still generated.
BOOLEANS
SELinux policy is customizable based on least access required. boot‐
loader policy is extremely flexible and has several booleans that allow
you to manipulate the policy and run bootloader with the tightest
access possible.
If you want to allow users to resolve user passwd entries directly from
ldap rather then using a sssd server, you must turn on the authlo‐
gin_nsswitch_use_ldap boolean. Disabled by default.
setsebool -P authlogin_nsswitch_use_ldap 1
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 allow s-c-kdump to run bootloader in bootloader_t, you
must turn on the kdumpgui_run_bootloader boolean. Disabled by default.
setsebool -P kdumpgui_run_bootloader 1
If you want to allow confined applications to run with kerberos, you
must turn on the kerberos_enabled boolean. Enabled by default.
setsebool -P kerberos_enabled 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 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 allow confined applications to use nscd shared memory,
you must turn on the nscd_use_shm boolean. Disabled by default.
setsebool -P nscd_use_shm 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
NSSWITCH DOMAIN
If you want to allow users to resolve user passwd entries directly from
ldap rather then using a sssd server for the bootloader_t, you must
turn on the authlogin_nsswitch_use_ldap boolean.
setsebool -P authlogin_nsswitch_use_ldap 1
If you want to allow confined applications to run with kerberos for the
bootloader_t, you must turn on the kerberos_enabled boolean.
setsebool -P kerberos_enabled 1
MANAGED FILES
The SELinux process type bootloader_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
FILE CONTEXTS
SELinux requires files to have an extended attribute to define the file
type.
You can see the context of a file using the -Z option to ls
Policy governs the access confined processes have to these files.
SELinux bootloader policy is very flexible allowing users to setup
their bootloader processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the bootloader, if you
wanted to store files with these types in a diffent paths, you need to
execute the semanage command to sepecify alternate labeling and then
use restorecon to put the labels on disk.
semanage fcontext -a-t bootloader_etc_t '/srv/bootloader/con‐
tent(/.*)?'
restorecon -R -v /srv/mybootloader_content
Note: SELinux often uses regular expressions to specify labels that
match multiple files.
The following file types are defined for bootloader:
bootloader_etc_t
- Set files with the bootloader_etc_t type, if you want to store boot‐
loader files in the /etc directories.
Paths:
/etc/lilo.conf.*, /etc/zipl.conf.*, /etc/yaboot.conf.*,
/etc/default/grub
bootloader_exec_t
- Set files with the bootloader_exec_t type, if you want to transition
an executable to the bootloader_t domain.
Paths:
/sbin/grub.*, /sbin/lilo.*, /sbin/ybin.*, /usr/sbin/grub.*,
/usr/sbin/lilo.*, /usr/sbin/ybin.*, /sbin/zipl, /usr/sbin/zipl
bootloader_tmp_t
- Set files with the bootloader_tmp_t type, if you want to store boot‐
loader temporary files in the /tmp directories.
bootloader_var_lib_t
- Set files with the bootloader_var_lib_t type, if you want to store
the bootloader files under the /var/lib directory.
bootloader_var_run_t
- Set files with the bootloader_var_run_t type, if you want to store
the bootloader files under the /run or /var/run directory.
Note: File context can be temporarily modified with the chcon command.
If you want to permanently change the file context you need to use the
semanage fcontext command. This will modify the SELinux labeling data‐
base. You will need to use restorecon to apply the labels.
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), bootloader(8), semanage(8), restorecon(8), chcon(1), sepol‐
icy(8) , setsebool(8)bootloader 13-11-20 bootloader_selinux(8)
