sysadm_selinux(8) - Linux man page

Name

sysadm_u - General system administration role - Security Enhanced Linux Policy

Description

sysadm_u is an SELinux User defined in the SELinux policy. SELinux users have default roles, sysadm_r. The default role has a default type, sysadm_t, associated with it.

The SELinux user will usually login to a system with a context that looks like:

sysadm_u:sysadm_r:sysadm_t:s0-s0:c0.c1023

Linux users are automatically assigned an SELinux users at login. Login programs use the SELinux User to assign initial context to the user's shell.

SELinux policy uses the context to control the user's access.

By default all users are assigned to the SELinux user via the __default__ flag

On Targeted policy systems the __default__ user is assigned to the unconfined_u SELinux user.

You can list all Linux User to SELinux user mapping using:

semanage login -l

If you wanted to change the default user mapping to use the sysadm_u user, you would execute:

semanage login -m -s sysadm_u __default__

User Description

The SELinux user sysadm_u is an admin user. It means that a mapped Linux user to this SELinux user is intended for administrative actions. Usually this is assigned to a root Linux user.

Sudo

The SELinux user sysadm can execute sudo.

You can set up sudo to allow sysadm to transition to an administrative domain:

Add one or more of the following record to sudoers using visudo.

USERNAME ALL=(ALL) ROLE=staff_r TYPE=staff_t COMMAND
sudo will run COMMAND as sysadm_u:staff_r:staff_t:LEVEL

You might also need to add one or more of these new roles to your SELinux user record.

List the SELinux roles your SELinux user can reach by executing:

$ semanage user -l |grep selinux_name

Modify the roles list and add sysadm_r to this list.

$ semanage user -m -R 'sysadm_r staff_r user_r' sysadm_u

For more details you can see semanage man page.

USERNAME ALL=(ALL) ROLE=user_r TYPE=user_t COMMAND
sudo will run COMMAND as sysadm_u:user_r:user_t:LEVEL

You might also need to add one or more of these new roles to your SELinux user record.

List the SELinux roles your SELinux user can reach by executing:

$ semanage user -l |grep selinux_name

Modify the roles list and add sysadm_r to this list.

$ semanage user -m -R 'sysadm_r staff_r user_r' sysadm_u

For more details you can see semanage man page.

The SELinux type sysadm_t is not allowed to execute sudo.

X Windows Login

The SELinux user sysadm_u is not able to X Windows login.

Network

The SELinux user sysadm_u is able to listen on the following tcp ports.

all ports with out defined types
The SELinux user sysadm_u is able to connect to the following tcp ports.: all ports
The SELinux user sysadm_u is able to listen on the following udp ports.: all ports with out defined types
ntp_port_t: 123
The SELinux user sysadm_u is able to connect to the following tcp ports.: all ports

Booleans

SELinux policy is customizable based on least access required. sysadm policy is extremely flexible and has several booleans that allow you to manipulate the policy and run sysadm with the tightest access possible.

If you want to allow ssh logins as sysadm_r:sysadm_t, you must turn on the ssh_sysadm_login boolean.

setsebool -P ssh_sysadm_login 1

If you want to allow xdm logins as sysadm, you must turn on the xdm_sysadm_login boolean.

setsebool -P xdm_sysadm_login 1

If you want to allow ssh logins as sysadm_r:sysadm_t, you must turn on the ssh_sysadm_login boolean.

setsebool -P ssh_sysadm_login 1

If you want to allow xdm logins as sysadm, you must turn on the xdm_sysadm_login boolean.

setsebool -P xdm_sysadm_login 1

HOME_EXEC

The SELinux user sysadm_u is able execute home content files.

Transitions

Three things can happen when sysadm_t attempts to execute a program.

1. SELinux Policy can deny sysadm_t from executing the program.

2. SELinux Policy can allow sysadm_t to execute the program in the current user type.: Execute the following to see the types that the SELinux user sysadm_t can execute without transitioning:
search -A -s sysadm_t -c file -p execute_no_trans
3. SELinux can allow sysadm_t to execute the program and transition to a new type.: Execute the following to see the types that the SELinux user sysadm_t can execute and transition:
$ search -A -s sysadm_t -c process -p transition

Managed Files

The SELinux process type sysadm_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.

auditd_etc_t

/etc/audit(/.*)?

auditd_log_t

/var/log/audit(/.*)?

/var/log/audit.log.*

boolean_type
etc_runtime_t

/[^/]+

/etc/mtab.*

/etc/blkid(/.*)?

/etc/nologin.*

/etc/smartd.conf.*

/etc/.fstab.hal..+

/etc/sysconfig/ip6?tables.save

/halt

/etc/motd

/fastboot

/poweroff

/etc/issue

/etc/cmtab

/forcefsck

/.autofsck

/.suspended

/fsckoptions

/etc/HOSTNAME

/.autorelabel

/etc/securetty

/etc/nohotplug

/etc/issue.net

/etc/killpower

/etc/ioctl.save

/etc/reader.conf

/etc/fstab.REVOKE

/etc/mtab.fuselock

/etc/network/ifstate

/etc/sysconfig/hwconf

/etc/ptal/ptal-printd-like

/etc/xorg.conf.d/00-system-setup-keyboard.conf

ethereal_home_t

/home/[^/]*/.ethereal(/.*)?

non_security_file_type
noxattrfs

all files on file systems which do not support extended attributes

sandbox_file_t
sandbox_tmpfs_type

all sandbox content in tmpfs file systems

screen_home_t

/root/.screen(/.*)?

/home/[^/]*/.screen(/.*)?

/home/[^/]*/.screenrc

screen_var_run_t

/var/run/screen(/.*)?

sysctl_type
usbfs_t
user_home_t

/home/[^/]*/.+

user_home_type

all user home files

user_tmp_t

/tmp/gconfd-.*

user_tmpfs_t

/dev/shm/mono.*

/dev/shm/pulse-shm.*

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 policy modules.

semanage boolean can also be used to manipulate the booleans

system-config-selinux is a GUI tool available to customize SELinux policy settings.

Author

This manual page was auto-generated using sepolicy manpage by mgrepl.