sysadm_selinux

Section: sysadm SELinux Policy documentation (8)
Updated: sysadm
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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_u: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

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.

X WINDOWS LOGIN

The SELinux user sysadm_u is 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 listen on the following udp ports.

ntp_port_t: 123

all ports with out defined types

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_t policy is extremely flexible and has several booleans that allow you to manipulate the policy and run sysadm_t with the tightest access possible.

If you want to allow users to connect to mysql, you must turn on the allow_user_mysql_connect boolean.

setsebool -P allow_user_mysql_connect 1

If you want to allow user processes to change their priority, you must turn on the user_setrlimit boolean.

setsebool -P user_setrlimit 1

If you want to control users use of ping and traceroute, you must turn on the user_ping boolean.

setsebool -P user_ping 1

If you want to allow w to display everyone, you must turn on the user_ttyfile_stat boolean.

setsebool -P user_ttyfile_stat 1

If you want to allow regular users direct dri device access, you must turn on the user_direct_dri boolean.

setsebool -P user_direct_dri 1

If you want to allow user to r/w files on filesystems that do not have extended attributes (FAT, CDROM, FLOPPY), you must turn on the user_rw_noexattrfile boolean.

setsebool -P user_rw_noexattrfile 1

If you want to allow users to run TCP servers (bind to ports and accept connection from the same domain and outside users) disabling this forces FTP passive mode and may change other protocols, you must turn on the user_tcp_server boolean.

setsebool -P user_tcp_server 1

If you want to allow regular users direct mouse access, you must turn on the user_direct_mouse boolean.

setsebool -P user_direct_mouse 1

If you want to allow users to connect to PostgreSQL, you must turn on the allow_user_postgresql_connect boolean.

setsebool -P allow_user_postgresql_connect 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:

sesearch -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:

$ sesearch -A -s sysadm_t -c process -p transition

COMMANDS

semanage login can also be used to manipulate the Linux User to SELinux User mappings

semanage user can also be used to manipulate SELinux user definitions.

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

AUTHOR

This manual page was autogenerated by genuserman.py.

This document was created by man2html, using the manual pages.
Time: 05:34:30 GMT, December 24, 2015