sysadm_selinux(8) sysadm SELinux Policy documentation sysadm_selinux(8)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__
If you want to map the one Linux user (joe) to the SELinux user sysadm,
you would execute:
$ semanage login -a -s sysadm_u joe
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=auditadm_r TYPE=auditadm_t COMMAND
sudo will run COMMAND as sysadm_u:auditadm_r:auditadm_t:LEVEL
USERNAME ALL=(ALL) ROLE=secadm_r TYPE=secadm_t COMMAND
sudo will run COMMAND as sysadm_u:secadm_r:secadm_t:LEVEL
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 auditadm_r secadm_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.
TERMINAL LOGIN
The SELinux user sysadm_u is able to terminal 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 the local mysql server, you
must turn on the allow_user_mysql_connect boolean.
setsebool -P allow_user_mysql_connect 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 user music sharing, you must turn on the
user_share_music boolean.
setsebool -P user_share_music 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 user processes to change their priority, you must
turn on the user_setrlimit boolean.
setsebool -P user_setrlimit 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
If you want to allow users to read system messages, you must turn on
the user_dmesg boolean.
setsebool -P user_dmesg 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 cur‐
rent 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 pol‐
icy settings.
AUTHOR
This manual page was autogenerated by genuserman.py.
SEE ALSOselinux(8), semanage(8).
mgrepl@redhat.com sysadm sysadm_selinux(8)
