guest_selinux(8) guest SELinux Policy documentation guest_selinux(8)NAME
guest_u - Least privledge terminal user role - Security Enhanced Linux
Policy
DESCRIPTION
guest_u is an SELinux User defined in the SELinux policy. SELinux users
have default roles, guest_r. The default role has a default type,
guest_t, associated with it.
The SELinux user will usually login to a system with a context that
looks like:
guest_u:guest_r:guest_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 guest_u
user, you would execute:
semanage login -m -s guest_u __default__
If you want to map the one Linux user (joe) to the SELinux user guest,
you would execute:
$ semanage login -a -s guest_u joe
USER DESCRIPTION
The SELinux user guest_u is defined in policy as a unprivileged user.
SELinux prevents unprivileged users from doing administration tasks
without transitioning to a different role.
SUDO
The SELinux type guest_t is not allowed to execute sudo.
X WINDOWS LOGIN
The SELinux user guest_u is not able to X Windows login.
TERMINAL LOGIN
The SELinux user guest_u is able to terminal login.
NETWORK
The SELinux user guest_u is able to connect to the following tcp ports.
dns_port_t: 53
ocsp_port_t: 9080
kerberos_port_t: 88,750,4444
BOOLEANS
SELinux policy is customizable based on least access required. guest_t
policy is extremely flexible and has several booleans that allow you to
manipulate the policy and run guest_t with the tightest access possi‐
ble.
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 guest_u is able execute home content files.
TRANSITIONS
Three things can happen when guest_t attempts to execute a program.
1. SELinux Policy can deny guest_t from executing the program.
2. SELinux Policy can allow guest_t to execute the program in the cur‐
rent user type.
Execute the following to see the types that the SELinux user
guest_t can execute without transitioning:
sesearch -A -s guest_t -c file -p execute_no_trans
3. SELinux can allow guest_t to execute the program and transition to a
new type.
Execute the following to see the types that the SELinux user
guest_t can execute and transition:
$ sesearch -A -s guest_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 guest guest_selinux(8)
