ssh_selinux(8) SELinux Policy ssh ssh_selinux(8)NAMEssh_selinux - Security Enhanced Linux Policy for the ssh processes
DESCRIPTION
Security-Enhanced Linux secures the ssh processes via flexible manda‐
tory access control.
The ssh processes execute with the ssh_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 ssh_t
ENTRYPOINTS
The ssh_t SELinux type can be entered via the ssh_exec_t file type.
The default entrypoint paths for the ssh_t domain are the following:
/usr/bin/ssh, /usr/libexec/nm-ssh-service
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
ssh policy is very flexible allowing users to setup their ssh processes
in as secure a method as possible.
The following process types are defined for ssh:
sshd_sandbox_t, ssh_keysign_t, ssh_keygen_t, sshd_net_t, ssh_t, sshd_t, sshd_keygen_t
Note: semanage permissive -a ssh_t can be used to make the process type
ssh_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. ssh
policy is extremely flexible and has several booleans that allow you to
manipulate the policy and run ssh with the tightest access possible.
If you want to allow host key based authentication, you must turn on
the ssh_keysign boolean. Disabled by default.
setsebool -P ssh_keysign 1
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 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 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 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 allow regular users direct dri device access, you must
turn on the selinuxuser_direct_dri_enabled boolean. Enabled by default.
setsebool -P selinuxuser_direct_dri_enabled 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 selinuxuser_tcp_server boolean. Disabled by default.
setsebool -P selinuxuser_tcp_server 1
If you want to support ecryptfs home directories, you must turn on the
use_ecryptfs_home_dirs boolean. Disabled by default.
setsebool -P use_ecryptfs_home_dirs 1
If you want to support fusefs home directories, you must turn on the
use_fusefs_home_dirs boolean. Disabled by default.
setsebool -P use_fusefs_home_dirs 1
If you want to support NFS home directories, you must turn on the
use_nfs_home_dirs boolean. Disabled by default.
setsebool -P use_nfs_home_dirs 1
If you want to support SAMBA home directories, you must turn on the
use_samba_home_dirs boolean. Disabled by default.
setsebool -P use_samba_home_dirs 1
If you want to allows clients to write to the X server shared memory
segments, you must turn on the xserver_clients_write_xshm boolean. Dis‐
abled by default.
setsebool -P xserver_clients_write_xshm 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
NSSWITCH DOMAIN
If you want to allow users to resolve user passwd entries directly from
ldap rather then using a sssd server for the ssh_keygen_t, ssh_t,
sshd_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
ssh_keygen_t, ssh_t, sshd_t, you must turn on the kerberos_enabled
boolean.
setsebool -P kerberos_enabled 1
PORT TYPES
SELinux defines port types to represent TCP and UDP ports.
You can see the types associated with a port by using the following
command:
semanage port -l
Policy governs the access confined processes have to these ports.
SELinux ssh policy is very flexible allowing users to setup their ssh
processes in as secure a method as possible.
The following port types are defined for ssh:
ssh_port_t
Default Defined Ports:
tcp 22
MANAGED FILES
The SELinux process type ssh_t can manage files labeled with the fol‐
lowing file types. The paths listed are the default paths for these
file types. Note the processes UID still need to have DAC permissions.
cifs_t
ecryptfs_t
/home/[^/]*/.Private(/.*)?
/home/[^/]*/.ecryptfs(/.*)?
fusefs_t
/var/run/[^/]*/gvfs
nfs_t
ssh_home_t
/var/lib/[^/]+/.ssh(/.*)?
/root/.ssh(/.*)?
/var/lib/one/.ssh(/.*)?
/var/lib/pgsql/.ssh(/.*)?
/var/lib/openshift/[^/]+/.ssh(/.*)?
/var/lib/amanda/.ssh(/.*)?
/var/lib/stickshift/[^/]+/.ssh(/.*)?
/var/lib/gitolite/.ssh(/.*)?
/var/lib/nocpulse/.ssh(/.*)?
/var/lib/gitolite3/.ssh(/.*)?
/var/lib/openshift/gear/[^/]+/.ssh(/.*)?
/root/.shosts
/home/[^/]*/.ssh(/.*)?
/home/[^/]*/.ansible/cp/.*
/home/[^/]*/.shosts
ssh_tmpfs_t
user_fonts_cache_t
/root/.fontconfig(/.*)?
/root/.fonts/auto(/.*)?
/root/.fonts.cache-.*
/home/[^/]*/.fontconfig(/.*)?
/home/[^/]*/.fonts/auto(/.*)?
/home/[^/]*/.fonts.cache-.*
user_tmp_t
/var/run/user(/.*)?
/tmp/gconfd-.*
user_tmp_type
all user tmp files
xserver_tmpfs_t
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 ssh policy is very flexible allowing users to setup their ssh
processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the ssh, 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 ssh_agent_exec_t '/srv/ssh/content(/.*)?'
restorecon -R -v /srv/myssh_content
Note: SELinux often uses regular expressions to specify labels that
match multiple files.
The following file types are defined for ssh:
ssh_agent_exec_t
- Set files with the ssh_agent_exec_t type, if you want to transition
an executable to the ssh_agent_t domain.
ssh_agent_tmp_t
- Set files with the ssh_agent_tmp_t type, if you want to store ssh
agent temporary files in the /tmp directories.
ssh_exec_t
- Set files with the ssh_exec_t type, if you want to transition an exe‐
cutable to the ssh_t domain.
Paths:
/usr/bin/ssh, /usr/libexec/nm-ssh-service
ssh_home_t
- Set files with the ssh_home_t type, if you want to store ssh files in
the users home directory.
Paths:
/var/lib/[^/]+/.ssh(/.*)?, /root/.ssh(/.*)?,
/var/lib/one/.ssh(/.*)?, /var/lib/pgsql/.ssh(/.*)?, /var/lib/open‐
shift/[^/]+/.ssh(/.*)?, /var/lib/amanda/.ssh(/.*)?,
/var/lib/stickshift/[^/]+/.ssh(/.*)?, /var/lib/gito‐
lite/.ssh(/.*)?, /var/lib/nocpulse/.ssh(/.*)?, /var/lib/gito‐
lite3/.ssh(/.*)?, /var/lib/openshift/gear/[^/]+/.ssh(/.*)?,
/root/.shosts, /home/[^/]*/.ssh(/.*)?, /home/[^/]*/.ansible/cp/.*,
/home/[^/]*/.shosts
ssh_keygen_exec_t
- Set files with the ssh_keygen_exec_t type, if you want to transition
an executable to the ssh_keygen_t domain.
ssh_keysign_exec_t
- Set files with the ssh_keysign_exec_t type, if you want to transition
an executable to the ssh_keysign_t domain.
Paths:
/usr/lib/openssh/ssh-keysign, /usr/libexec/openssh/ssh-keysign
ssh_tmpfs_t
- Set files with the ssh_tmpfs_t type, if you want to store ssh files
on a tmpfs file system.
sshd_exec_t
- Set files with the sshd_exec_t type, if you want to transition an
executable to the sshd_t domain.
Paths:
/usr/sbin/sshd, /usr/sbin/gsisshd
sshd_initrc_exec_t
- Set files with the sshd_initrc_exec_t type, if you want to transition
an executable to the sshd_initrc_t domain.
sshd_key_t
- Set files with the sshd_key_t type, if you want to treat the files as
sshd key data.
Paths:
/etc/ssh/ssh_host.*_key, /etc/ssh/ssh_host.*_key.pub,
/etc/ssh/primes
sshd_keygen_exec_t
- Set files with the sshd_keygen_exec_t type, if you want to transition
an executable to the sshd_keygen_t domain.
sshd_keygen_unit_file_t
- Set files with the sshd_keygen_unit_file_t type, if you want to treat
the files as sshd keygen unit content.
sshd_keytab_t
- Set files with the sshd_keytab_t type, if you want to treat the files
as kerberos keytab files.
sshd_tmpfs_t
- Set files with the sshd_tmpfs_t type, if you want to store sshd files
on a tmpfs file system.
sshd_unit_file_t
- Set files with the sshd_unit_file_t type, if you want to treat the
files as sshd unit content.
sshd_var_run_t
- Set files with the sshd_var_run_t type, if you want to store the sshd
files under the /run or /var/run directory.
Paths:
/var/run/sshd.pid, /var/run/sshd.init.pid
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 port can also be used to manipulate the port definitions
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), ssh(8), semanage(8), restorecon(8), chcon(1), sepolicy(8) ,
setsebool(8), ssh_keygen_selinux(8), ssh_keygen_selinux(8),
ssh_keysign_selinux(8), ssh_keysign_selinux(8)ssh 13-11-20 ssh_selinux(8)
