sshd_session_selinux - Man Page

Security-Enhanced Linux secures the sshd_session processes via flexible mandatory access control.

The sshd_session processes execute with the sshd_session_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 sshd_session_t

The sshd_session_t SELinux type can be entered via the sshd_session_exec_t file type.

The default entrypoint paths for the sshd_session_t domain are the following:

/usr/libexec/openssh/sshd-session

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 psbP

Policy governs the access confined processes have to files. SELinux sshd_session policy is very flexible allowing users to setup their sshd_session processes in as secure a method as possible.

The following process types are defined for sshd_session:

sshd_session_t

Note: semanage permissive -a sshd_session_t can be used to make the process type sshd_session_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.

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

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 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 enable polyinstantiated directory support, you must turn on the polyinstantiation_enabled boolean. Disabled by default.

setsebool -P polyinstantiation_enabled 1

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

setsebool -P ssh_sysadm_login 1

If you want to allow a user to login as an unconfined domain, you must turn on the unconfined_login boolean. Enabled by default.

setsebool -P unconfined_login 1

The SELinux process type sshd_session_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.

auth_cache_t

/var/cache/coolkey(/.*)?

auth_home_t

/root/.yubico(/.*)?
/root/.config/Yubico(/.*)?
/root/.google_authenticator
/root/.google_authenticator~
/home/[^/]+/.yubico(/.*)?
/home/[^/]+/.config/Yubico(/.*)?
/home/[^/]+/.google_authenticator
/home/[^/]+/.google_authenticator~

cifs_t

ecryptfs_t

/home/[^/]+/.Private(/.*)?
/home/[^/]+/.ecryptfs(/.*)?

faillog_t

/var/log/btmp.*
/run/faillock(/.*)?
/var/log/faillog.*
/var/log/tallylog.*

fusefs_t

/run/user/[0-9]+/gvfs

initrc_var_run_t

/run/utmp
/run/runlevel.dir
/run/setmixer_flag

krb5_host_rcache_t

/var/tmp/krb5_0.rcache2
/var/cache/krb5rcache(/.*)?
/var/tmp/nfs_0
/var/tmp/DNS_25
/var/tmp/host_0
/var/tmp/imap_0
/var/tmp/HTTP_23
/var/tmp/HTTP_48
/var/tmp/ldap_55
/var/tmp/ldap_487
/var/tmp/ldapmap1_0

nfs_t

pam_var_run_t

/var/(db|adm)/sudo(/.*)?
/run/sudo(/.*)?
/run/pam_ssh(/.*)?
/run/sepermit(/.*)?
/var/lib/sudo(/.*)?
/run/pam_mount(/.*)?
/run/pam_timestamp(/.*)?

security_t

/selinux

sshd_session_var_run_t

user_tmp_t

/run/tlog(/.*)?
/run/user/[^/]+
/dev/shm/mono.*
/tmp/.ICE-unix(/.*)?
/tmp/.X11-unix(/.*)?
/dev/shm/pulse-shm.*
/run/user
/tmp/.X0-lock
/tmp/hsperfdata_root
/var/tmp/hsperfdata_root
/home/[^/]+/tmp
/home/[^/]+/.tmp
/run/user/[0-9]+
/tmp/gconfd-[^/]+

var_auth_t

/var/ace(/.*)?
/var/rsa(/.*)?
/var/lib/abl(/.*)?
/var/lib/rsa(/.*)?
/var/lib/pam_ssh(/.*)?
/var/lib/pam_shield(/.*)?
/var/opt/quest/vas/vasd(/.*)?
/var/lib/google-authenticator(/.*)?

wtmp_t

/var/log/wtmp.*

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 lsbP

Policy governs the access confined processes have to these files. SELinux sshd_session policy is very flexible allowing users to setup their sshd_session processes in as secure a method as possible.

STANDARD FILE CONTEXT

SELinux defines the file context types for the sshd_session, if you wanted to store files with these types in a different paths, you need to execute the semanage command to specify alternate labeling and then use restorecon to put the labels on disk.

semanage fcontext -a -t sshd_session_tmpfs_t '/srv/sshd_session/content(/.*)?'
restorecon -R -v /srv/mysshd_session_content

Note: SELinux often uses regular expressions to specify labels that match multiple files.

The following file types are defined for sshd_session:

sshd_session_exec_t

- Set files with the sshd_session_exec_t type, if you want to transition an executable to the sshd_session_t domain.

sshd_session_tmpfs_t

- Set files with the sshd_session_tmpfs_t type, if you want to store sshd session files on a tmpfs file system.

sshd_session_var_run_t

- Set files with the sshd_session_var_run_t type, if you want to store the sshd session files under the /run or /var/run directory.

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 database.  You will need to use restorecon to apply the labels.

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.

This manual page was auto-generated using sepolicy manpage .

selinux(8), sshd_session(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8)

sshd_selinux(8).