Security-Enhanced Linux secures the pppd processes via flexible mandatory access control.
The pppd processes execute with the pppd_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 pppd_t
The pppd_t SELinux type can be entered via the pppd_exec_t file type.
The default entrypoint paths for the pppd_t domain are the following:
/usr/sbin/pppd, /sbin/ppp-watch, /usr/sbin/ipppd, /sbin/pppoe-server, /usr/sbin/ppp-watch, /usr/sbin/pppoe-server
You can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux pppd policy is very flexible allowing users to setup their pppd processes in as secure a method as possible.
The following process types are defined for pppd:
pppd_t
Note: semanage permissive -a pppd_t can be used to make the process type pppd_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.
If you want to allow pppd to load kernel modules for certain modems, you must turn on the pppd_can_insmod boolean. Disabled by default.
setsebool -P pppd_can_insmod 1
If you want to allow pppd to be run for a regular user, you must turn on the pppd_for_user boolean. Disabled by default.
setsebool -P pppd_for_user 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 authlogin_nsswitch_use_ldap boolean. Disabled by default.
setsebool -P authlogin_nsswitch_use_ldap 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 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. Enabled by default.
setsebool -P nscd_use_shm 1
The SELinux process type pppd_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.
cluster_conf_t
/etc/cluster(/.*)?
cluster_var_lib_t
/var/lib/pcsd(/.*)?
/var/lib/cluster(/.*)?
/var/lib/openais(/.*)?
/var/lib/pengine(/.*)?
/var/lib/corosync(/.*)?
/usr/lib/heartbeat(/.*)?
/var/lib/heartbeat(/.*)?
/var/lib/pacemaker(/.*)?
cluster_var_run_t
/var/run/crm(/.*)?
/var/run/cman_.*
/var/run/rsctmp(/.*)?
/var/run/aisexec.*
/var/run/heartbeat(/.*)?
/var/run/corosync-qnetd(/.*)?
/var/run/corosync-qdevice(/.*)?
/var/run/corosync.pid
/var/run/cpglockd.pid
/var/run/rgmanager.pid
/var/run/cluster/rgmanager.sk
etc_runtime_t
/[^/]+
/etc/mtab.*
/etc/blkid(/.*)?
/etc/nologin.*
/etc/.fstab.hal..+
/halt
/fastboot
/poweroff
/.autofsck
/etc/cmtab
/forcefsck
/.suspended
/fsckoptions
/.autorelabel
/etc/.updated
/var/.updated
/etc/killpower
/etc/nohotplug
/etc/securetty
/etc/ioctl.save
/etc/fstab.REVOKE
/etc/network/ifstate
/etc/sysconfig/hwconf
/etc/ptal/ptal-printd-like
/etc/sysconfig/iptables.save
/etc/xorg.conf.d/00-system-setup-keyboard.conf
/etc/X11/xorg.conf.d/00-system-setup-keyboard.conf
faillog_t
/var/log/btmp.*
/var/log/faillog.*
/var/log/tallylog.*
/var/run/faillock(/.*)?
net_conf_t
/etc/hosts[^/]*
/etc/yp.conf.*
/etc/denyhosts.*
/etc/hosts.deny.*
/etc/resolv.conf.*
/etc/.resolv.conf.*
/etc/resolv-secure.conf.*
/var/run/cloud-init(/.*)?
/var/run/systemd/network(/.*)?
/etc/sysconfig/networking(/.*)?
/etc/sysconfig/network-scripts(/.*)?
/etc/sysconfig/network-scripts/.*resolv.conf
/var/run/NetworkManager/resolv.conf.*
/etc/ethers
/etc/ntp.conf
/var/run/systemd/resolve/resolv.conf
/var/run/systemd/resolve/stub-resolv.conf
pppd_etc_rw_t
/etc/ppp(/.*)?
/etc/ppp/peers(/.*)?
/etc/ppp/resolv.conf
pppd_lock_t
/var/lock/ppp(/.*)?
pppd_log_t
/var/log/ppp(/.*)?
/var/log/ppp-connect-errors.*
pppd_tmp_t
pppd_var_run_t
/var/run/(i)?ppp.*pid[^/]*
/var/run/ppp(/.*)?
/var/run/pppd[0-9]*.tdb
root_t
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
wtmp_t
/var/log/wtmp.*
You can see the context of a file using the -Z option to lsP Policy governs the access confined processes have to these files. SELinux pppd policy is very flexible allowing users to setup their pppd processes in as secure a method as possible.
EQUIVALENCE DIRECTORIES
pppd policy stores data with multiple different file context types under the /var/log/ppp directory. If you would like to store the data in a different directory you can use the semanage command to create an equivalence mapping. If you wanted to store this data under the /srv dirctory you would execute the following command:
semanage fcontext -a -e /var/log/ppp /srv/ppp
restorecon -R -v /srv/ppp
pppd policy stores data with multiple different file context types under the /var/run/ppp directory. If you would like to store the data in a different directory you can use the semanage command to create an equivalence mapping. If you wanted to store this data under the /srv dirctory you would execute the following command:
semanage fcontext -a -e /var/run/ppp /srv/ppp
restorecon -R -v /srv/ppp
STANDARD FILE CONTEXT
SELinux defines the file context types for the pppd, 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 pppd_var_run_t '/srv/mypppd_content(/.*)?'
restorecon -R -v /srv/mypppd_content
Note: SELinux often uses regular expressions to specify labels that match multiple files.
The following file types are defined for pppd:
pppd_etc_rw_t
- Set files with the pppd_etc_rw_t type, if you want to treat the files as pppd etc read/write content.
pppd_etc_t
- Set files with the pppd_etc_t type, if you want to store pppd files in the /etc directories.
pppd_exec_t
- Set files with the pppd_exec_t type, if you want to transition an executable to the pppd_t domain.
pppd_initrc_exec_t
- Set files with the pppd_initrc_exec_t type, if you want to transition an executable to the pppd_initrc_t domain.
pppd_lock_t
- Set files with the pppd_lock_t type, if you want to treat the files as pppd lock data, stored under the /var/lock directory
pppd_log_t
- Set files with the pppd_log_t type, if you want to treat the data as pppd log data, usually stored under the /var/log directory.
pppd_secret_t
- Set files with the pppd_secret_t type, if you want to treat the files as pppd se secret data.
pppd_tmp_t
- Set files with the pppd_tmp_t type, if you want to store pppd temporary files in the /tmp directories.
pppd_unit_file_t
- Set files with the pppd_unit_file_t type, if you want to treat the files as pppd unit content.
pppd_var_run_t
- Set files with the pppd_var_run_t type, if you want to store the pppd 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 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.