Security-Enhanced Linux secures the passwd processes via flexible mandatory access control.
If you want to allow users to resolve user passwd entries directly from ldap rather then using a sssd serve for the passwd_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 passwd_t, you must turn on the kerberos_enabled boolean.
setsebool -P kerberos_enabled 1
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 passwd policy is very flexible allowing users to setup their passwd processes in as secure a method as possible.
The following file types are defined for passwd:
passwd_exec_t
- Set files with the passwd_exec_t type, if you want to transition an executable to the passwd_t domain.
passwd_file_t
- Set files with the passwd_file_t type, if you want to treat the files as passwd content.
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.
You can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux passwd policy is very flexible allowing users to setup their passwd processes in as secure a method as possible.
The following process types are defined for passwd:
passwd_t
Note: semanage permissive -a PROCESS_TYPE can be used to make a process type permissive. Permissive process types are not denied access by SELinux. AVC messages will still be generated.
The SELinux user type passwd_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.
faillog_t
/var/log/btmp.*
/var/run/faillock(/.*)?
/var/log/faillog
/var/log/tallylog
krb5_host_rcache_t
/var/cache/krb5rcache(/.*)?
/var/tmp/nfs_0
/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
lastlog_t
/var/log/lastlog
passwd_file_t
/etc/group[-+]?
/etc/passwd[-+]?
/etc/ptmptmp
/etc/passwd.OLD
pcscd_var_run_t
/var/run/pcscd(/.*)?
/var/run/pcscd.events(/.*)?
/var/run/pcscd.pid
/var/run/pcscd.pub
/var/run/pcscd.comm
security_t
/selinux
shadow_t
/etc/shadow.*
/etc/gshadow.*
/var/db/shadow.*
/etc/passwd.adjunct.*
/etc/.pwd.lock
/etc/group.lock
/etc/passwd.lock
/etc/security/opasswd
/etc/security/opasswd.old
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.
system-config-selinux is a GUI tool available to customize SELinux policy settings.