# namespace.conf

## NAME



           namespace.conf - the namespace configuration file
    


## DESCRIPTION



           The _pam_namespace.so_ module allows setup of private namespaces
           with polyinstantiated directories. Directories can be
           polyinstantiated based on user name or, in the case of SELinux,
           user name, sensitivity level or complete security context. If an
           executable script /etc/security/namespace.init exists, it is used
           to initialize the namespace every time an instance directory is
           set up and mounted. The script receives the polyinstantiated
           directory path and the instance directory path as its arguments.
    
           The /etc/security/namespace.conf file specifies which directories
           are polyinstantiated, how they are polyinstantiated, how instance
           directories would be named, and any users for whom
           polyinstantiation would not be performed.
    
           When someone logs in, the file namespace.conf is scanned. Comments
           are marked by _#_ characters. Each non comment line represents one
           polyinstantiated directory. The fields are separated by spaces but
           can be quoted by _"_ characters also escape sequences _\b_ , _\n_ , and _\t_
           are recognized. The fields are as follows:
    
           _polydir instance_prefix method list_of_uids_
    
           The first field, _polydir_ , is the absolute pathname of the
           directory to polyinstantiate. The special string _$HOME_ is replaced
           with the user's home directory, and _$USER_ with the username. This
           field cannot be blank.
    
           The second field, _instance_prefix_ is the string prefix used to
           build the pathname for the instantiation of <polydir>. Depending
           on the polyinstantiation _method_ it is then appended with "instance
           differentiation string" to generate the final instance directory
           path. This directory is created if it did not exist already, and
           is then bind mounted on the <polydir> to provide an instance of
           <polydir> based on the <method> column. The special string _$HOME_
           is replaced with the user's home directory, and _$USER_ with the
           username. This field cannot be blank.
    
           The third field, _method_ , is the method used for polyinstantiation.
           It can take these values; "user" for polyinstantiation based on
           user name, "level" for polyinstantiation based on process MLS
           level and user name, "context" for polyinstantiation based on
           process security context and user name, "tmpfs" for mounting tmpfs
           filesystem as an instance dir, and "tmpdir" for creating temporary
           directory as an instance dir which is removed when the user's
           session is closed. Methods "context" and "level" are only
           available with SELinux. This field cannot be blank.
    
           The fourth field, _list_of_uids_ , is a comma separated list of user
           names for whom the polyinstantiation is not performed. If left
           blank, polyinstantiation will be performed for all users. If the
           list is preceded with a single "~" character, polyinstantiation is
           performed only for users in the list.
    
           The _method_ field can contain also following optional flags
           separated by _:_ characters.
    
           _create_ =_mode_ ,_owner_ ,_group_ - create the polyinstantiated directory.
           The mode, owner and group parameters are optional. The default for
           mode is determined by umask, the default owner is the user whose
           session is opened, the default group is the primary group of the
           user.
    
           _iscript_ =_path_ - path to the instance directory init script. The
           base directory for relative paths is /etc/security/namespace.d.
    
           _noinit_ - instance directory init script will not be executed.
    
           _shared_ - the instance directories for "context" and "level"
           methods will not contain the user name and will be shared among
           all users.
    
           _mntopts_ =_value_ - value of this flag is passed to the mount call
           when the tmpfs mount is done. It allows for example the
           specification of the maximum size of the tmpfs instance that is
           created by the mount call. In addition to options specified in the
           tmpfs(5) manual the _nosuid_ , _noexec_ , and _nodev_ flags can be used to
           respectively disable setuid bit effect, disable running
           executables, and disable devices to be interpreted on the mounted
           tmpfs filesystem.
    
           The directory where polyinstantiated instances are to be created,
           must exist and must have, by default, the mode of 0000. The
           requirement that the instance parent be of mode 0000 can be
           overridden with the command line option
           _ignore_instance_parent_mode_
    
           In case of context or level polyinstantiation the SELinux context
           which is used for polyinstantiation is the context used for
           executing a new process as obtained by getexeccon. This context
           must be set by the calling application or pam_selinux.so module.
           If this context is not set the polyinstatiation will be based just
           on user name.
    
           The "instance differentiation string" is <user name> for "user"
           method and <user name>_<raw directory context> for "context" and
           "level" methods. If the whole string is too long the end of it is
           replaced with md5sum of itself. Also when command line option
           _gen_hash_ is used the whole string is replaced with md5sum of
           itself.
    


## EXAMPLES



           These are some example lines which might be specified in
           /etc/security/namespace.conf.
    
                     # The following three lines will polyinstantiate /tmp,
                     # /var/tmp and user's home directories. /tmp and /var/tmp
                     # will be polyinstantiated based on the security level
                     # as well as user name, whereas home directory will be
                     # polyinstantiated based on the full security context and user name.
                     # Polyinstantiation will not be performed for user root
                     # and adm for directories /tmp and /var/tmp, whereas home
                     # directories will be polyinstantiated for all users.
                     #
                     # Note that instance directories do not have to reside inside
                     # the polyinstantiated directory. In the examples below,
                     # instances of /tmp will be created in /tmp-inst directory,
                     # where as instances of /var/tmp and users home directories
                     # will reside within the directories that are being
                     # polyinstantiated.
                     #
                     /tmp     /tmp-inst/               level      root,adm
                     /var/tmp /var/tmp/tmp-inst/        level      root,adm
                     $HOME    $HOME/$USER.inst/inst- context
    
           For the <service>s you need polyinstantiation (login for example)
           put the following line in /etc/pam.d/<service> as the last line
           for session group:
    
           session required pam_namespace.so [arguments]
    
           This module also depends on pam_selinux.so setting the context.
    


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