NAME | DESCRIPTION | EXAMPLES | SEE ALSO | AUTHORS | COLOPHON

NAMESPACE.CONF(5)             Linux-PAM Manual             NAMESPACE.CONF(5)

NAME         top

       namespace.conf - the namespace configuration file

DESCRIPTION         top

       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:

       polydirinstance_prefixmethodlist_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. See mount(8) for details.

       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         top

       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.

SEE ALSO         top

       pam_namespace(8), pam.d(5), pam(8)

AUTHORS         top

       The namespace.conf manual page was written by Janak Desai
       <janak@us.ibm.com>. More features added by Tomas Mraz
       <tmraz@redhat.com>.

COLOPHON         top

       This page is part of the linux-pam (Pluggable Authentication Modules
       for Linux) project.  Information about the project can be found at 
       ⟨https://fedorahosted.org/linux-pam/⟩.  If you have a bug report for
       this manual page, see ⟨https://fedorahosted.org/linux-pam/report⟩.
       This page was obtained from the tarball Linux-PAM-1.3.0.tar.gz
       fetched from ⟨http://www.linux-pam.org/library/⟩ on 2017-04-25.  If
       you discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for the
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       this COLOPHON (which is not part of the original manual page), send a
       mail to man-pages@man7.org

Linux-PAM Manual                 04/01/2016                NAMESPACE.CONF(5)

Pages that refer to this page: pam_namespace(8)