PAM_SELINUX(8) Linux-PAM Manual PAM_SELINUX(8)NAME
pam_selinux - PAM module to set the default security context
SYNOPSIS
pam_selinux.so [close] [debug] [open] [nottys] [verbose] [select_context] [env_params] [use_current_range]
DESCRIPTION
In a nutshell, pam_selinux sets up the default security context for the next execed shell.
When an application opens a session using pam_selinux, the shell that gets executed will be run in the default security context, or if the
user chooses and the pam file allows the selected security context. Also the controlling tty will have it's security context modified to
match the users.
Adding pam_selinux into a pam file could cause other pam modules to change their behavior if the exec another application. The close and
open option help mitigate this problem. close option will only cause the close portion of the pam_selinux to execute, and open will only
cause the open portion to run. You can add pam_selinux to the config file twice. Add the pam_selinux close as the executes the open pass
through the modules, pam_selinux open_session will happen last. When PAM executes the close pass through the modules pam_selinux
close_session will happen first.
OPTIONS
close
Only execute the close_session portion of the module.
debug
Turns on debugging via syslog(3).
open
Only execute the open_session portion of the module.
nottys
Do not try to setup the ttys security context.
verbose
attempt to inform the user when security context is set.
select_context
Attempt to ask the user for a custom security context role. If MLS is on ask also for sensitivity level.
env_params
Attempt to obtain a custom security context role from PAM environment. If MLS is on obtain also sensitivity level. This option and the
select_context option are mutually exclusive. The respective PAM environment variables are SELINUX_ROLE_REQUESTED,
SELINUX_LEVEL_REQUESTED, and SELINUX_USE_CURRENT_RANGE. The first two variables are self describing and the last one if set to 1 makes
the PAM module behave as if the use_current_range was specified on the command line of the module.
use_current_range
Use the sensitivity level of the current process for the user context instead of the default level. Also suppresses asking of the
sensitivity level from the user or obtaining it from PAM environment.
MODULE TYPES PROVIDED
Only the session module type is provided.
RETURN VALUES
PAM_AUTH_ERR
Unable to get or set a valid context.
PAM_SUCCESS
The security context was set successfully.
PAM_USER_UNKNOWN
The user is not known to the system.
EXAMPLES
auth required pam_unix.so
session required pam_permit.so
session optional pam_selinux.so
SEE ALSO pam.conf(5), pam.d(5), pam(8)AUTHOR
pam_selinux was written by Dan Walsh <dwalsh@redhat.com>.
Linux-PAM Manual 06/16/2009 PAM_SELINUX(8)
Check Out this Related Man Page
NAMESPACE.CONF(5) Linux-PAM Manual NAMESPACE.CONF(5)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 ,
, and 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.
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.
SEE ALSO pam_namespace(8), pam.d(5), pam(7)AUTHORS
The namespace.conf manual page was written by Janak Desai <janak@us.ibm.com>. More features added by Tomas Mraz <tmraz@redhat.com>.
Linux-PAM Manual 06/04/2011 NAMESPACE.CONF(5)