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Diffstat (limited to 'modules/pam_namespace/pam_namespace.8')
| -rw-r--r-- | modules/pam_namespace/pam_namespace.8 | 184 |
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diff --git a/modules/pam_namespace/pam_namespace.8 b/modules/pam_namespace/pam_namespace.8 new file mode 100644 index 0000000..6fca41f --- /dev/null +++ b/modules/pam_namespace/pam_namespace.8 @@ -0,0 +1,184 @@ +'\" t +.\" Title: pam_namespace +.\" Author: [see the "AUTHORS" section] +.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/> +.\" Date: 06/08/2020 +.\" Manual: Linux-PAM Manual +.\" Source: Linux-PAM Manual +.\" Language: English +.\" +.TH "PAM_NAMESPACE" "8" "06/08/2020" "Linux-PAM Manual" "Linux-PAM Manual" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +pam_namespace \- PAM module for configuring namespace for a session +.SH "SYNOPSIS" +.HP \w'\fBpam_namespace\&.so\fR\ 'u +\fBpam_namespace\&.so\fR [debug] [unmnt_remnt] [unmnt_only] [require_selinux] [gen_hash] [ignore_config_error] [ignore_instance_parent_mode] [unmount_on_close] [use_current_context] [use_default_context] [mount_private] +.SH "DESCRIPTION" +.PP +The pam_namespace PAM module sets up a private namespace for a session with polyinstantiated directories\&. A polyinstantiated directory provides a different instance of itself based on user name, or when using SELinux, user name, security context or both\&. If an executable script +/etc/security/namespace\&.init +exists, it is used to initialize the instance directory after it is set up and mounted on the polyinstantiated directory\&. The script receives the polyinstantiated directory path, the instance directory path, flag whether the instance directory was newly created (0 for no, 1 for yes), and the user name as its arguments\&. +.PP +The pam_namespace module disassociates the session namespace from the parent namespace\&. Any mounts/unmounts performed in the parent namespace, such as mounting of devices, are not reflected in the session namespace\&. To propagate selected mount/unmount events from the parent namespace into the disassociated session namespace, an administrator may use the special shared\-subtree feature\&. For additional information on shared\-subtree feature, please refer to the mount(8) man page and the shared\-subtree description at http://lwn\&.net/Articles/159077 and http://lwn\&.net/Articles/159092\&. +.SH "OPTIONS" +.PP +\fBdebug\fR +.RS 4 +A lot of debug information is logged using syslog +.RE +.PP +\fBunmnt_remnt\fR +.RS 4 +For programs such as su and newrole, the login session has already setup a polyinstantiated namespace\&. For these programs, polyinstantiation is performed based on new user id or security context, however the command first needs to undo the polyinstantiation performed by login\&. This argument instructs the command to first undo previous polyinstantiation before proceeding with new polyinstantiation based on new id/context +.RE +.PP +\fBunmnt_only\fR +.RS 4 +For trusted programs that want to undo any existing bind mounts and process instance directories on their own, this argument allows them to unmount currently mounted instance directories +.RE +.PP +\fBrequire_selinux\fR +.RS 4 +If selinux is not enabled, return failure +.RE +.PP +\fBgen_hash\fR +.RS 4 +Instead of using the security context string for the instance name, generate and use its md5 hash\&. +.RE +.PP +\fBignore_config_error\fR +.RS 4 +If a line in the configuration file corresponding to a polyinstantiated directory contains format error, skip that line process the next line\&. Without this option, pam will return an error to the calling program resulting in termination of the session\&. +.RE +.PP +\fBignore_instance_parent_mode\fR +.RS 4 +Instance parent directories by default are expected to have the restrictive mode of 000\&. Using this option, an administrator can choose to ignore the mode of the instance parent\&. This option should be used with caution as it will reduce security and isolation goals of the polyinstantiation mechanism\&. +.RE +.PP +\fBunmount_on_close\fR +.RS 4 +Explicitly unmount the polyinstantiated directories instead of relying on automatic namespace destruction after the last process in a namespace exits\&. This option should be used only in case it is ensured by other means that there cannot be any processes running in the private namespace left after the session close\&. It is also useful only in case there are multiple pam session calls in sequence from the same process\&. +.RE +.PP +\fBuse_current_context\fR +.RS 4 +Useful for services which do not change the SELinux context with setexeccon call\&. The module will use the current SELinux context of the calling process for the level and context polyinstantiation\&. +.RE +.PP +\fBuse_default_context\fR +.RS 4 +Useful for services which do not use pam_selinux for changing the SELinux context with setexeccon call\&. The module will use the default SELinux context of the user for the level and context polyinstantiation\&. +.RE +.PP +\fBmount_private\fR +.RS 4 +This option can be used on systems where the / mount point or its submounts are made shared (for example with a +\fBmount \-\-make\-rshared /\fR +command)\&. The module will mark the whole directory tree so any mount and unmount operations in the polyinstantiation namespace are private\&. Normally the pam_namespace will try to detect the shared / mount point and make the polyinstantiated directories private automatically\&. This option has to be used just when only a subtree is shared and / is not\&. +.sp +Note that mounts and unmounts done in the private namespace will not affect the parent namespace if this option is used or when the shared / mount point is autodetected\&. +.RE +.SH "MODULE TYPES PROVIDED" +.PP +Only the +\fBsession\fR +module type is provided\&. The module must not be called from multithreaded processes\&. +.SH "RETURN VALUES" +.PP +PAM_SUCCESS +.RS 4 +Namespace setup was successful\&. +.RE +.PP +PAM_SERVICE_ERR +.RS 4 +Unexpected system error occurred while setting up namespace\&. +.RE +.PP +PAM_SESSION_ERR +.RS 4 +Unexpected namespace configuration error occurred\&. +.RE +.SH "FILES" +.PP +/etc/security/namespace\&.conf +.RS 4 +Main configuration file +.RE +.PP +/etc/security/namespace\&.d +.RS 4 +Directory for additional configuration files +.RE +.PP +/etc/security/namespace\&.init +.RS 4 +Init script for instance directories +.RE +.SH "EXAMPLES" +.PP +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: +.PP +session required pam_namespace\&.so [arguments] +.PP +To use polyinstantiation with graphical display manager gdm, insert the following line, before exit 0, in /etc/gdm/PostSession/Default: +.PP +/usr/sbin/gdm\-safe\-restart +.PP +This allows gdm to restart after each session and appropriately adjust namespaces of display manager and the X server\&. If polyinstantiation of /tmp is desired along with the graphical environment, then additional configuration changes are needed to address the interaction of X server and font server namespaces with their use of /tmp to create communication sockets\&. Please use the initialization script +/etc/security/namespace\&.init +to ensure that the X server and its clients can appropriately access the communication socket X0\&. Please refer to the sample instructions provided in the comment section of the instance initialization script +/etc/security/namespace\&.init\&. In addition, perform the following changes to use graphical environment with polyinstantiation of /tmp: +.PP +.if n \{\ +.RS 4 +.\} +.nf + 1\&. Disable the use of font server by commenting out "FontPath" + line in /etc/X11/xorg\&.conf\&. If you do want to use the font server + then you will have to augment the instance initialization + script to appropriately provide /tmp/\&.font\-unix from the + polyinstantiated /tmp\&. + 2\&. Ensure that the gdm service is setup to use pam_namespace, + as described above, by modifying /etc/pam\&.d/gdm\&. + 3\&. Ensure that the display manager is configured to restart X server + with each new session\&. This default setup can be verified by + making sure that /usr/share/gdm/defaults\&.conf contains + "AlwaysRestartServer=true", and it is not overridden by + /etc/gdm/custom\&.conf\&. + +.fi +.if n \{\ +.RE +.\} +.sp +.SH "SEE ALSO" +.PP +\fBnamespace.conf\fR(5), +\fBpam.d\fR(5), +\fBmount\fR(8), +\fBpam\fR(8)\&. +.SH "AUTHORS" +.PP +The namespace setup scheme was designed by Stephen Smalley, Janak Desai and Chad Sellers\&. The pam_namespace PAM module was developed by Janak Desai <janak@us\&.ibm\&.com>, Chad Sellers <csellers@tresys\&.com> and Steve Grubb <sgrubb@redhat\&.com>\&. Additional improvements by Xavier Toth <txtoth@gmail\&.com> and Tomas Mraz <tmraz@redhat\&.com>\&. |