NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | AUTHOR | COLOPHON |
LXC-USERNSEXEC(1) LXC-USERNSEXEC(1)
lxc-usernsexec - Run a task as root in a new user namespace.
lxc-usernsexec [ -m uid-map ] -- command
lxc-usernsexec can be used to run a task as root in a new user namespace.
-m uid-map The uid map to use in the user namespace. Each map consists of four colon-separate values. First a character 'u', 'g' or 'b' to specify whether this map pertains to user ids, group ids, or both; next the first userid in the user namespace; next the first userid as seen on the host; and finally the number of ids to be mapped. More than one map can be specified. If no map is specified, then by default the full uid and gid ranges granted by /etc/subuid and /etc/subgid will be mapped to the uids and gids starting at 0 in the container. Note that lxc-usernsexec always tries to setuid and setgid to 0 in the namespace. Therefore uid 0 in the namespace must be mapped.
To spawn a shell with the full allotted subuids mapped into the container, use lxc-usernsexec To run a different shell than /bin/sh, use lxc-usernsexec -- /bin/bash If your user id is 1000, root in a container is mapped to 190000, and you wish to chown a file you own to root in the container, you can use: lxc-usernsexec -m b:0:1000:1 -m b:1:190000:1 -- /bin/chown 1:1 $file This maps your userid to root in the user namespace, and 190000 to uid 1. Since root in the user namespace is privileged over all userids mapped into the namespace, you are allowed to change the file ownership, which you could not do on the host using a simple chown.
lxc(7), lxc-create(1), lxc-copy(1), lxc-destroy(1), lxc-start(1), lxc-stop(1), lxc-execute(1), lxc-console(1), lxc-monitor(1), lxc-wait(1), lxc-cgroup(1), lxc-ls(1), lxc-info(1), lxc-freeze(1), lxc-unfreeze(1), lxc-attach(1), lxc.conf(5)
Serge Hallyn <serge.hallyn@ubuntu.com>
This page is part of the lxc (Linux containers) project. Information
about the project can be found at ⟨http://linuxcontainers.org/⟩. If
you have a bug report for this manual page, send it to
lxc-devel@lists.linuxcontainers.org. This page was obtained from the
project's upstream Git repository ⟨git://github.com/lxc/lxc⟩ on
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to man-pages@man7.org
2017-07-05 LXC-USERNSEXEC(1)