NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | COLOPHON |
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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 con‐ sists 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 speci‐ fied, 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)
This page is part of the lxc (Linux containers) project. Infor‐
mation about the project can be found at
⟨http://linuxcontainers.org/⟩. If you have a bug report for this
manual page, send it to [email protected].
This page was obtained from the project's upstream Git repository
⟨https://github.com/lxc/lxc.git⟩ on 2024-06-14. (At that time,
the date of the most recent commit that was found in the
repository was 2024-06-05.) If you discover any rendering
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corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
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2024-04-03 lxc-usernsexec(1)