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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-12 03:50:42 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-12 03:50:42 +0000 |
commit | 78e9bb837c258ac0ec7712b3d612cc2f407e731e (patch) | |
tree | f515d16b6efd858a9aeb5b0ef5d6f90bf288283d /man/systemd-nsresourced.service.xml | |
parent | Adding debian version 255.5-1. (diff) | |
download | systemd-78e9bb837c258ac0ec7712b3d612cc2f407e731e.tar.xz systemd-78e9bb837c258ac0ec7712b3d612cc2f407e731e.zip |
Merging upstream version 256.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | man/systemd-nsresourced.service.xml | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/man/systemd-nsresourced.service.xml b/man/systemd-nsresourced.service.xml new file mode 100644 index 0000000..d0a561e --- /dev/null +++ b/man/systemd-nsresourced.service.xml @@ -0,0 +1,81 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="systemd-nsresourced.service" conditional='ENABLE_NSRESOURCED'> + + <refentryinfo> + <title>systemd-nsresourced.service</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd-nsresourced.service</refentrytitle> + <manvolnum>8</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd-nsresourced.service</refname> + <refname>systemd-nsresourced</refname> + <refpurpose>User Namespace Resource Delegation Service</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>systemd-nsresourced.service</filename></para> + <para><filename>/usr/lib/systemd/systemd-nsresourced</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><command>systemd-nsresourced</command> is a system service that permits transient delegation of a a + UID/GID range to a user namespace (see <citerefentry + project='man-pages'><refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>) + allocated by a client, via a Varlink IPC API.</para> + + <para>Unprivileged clients may allocate a user namespace, and then request a UID/GID range to be assigned + to it via this service. The user namespace may then be used to run containers and other sandboxes, and/or + apply it to an id-mapped mount.</para> + + <para>Allocations of UIDs/GIDs this way are transient: when a user namespace goes away, its UID/GID range + is returned to the pool of available ranges. In order to ensure that clients cannot gain persistency in + their transient UID/GID range a BPF-LSM based policy is enforced that ensures that user namespaces set up + this way can only write to file systems they allocate themselves or that are explicitly allowlisted via + <command>systemd-nsresourced</command>.</para> + + <para><command>systemd-nsresourced</command> automatically ensures that any registered UID ranges show up + in the system's NSS database via the <ulink url="https://systemd.io/USER_GROUP_API">User/Group Record + Lookup API via Varlink</ulink>.</para> + + <para>Currently, only UID/GID ranges consisting of either exactly 1 or exactly 65536 UIDs/GIDs can be + registered with this service. Moreover, UIDs and GIDs are always allocated together, and + symmetrically.</para> + + <para>The service provides API calls to allowlist mounts (referenced via their mount file descriptors as + per Linux <function>fsmount()</function> API), to pass ownership of a cgroup subtree to the user + namespace and to delegate a virtual Ethernet device pair to the user namespace. When used in combination + this is sufficient to implement fully unprivileged container environments, as implemented by + <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>, fully + unprivileged <varname>RootImage=</varname> (see + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>) or + fully unprivileged disk image tools such as + <citerefentry><refentrytitle>systemd-dissect</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> + + <para>This service provides one <ulink url="https://varlink.org/">Varlink</ulink> service: + <constant>io.systemd.NamespaceResource</constant> allows registering user namespaces, and assign mounts, + cgroups and network interfaces to it.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-mountfsd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-dissect</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>user_namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> +</refentry> |